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Best Brain Structure of All Time

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    1
    Broca's area

    Broca's area

    Broca's area is a region of the hominid brain with functions linked to speech production. The production of language has been linked to the Broca's area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal gyrus of the brain. Since then, the approximate region he identified has become known as Broca's area, and the deficit in language production as Broca's aphasia. Broca's area is now typically defined in terms of the pars opercularis and pars triangularis of the inferior frontal gyrus, represented in Brodmann's cytoarchitectonic map as areas 44 and 45 of the dominant hemisphere. Studies of chronic aphasia have implicated an essential role of Broca's area in various speech and language functions. Further, functional MRI studies have also identified activation patterns in Broca's area associated with various language tasks. However, slow destruction of the Broca's area by brain tumors can leave speech relatively intact suggesting its functions can shift to nearby areas in the brain. Broca's area is often identified by visual inspection of the topography of the brain either by macrostructural
    8.14
    7 votes
    2
    Mesencephalon

    Mesencephalon

    The midbrain or mesencephalon (from the Greek mesos - middle, and enkephalos - brain) is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation. Anatomically, it comprises the tectum (or corpora quadrigemina), tegmentum, the ventricular mesocoelia (or "iter"), and the cerebral peduncles, as well as several nuclei and fasciculi. Caudally the mesencephalon adjoins the pons (metencephalon) and rostrally it adjoins the diencephalon (Thalamus, hypothalamus, etc.). The midbrain is located below the cerebral cortex, and above the hindbrain placing it near the center of the brain. During embryonic development, the midbrain arises from the second vesicle, also known as the mesencephalon, of the neural tube. Unlike the other two vesicles, the prosencephalon and rhombencephalon, the mesencephalon remains undivided for the remainder of neural development. It does not split into other brain areas. while the prosencephalon, for example, divides into the telencephalon and the diencephalon. Throughout embryonic development, the cells within the midbrain continually multiply and compress the still-forming
    8.14
    7 votes
    3
    Tentorium cerebelli

    Tentorium cerebelli

    The tentorium cerebelli or cerebellar tentorium (Latin: "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes. The tentorium cerebelli is an arched lamina, elevated in the middle, and inclining downward toward the circumference. It covers the superior surface of the cerebellum, and supports the occipital lobes of the brain. Its anterior border is free and concave, and bounds a large oval opening, the tentorial incisure, for the transmission of the cerebral peduncles. It is attached, behind, by its convex border, to the transverse ridges upon the inner surface of the occipital bone, and there encloses the transverse sinuses; in front, to the superior angle of the petrous part of the temporal bone on either side, enclosing the superior petrosal sinuses. At the apex of the petrous part of the temporal bone the free and attached borders meet, and, crossing one another, are continued forward to be fixed to the anterior and posterior clinoid processes respectively. To the middle line of its upper surface the posterior border of the falx cerebri is attached, the straight sinus being placed at their line
    7.71
    7 votes
    4
    Abducens nucleus

    Abducens nucleus

    The abducens nucleus is the originating nucleus from which the abducens nerve (VI) emerges - a cranial nerve nucleus. This nucleus is located beneath the fourth ventricle in the caudal portion of the pons, medial to the sulcus limitans. The abducens nucleus along with the internal genu of the facial nerve make up the facial colliculus, a hump at the caudal end of the medial eminence on the dorsal aspect of the pons. Two primary neuron types are located in the abducens nucleus: motorneurons and interneurons. The former directly drive the contraction of the ipsilateral lateral rectus muscle via the abducens nerve (sixth cranial nerve); contraction of this muscle rotates the eye outward (abduction). The latter relay signals from the abducens nucleus to the contralateral oculomotor nucleus, where motoneurons drive the contraction of the ipsilateral medial rectus muscle (hence, contralateral to the abducens nucleus that issues the command) ; contraction of this muscle rotates the eye inward (adduction). This "wiring" pattern suggests that the main function of the abducens nucleus is to generate coordinated movements of both eyes in the same direction. Indeed, electrical stimulation of
    8.33
    6 votes
    5

    Sublingual nucleus

    In the substance of the formatio reticularis are two small nuclei of gray matter. The one near the dorsal aspect of the hilus of the inferior olivary nucleus is called the Sublingual nucleus (inferior central nucleus, nucleus of Roller.) This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    8.33
    6 votes
    6
    Superior parietal lobule

    Superior parietal lobule

    The superior parietal lobule is bounded in front by the upper part of the postcentral sulcus, but is usually connected with the postcentral gyrus above the end of the sulcus. Behind it is the lateral part of the parietooccipital fissure, around the end of which it is joined to the occipital lobe by a curved gyrus, the arcus parietooccipitalis. Below, it is separated from the inferior parietal lobule by the horizontal portion of the intraparietal sulcus. The superior parietal lobule is involved with spatial orientation, and receives a great deal of visual input as well as sensory input from one's hand. It is also involved with other functions of the parietal lobe in general. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    6.86
    7 votes
    7
    Central sulcus

    Central sulcus

    The central sulcus is a fold in the cerebral cortex of brains in vertebrates. Also called the central fissure, it was originally called the fissure of Rolando or the Rolandic fissure, after Luigi Rolando. The central sulcus is a prominent landmark of the brain, separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex. List of human anatomical parts named after people
    7.33
    6 votes
    8
    Vestibular nuclei

    Vestibular nuclei

    The vestibular nuclei are the cranial nuclei for the vestibular nerve. In Terminologia Anatomica they are grouped in both the pons and medulla. There are 4 subnuclei; they are situated at the floor of the fourth ventricle. The fibers of the vestibular nerve enter the medulla oblongata on the medial side of those of the cochlear, and pass between the inferior peduncle and the spinal tract of the trigeminal. They then divide into ascending and descending fibers. The latter end by arborizing around the cells of the medial nucleus, which is situated in the area acustica of the rhomboid fossa. The ascending fibers either end in the same manner or in the lateral nucleus, which is situated lateral to the area acustica and farther from the ventricular floor. Some of the axons of the cells of the lateral nucleus, and possibly also of the medial nucleus, are continued upward through the inferior peduncle to the roof nuclei of the opposite side of the cerebellum, to which also other fibers of the vestibular root are prolonged without interruption in the nuclei of the medulla oblongata. A second set of fibres from the medial and lateral nuclei end partly in the tegmentum, while the remainder
    8.40
    5 votes
    9
    Cisterna magna

    Cisterna magna

    The cisterna magna (or cerebellomedullary cistern) is one of three principal openings in the subarachnoid space between the arachnoid and pia mater layers of the meninges surrounding the brain. The openings are collectively referred to as cisterns. The cisterna magna is located between the cerebellum and the dorsal surface of the medulla oblongata. Cerebrospinal fluid produced in the fourth ventricle drains into the cisterna magna via the lateral apertures and median aperture. The two other principal cisterns are the pontine cistern located between the pons and the medulla, and the interpeduncular cistern located between the cerebral peduncles. Cerebral spinal fluid can also be obtained by puncture of the cisterna magna (cistern puncture).
    9.50
    4 votes
    10
    Dentate gyrus

    Dentate gyrus

    The dentate gyrus is part of the hippocampal formation. It is thought to contribute to the formation of new memories, as well as possessing other functional roles. It is notable as being one of a select few brain structures currently known to have high rates of neurogenesis in adult rats (other sites include the olfactory bulb and cerebellum). The dentate gyrus cells receive excitatory input from the entorhinal cortex, in the medial temporal lobe, through the perforant path into the molecular layer. This activates pyramidal cells among the CA4 and CA3 pyramidal neurons (CA stands for cornu ammonis), which are components of Ammon's horn within the hippocampus. Tracts exit CA3 neurons via the Schaffer collaterals and activate CA1 pyramidal cells, allowing the dentate gyrus to be in a position to control the flow of information within the hippocampus. The dentate gyrus consists of three layers of neurons: molecular, granular, and polymorphic. The middle layer is most prominent and contains granule cells that project to the CA3 subfield of the hippocampus. These granule cells project mostly to interneurons, but also to pyramidal cells and are the principal excitatory neurons of the
    9.50
    4 votes
    11
    Area postrema

    Area postrema

    The area postrema is a medullary structure in the brain that controls vomiting. Its privileged location in the brain also allows the area postrema to play a vital role in the control of autonomic functions by the central nervous system. The area postrema is a small protuberance found at the inferoposterior limit of the fourth ventricle. Specialized ependymal cells are found within the area postrema. These specialized ependymal cells differ slightly from the majority of ependymal cells (ependymocytes), forming a unicellular epithelium lining of the ventricles and central canal. The area postrema is separated from the vagal triangle by the funiculus separans, a thin semitransparent ridge. The vagal triangle overlies the dorsal vagal nucleus and is situated on the caudal end of the rhomboid fossa or 'floor' of the fourth ventricle. The area postrema is situated just before the obex, the inferior apex of the caudal ventricular floor. Both the funiculus separans and area postrema have a similar thick ependyma-containing tanycyte covering. Ependyma and tanycytes can participate in transport of neurochemicals into and out of the cerebrospinal fluid from its cells or adjacent neurons, glia
    8.20
    5 votes
    12
    Optic recess

    Optic recess

    At the junction of the floor and anterior wall of the third ventricle, immediately above the optic chiasma, the ventricle presents a small angular recess or diverticulum, the optic recess (or supraoptic recess). This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    8.20
    5 votes
    13
    Middle frontal gyrus

    Middle frontal gyrus

    The middle frontal gyrus makes up about one-third of the frontal lobe of the human brain. (A gyrus is one of the prominent "bumps" or "ridges" on the surface of the human brain.) The middle frontal gyrus, like the inferior frontal gyrus and the superior frontal gyrus, is more of a region than a true gyrus. The borders of the middle frontal gyrus are the inferior frontal sulcus below; the superior frontal sulcus above; and the precentral sulcus behind.
    7.00
    6 votes
    14
    Brodmann area 39

    Brodmann area 39

    Brodmann area 39, or BA39, is part of the parietal cortex in the human brain. BA39 encompasses the angular gyrus, lying near to the junction of temporal, occipital and parietal lobes. This area is also known as angular area 39 (H). It corresponds to the angular gyrus surrounding the caudal tip of the superior temporal sulcus. Dorsally it is bounded approximately by the intraparietal sulcus. Cytoarchitecturally it is bounded rostrally by the supramarginal area 40 (H), dorsally and caudally by the peristriate area 19, and ventrally by the occipitotemporal area 37 (H) (Brodmann-1909). Damage to Brodmann area 39 plays a role in semantic aphasia. It was regarded by Alexander Luria as a part of the temporo-parieto-occipital area, which includes Brodmann area 40, Brodmann area 19, and Brodmann area 37.
    6.83
    6 votes
    15
    Arbor vitae

    Arbor vitae

    The arbor vitae /ˌɑrbɔr ˈvaɪtiː/ (Latin for "Tree of Life") is the cerebellar white matter, so called for its branched, tree-like appearance. It brings sensory and motor information to and from the cerebellum. Godfrey Blount's 1899 book Arbor Vitae was ‘a book on the nature and development of imaginative design for the use of teachers and craftsmen’.
    9.00
    4 votes
    16

    Tela chorioidea of the fourth ventricle

    The tela chorioidea of the fourth ventricle is the name applied to the triangular fold of pia mater which is carried upward between the cerebellum and the medulla oblongata. It consists of two layers, which are continuous with each other in front, and are more or less adherent throughout: This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.60
    5 votes
    17
    Medial geniculate nucleus

    Medial geniculate nucleus

    The medial geniculate nucleus (MGN) or medial geniculate body (MGB) is part of the auditory thalamus and represents the thalamic relay between the inferior colliculus (IC) and the auditory cortex (AC). It is made up of a number of sub-nuclei that are distinguished by their neuronal morphology and density, by their afferent and efferent connections, and by the coding properties of their neurons. It is thought that the MGB influences the direction and maintenance of attention. The MGB has three major divisions; ventral (VMGB), dorsal (DMGB) and medial (MMGB). Whilst the VMGB is specific to auditory information processing, the DMGB and MMGB also receive information from non-auditory pathways. There are two main VMGB cell types: The VMGB is thought to be primarily responsible for relaying frequency, intensity and binaural information to the cortex. The responses in the VMGB appear to be organized in a tonotopically similar way to those in the IC. The primary difference being that the iso-frequency bands are arranged such that lateral regions are most responsive to low frequencies and medial regions are responsive to high frequencies. Spatiotopic and modulotopic maps (as in the IC)
    8.75
    4 votes
    18
    Basal optic nucleus of Meynert

    Basal optic nucleus of Meynert

    Nucleus basalis of Meynert, abbreviated NBM and also known as the nucleus basalis, is a group of neurons in the substantia innominata of the basal forebrain which has wide projections to the neocortex and is rich in acetylcholine and choline acetyltransferase. In Parkinson and Alzheimer diseases the nucleus undergoes degeneration. A decrease in acetylcholine production is seen in Alzheimer's disease, Lewy body dementia and some Parkinson disease patients showing abnormal brain function, leading to a general decrease of mental capacity and learning. Most pharmacological treatments of dementia focus on compensating for a faltering NBM function through artificially increasing acetylcholine levels. The NBM is inferior to the globus pallidus and within an area known as the substantia innominata. The NBM is immediately inferior to the Anterior Commissure and superior and lateral to the anterior portion of the Hypothalamus. The primary concentration of cholinergic neurons/cell bodies that project to the neocortex are in the basal nucleus of Meynert which is located in the substantia innominata of the anterior perforated substance. These cholinergic neurons have a number of important
    8.50
    4 votes
    19
    Posterior cingulate

    Posterior cingulate

    The posterior cingulate cortex is the backmost part of the cingulate cortex, lying behind the anterior cingulate cortex. This is the upper part of the "limbic lobe". The cingulate cortex is made up of an area around the midline of the brain. Surrounding areas include the retrosplenial cortex and the precuneus. Cytoarchitectonically the posterior cingulate cortex is associated with Brodmann areas 23 and 31. The posterior cingulate cortex forms a central node in the "default mode" network of the brain. Along with the precuneus, it has been implicated as a neural substrate for human awareness in numerous studies of both the anesthesized and vegetative (coma) state. Imaging studies indicate a prominent role for the posterior cingulate cortex in pain and episodic memory retrieval. The posterior cingulate may also be involved in the capacity to understand what other people believe. For details regarding MRI definitions of the cingulate cortex based on the Desikan-Killiany Brain atlas, see:
    8.50
    4 votes
    20
    Brodmann area 6

    Brodmann area 6

    Brodmann area 6 is part of the brain. Brodmann area 6 (BA6) is part of the frontal cortex in the human brain. Situated just anterior to the primary motor cortex (BA4), it is composed of the premotor cortex and, medially, the supplementary motor area, or SMA. This large area of the frontal cortex is believed to play a role in the planning of complex, coordinated movements. Brodmann area 6 is also called agranular frontal area 6 in humans because it lacks an internal granular cortical layer (layer IV). It is a subdivision of the cytoarchitecturally defined precentral region of cerebral cortex. In the human brain, it is located on the portions of the precentral gyrus that are not occupied by the gigantopyramidal area 4; furthermore, BA6 extends onto the caudal portions of the superior frontal and middle frontal gyri. It extends from the cingulate sulcus on the medial aspect of the hemisphere to the lateral sulcus on the lateral aspect. It is bounded rostrally by the granular frontal region and caudally by the gigantopyramidal area 4 (Brodmann, 1909). Brodmann area 6 is a cytoarchitecturally defined portion of the frontal lobe of the guenon. Brodmann-1909 regarded it as topographically
    8.25
    4 votes
    21
    Corpus callosum

    Corpus callosum

    The corpus callosum (Latin: tough body), also known as the colossal commissure, is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates interhemispheric communication. It is the largest white matter structure in the brain, consisting of 200–250 million contralateral axonal projections. The posterior portion of the corpus callosum is called the splenium; the anterior is called the genu (or "knee"); between the two is the truncus, or "body", of the corpus callosum. The part between the body and the splenium is often markedly thinned and thus referred to as the "isthmus". The rostrum is the part of the corpus callosum that projects posteriorly and inferiorly from the anteriormost genu, as can be seen on the sagittal image of the brain displayed on the right. The rostrum is so named for its resemblance to a bird's beak. Thinner axons in the genu connect the prefrontal cortex between the two halves of the brain. Thicker axons in the midbody of the corpus callosum and in the splenium interconnect areas of the premotor and supplementary motor regions and motor cortex,
    8.25
    4 votes
    22
    Prefrontal cortex

    Prefrontal cortex

    The prefrontal cortex (PFC) is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making and moderating social behavior. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals. The most typical psychological term for functions carried out by the prefrontal cortex area is executive function. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable outcomes). Many authors have indicated an integral link between a person's personality and the functions of the prefrontal cortex. There are three possible ways to define the prefrontal cortex: The prefrontal cortex has been defined based on cytoarchitectonics by the presence of a
    8.25
    4 votes
    23
    Brodmann area 44

    Brodmann area 44

    Brodmann area 44, or BA44, is part of the frontal cortex in the human brain. Situated just anterior to premotor cortex (BA6) and on the lateral surface, inferior to BA9. This area is also known as pars opercularis (of the inferior frontal gyrus), and it refers to a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex. In the human it corresponds approximately to the opercular part of inferior frontal gyrus (H). Thus, it is bounded caudally by the inferior precentral sulcus (H) and rostrally by the anterior ascending limb of lateral sulcus (H). It surrounds the diagonal sulcus (H). In the depth of the lateral sulcus it borders on the insula. Cytoarchitectonically it is bounded caudally and dorsally by the agranular frontal area 6, dorsally by the granular frontal area 9 and rostrally by the triangular area 45 (Brodmann-1909). Recent neuroimaging studies show BA44 involvement in selective response suppression in go/no- go tasks and is therefore believed to play an important role in the suppression of response tendencies. Scott Flansburg of San Diego, California is a "human calculator" who can perform complex arithmetic in his head. Interestingly when his
    7.00
    5 votes
    24
    Brodmann area 47

    Brodmann area 47

    Brodmann area 47, or BA47, is part of the frontal cortex in the human brain. Curving from the lateral surface of the frontal lobe into the ventral (orbital) frontal cortex. It is below areas BA10 and BA45, and beside BA11. This area is also known as orbital area 47. In the human, on the orbital surface it surrounds the caudal portion of the orbital sulcus (H) from which it extends laterally into the orbital part of inferior frontal gyrus (H). Cytoarchitectonically it is bounded caudally by the triangular area 45, medially by the prefrontal area 11 of Brodmann-1909, and rostrally by the frontopolar area 10 (Brodmann-1909). It incorporates the region that Brodmann identified as "Area 12" in the monkey, and therefore, following the suggestion of Michael Petrides, some contemporary neuroscientists refer to the region as "BA47/12." BA47 has been implicated in the processing of syntax in oral and sign languages, and more recently in musical syntax.
    7.00
    5 votes
    25
    Reticular formation

    Reticular formation

    The reticular formation is a region in the brainstem that is involved in multiple tasks such as regulating the sleep-wake cycle and filtering incoming stimuli to discriminate irrelevant background stimuli. It is essential for governing some of the basic functions of higher organisms, and is one of the phylogenetically oldest portions of the brain. The reticular formation consists of more than 100 small neural networks, with varied functions including the following: 1. Somatic motor control - Some motor neurons send their axons to the reticular formation nuclei, giving rise to the reticulospinal tracts of the spinal cord. These tracts function in maintaining tone, balance, and posture--especially during body movements. The reticular formation also relays eye and ear signals to the cerebellum so that the cerebellum can integrate visual, auditory, and vestibular stimuli in motor coordination. Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators, which produce rhythmic signals to the muscles of breathing and swallowing. 2. Cardiovascular control - The reticular formation includes the cardiac and vasomotor centers of
    9.33
    3 votes
    26
    Pulvinar

    Pulvinar

    The pulvinar nuclei (nuclei pulvinares) are a collection of nuclei located in the pulvinar thalamus. The pulvinar part is the most posterior region of the thalamus. The pulvinar is usually grouped as one of the lateral thalamic nuclei in rodents and carnivores, and stands as an independent complex in primates. The word is derived from the Latin pulvinus for "cushion". In Ancient Roman religion a pulvinar was an "empty throne" or cushioned couch for occupation by a deity. It is conventionally divided into anterior, inferior, lateral, and medial subdivisions, each containing multiple nuclei. The pulvinar varies in importance in different animals: it is virtually nonexistent in the rat, and grouped as the lateral posterior-pulvinar complex" with the lateral posterior thalamic nucleus due to its small size in cats. In humans it makes up roughly 40% of the thalamus making it the largest of its nuclei. Lesions of the pulvinar can result in neglect syndromes and attentional deficits.
    8.00
    4 votes
    27
    Superior salivary nucleus

    Superior salivary nucleus

    The Superior salivary nucleus (or superior salivatory nucleus) of the facial nerve is a visceromotor cranial nerve nucleus located in the pontine tegmentum. Parasympathetic efferent fibers of the facial nerve (preganglionic fibers) arise according to some authors from the small cells of the facial nucleus, or according to others from a special nucleus of cells scattered in the reticular formation, dorso-medial to the facial nucleus. This is sometimes called the superior salivatory nucleus. These preganglionic fibers are distributed partly via the chorda tympani and lingual nerves to the submandibular ganglion, thence by postganglionic (vasodilator) fibers to the submandibular gland and sublingual gland. Some of the preganglionic fibers travel along the greater petrosal nerve through the pterygoid canal (where they join the postsynaptic fibers of the deep petrosal nerve and are called the Vidian nerve) and synapse in the pterygopalatine ganglion, whereupon the postganglionic, postsynaptic, efferent fibers travel to innervate the lacrimal gland and the mucosal glands of the nose, palate, and pharynx. The term "lacrimal nucleus" is sometimes used to refer to a portion of the superior
    8.00
    4 votes
    28
    Corticospinal tract

    Corticospinal tract

    The pyramidal tracts refers to both the corticospinal and corticobulbar tracts. The corticospinal tract conducts impulses from the brain to the spinal cord. It contains mostly motor axons. The corticospinal tract is made up of two separate tracts in the spinal cord: the lateral corticospinal tract and the anterior corticospinal tract. The corticospinal tract also contains the Betz Cell (the largest pyramidal cells) that are not found in any other region of the body. An understanding of these tracts leads to an understanding of why one side of the body is controlled by the opposite side of the brain. The corticospinal tract is concerned specifically with discrete voluntary skilled movements, such as precise movement of the fingers and toes. The brain sends impulses to the spinal cord relaying the message. This is imperative in understanding that the left hemisphere of the brain controls the RIGHT side of the body, while the right hemisphere of the brain controls the LEFT side of the body. The signals cross in the medulla oblongata, this process is also known as decussation. The corticobulbar tract carries information to motor neurons of the cranial nerve nuclei, rather than the
    6.80
    5 votes
    29
    Metathalamus

    Metathalamus

    The metathalamus is a composite structure of the thalamus, consisting of the medial geniculate nucleus and the lateral geniculate nucleus.
    6.80
    5 votes
    30
    Taenia of fourth ventricle

    Taenia of fourth ventricle

    In the brain, the taenia of the fourth ventricle (ligula, tenia of fourth ventricle) are two narrow bands of white matter, one on either side, which complete the lower part of the roof of the fourth ventricle. Each consists of a vertical and a horizontal part. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.75
    4 votes
    31
    Arachnoid mater

    Arachnoid mater

    The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord. It is interposed between the two other meninges, the more superficial and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The delicate arachnoid layer is attached to the inside of the dura and surrounds the brain and spinal cord. It does not line the brain down into its sulci (folds), as does the pia mater, with the exception of the longitudinal fissure, which divides the left and right cerebral hemispheres. Cerebrospinal fluid (CSF) flows under the arachnoid in the subarachnoid space. The arachnoid mater makes arachnoid villi, small protrusions through the dura mater into the venous sinuses of the brain, which allow CSF to exit the sub-arachnoid space and enter the blood stream. The arachnoid mater is named after the Greek words "Arachne" ("spider") and suffix "-oid" ("in the image of"), and "mater" (the Latin word for mother), because of the fine spider web-like appearance of the delicate fibres of the arachnoid which extend down through the subarachnoid space and attach to the pia mater. The arachnoid mater
    6.60
    5 votes
    32
    Transverse temporal gyrus

    Transverse temporal gyrus

    The transverse temporal gyri (also called Heschl's gyri or Heschl's convolutions) are found in the area of primary auditory cortex buried within the lateral sulcus of the human brain, occupying Brodmann areas 41. It is the first cortical structure to process incoming auditory information. Anatomically, the transverse temporal gyri are distinct in that they run mediolaterally (towards the center of the brain) rather than dorsiventrally (front to back) as all other temporal lobe gyri run. The transverse temporal gyri are active during auditory processing under fMRI for tone and semantic tasks. The Heschl's gyri are named after Richard L. Heschl.
    7.50
    4 votes
    33
    Brodmann area 12

    Brodmann area 12

    Brodmann area 12 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It occupies the most rostral portion of the frontal lobe. Brodmann-1909 did not regard it as homologous, either topographically or cytoarchitecturally, to rostral area 12 of the human. Distinctive features (Brodmann-1905): a quite distinct internal granular layer (IV) separates slender pyramidal cells of the external pyramidal layer (III) and the internal pyramidal layer (V); the multiform layer (VI) is expanded, contains widely dispersed spindle cells and merges gradually with the underlying cortical white matter; all cells, including the pyramidal cells of the external and internal pyramidal layers are inordinately small; the internal pyramidal layer (V) also contains spindle cells in groups of two to five located close to its border with the internal granular layer (IV). It is indirectly connected to the global palladius as well as the substantia nigra, due to efferents to the striatum. Glutaminergic input is turned into GABAergic input there, which allows the frontal lobes to exhibit some control over basal ganglia activity.
    8.67
    3 votes
    34
    Nucleus ambiguus

    Nucleus ambiguus

    The nucleus ambiguus (literally "ambiguous nucleus") is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. It receives upper motor neuron innervation directly via the corticobulbar tract. This nucleus gives rise to the branchial efferent motor fibers of the vagus nerve (CN X) terminating in the laryngeal, pharyngeal muscles, and musculus uvulae; as well as to the efferent motor fibers of the glossopharyngeal nerve (CN IX) terminating in the stylopharyngeus muscle. The muscles supplied by the vagus (included with this is the cranial part of the accessory nerve), such as levator veli palatini, are also necessary to swallow properly through integration by the nucleus of the solitary tract. The vagus also supplies the upper part of the esophagus, and other parts of the pharynx and larynx. As well as motor neurons, the nucleus ambiguus in its "external formation" contains cholinergic preganglionic parasympathetic neurons for the heart. These neurons are cardioinhibitory. This cardioinhibitory effect is one of the means by which quick changes in blood pressure are achieved by
    8.67
    3 votes
    35

    Pontine nuclei

    The pontine nuclei (or griseum pontis) are a part of the pons involved in motor activity. Corticopontine fibres carry information from the primary motor cortex to the ipsilateral pontine nucleus in the ventral pons, and the pontocerebellar projection then carries that information to the contralateral cerebellum via the middle cerebellar peduncle. They therefore allow modification of actions in the light of their outcome, or error correction, and are hence important in learning motor skills.
    8.67
    3 votes
    36
    Angular gyrus

    Angular gyrus

    The angular gyrus is a region of the brain in the parietal lobe, that lies near the superior edge of the temporal lobe, and immediately posterior to the supramarginal gyrus; it is involved in a number of processes related to language, mathematics and cognition. It is Brodmann area 39 of the human brain. Geschwind proposed that written word is translated to internal monologue via the angular gyrus. V. S. Ramachandran, and Edward Hubbard published a paper in 2003 in which they speculated that the angular gyrus is at least partially responsible for understanding metaphors. They stated: There may be neurological disorders that disturb metaphor and synaesthesia.This has not been studied in detail but we have seen disturbances in the Bouba/Kiki effect (Ramachandran & Hubbard, 2001a) as well as with proverbs in patients with angular gyrus lesions. It would be interesting to see whether they have deficits in other types of synaesthetic metaphor, e.g. ‘sharp cheese’ or ‘loud shirt’. There are also hints that patients with right hemisphere lesions show problems with metaphor. It is possible that their deficits are mainly with spatial metaphors,such as ‘He stepped down as director’. The fact
    10.00
    2 votes
    37
    Brodmann area 34

    Brodmann area 34

    Brodmann area 34 is a part of the brain. It has been described as part of the entorhinal area. It has been described as part of the superior temporal gyrus.
    10.00
    2 votes
    38
    Locus ceruleus

    Locus ceruleus

    The locus coeruleus (also spelled locus caeruleus or locus ceruleus) is a nucleus in the pons (part of the brainstem) involved with physiological responses to stress and panic. It was discovered in the 18th century by Félix Vicq-d'Azyr, or maybe later by Johann Christian Reil. The locus coeruleus is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the norepinephrine it produces are described collectively as the locus coeruleus-noradrenergic system or LC-NA system. Norepinephrine may also be released directly into the blood from the adrenal medulla. The name is derived from the Latin words coeruleus and locus. Literally, this means "the dark blue spot", a name derived from its azure appearance in unstained brain tissue. The color is due to light scattering from melanin in noradrenergic (producing or activated by norepinephrine) nerve cell bodies. Caeruleus is the classical Latin spelling, but coeruleus is the more common spelling. The spelling ceruleus, formed by contraction of the digraph ae or oe into e, is an American English form. The locus coeruleus (or "LC") is located in the posterior area of
    10.00
    2 votes
    39
    Lateral sulcus

    Lateral sulcus

    The lateral sulcus (also called Sylvian fissure or lateral fissure) is one of the most prominent structures of the human brain. It divides the frontal lobe and parietal lobe above from the temporal lobe below. It is in both hemispheres of the brain but is longer in the left hemisphere. The lateral sulcus is one of the earliest-developing sulci of the human brain. It first appears around the fourteenth gestational week. The lateral sulcus has a number of side branches. Two of the most prominent and most regularly found are the ascending (also called vertical) ramus and the horizontal ramus of the lateral fissure, which subdivide the inferior frontal gyrus. The lateral sulcus also contains the transverse temporal gyri, which are part of the primary and below the surface auditory cortex. Partly due to a phenomenon called Yakovlevian torque, the lateral sulcus is often longer and less curved on the left hemisphere than on the right. It is also located near Sylvian Point. The cerebral cortex was not depicted in a realistic manner until the 17th century with the Sylvian fissure being first accurately painted by Girolamo Fabrici d'Acquapendente in 1600 to provide plates for his Tabulae
    5.50
    6 votes
    40

    Brodmann area 49

    In the rodent, the parasubiculum is a retrohippocampal isocortical structure, and a major component of the subicular complex. It receives numerous subcortical and cortical inputs, and sends major projections to the superficial layers of the entorhinal cortex (Amaral & Witter, 1995). The parasubicular area is a transitional zone between the presubiculum and the entorhinal area in the mouse (Paxinos-2001), the rat (Swanson, 1998) and the primate (Zilles, 1990). Defined on the basis of cytoarchitecture, it is more similar to the presubiculum than to the entorhinal area (Zilles, 1990), however electrophysiological evidence suggests a similarity with the entorhinal cortex (Funahashi and Stewart, 1997; Glasgow & Chapman, 2007). Specifically, cells in this area are modulated by local theta rhythm, and display theta-frequency membrane potential oscillations (Glasgow & Chapman, 2007; Taube, 1995). Furthermore, cells in the parasubiculum, and neighboring presubiculum, fire in relation to the animal's location in space, suggesting properties similar to place cells. It is postulated that this area may play an integral role in spatial navigation and the integration of head-directional
    7.25
    4 votes
    41
    Brodmann area 8

    Brodmann area 8

    Brodmann area 8 is one of Brodmann's cytologically defined regions of the brain. It is involved in planning complex movements. Brodmann area 8, or BA8, is part of the frontal cortex in the human brain. Situated just anterior to the premotor cortex (BA6), it includes the frontal eye fields (so-named because they are believed to play an important role in the control of eye movements). Damage to this area, by stroke, trauma or infection, causes tonic deviation of the eyes towards the side of the injury. This finding occurs during the first few hours of an acute event such as cerebrovascular infarct (stroke) or hemorrhage (bleeding). The term Brodmann area 8 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. Located rostral to the arcuate sulcus, it was not considered by Brodmann-1909 to be topographically homologous to the intermediate frontal area 8 of the human. Distinctive features (Brodmann-1905): compared to Brodmann area 6-1909, area 8 has a diffuse but clearly present internal granular layer (IV); sublayer 3b of the external pyramidal layer (III) has densely distributed medium sized pyramidal cells; the internal pyramidal layer (V) has larger
    7.25
    4 votes
    42
    Olivocerebellar tract

    Olivocerebellar tract

    The olivocerebellar tract, also known as olivocerebellar fibers, are neural fibers which originate at the olivary nucleus and pass out through the hilum and decussate with those from the opposite olive in the raphé, then as internal arcuate fibers they pass partly through and partly around the opposite olive and enter the inferior peduncle to be distributed to the cerebellar hemisphere of the opposite side from which they arise. They terminate directly on Purkinje cells as the climbing fiber input system. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.25
    4 votes
    43
    Posterior nucleus

    Posterior nucleus

    The posterior nucleus of the hypothalamus is one of the many nuclei that make up the hypothalamic region of the brain. Its function is thermoregulation (heating) of the body. Damage or destruction of this nucleus causes hypothermia. Descending efferents from the nucleus synapse on the sympathetic neurons of the spinal cord, which exist in the thoracic and lumbar regions in the lateral horns.
    7.25
    4 votes
    44
    Suprachiasmatic nucleus

    Suprachiasmatic nucleus

    The suprachiasmatic nucleus or nuclei, abbreviated SCN, is a tiny region on the brain's midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle, using around 20,000 neurons. The SCN, which is pine cone-shaped and the size of a grain of rice, interacts with many other regions of the brain. It contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters. The SCN is situated in the anterior part of the hypothalamus immediately dorsal, or superior (hence supra) to the optic chiasm (CHO) bilateral to (on either side of) the third ventricle. Organisms in every kingdom of life—bacteria, plants, fungi, and animals—show genetically-based 24-hour rhythms. Although all of these clocks appear to be based on a similar type of genetic feedback loop, the specific genes involved are thought to have evolved independently in each kingdom. Within the animal kingdom, however, a related set of genes are used by a wide variety of animals: the circadian genes in fruit flies,
    7.25
    4 votes
    45
    Brodmann area 37

    Brodmann area 37

    Brodmann area 37, or BA37, is part of the temporal cortex in the human brain. This area is known as occipitotemporal area 37 (H). It is a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. It is located primarily in the caudal portions of the fusiform gyrus and inferior temporal gyrus on the mediobasal and lateral surfaces at the caudal extreme of the temporal lobe. Cytoarchitecturally it is bounded caudally by the peristriate Brodmann area 19, rostrally by the inferior temporal area 20 and middle temporal area 21 and dorsally on the lateral aspect of the hemisphere by the angular area 39 (H) (Brodmann-1909).
    8.33
    3 votes
    46
    Epithalamus

    Epithalamus

    The epithalamus is a (dorsal) posterior segment of the diencephalon (a segment in the middle of the brain also containing the hypothalamus and the thalamus) which includes the habenula and their interconnecting fibers the habenular commissure, the stria medullaris and the pineal body. Its function is the connection between the limbic system to other parts of the brain. Some functions of its components include the secretion of melatonin by the pineal gland (involved in circadian rhythms), and regulation of motor pathways and emotions. It is wired with the limbic system and basal ganglia. The epithalamus comprises the trigonum habenulæ, the pineal body, and the posterior commissure.
    8.33
    3 votes
    47

    Inferior occipitofrontal fasciculus

    The occipitofrontal fasciculus passes backward from the frontal lobe, along the lateral border of the caudate nucleus, and on the medial aspect of the corona radiata; its fibers radiate in a fan-like manner and pass into the occipital and temporal lobes lateral to the posterior and inferior cornua. Some sources distinguish between a "Inferior occipitofrontal fasciculus" and "superior occipitofrontal fasciculus." This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    8.33
    3 votes
    48
    Olivary body

    Olivary body

    In anatomy, the olivary bodies or simply olives (Latin oliva and olivae, singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. They contain the olivary nuclei. The olivary body is located on the anterior surface of the medulla lateral to the pyramid, from which it is separated by the antero-lateral sulcus and the fibers of the hypoglossal nerve. Behind, it is separated from the postero-lateral sulcus by the ventral spinocerebellar fasciculus. In the depression between the upper end of the olive and the pons lies the vestibulocochlear nerve. In humans, it measures about 1.25 cm. in length, and between its upper end and the pons there is a slight depression to which the roots of the facial nerve are attached. The external arcuate fibers wind across the lower part of the pyramid and olive and enter the inferior peduncle. The olive consists of two separate parts: which is a part of the olivo-cerebellar system and is mainly involved in cerebellar motor-learning and function. The inferior olive in itself is divided to 3 main nuclei:. small additional inferior olivary structures consist of the dorsal cap
    8.33
    3 votes
    49
    Anterior olfactory nucleus

    Anterior olfactory nucleus

    The anterior olfactory nucleus (AON; also called the anterior olfactory cortex) is a portion of the forebrain of vertebrates. It is involved in olfaction. The AON is found behind the olfactory bulb and in front of the piriform cortex (laterally) and olfactory tubercle (medially) in a region often referred to as the olfactory peduncle or retrobulbar area. The peduncle contains the AON as well as two other much smaller regions, the tenia tecta (or dorsal hippocampal rudiment) and the dorsal peduncular cortex. The AON plays a pivotal but relatively poorly understood role in the processing of odor information. Odors enter the nose (or olfactory rosette in fishes) and interact with the cilia of olfactory receptor neurons. The information is sent via the olfactory nerve (Cranial Nerve I) to the olfactory bulb. After the processing in the bulb the signal is transmitted caudally via the axons of mitral and tufted cells in the lateral olfactory tract. The tract forms on the ventrolateral surface of the brain and passes through the AON, continuing on to run the length of the piriform cortex, while synapsing in both regions. The AON distributes the information to the contralateral olfactory
    9.50
    2 votes
    50
    Brodmann area 28

    Brodmann area 28

    Brodmann area 28 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. Brodmann regarded its location adjacent to the hippocampus as imprecisely represented in the illustration of the cortex of the guenon brain in Brodmann-1909. It is located on the medial aspect of the temporal lobe. In the human it and the dorsal entorhinal area 34 (H) together constitute approximately the entorhinal area (Brodmann-1909). The molecular layer (I) is unusually wide; the external granular layer (II) contains nests of, for the most part, multipolar cells: the external pyramidal layer (III) contains medium sized pyramidal cells which merge with cells of the internal pyramidal layer (V); a clear cell free zone represents sublayer 5b of layer V; the multiform layer is wide and has a less clear two sublayer structure; the internal granular layer (IV) is totally absent.
    9.50
    2 votes
    51
    Lateral hypothalamus

    Lateral hypothalamus

    The lateral hypothalamus or lateral hypothalamic area is a part of the hypothalamus. It is concerned with hunger. Damage to this area can cause reduced food intake. Stimulating the lateral hypothalamus causes a desire to eat, while stimulating the ventromedial hypothalamus causes a desire to stop eating. The glucostatic explanation is based on the homeostatic theory which indicates that the body has balanced states of equilibrium for each system. When out of balance, the body will be pushed to restore balance. Therefore, when the blood sugar level drops, the glucostatic receptors in the blood take a message to the lateral hypothalamus, which is the feeding center of the brain. This causes certain neurons in the brain to fire in unison, creating the sensation of hunger. Now the person wants to eat. When the glucose level increases because the person is eating or has eaten, the glucostatic receptors in the blood then send a message to the Ventro-medial Hypothalamus (the satiety or satisfaction center) and the sensation of fullness occurs. Damage to the lateral hypothalamus may lead to a condition known as Frölich's syndrome. The "lateral zone of hypothalamus" is a similarly named
    7.00
    4 votes
    52
    Uncinate fasciculus

    Uncinate fasciculus

    The uncinate fasciculus is a white matter tract in the human brain that connects parts of the limbic system such as the hippocampus and amygdala in the temporal lobe with frontal ones such as the orbitofrontal cortex. Its function is unknown though it is affected in several psychiatric conditions. It is the last white matter tract to mature in the human brain. The uncinate fasciculus is a hook-shaped bundle that links the forward portions of the temporal lobe with the inferior frontal gyrus and the lower surfaces of the frontal lobe. It does this by arising lateral to the amygdala and hippocampus in the temporal lobe curving in an upward pathway behind the external capsule inward of the insular cortex and continuing up into the posterior part of the orbital gyrus. The average length of the uncinate fasciculus is 45 mm with a range 40–49 mm. Its volume in adults is 1425.9±138.6 mm, being slightly larger in men, at 1504.3±150.4, than women 1378.5±107.4. It has three parts: a ventral or frontal extension, an intermediary segment called the isthmus or insular segment and a temporal or dorsal segment. The function of the uncinate fasciculus is not known, though it is traditionally
    7.00
    4 votes
    53
    Primary motor cortex

    Primary motor cortex

    The primary motor cortex is a brain region that in humans is located in the posterior portion of the frontal lobe. It works in association with other motor areas including premotor cortex, the supplementary motor area, posterior parietal cortex, and several subcortical brain regions, to plan and execute movements. Primary motor cortex is defined anatomically as the region of cortex that contains large neurons known as Betz cells. Betz cells, along with other cortical neurons, send long axons down the spinal cord to synapse onto the interneuron circuitry of the spinal cord and also directly onto the alpha motor neurons in the spinal cord which connect to the muscles. The primary motor cortex contains a rough map of the body, with different body parts controlled by partially overlapping regions of cortex arranged from the toe (at the top of the cerebral hemisphere) to mouth (at the bottom) along a fold in the cortex called the central sulcus. Each cerebral hemisphere contains a map that controls mainly the opposite side of the body. For the discovery of the primary motor cortex and its relationship to other motor cortical areas, see the main article on the motor cortex. The human
    6.00
    5 votes
    54

    Accessory cuneate nucleus

    The accessory cuneate nucleus is located lateral to the cuneate nucleus in the medulla oblongata at the level of the sensory decussation (the crossing fibers of the posterior column/medial lemniscus tract). It receives input from cervical spinal nerves and transmits that information to the cerebellum. These fibers are called cuneocerebellar (cuneate nucleus -> cerebellum) fibers. In this function, the accessory cuneate nucleus is the upper extremity equivalent of Clarke's column.
    8.00
    3 votes
    55
    Deep cerebellar nuclei

    Deep cerebellar nuclei

    The cerebellum has four deep cerebellar nuclei embedded in the white matter in its center. These nuclei receive inhibitory (GABAergic) inputs from Purkinje cells in the cerebellar cortex and excitatory (glutamatergic) inputs from mossy fiber and climbing fiber pathways. Most output fibers of the cerebellum originate from these nuclei. One exception is that fibers from the flocculonodular lobe synapse directly on vestibular nuclei without first passing through the deep cerebellar nuclei. The vestibular nuclei in the brainstem are analogous structures to the deep nuclei, since they receive both mossy fiber and Purkinje cell inputs. From lateral to medial, the four deep cerebellar nuclei are the dentate, emboliform, globose, and fastigii. An easy mnemonic device to remember their names and positions relative to the midline is the phrase "Don't Eat Greasy Food," where each letter indicates the lateral to medial location in the cerebellar white matter, and the Too reflects the presence of two globus nuclei on each side. Some animals, including humans, do not have distinct emboliform and globose nuclei, instead having a single, fused nucleus interpositus (interposed nucleus). In animals
    8.00
    3 votes
    56
    Inferior colliculus

    Inferior colliculus

    The inferior colliculus (IC) (Latin, lower hill) is the principal midbrain nucleus of the auditory pathway and receives input from several more peripheral brainstem nuclei in the auditory pathway, as well as inputs from the auditory cortex. The inferior colliculus has three subdivisions: the central nucleus (CIC), a dorsal cortex (DCIC) by which it is surrounded, and an external cortex (ICX) which is located laterally. Its bimodal neurons are implied in auditory-somatosensory interaction, receiving projections from somatosensory nuclei. This multisensory integration may underlie a filtering of self-effected sounds from vocalisation, chewing, or respiration activities. The inferior colliculi together with the superior colliculi form the eminences of the corpora quadrigemina, and also part of the tectal region of the midbrain. The inferior colliculus lies caudal to its counterpart - the superior colliculus - above the trochlear nerve, and at the base of the projection of the medial geniculate nucleus (MGN) and the lateral geniculate nucleus (LGN). The inferior colliculi of the midbrain are located just below the visual processing centers known as the superior colliculi. The inferior
    8.00
    3 votes
    57
    Lentiform nucleus

    Lentiform nucleus

    The lentiform nucleus or lenticular nucleus comprises the putamen and the globus pallidus within the basal ganglia. It is a large, cone-shaped mass of gray matter just lateral to the internal capsule. The name comes from Latin and means lens-shaped, probably referring to the appearance of the nucleus from the side. When divided horizontally, it exhibits, to some extent, the appearance of a biconvex lens, while a coronal section of its central part presents a somewhat triangular outline. It is shorter than the caudate nucleus and does not extend as far forward. It is lateral to the caudate nucleus and thalamus, and is seen only in sections of the hemisphere. It is bounded laterally by a lamina of white substance called the external capsule, and lateral to this is a thin layer of gray substance termed the claustrum. Its anterior end is continuous with the lower part of the head of the caudate nucleus and with the anterior perforated substance. In a coronal section through the middle of the lentiform nucleus, two medullary laminæ are seen dividing it into three parts. The lateral and largest part is of a reddish color, and is known as the putamen, while the medial and intermediate are
    8.00
    3 votes
    58
    Substantia nigra

    Substantia nigra

    The substantia nigra is a brain structure located in the mesencephalon (midbrain) that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas. This is due to high levels of melanin in dopaminergic neurons. Parkinson's disease is characterized by the death of dopaminergic neurons in the substantia nigra pars compacta. Although the substantia nigra appears as a continuous band in brain sections, anatomical studies have found that it actually consists of two parts with very different connections and functions, the pars compacta and pars reticulata. The pars compacta serves mainly as an input to the basal ganglia circuit, supplying the striatum with dopamine. The pars reticulata, on the other hand, serves mainly as an output, conveying signals from the basal ganglia to numerous other brain structures. The substantia nigra, along with four other nuclei, is part of the basal ganglia. The substantia nigra lies in the midbrain, dorsal to the cerebral peduncles. Humans have two substantiae nigrae, one on each side of the midline. The substantia
    8.00
    3 votes
    59
    Cerebral aqueduct

    Cerebral aqueduct

    The mesencephalic duct, also known as the aqueductus mesencephali, aqueduct of Sylvius or the cerebral aqueduct, contains cerebrospinal fluid (CSF), is within the mesencephalon (or midbrain) and connects the third ventricle in the diencephalon to the fourth ventricle within the region of the mesencephalon and metencephalon, located dorsal to the pons and ventral to the cerebellum. The cerebral aqueduct, similarly to other parts of the ventricular system of the brain, develops from the central canal of the neural tube. Specifically, the duct originates from the portion of the neural tube that is present in the developing mesencephalon, hence the name "mesencephalic duct." A blockage in this duct is a cause of hydrocephalus.
    6.75
    4 votes
    60
    Postcentral gyrus

    Postcentral gyrus

    The lateral postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the sensory homunculus. The primary somatosensory cortex was initially defined from surface stimulation studies of Wilder Penfield, and parallel surface potential studies of Bard, Woolsey, and Marshall. Although initially defined to be roughly the same as Brodmann areas 3, 1 and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it receives the bulk of the thalamocortical projections from the sensory input fields. The lateral postcentral gyrus is bounded by: Brodmann areas 3, 1, and 2 make up the primary somatosensory cortex of the human brain (or S1). Because Brodmann sliced the brain somewhat obliquely, he encountered area 1 first; however, from rostral to caudal, the Brodmann designations are 3, 1, and 2, respectively. Brodmann area 3 is subdivided into areas 3a
    6.75
    4 votes
    61
    Red nucleus

    Red nucleus

    The red nucleus is a structure in the rostral midbrain involved in motor coordination. It comprises a caudal magnocellular and a rostral parvocellular part. It is located in the tegmentum of the midbrain next to the substantia nigra. Nucleus red and substantia nigra are subcortical centers of the extrapyramidal motor system. In animals without a significant corticospinal tract, gait is mainly controlled by the red nucleus. However, where the corticospinal tract is dominant, the rubrospinal tract may be considered to be vestigial. Therefore, here the red nucleus is less important in motor functions than in many other mammals. However, the crawling of babies is controlled by the red nucleus, as is arm swinging in normal walking. The red nucleus may play an additional role in controlling muscles of the shoulder and upper arm via projections of its magnocellular part. In humans, the red nucleus also has sparse control over hands, as the rubrospinal tract is more involved in large muscle movement such as that for arms (but not the legs, as the tract terminates in the superior thoracic region of the spinal cord). Fine control of the fingers is not modified by the functioning of the red
    6.75
    4 votes
    62
    Corpora quadrigemina

    Corpora quadrigemina

    In the brain, the corpora quadrigemina (Latin for "quadruplet bodies") are the four colliculi—two inferior, two superior—located on the tectum of the dorsal aspect of the midbrain.They are respectively named the inferior and superior colliculus. The corpora quadrigemina are reflex centers involving vision and hearing.
    9.00
    2 votes
    63
    Gracile nucleus

    Gracile nucleus

    Located in the medulla oblongata, the gracile nucleus is one of the dorsal column nuclei that participate in the sensation of fine touch and proprioception of the lower body (legs and trunk). It contains second-order neurons of the dorsal column-medial lemniscus system, which receive inputs from sensory neurons of the dorsal root ganglia and send axons that synapse in the thalamus. The neurons contained within the nucleus form a visible bump called the gracile tubercle on the posterior side of the closed medulla at the floor of the fourth ventricle. The gracile nucleus and fasciculus carry epicritic, kinesthetic, and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). The counterpart to the gracile nucleus and fasciculus is the cuneate nucleus and fasciculus, which carries the same type of information, but from the upper body (above T6, excepting the face and ear - the information from the face and ear is carried by the principal sensory nucleus of trigeminal nerve).
    9.00
    2 votes
    64
    Oculomotor nucleus

    Oculomotor nucleus

    The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. From this nucleus the fibers pass forward through the tegmentum, the red nucleus, and the medial part of the substantia nigra, forming a series of curves with a lateral convexity, and emerge from the oculomotor sulcus on the medial side of the cerebral peduncle. The nucleus of the oculomotor nerve does not consist of a continuous column of cells, but is broken up into a number of smaller nuclei, which are arranged in two groups, anterior and posterior. Those of the posterior group are six in number, five of which are symmetrical on the two sides of the middle line, while the sixth is centrally placed and is common to the nerves of both sides. The anterior group consists of two nuclei, an antero-medial and an antero-lateral . The nucleus of the oculomotor nerve, considered from a physiological standpoint, can be subdivided into several smaller groups of cells, each group controlling a particular muscle. A nearby nucleus, the Edinger-Westphal
    9.00
    2 votes
    65
    Posterior proper fasciculus

    Posterior proper fasciculus

    The posterior proper fasciculus (posterior ground bundle; posterior basis bundle) arises from cells in the posterior column; their axons bifurcate into ascending and descending branches which occupy the ventral part of the funiculus close to the gray column. They are intersegmental and run for varying distances sending off collaterals and terminals to the gray matter. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    9.00
    2 votes
    66
    Ventromedial nucleus

    Ventromedial nucleus

    The ventromedial nucleus (sometimes referred to as the ventromedial hypothalamus or VMH) is a nucleus of the hypothalamus."The ventromedial hypothalamus (VMH) is a distinct morphological nucleus involved in feeding, fear, thermoregulation, and sexual activity." It has four subdivisions: These subdivisions differ anatomically, neurochemically, and behaviorally. Lateral Hypothalamus: This region of the brain is associated with hunger recognition. Ventromedial Hypothalamus: This nuclear region is involved with the recognition of the feeling of fullness. The ventromedial nucleus (VMN) is most commonly associated with satiety. Early studies showed that VMN lesions caused over-eating and obesity in rats. However, the interpretation of these experiments was summarily discredited when Gold's research demonstrated that precision lesioning of the VMN did not result in hyperphagia. Nevertheless, numerous studies have shown that the immediacy of hyperphagia and obesity syndrome are a consequence of VMN lesions or procaine injections, and point to the VMN's role in satiety. A major review of the subject in 2006 concluded that, "anatomical studies done both before and after Gold's study did not
    9.00
    2 votes
    67
    Basal ganglia

    Basal ganglia

    The basal ganglia (or basal nuclei) are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas. The basal ganglia are associated with a variety of functions, including voluntary motor control, procedural learning relating to routine behaviors or "habits" such as bruxism, eye movements, and cognitive, emotional functions. Currently popular theories implicate the basal ganglia primarily in action selection, that is, the decision of which of several possible behaviors to execute at a given time. Experimental studies show that the basal ganglia exert an inhibitory influence on a number of motor systems, and that a release of this inhibition permits a motor system to become active. The "behavior switching" that takes place within the basal ganglia is influenced by signals from many parts of the brain, including the prefrontal cortex, which plays a key role in executive functions. The main components of the basal ganglia are the striatum, the globus pallidus, the substantia nigra, and the subthalamic nucleus.
    7.67
    3 votes
    68
    Brodmann area 4

    Brodmann area 4

    Brodmann area 4 comprises the primary motor cortex of the human brain. It is located in the posterior portion of the frontal lobe. Brodmann area 4 is about the same as the precentral gyrus. The borders of this area are: the precentral sulcus in front (anteriorly), the medial longitudinal fissure at the top (medially), the central sulcus in back (posteriorly), and the lateral sulcus along the bottom (laterally). This area of cortex, as shown by Wilder Penfield and others, has the pattern of a homunculus. That is, the legs and trunk fold over the midline; the arms and hands are along the middle of the area shown here; and the face is near the bottom of the figure. Because Brodmann area 4 is in the same general location as primary motor cortex, the homunculus here is called the motor homunculus. The term area 4 of Brodmann-1909 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. It is located predominantly in the precentral gyrus. Brodmann-1909 regarded it as topographically and cytoarchitecturally homologous to the human gigantopyramidal area 4 and noted that it occupies a much greater fraction of the frontal lobe in the monkey than in the human.
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    69

    Brodmann area 43

    Brodmann area 43 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It was described (but not labeled) on the map of cortical areas in Brodmann-1909, and it was regarded as cytoarchitecturally homologous to area 30 of Mauss in 1908 in the guenon and subcentral area 43 of the human (Brodmann-1909). The Vogts found no distinctive architectonic area of the corresponding location in the guenon (Vogts-1919). In the human subcentral area 43, a subdivision of the cytoarchitecturally is defined in the postcentral region of cerebral cortex. It occupies the postcentral gyrus and the precentral gyrus between the ventrolateral extreme of the central sulcus and the depth of the lateral sulcus at the insula. Its rostral and caudal borders are approximated by the anterior subcentral sulcus (H) and the posterior subcentral sulcus respectively. Cytoarchitecturally it is bounded rostrally by the agranular frontal area 6 and caudally, for the most part, by the caudal postcentral area 2 and the supramarginal area 40 (H) (Brodmann-1909). One of the functions is as the "gustatory cortical area".
    7.67
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    70
    Calcarine fissure

    Calcarine fissure

    The calcarine fissure (or calcarine sulcus) is an anatomical landmark located at the caudal end of the medial surface of the brain. Its name comes from the Latin "calcar" meaning "spur.". It is a complete sulcus. The calcarine sulcus begins near the occipital pole in two converging rami and runs forward to a point a little below the splenium of the corpus callosum, where it is joined at an acute angle by the medial part of the parieto-occipital sulcus. The anterior part of this fissure gives rise to the prominence of the calcar avis in the posterior cornu of the lateral ventricle. The calcarine sulcus is where the primary visual cortex is concentrated. The central visual field is located in posterior portion of the calcarine sulcus and the peripheral visual field in the anterior portion.
    7.67
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    71
    Cerebrospinal fibers

    Cerebrospinal fibers

    The cerebrospinal fibers, derived from the cells of the motor area of the cerebral cortex, occupy the middle three-fifths of the base; they are continued partly to the nuclei of the motor cranial nerves, but mainly into the pyramids of the medulla oblongata. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.67
    3 votes
    72
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    73

    Brodmann area 13

    Brodmann area 13 is a subdivision of the cerebral cortex as defined on the guenon monkey and on the basis of cytoarchitecture. Brodmann area 13 is found in humans, however it seems to act as a bridge between the lateral and medial layers of the brain. Thus it is sometimes misidentified as not being a Brodmann area. Located in the posterior of the insular cortex, Brodmann area 13 shares with other parts of the insular cortex a wide molecular layer (I) and very wide multiform layer (VI). The external granular layer (II) is relatively dense. The external lamina pyramidalis externa (III) has a central stripe of less cellular density that separates two sublayers, IIIa and IIIb. The internal granular layer (IV) is sufficiently wide and dense to separate clearly sublayer IIIb from layer V. The boundary between layers V and VI is defined by larger ganglion cells, more pyramidal in shape, in layer V giving way to smaller, more spindle-shaped cells that become denser and more homogeneous deeper in layer VI. Often the spindle cells are arrayed horizontally as in the claustrum (VICl), which Brodmann considered a likely extension of layer VI beyond the extreme capsule (VICe) (Brodmann-1905).
    10.00
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    74
    Horizontal sulcus

    Horizontal sulcus

    The largest and deepest fissure in the cerebellum is named the horizontal sulcus (or horizontal fissure). It commences in front of the pons, and passes horizontally around the free margin of the hemisphere to the middle line behind, and divides the cerebellum into an upper and a lower portion. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
    10.00
    1 votes
    75
    Insular cortex

    Insular cortex

    In each hemisphere of the mammalian brain the insular cortex (often called insula, insulary cortex or insular lobe) is a portion of the cerebral cortex folded deep within the lateral sulcus, the fissure separating the temporal and the frontal lobes. The insulae are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body's homeostasis. These functions include perception, motor control, self-awareness, cognitive functioning, and interpersonal experience. In relation to these it is involved in psychopathology. The insular cortex is divided into two parts: the larger anterior insula and the smaller posterior insula in which more than a dozen field areas have been identified. The cortical area overlying the insula towards the lateral surface of the brain is the operculum (meaning "lid"). The opercula are formed from parts of the enclosing frontal, temporal and parietal lobes. The insula was first described by Johann Christian Reil while describing cranial and spinal nerves and plexi. Henry Gray in Gray's Anatomy is responsible for it being known as the Island of Reil. The right anterior insula aids
    10.00
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    76
    Interpeduncular fossa

    Interpeduncular fossa

    The interpeduncular fossa is a somewhat lozenge-shaped area of the base of the brain, limited in front by the optic chiasma, behind by the antero-superior surface of the pons, antero-laterally by the converging optic tracts, and postero-laterally by the diverging cerebral peduncles. The structures contained in it, from behind forward, are the posterior perforated substance, corpora mamillaria, tuber cinereum, infundibulum, and hypophysis. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    10.00
    1 votes
    77
    Islands of Calleja

    Islands of Calleja

    The islands of Calleja (IC, ISC, or IClj) are a group of neural granule cells located within the ventral striatum in the brains of most animals. This region of the brain is part of the limbic system, where it aids in the reinforcing effects of reward-like activities. Within most species, the islands are specifically located within the olfactory tubercle; however, in primates, these islands are located within the nucleus accumbens, the reward center of the brain, since the olfactory tubercle has practically disappeared in the brains of primates. Both of these structures have been implicated in the processing of incentives as well as addictions to drugs. Projections to and from the islands supplement this knowledge with their involvement in the reward pathways for both cocaine and amphetamines. The islands of Calleja are specifically located within the ventral and medial lining of the ventral striatum in the brain, meaning that they lie towards the front and middle of this region within the temporal lobe. The insula magna, or the major island, of these complexes is located in the medial border of the nucleus accumbens. The ventral group of the islands lies along the pial border of
    10.00
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    78
    Olfactory tract

    Olfactory tract

    The olfactory tract is a bundle of axons connecting the mitral and tufted cells of the olfactory bulb to several target regions in the brain, including piriform cortex, amygdala, and entorhinal cortex. It is a narrow white band, triangular on coronal section, the apex being directed upward. It lies in the olfactory sulcus on the inferior surface of the frontal lobe, and divides posteriorly into two striæ, a medial olfactory stria and a lateral olfactory stria. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    10.00
    1 votes
    79
    Olfactory trigone

    Olfactory trigone

    The olfactory trigone is a small triangular area in front of the anterior perforated substance. Its apex, directed forward, occupies the posterior part of the olfactory sulcus, and is brought into view by throwing back the olfactory tract. It is part of the olfactory pathway. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    10.00
    1 votes
    80
    Superior colliculus

    Superior colliculus

    The optic tectum or simply tectum is a paired structure that forms a major component of the vertebrate midbrain. In mammals, this structure is more commonly called the superior colliculus (Latin, upper hill), but, even in mammals, the adjective tectal is commonly used. The tectum is a layered structure, with a number of layers that vary by species. The superficial layers are sensory-related, and receive input from the eyes as well as other sensory systems. The deep layers are motor-related, capable of activating eye movements as well as other responses. There are also intermediate layers, with multi-sensory cells and motor properties. The general function of the tectal system is to direct behavioral responses toward specific points in egocentric ("body-centered") space. Each layer of the tectum contains a topographic map of the surrounding world in retinotopic coordinates, and activation of neurons at a particular point in the map evokes a response directed toward the corresponding point in space. In primates, the tectum ("superior colliculus") has been studied mainly with respect to its role in directing eye movements. Visual input from the retina, or "command" input from the
    10.00
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    81
    Superior medullary velum

    Superior medullary velum

    The superior medullary velum (anterior medullary velum, valve of Vieussens) is a thin, transparent lamina of white matter, which stretches between the superior cerebellar peduncles; on the dorsal surface of its lower half the folia and lingula are prolonged. It forms, together with the superior cerebellar peduncle, the roof of the upper part of the fourth ventricle; it is narrow above, where it passes beneath the facial colliculi, and broader below, where it is continuous with the white substance of the superior vermis. A slightly elevated ridge, the fraenulum veli, descends upon its upper part from between the inferior colliculi, and on either side of this the trochlear nerve emerges. Blood is supplied by branches from the superior cerebellar artery. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    10.00
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    82
    Solitary nucleus

    Solitary nucleus

    The solitary tract and nucleus are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX) and vagus (X) cranial nerves. The nucleus of the solitary tract, or NTS (Latin: nucleus tractus solitarii), is located along the length of the medulla oblongata within the dorsal respiratory group (DRG). The solitary tract runs in the middle of the nucleus, creating a speck of white matter (myelinated axons of the tract), surrounded by grey matter (the nucleus). This stands out on a stained section, which is where the name solitary comes from. The NTS is divided into a rostral gustatory nucleus and caudal region of neurons. Sub regions of the NTS can be related to the distribution of inputs - particularly contacts from cranial primary afferent neurons (see below) related to cardiovascular, respiratory and gastrointestinal functions. There is some degree of localization within the caudal region so that many cardiovascular neurons sit near the midline of the nucleus, and many respiratory related neurons are located laterally within the nucleus. Neurons that synapse in this nucleus mediate the gag reflex, the carotid sinus
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    83
    Temporal lobe

    Temporal lobe

    The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in auditory perception and is home to the primary auditory cortex. It is also important for the processing of semantics in both speech and vision. The temporal lobe contains the hippocampus and plays a key role in the formation of long-term memory. The superior temporal gyrus includes an area (within the Sylvian fissure) where auditory signals from the cochlea (relayed via several subcortical nuclei) first reach the cerebral cortex. This part of the cortex (primary auditory cortex) is involved in hearing. Adjacent areas in the superior, posterior and lateral parts of the temporal lobes are involved in high-level auditory processing. In humans this includes speech, for which the left temporal lobe in particular seems to be specialized. Wernicke's area, which spans the region between temporal and parietal lobes, plays a key role (in tandem with Broca's area, which is in the frontal lobe). The functions of the left temporal lobe are not limited to low-level perception but extend to comprehension, naming,
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    84
    Ventral supraoptic decussation

    Ventral supraoptic decussation

    The ventral supraoptic decussation is the crossover (decussation) point for signals from the left and right eye, en route respectively to the right and left sides of the visual cortex. Occupying the posterior part of the commissure of the optic chiasma is a strand of fibers, the Ventral supraoptic decussation (commissure of Gudden, Gudden's inferior commissure), which is not derived from the optic nerves; it forms a connecting link between the medial geniculate bodies. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
    6.50
    4 votes
    85
    Poles of cerebral hemispheres

    Poles of cerebral hemispheres

    The anterior end of the hemisphere is named the frontal pole. (See also frontal lobe.) The posterior end is named the occipital pole. (See also occipital lobe.) The anterior end of the temporal lobe, the temporal pole. (See also temporal lobe.) This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.60
    5 votes
    86
    Brodmann area 11

    Brodmann area 11

    Brodmann area 11 is one of Brodmann's cytologically defined regions of the brain. It is involved in planning, reasoning, and decision making. Brodmann area 11, or BA11, is part of the frontal cortex in the human brain. BA11 covers the medial part of the ventral surface of the frontal lobe. Prefrontal area 11 of Brodmann-1909 is a subdivision of the frontal lobe in the human defined on the basis of cytoarchitecture. Defined and illustrated in Brodmann-1909, it included the areas subsequently illustrated in Brodmann-10 as prefrontal area 11 and rostral area 12. prefrontal area 11 is a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex of the human. As illustrated in Brodmann-10, It constitutes most of the orbital gyri, gyrus rectus and the most rostral portion of the superior frontal gyrus. It is bounded medially by the inferior rostral sulcus (H) and laterally approximately by the frontomarginal sulcus (H). Cytoarchitecturally it is bounded on the rostral and lateral aspects of the hemisphere by the frontopolar area 10, the orbital area 47, and the triangular area 45; on the medial surface it is bounded dorsally by the rostral area 12 and caudally by
    8.50
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    87
    Brodmann area 23

    Brodmann area 23

    Brodmann area 23 (BA23) is a region in the brain corresponding to some portion of the posterior cingulate cortex. It lies between Brodmann area 30 and Brodmann area 31 and is located on the medial wall of the cingulate gyrus between the callosal sulcus and the cingulate sulcus. This area is also known as ventral posterior cingulate area 23. It is a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. In the human it occupies most of the posterior cingulate gyrus adjacent to the corpus callosum. At the caudal extreme it is bounded approximately by the parieto-occipital sulcus. Cytoarchitecturally it is bounded dorsally by the dorsal posterior cingulate area 31, rostrally by the ventral anterior cingulate area 24, and ventrorostrally in its caudal half by the retrosplenial region (Brodmann-1909). Brodmann area 23 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. Brodmann regarded it as topographically and cytoarchitecturally homologous to the combined ventral posterior cingulate area 23 and dorsal posterior cingulate Brodmann area 31 of the human (Brodmann-1909). Distinctive Features (Brodmann-1905): the
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    88
    Inferior salivatory nucleus

    Inferior salivatory nucleus

    In the brain, the inferior salivatory nucleus is a cluster of neurons controlling the parasympathetic input to the parotid gland. It is one of the components of the glossopharyngeal nerve (cranial nerve IX). Its precise location in humans has not yet been identified, but in other mammals it is located in the medulla within the general visceral efferent cell column, superior to the nucleus ambiguus and inferior to the superior salivatory nucleus. While still in the medulla, fibers of the inferior salivatory nucleus join with fibers of the gustatory nucleus, nucleus ambiguus, and spinal nucleus of the trigeminal nerve, and exit the medulla as the mixed glossopharyngeal nerve (cranial nerve IX). It sends fibers through the glossopharyngeal nerve's tympanic nerve and into the tympanic plexus. Exiting the plexus within the lesser petrosal nerve, these preganglionic fibers synapse with cells in the otic ganglion, which send postganglionic fibers into the mandibular division of the trigeminal nerve, then into the auriculotemporal nerve, finally reaching their target, the parotid gland. Parasympathetic input from fibers of the inferior salivatory nucleus stimulates the parotid gland to
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    89

    Rhinal fissure

    In the human brain, the rhinencephalon appears as a longitudinal elevation, with a corresponding internal furrow, on the under surface of the hemisphere close to the lamina terminalis; it is separated from the lateral surface of the hemisphere by a furrow, the external rhinal fissure (or rhinal sulcus), and is continuous behind with that part of the hemisphere, which will ultimately form the anterior end of the temporal lobe. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    90
    Splenium

    Splenium

    The posterior end of the corpus callosum is the thickest part, and is termed the splenium (Greek splenion = a bandage). It overlaps the tela chorioidea of the third ventricle and the mid-brain, and ends in a thick, convex, free border. A sagittal section of the splenium shows that the posterior end of the corpus callosum is acutely bent forward, the upper and lower parts being applied to each other. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    8.50
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    91
    Superior olivary nucleus

    Superior olivary nucleus

    The superior olivary complex (or SOC or superior olive) is a collection of brainstem nuclei that functions in multiple aspects of hearing and is an important component of the ascending and descending auditory pathways. The SOC is intimately related to the trapezoid body: most of the cell groups of the SOC are dorsal (posterior in primates) to this axon bundle while a number of cell groups are embedded in the trapezoid body. Overall, the SOC displays a significant interspecies variation, being largest in bats and rodents and smaller in primates. The superior olivary nucleus plays a number of roles in hearing. The medial superior olive (MSO) is a specialized nucleus that is believed to measure the time difference of arrival of sounds between the ears (the interaural time difference or ITD). The ITD is a major cue for determining the azimuth of low-frequency sounds, i.e., localising them on the azimuthal plane – their degree to the left or the right. The lateral superior olive (LSO) is believed to be involved in measuring the difference in sound intensity between the ears (the interaural level difference or ILD). The ILD is a second major cue in determining the azimuth of
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    92
    Brodmann area 22

    Brodmann area 22

    Brodmann area 22 is one of Brodmann's cytologically defined regions of the brain. It is involved in auditory processing. Brodmann area 22 is a region of the human brain (the 22nd numbered Brodmann area). On the left side of the brain this area helps with generation and understanding of individual words. On the right side of the brain it helps tell the difference between melody, pitch, and sound intensity, that is prosody. Researchers believe this part of the brain is active in processing language. This area is also known as superior temporal area 22, and it refers to a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. In the human it corresponds approximately to the lateral and caudal two thirds of the superior temporal gyrus. It is bounded rostrally by the temporopolar area 38 (H), medially by the posterior transverse temporal area 42 (H), ventrocaudally by the middle temporal area 21 and dorsocaudally by the supramarginal area 40 (H) and the angular area 39 (H) (Brodmann-1909). The posterior section of Brodmann area 22 is home to Wernicke's area (most commonly in the left hemisphere only). Brodmann area 22 is a subdivision of the cerebral cortex
    7.33
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    93
    Facial motor nucleus

    Facial motor nucleus

    The facial motor nucleus is a collection of neurons in the brainstem that belong to the facial nerve (cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius. The nucleus is situated in the caudal portion of the ventrolateral pontine tegmentum. Its axons take an unusual course, traveling dorsally and looping around the abducens nucleus, then traveling ventrally to exit the ventral pons medial to the spinal trigeminal nucleus. These axons form the motor component of the facial nerve, with parasympathetic and sensory components forming the nervus intermedius. The nucleus has a dorsal and ventral region, with neurons in the dorsal region innervating muscles of the upper face and neurons in the ventral region innervating muscles of the lower face. Because it innervates muscles derived from pharyngeal arches, the facial motor nucleus is considered part of the special visceral efferent (SVE) cell column, which also includes the trigeminal motor nucleus, nucleus ambiguus, and (arguably) the spinal accessory nucleus. Like all lower motor neurons, cells of the facial motor nucleus receive cortical input from the primary motor cortex in the
    7.33
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    94

    Lingual gyrus

    The lingual gyrus of the occipital lobe lies between the calcarine sulcus and the posterior part of the collateral sulcus; behind, it reaches the occipital pole; in front, it is continued on to the tentorial surface of the temporal lobe, and joins the parahippocampal gyrus. The lingual gyrus is so-named because it resembles the tongue in shape. This region is believed to play an important role in dreaming and vision, especially in recognizing words, regardless of size, font, etc. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.33
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    95
    Myelencephalon

    Myelencephalon

    The myelencephalon is categorized as a secondary vesicle in the development of the central nervous system. The prefix "myelen" is derived from Greek for medulla (myelos). The myelencephalon differentiates primarily into the medulla oblongata and a caudal portion of the fourth ventricle, but will also contain portions of the following cranial nerves: vestibulocochlear nerve (CN VIII), glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve (CN XI), and hypoglossal nerve (CN XII). The myelencephalon develops from the primary vesicular structure called the rhombencephalon (or hindbrain), which is present in all vertebrate embryos. The rhombencephalon normally begins its differentiation into the myelencephalon and the metencephalon at approximately 5 weeks of gestational development in humans. Evolutionarily, the myelencephalon is the area of the brain which is the most ancestral, eventually controlling visceral mechanisms (basic bodily functions) such as breathing, heart and blood vessel activity, digestions, and peristalsis.
    7.33
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    96
    Spinal accessory nucleus

    Spinal accessory nucleus

    The spinal accessory nucleus lies within the cervical spinal cord (C1-C5) in the ventral horn. The nucleus ambiguus is classically said to provide the "cranial component" of the accessory nerve. However, the very existence of this cranial component has been recently questioned and seen as contributing exclusively to the vagus nerve. The terminology continues to be used in describing both human anatomy, and that of other animals.
    7.33
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    97
    Anterior commissure

    Anterior commissure

    The anterior commissure (also known as the precommissure) is a bundle of nerve fibers (white matter), connecting the two cerebral hemispheres across the midline, and placed in front of the columns of the fornix. The great majority of fibers connecting the two hemispheres travel through the corpus callosum, which is over 10 times larger than the anterior commissure, and other routes of communication pass through the hippocampal commissure or, indirectly, via subcortical connections. Nevertheless, the anterior commissure is a significant pathway that can be clearly distinguished in the brains of all mammals. The anterior commissure plays a key role in pain and pain sensation, more specifically sharp, acute pain. It also contains decussating fibers from the olfactory tracts, vital for the sense of smell and chemoreception. The anterior commissure works with the posterior commissure to link the two cerebral hemispheres of the brain and also interconnects the amygdalas and temporal lobes, contributing to the role of memory, emotion, speech and hearing. It also is involved in olfaction, instinct, and sexual behavior. In a sagittal section, the anterior commissure is oval in shape, having
    6.25
    4 votes
    98

    Stratum zonale

    The thalamus consists chiefly of gray substance, but its upper surface is covered by a layer of white substance, named the stratum zonale. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    6.25
    4 votes
    99
    Brodmann area 19

    Brodmann area 19

    Brodmann area 19, or BA19, is part of the occipital lobe cortex in the human brain. Along with area 18, it comprises the extrastriate (or peristriate) cortex. In normally-sighted humans, extrastriate cortex is a visual association area, with feature-extracting, shape recognition, attentional, and multimodal integrating functions. This area is also known as peristriate area 19, and it refers to a subdivision of the cytoarchitecturally defined occipital region of cerebral cortex. In the human it is located in parts of the lingual gyrus, the cuneus, the lateral occipital gyrus (H) and the superior occipital gyrus (H) of the occipital lobe where it is bounded approximately by the parieto-occipital sulcus. Cytoarchitecturally it is bounded on one side by the parastriate area 18 which it surrounds. Rostrally it is bounded by the angular area 39 (H) and the occipitotemporal area 37 (H) (Brodmann-1909). Brodmann area 19-1909 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous to the peristriate area 19 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): Compared to Brodmann area 18-1909, the
    7.00
    3 votes
    100
    Commissure of fornix

    Commissure of fornix

    The lateral portions of the body of the fornix are joined by a thin triangular lamina, named the psalterium (lyra). This lamina contains some transverse fibers that connect the two hippocampi across the middle line and constitute the commissure of fornix (hippocampal commissure). The terminal lamina creates the commisure plate. This structure gives existence to the corpus callosum, the septum pellucidum, and the fornix. The latter splits into two columnae fornicis (anterior), and then splits into two crura fornicis (posterior). These two crura are joined together through the commissura hippocampalis. The beginning of the splitting is called the psalterium or Lyra Davidis. The latter name is used because the structure resembles a lyra (or triangular harp): The two crura are the "chassis" of the lyra, and the commisure connections are the fibers. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    101
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    102
    Fasciculus solitarius

    Fasciculus solitarius

    The solitary tract (Latin: tractus solitarius) is a compact fiber bundle that extends longitudinally through the posterolateral region of the medulla. The solitary tract is surrounded by the nucleus of the solitary tract, and descends to the upper cervical segments of the spinal cord. The solitary tract is made up of primary sensory fibers and descending fibers of the vagus, glossopharyngeal, and facial nerves. The solitary tract conveys afferent information from stretch receptors and chemoreceptors in the walls of the cardiovascular, respiratory, and intestinal tracts. Afferent fibers from cranial nerves 7, 9 and 10 convey taste (SVA) in its rostral portion, and general visceral sense (GVA) in its caudal part. Taste buds in the mucosa of the tongue can also generate impulses in the rostral regions of the solitary tract. The efferent fibers are distributed to the solitary tract nucleus. There are numerous synonyms for the solitary tract:
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    103

    Hypothalamic sulcus

    The hypothalamic sulcus (sulcus of Monro) is a groove in lateral wall of third ventricle, marking the boundary between the thalamus and hypothalamus. The upper and lower portions of the lateral wall of the third ventricle correspond to the alar lamina and basal lamina, respectively, of the lateral wall of the fore-brain vesicle and are separated from each other by a furrow, the hypothalamic sulcus, which extends from the interventricular foramen to the cerebral aqueduct. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    104
    Inferior frontal gyrus

    Inferior frontal gyrus

    The inferior frontal gyrus is a gyrus of the frontal lobe (the yellow area of the human brain image to the right). It is labelled gyrus frontalis inferior, its Latin name. In the yellow area, its superior border is the inferior frontal sulcus (which divides it from the gyrus frontalis medius in the yellow area), its inferior border the lateral fissure (which divides it from the gyrus temporalis superior in the green area), and its posterior border is the inferior precentral sulcus (in the yellow area). Above it is the middle frontal gyrus (the gyrus frontalis medius), behind it the precentral gyrus (the gyrus praecentralis), both gyri in the yellow area of the image. The inferior frontal gyrus can be subdivided into the following macroanatomical structures, shown in yellow in the top image, just below the label gyrus frontalis inferior: The inferior frontal gyrus includes the following cytoarchitectonic areas: The cytoarchitectonic areas very roughly correspond to the following macroanatomic structures: Brodmann area 44 to Pars opercularis, Brodmann area 45 to Pars triangularis, and Brodmann area 47 to Pars orbitalis. Brodmann area 44 corresponds to Broca's area (sometimes Broca's
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    105
    Inferior parietal lobule

    Inferior parietal lobule

    The inferior parietal lobule (IPL, subparietal district or lobule) lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. Also known as Geschwind’s territory after Norman Geschwind, an American neurologist, who in the early 1960s foresaw its importance. It is divided from before backward into two gyri: Functional imaging experiments suggest that the left anterior supramarginal gyrus (aSMG) of the human inferior parietal lobule exhibits an evolved specialization related to tool use. It is not currently known if this functional specialization is unique to humans as complementary experiments have only been performed with macaque monkeys and not apes. The habitual use of tools by chimpanzees makes the uniqueness of the human aSMG an open question as its function may have evolved prior to the split from our last common ancestor. The IPL is known to be larger in males than in females. The left side IPL in men is larger than the right side. This asymmetry is reversed for females. Inferior parietal lobule has been involved in the perception of emotions in facial stimuli, and interpretation of sensory information. The Inferior
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    Infundibular recess

    Infundibular recess

    The floor of the third ventricle is prolonged downward as a funnel-shaped recess, the infundibular recess, into the infundibulum, and to the apex of the latter the hypophysis or pituitary is attached. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Paraterminal gyrus

    Paraterminal gyrus

    The paraterminal gyrus (subcallosal gyrus, peduncle of the corpus callosum) is a narrow lamina on the medial surface of the hemisphere in front of the lamina terminalis, behind the parolfactory area, and below the rostrum of the corpus callosum. It is continuous around the genu of the corpus callosum with the supracallosal gyrus. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Stratum lucidum of hippocampus

    The stratum lucidum of the hippocampus is also a layer of the hippocampus between the stratum pyramidale and the stratum radiatum. It is the tract of the mossy fiber projections, both inhibitory and excitatory from the granule cells of the dentate gyrus. One mossy fiber may make up to 37 connections to a single pyramid cell, and innervate around 12 pyramidal cells on top of that. Any given pyramidal cell in the stratum lucidum may get input from as many as 50 granule cells. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Superior frontal gyrus

    Superior frontal gyrus

    The superior frontal gyrus makes up about one-third of the frontal lobe of the human brain. It is bounded laterally by the superior frontal sulcus. The superior frontal gyrus, like the inferior frontal gyrus and the middle frontal gyrus, is more of a region than a true gyrus. In fMRI experiments, Goldberg et al. have found evidence that the superior frontal gyrus is involved in self-awareness, in coordination with the action of the sensory system. In 1998, neurosurgeon Itzhak Fried, MD, PhD described a 16-year-old female patient (referred to as "patient AK") who laughed when her SFG was stimulated with electric current during treatment for epilepsy. Electrical stimulation was applied to the cortical surface of AK's left frontal lobe while an attempt was made to locate the focus of her epileptic seizures (which were never accompanied by laughter). Fried identified a 2 cm by 2 cm area on the left SFG where stimulation produced laughter consistently (over several trials). AK reported that the laughter was accompanied by a sensation of merriment or mirth. AK gave a different explanation for the laughter each time, attributing it to an (unfunny) external stimulus. Thus, laughter was
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    110
    Brodmann area 29

    Brodmann area 29

    Brodmann area 29, also known as granular retrolimbic area 29 or granular retroslenial cortex, is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. In the human it is a narrow band located in the isthmus of cingulate gyrus. Cytoarchitecturally it is bounded internally by the ectosplenial area 26 and externally by the agranular retrolimbic area 30 (Brodmann-1909). Brodmann has this to say about area 29, amongst his other comments on it: : " An unusual regression of layer II together with layer III in found in the __granular retrosplenial cortex, illustrated in Figures 38 to 41 for four different animals. Here, in addition to the regression of layers II and III, there is fusion of the original layers V and VI and at the same time an isolated massive increase of the inner granular layer, that is particularly prominent in Figures 38 and 39;..."
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    111
    Taenia thalami

    Taenia thalami

    In the front, superior surface of the thalamus but separate from the inner, medial surface by a salient margin is the taenia thalami (Latin for "flat band"). The bottom epithelial lining of the third ventricle is in between the tela chorioidea and the taenia thalami. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    112
    Brodmann area 33

    Brodmann area 33

    Brodmann area 33, also known as pregenual area 33, is a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. It is a narrow band located in the anterior cingulate gyrus adjacent to the supracallosal gyrus in the depth of the callosal sulcus, near the genu of the corpus callosum. Cytoarchitecturally it is bounded by the ventral anterior cingulate area 24 and the supracallosal gyrus (Brodmann-1909).
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    Brodmann area 52

    Parainsular area 52 (H) is a subdivision of the cytoarchitecturally defined temporal region of the cerebral cortex in the brain. It is located in the bank of the lateral sulcus on the dorsal surface of the temporal lobe. Its medial boundary corresponds approximately to the junction between the temporal lobe and the insula. Cytoarchitecturally it is bounded laterally by the anterior transverse temporal area 42 (H) (Brodmann-1909).
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    Choroid plexus

    Choroid plexus

    The choroid plexus (from Greek khorion "membrane enclosing the fetus, afterbirth"; "plexus": Mod.L., lit. "braid, network") is a structure in the ventricles of the brain where cerebrospinal fluid (CSF) is produced. The choroid plexus consists of modified ependymal cells. Choroid plexus is present in all components of the ventricular system except for the cerebral aqueduct, frontal horn of the lateral ventricle, and occipital horn of the lateral ventricle. It is found in the superior part of the inferior horn of the lateral ventricles. It follows up along this boundary, continuous with the inferior of the body of the lateral ventricles. It passes into the interventricular foramen, and is present at the top of the third ventricle. There is also choroid plexus in the fourth ventricle, in the section closest to the bottom half of the cerebellum. The choroid plexus (CP) consists of many capillaries, separated from the ventricles by choroid epithelial cells. Liquid filters through these cells from blood to become cerebrospinal fluid. There is also much active transport of substances into, and out of, the CSF as it is made. There are four choroid plexi in the brain, one in each of the
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    115
    Dentate nucleus

    Dentate nucleus

    The dentate nucleus is located within the deep white matter of each cerebellar hemisphere, and it is the largest single structure linking the cerebellum to the rest of the brain. It is the largest and most lateral, or farthest from the midline, of the four pairs of deep cerebellar nuclei, the others being the fastigial and the interposed nuclei (globose and emboliform nuclei combined). The dentate nucleus is responsible for the planning, initiation and control of voluntary movements. The dorsal region of the dentate nucleus contains output channels involved in motor function, which is the movement of skeletal muscle, while the ventral region contains output channels involved in nonmotor function, such as conscious thought and visuospatial function. The dentate nucleus is highly convoluted, and gyral, or groove, formation is coincident with a critical period of extensive growth in the fetal dentate. The dentate nucleus becomes visible in the cerebellar white matter as early as 11-12 weeks of gestation, containing only smooth lateral and medial surfaces. During this time, the neurons of the dentate nucleus are similar in shape and form, being mainly bipolar cells. During 22-28 weeks
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    116
    Flocculus

    Flocculus

    The flocculus (Latin: tuft of wool, diminutive) is a small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle anterior to the biventer lobule. It is associated with the nodulus of the vermis; together, these two structures compose the vestibular part of the cerebellum. At its base, the flocculus receives input from the middle ears vestibular system and regulates balance. Many floccular projections descend to the spinal cord and connect to the motor nuclei involved in control of eye movement.
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    Inferior olivary nucleus

    Inferior olivary nucleus

    The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata. It is closely associated with the cerebellum, meaning that it is involved in control and coordination of movements, sensory processing and cognitive tasks likely by encoding the timing of sensory input independently of attention or awareness . Lesions to the inferior olive have been associated with a decreased ability to perfect highly specialized motor tasks, such as improving one's accuracy in hitting a target with a ball. There is some evidence that it is stimulated by ghrelin. It consists of a gray folded lamina arranged in the form of an incomplete capsule, opening medially by an aperture called the hilum. Olivocerebellar fibers are neurons that have their cell bodies in the inferior olivary nucleus. Their axons leave medially through the hilum, cross the midline, and ascend into the cerebellum via the inferior cerebellar peduncle. Once they enter the cerebellum, they are referred to as the climbing fibers. Finally, they terminate by synapsing in the cerebellar cortex, including the cortex of the vermis, paramedian lobule, and the cerebellar hemispheres. The
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    Preoptic area

    Preoptic area

    The preoptic area is a region of the hypothalamus. According to the MeSH classification, it is considered part of the anterior hypothalamus. There are four nuclei in this region, according to Terminologia Anatomica (Medial, Median, Lateral, and Paraventricular). The preoptic area is responsible for thermoregulation and receives nervous stimulation from thermoreceptors in the skin, mucous membranes, and hypothalamus itself. This area propagates stimuli to either the heat-losing or the heat-promoting centers of the hypothalamus. The median preoptic nucleus is located along the midline in a position significantly dorsal to the other 3 preoptic nuclei, at least in the macaca fascicularis brain. It wraps around the top (dorsal), front, and bottom (ventral) surfaces of the anterior commissure. The median preoptic nucleus generates thirst. Drinking decreases noradrenaline release in the median preoptic nucleus. The medial preoptic nucleus is bounded laterally by the lateral preoptic nucleus, and medially by the preoptic periventricular nucleus. It releases gonadotropin-releasing hormone (GnRH), controls copulation in males, and is larger in males than in females. The lateral preoptic
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    Supracallosal gyrus

    Supracallosal gyrus

    The supracallosal gyrus (induseum griseum; gyrus epicallosus) consists of a thin layer of grey matter in contact with the dorsal surface of the corpus callosum and continuous laterally with the grey matter of the cingulate gyrus. It contains two longitudinally directed strands of fibers termed respectively the medial and lateral longitudinal striae (of Lancisi). The supracallosal gyrus is prolonged around the splenium of the corpus callosum as a delicate lamina, the fasciola cinerea, which is continuous below with the fascia dentata hippocampi. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Corpus striatum

    Corpus striatum

    The corpus striatum (striated body) is a compound structure consisting of the caudate nucleus and the lentiform nucleus, which consists of the putamen and the globus pallidus. The term has been used in a few different ways: From lateral to medial, the corpus striatum is composed of the external capsule (white matter), the lentiform nucleus (gray matter), the internal capsule (white matter), and the caudate nucleus (gray matter). The alternating white and gray matter give it a striated appearance. The corpus striatum has received its name from the striped appearance which a section of its anterior part presents, in consequence of diverging white fibers being mixed with the gray substance which forms its chief mass. A part of the corpus striatum is imbedded in the white substance of the hemisphere, and is therefore external to the ventricle; it is termed the extraventricular portion, or the lenticular nucleus. The remainder, however, projects into the ventricle, and is named the intraventricular portion, or the caudate nucleus. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be
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    Fornix

    Fornix

    The fornix (Latin, "vault" or "arch") is a C-shaped bundle of fibers (axons) in the brain, and carries signals from the hippocampus to the hypothalamus. The fibres begin in the hippocampus on each side of the brain (where they are also known as the fimbria); the separate left and right side are each called the crus of the fornix. The bundles of fibres come together in the midline of the brain, forming the body of the fornix. The inferior edge of the septum pellucidum (a membrane that separates the two lateral ventricles) is attached to the upper face of the fornix body. The body of the fornix travels anteriorly and divides again near the anterior commissure. The left and right parts reseparate, but there is also an anterior/posterior divergence.
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    Middle temporal gyrus

    Middle temporal gyrus

    Middle temporal gyrus is a gyrus in the brain on the Temporal lobe. It is located between the superior temporal gyrus and inferior temporal gyrus. Its exact function is unknown, but it has been connected with processes as different as contemplating distance, recognition of known faces, and accessing word meaning while reading.
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    Nucleus centralis superior

    The median raphe nucleus (MRN) (also known as the nucleus raphe medianus (NRM) or superior central nucleus) is composed of polygonal, fusiform and pyriform neurons and exists rostral to the nucleus raphe pontis. Inhibition of the MRN in cats by lysergic acid diethylamide (LSD) and psilocin, two serotonin antagonist hallucinogens, leads to dose dependent behavioral changes, indicating the MRN may be an important site of action for humans hallucinations.
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    Pontine tegmentum

    Pontine tegmentum

    The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. It includes the pedunculopontine nucleus and the laterodorsal tegmental nucleus, among others, and is located near the raphe nucleus and the locus ceruleus. The trapezoid body is part of the pontine tegmentum. In animal studies, lesions of the pontine tegmentum greatly reduce or even eliminate REM sleep. Injection of a cholinergic agonist (e.g. carbachol), into the pontine tegmentum produces a state of REM sleep in cats. PET studies seem to indicate that there is a correlation between blood flow in the pontine tegmentum, REM sleep, and dreaming  . Pontine waves (P-waves, or ponto-geniculate-occipital waves) are brain waves generated in the pontine tegmentum. They can be observed in mammals, precede the onset of REM sleep, and continue throughout its course. After periods of memory training, P-wave density increases during subsequent sleep periods in rats. This may be an indication of a link between sleep and learning.
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    Subiculum

    Subiculum

    The subiculum (Latin for "support") is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper. It receives input from CA1 and entorhinal cortical layer III pyramidal neurons and is the main output of the hippocampus. The pyramidal neurons send projections to the nucleus accumbens, septal nuclei, prefrontal cortex, lateral hypothalamus, nucleus reuniens, mammillary nuclei, entorhinal cortex and amygdala. The pyramidal neurons in the subiculum exhibit transitions between two modes of action potential output: bursting and single spiking. The transitions between these two modes is thought to be important for routing information out of the hippocampus. It is believed to play a role in some cases of human epilepsy. It has also been implicated in working memory and drug addiction. It has been suggested that the dorsal subiculum is involved in spatial relations, and the ventral subiculum regulates the hypothalamic-pituitary-adrenal axis.
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    Brodmann area 7

    Brodmann area 7

    Brodmann area 7 is one of Brodmann's cytologically defined regions of the brain. It is involved in locating objects in space. It serves as a point of convergence between vision and proprioception to determine where objects are in relation to parts of the body. Brodmann area 7, is part of the parietal cortex in the human brain. It also corresponds to the precuneus. Situated posterior to the primary somatosensory cortex (Brodmann areas 3, 1 and 2), and superior to visual cortices (Brodmann areas 17, 18 and 19), this region is believed to play a role in visuo-motor coordination (e.g., in reaching to grasp an object). Brodmann area 7 is a subdivision of the cytoarchitecturally defined parietal region of cerebral cortex. It occupies most of the parietal lobe excluding the postcentral gyrus and superior parietal lobule. Brodmann-1909 considered it topologically homologous to the combined superior parietal area 7, the supramarginal area 40 (H) and the angular area 39 (H) of the human. Cytoarchitecurally he regarded it as "a still undifferentiated precursor zone for all parietal areas (apart from area 5)" (Garey-1999). Distinctive features (Brodmann-1905): in area 7 compared to Brodmann
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    Fastigial nucleus

    Fastigial nucleus

    The fastigial nucleus or nucleus fastigii refers specifically to the concentration of gray matter nearest to the middle line at the anterior end of the superior vermis, and immediately over the roof of the fourth ventricle, from which it is separated by a thin layer of white matter. It is smaller than the nucleus dentatus, but somewhat larger than the nucleus emboliformis and nucleus globosus, the other two independent centers of gray matter in the cerebellum. The fastigial nucleus is the smallest in size, with the dentate being the largest and the interposed being intermediate in size. Although it is one dense mass, it is made up of two sections: the rostral fastigial nucleus and the caudal fastigial nucleus. The fastigial nucleus receives its afferent input from the vermis. Most of its efferent connections travel via the inferior cerebellar peduncle to the vestibular nuclei, which is located at the junction of the pons and the medulla oblongata. The fastigial nucleus contains excitatory axons which project beyond the cerebellum, unlike the Purkinje cells that convey the purely-inhibitory output of the cerebellar cortex. The likely neurotransmitters of the excitatory fastigial
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    Medial lemniscus

    Medial lemniscus

    The medial lemniscus, also known as Reil's band or Reil's ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus. After neurons carrying proprioceptive or touch information synapse at the gracile and cuneate nuclei, axons from secondary neurons decussate at the level of the medulla and travel up the brainstem as the medial lemniscus on the contralateral (opposite) side. It is part of the posterior column-medial lemniscus system, which transmits touch, vibration sense, as well as the pathway for proprioception. The medial lemniscus carries axons from most of the body and synapses in the ventral posterolateral nucleus of the thalamus, at the level of the mamillary bodies. Sensory axons transmitting information from the head and neck via the trigeminal nerve synapse at the ventral posteromedial nucleus of the thalamus.
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    Nucleus raphe pallidus

    Nucleus raphe pallidus

    The nucleus raphe pallidus receives afferent connections from the periaqueductal gray, the Paraventricular nucleus of hypothalamus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. Also, the pallidus receives afferents from the medial preoptic area, median preoptic nucleus and lateral paragigantocellular reticular nuclei . The pallidus has recently been shown to be involved in the activation of a fever as an immunoreaction. It has been implied that the preoptic area is constantly inhibiting the raphe pallidus, especially the rostral portion, with GABA. When the preoptic area receives immune signals from the body, the inhibition stops and the rostral portion of the raphe pallidus excites the intermediolateral cell column, which induces a fever . The raphe pallidus has also been known to mediate the tachycardia response, an extremely high heart rate known to be incited by emotional or psychological stress. Microinjections of a GABA-a antagonist into the raphe pallidus, induces an increased heart rate. Conversely, microinjections of muscimol, a GABA-a agonist, inhibit tachycardia in rats under air-stress stimuli. In both of these cases,
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    Paraventricular nucleus

    Paraventricular nucleus

    The paraventricular nucleus (PVN, PVA, or PVH) is a neuronal nucleus in the hypothalamus. It contains multiple subpopulations of neurons that are activated by a variety of stressful and/or physiological changes. Many PVN neurons project directly to the posterior pituitary where they release oxytocin or vasopressin into the general circulation. Other PVN neurons control various anterior pituitary functions, while still others directly regulate appetite and autonomic functions in the brainstem and spinal cord. The paraventricular nucleus lies adjacent to the third ventricle, from which it derives its name, "paraventricular" meaning "alongside a ventricle." It does lie within the periventricular zone and must not be confused with the periventricular nucleus, which occupies a more medial position, beneath the third ventricle. The PVN is highly vascularised and is protected by the blood–brain barrier, although its neuroendocrine neurons extend to sites (in the median eminence and in the posterior pituitary) beyond the blood–brain barrier. The PVN contains magnocellular neurosecretory cells whose axons extend into the posterior pituitary, parvocellular neurosecretory cells that project
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    Pars triangularis

    Pars triangularis

    Pars triangularis is a region of the human cortex, located in the inferior frontal gyrus of the frontal lobe in the corresponding Brodmann area 45. The inferior frontal sulcus forms the superior boundary, the anterior horizontal ramus provides its inferior boundary, and the caudal boundary is made by the anterior ascending ramus (ascending branch of lateral sulcus). The pars triangularis contributes to propositional language comprehension, as in the dominant cortical hemisphere it contributes to the Broca's area. Lesions of the Pars triangularis lead to the characteristic findings of Expressive aphasia in individuals who are left hemispheric dominant. There is also extensive research on role of Pars triangularis and cortical functions such as language. A strong correlation has been found between speech-language and the anatomically asymmetric pt. Foundas, et al. showed that language function can be localized to one region of the brain, as Broca had done before them, but they also supported the idea that one side of the brain is more involved with language than the other. The human brain has two hemispheres, and each one looks similar to the other; that is, it looks like one
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    Posterior commissure

    Posterior commissure

    The posterior commissure (also known as the epithalamic commissure) is a rounded band of white fibers crossing the middle line on the dorsal aspect of the upper end of the cerebral aqueduct. It is important in the bilateral pupillary light reflex. Its fibers acquire their medullary sheaths early, but their connections have not been definitively determined. Most of them have their origin in a nucleus, the nucleus of the posterior commissure (nucleus of Darkschewitsch), which lies in the central gray substance of the upper end of the cerebral aqueduct, in front of the oculomotor nucleus. Some are probably derived from the posterior part of the thalamus and from the superior colliculus, whereas others are believed to be continued downward into the medial longitudinal fasciculus. The posterior commissure interconnects the pretectal nuclei, mediating the consensual pupillary light reflex. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Ventricular system

    Ventricular system

    The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord. The system comprises four ventricles: There are several small holes or foramina that connect these ventricles, though only the first two of the list below are generally considered part of the ventricular system: The ventricles are filled with cerebrospinal fluid (CSF) which bathes and cushions the brain and spinal cord within their bony confines. Cerebrospinal fluid is produced by modified ependymal cells of the choroid plexus found in all components of the ventricular system except for the cerebral aqueduct and the posterior and anterior horns of the lateral ventricles. CSF flows from the lateral ventricles via the foramina of Monro into the third ventricle, and then the fourth ventricle via the cerebral aqueduct in the brainstem. From there it can pass into the central canal of the spinal cord or into the cisterns of the subarachnoid space via three small foramina: the central foramen of Magendie and the two lateral foramina of Luschka. The fluid then flows around the superior sagittal sinus to be reabsorbed via the arachnoid villi
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    Alveus of the hippocampus

    Alveus of the hippocampus

    The alveus of the hippocampus borders the wall of the lateral ventricle and is composed of white, myelinated fibers. The alveus arises from cell bodies in the subiculum and hippocampus, and eventually merges with the fimbria of the hippocampus. The fimbria goes on to become the fornix. These structures are part of the limbic system.
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    Band of Gennari

    Band of Gennari

    In the human brain, the stria of Gennari (also called the "band" or "line" of Gennari) is a band of myelinated axons projecting into layer 4B of the primary visual cortex from layer 4Cα. This formation is visible to the naked eye, and is coterminous with area V1. Although other species have areas which are designated primary visual cortex, some (if not all) lack a stria of Gennari.
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    Brodmann area 46

    Brodmann area 46

    Brodmann area 46, or BA46, is part of the frontal cortex in the human brain. It is between BA10 and BA45. BA46 is known as middle frontal area 46. In the human brain it occupies approximately the middle third of the middle frontal gyrus and the most rostral portion of the inferior frontal gyrus. Brodmann area 46 roughly corresponds with the dorsolateral prefrontal cortex (DLPFC), although the borders of area 46 are based on cytoarchitecture rather than function. The DLPFC also encompasses part of granular frontal area 9, directly adjacent on the dorsal surface of the cortex. Cytoarchitecturally, BA46 is bounded dorsally by the granular frontal area 9, rostroventrally by the frontopolar area 10 and caudally by the triangular area 45 (Brodmann-1909). There is some discrepancy between the extent of BA8 (Brodmann-1905) and the same area as described by Walker (1940) The DLPFC plays a role in sustaining attention and working memory. Lesions to the DLPFC impair short-term memory and cause difficulty inhibiting responses. Lesions may also eliminate much of the ability to make judgements about what's relevant and what's not as well as causing problems in organization. The DLPFC has
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    Brodmann area 48

    Retrosubicular area 48 is a subdivision of the cytoarchitecturally defined hippocampal region of the cerebral cortex. In the human it is located on the medial surface of the temporal lobe. Cytoarchitectually it is bounded rostrally by the perirhinal area 35 and medially by the presubiculum. While described by Brodmann (Brodmann-1909), it was not included in his areal maps of human cortex (Brodmann-1909; Brodmann-1910).
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    Caudate nucleus

    Caudate nucleus

    The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system. The caudate nuclei are located near the center of the brain, sitting astride the thalamus. There is a caudate nucleus within each hemisphere of the brain. Individually, they resemble a C-shape structure with a wider "head" (caput in Latin) at the front, tapering to a "body" (corpus) and a "tail" (cauda). Sometimes a part of the caudate nucleus is referred to as the "knee" (genu). The head and body of the caudate nucleus form part of the floor of the anterior horn of the lateral ventricle. After the body travels briefly towards the back of the head, the tail curves back toward the anterior, forming the roof of the inferior horn of the lateral ventricle. This means that a coronal (on a plane parallel to the face) section that cuts through the tail will also cross the body and head of the caudate nucleus. The caudate nucleus is related anatomically to a number of other structures. It is separated from the lenticular nucleus (made up of the globus pallidus and the putamen) by the anterior limb of the
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    Entorhinal cortex

    Entorhinal cortex

    The entorhinal cortex (EC) (ento = interior, rhino = nose, entorinal = interior to the rhinal sulcus) is located in the medial temporal lobe and functions as a hub in a widespread network for memory and navigation. The EC is the main interface between the hippocampus and neocortex. The EC-hippocampus system plays an important role in autobiographical/declarative/episodic memories and in particular spatial memories including memory formation, memory consolidation, and memory optimization in sleep. The EC is also responsible for the pre-processing (familiarity) of the input signals in the reflex nictitating membrane response of classical trace conditioning, the association of impulses from the eye and the ear occurs in the entorhinal cortex. In rodents, the EC is located at the caudal end of the temporal lobe. In primates it is located at the rostral end of the temporal lobe and stretches dorsolaterally. It is usually divided into medial and lateral regions with three bands with distinct properties and connectivity running perpendicular across the whole area. A distinguishing characteristic of the EC is the lack of cell bodies where layer IV should be; this layer is called the lamina
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    Mammillary body

    Mammillary body

    The mammillary bodies (mamillary bodies) are a pair of small round bodies, located on the undersurface of the brain, that, as part of the diencephalon form part of the limbic system. They are located at the ends of the anterior arches of the fornix. They consist of two groups of nuclei, the medial mammillary nuclei and the lateral mammillary nuclei. Neuroanatomists have often categorized the mammillary bodies as part of the hypothalamus. They are connected to other parts of the brain (as shown in the schematic, below left), and act as a relay for impulses coming from the amygdalae and hippocampi, via the mamillo-thalamic tract to the thalamus. This circuit, from amygdalae to mammillary bodies, and then on to the thalamus, is part of the larger 'Papez circuit'. They, along with the anterior and dorsomedial nuclei in the thalamus, are involved with the processing of recognition memory. They are believed to add the element of smell to memories. Damage to the mammillary bodies due to thiamine deficiency is implied in pathogenesis of Wernicke-Korsakoff syndrome. Symptoms include impaired memory, also called anterograde amnesia, suggesting that the mammillary bodies may be important for
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    Pituitary stalk

    Pituitary stalk

    The pituitary stalk (also known as the infundibular stalk or simply the infundibulum) is the connection between the hypothalamus and the posterior pituitary. It carries axons from the magnocellular neurosecretory cells of the hypothalamus down to the posterior pituitary where they release their hormones into the blood. This connection is called the hypothalamohypophyseal tract, and is responsible for the release of oxytocin and antidiuretic hormone. It has been thought that the pituitary stalk may become compressed due to suprasellar tumors in the pars tuberalis region, and that the resulting compression may cause hyperprolactinemia. This phenomenon has been described as the stalk effect or pituitary stalk compression syndrome. However, at least one article suggests that the increase in prolactin in these cases may instead be caused by the tumor's secretion of preprotachykinin A derived tachykinins, substance P, and/or neurokinin A.
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    Raphe nuclei

    Raphe nuclei

    The raphe nuclei ("raffe", Greek: ραφή = seam) are a moderate-size cluster of nuclei found in the brain stem. Their main function is to release serotonin to the rest of the brain. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets. The raphe nuclei are traditionally considered to be the medial portion of the reticular formation, and they appear as a ridge of cells in the center and most medial portion of the brain stem. In order from caudal to rostral, the raphe nuclei are known as the nucleus raphe obscurus, the raphe magnus, the raphe pontis, the raphe pallidus, the nucleus centralis superior, nucleus raphe dorsalis, nuclei linearis intermedius and linearis rostralis. Some scientists chose to group the linearis nuclei into one nucleus, shrinking the number of raphe to seven, e.g., NeuroNames makes the following ordering: These nuclei interact with almost every pertinent portion of the brain, but only a few of them have specifically independent interaction. These select nuclei are discussed as follows. Overall, the caudal raphe nuclei, including the raphe magnus, pallidus and raphe obscurus, all project
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    Temporopontine fibers

    Temporopontine fibers

    In the human nervous system the temporopontine fibers, a component of the corticopontine tract, are lateral to the cerebrospinal fibers; they originate in the temporal lobe and end in the nuclei pontis. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Brodmann area

    Brodmann area

    A Brodmann area is a region of the cerebral cortex defined based on its cytoarchitectonics, or structure and organization of cells. Brodmann areas were originally defined and numbered by the German anatomist Korbinian Brodmann based on the cytoarchitectural organization of neurons he observed in the cerebral cortex using the Nissl stain. Brodmann published his maps of cortical areas in humans, monkeys, and other species in 1909, along with many other findings and observations regarding the general cell types and laminar organization of the mammalian cortex. (The same Brodmann area number in different species does not necessarily indicate homologous areas.) A similar, but more detailed cortical map was published by Constantin von Economo and Georg N. Koskinas in 1925. Brodmann areas have been discussed, debated, refined, and renamed exhaustively for nearly a century and remain the most widely known and frequently cited cytoarchitectural organization of the human cortex. Many of the areas Brodmann defined based solely on their neuronal organization have since been correlated closely to diverse cortical functions. For example, Brodmann areas 1, 2 and 3 are the primary somatosensory
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    Claustrum

    Claustrum

    The claustrum is a thin, irregular, sheet of neurons which is attached to the underside of the neocortex in the center of the brain. It is suspected to be present in the brains of all mammals. The claustrum is a fraction of a millimetre to a few millimetres deep, and is a vertical curved sheet of subcortical gray matter oriented sagittally between the white matter tracts of the external capsule and extreme capsule. The claustrum is lateral to the putamen and medial to the insular cortex and is considered by some sources to be part of the basal ganglia. There are lateral and medial tracts connecting the claustrum to many parts of the cortex and perhaps to the hippocampus, the amygdala, and the caudate nucleus (connections with subcortical centers are a matter of debate). One of the interesting features of the claustrum is the uniformity in the types of cells, indicating a uniform type of processing by all claustral neurons. Though organized into modality specific regions, the claustrum contains a great deal of longitudinal connections between its neurons that could serve to synchronize the entire anterior-posterior extent of the claustrum. Francis Crick and Christof Koch have
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    146
    Falx cerebri

    Falx cerebri

    The falx cerebri, also known as the cerebral falx, so named from its sickle-like form, is a strong, arched fold of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres. It is narrow in front, where it is attached to the crista galli of the ethmoid; and broad behind, where it is connected with the upper surface of the tentorium cerebelli. Its upper margin is convex, and attached to the inner surface of the skull in the middle line, as far back as the internal occipital protuberance; it contains the superior sagittal sinus. Its lower margin is free and concave, and contains the inferior sagittal sinus. The falx cerebri is known to calcify with age. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Lateral apertures

    The lateral aperture is a paired structure in human anatomy. It is an opening in each lateral extremity of the lateral recess of the fourth ventricle of the human brain, which also has a single median aperture. The two lateral apertures provide a conduit for cerebrospinal fluid to flow from the brain's ventricular system into the subarachnoid space; specifically into the cerebellopontine angle. The structure is also called the lateral aperture of the fourth ventricle or the foramen of Luschka after anatomist Hubert von Luschka. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Projection fibers

    The projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. The principal efferent strands are: The chief afferent fibers are: This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Rhombencephalon

    Rhombencephalon

    The rhombencephalon (or hindbrain) is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla, pons, and cerebellum. The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres. In the human embryo eight rhombomeres can be distinguished, from caudal to rostral: Rh7-Rh1 and the isthmus (a borderline between midbrain and hindbrain in the most rostral part of the rhombomeres). A rare disease of the rhombencephalon, "rhombencephalosynapsis," is characterized by a missing vermis resulting in a fused cerebellum. Patients generally present with cerebellar ataxia. The caudal rhombencephalon has been generally considered as the initiation site for neural tube closure. Rhombomeres Rh7-Rh4 form the myelencephalon. The myelencephalon forms the medulla oblongata in the adult brain; it contains: Rhombomeres Rh3-Rh1 form the metencephalon. The metencephalon is composed of the pons and the cerebellum; it contains: The hindbrain is homologous to a part of the arthropod brain known as the sub-oesophageal ganglion. On this basis, it has been suggested that the hindbrain first evolved in the
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    Trigeminal nerve nuclei

    Trigeminal nerve nuclei

    The sensory trigeminal nerve nuclei are the largest of the cranial nerve nuclei, and extend through the whole of the midbrain, pons and medulla. The nucleus is divided into three parts, from rostral to caudal (top to bottom in humans): The spinal trigeminal nucleus is further subdivided into three parts, from rostral to caudal: There is also a distinct trigeminal motor nucleus that is medial to the chief sensory nucleus.
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    Anterior perforated substance

    Anterior perforated substance

    The anterior perforated substance is an irregularly quadrilateral area in front of the optic tract and behind the olfactory trigone, from which it is separated by the fissure prima; medially and in front, it is continuous with the subcallosal gyrus; it is bounded laterally by the lateral stria of the olfactory tract and is continued into the uncus. Its gray substance is confluent above with that of the corpus striatum, and is perforated anteriorly by numerous small blood vessels that supply such areas as the internal capsule. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    152
    Brodmann area 45

    Brodmann area 45

    Brodmann area 45 (BA45), is part of the frontal cortex in the human brain. Situated on the lateral surface, inferior to BA9 and adjacent to BA46. This area is also known as pars triangular (of the inferior frontal gyrus). In the human, it occupies the triangular part of inferior frontal gyrus (H) and, surrounding the anterior horizontal limb of lateral sulcus (H), a portion of the orbital part of inferior frontal gyrus (H). Bounded caudally by the anterior ascending limb of lateral sulcus (H), it borders on the insula in the depth of the lateral sulcus. In terms of cytoarchitecture, it is bounded caudally by the opercular area 44 (BA44), rostrodorsally by the middle frontal area 46 (BA46), and ventrally by the orbital area 47 (BA47) (Brodmann-1909). Together with BA 44, it comprises Broca's area, a region that is active in semantic tasks, such as semantic decision tasks (determining whether a word represents an abstract or a concrete entity) and generation tasks (generating a verb associated with a noun). The precise role of BA45 in semantic tasks remains controversial. For some researchers, its role would be to subserve semantic retrieval or semantic working memory processes.
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    Cochlear nuclei

    Cochlear nuclei

    The cochlear nuclei (CN) are two heterogeneous collections of neurons in the mammalian brainstem that receive input from the cochlear nerve, which carry sound information from the cochleae. The outputs from the CN are to higher regions of the auditory brainstem. The CN is located at the dorso-lateral side of the brainstem, spanning the junction of the pons and medulla. Each CN can be anatomically divided into 2 regions: The ventral cochlear nucleus is further divided into the posteroventral cochlear nucleus (PVCN) and the anteroventral cochlear nucleus (AVCN). The major input to the cochlear nucleus is from the auditory nerve, a part of Cranial nerve VIII (the vestibulocochlear nerve). The auditory nerve fibers form a highly organized system of connections according to their peripheral innervation of the cochlea. Axons from the spiral ganglion cells of the lower frequencies innervate the lateral-ventral portions of the dorsal cochlear nucleus and the ventrolateral portions of the anteroventral cochlear nucleus. In contrast, the axons from the higher frequency organ of corti hair cells project to the dorsal portion of the anteroventral cochlear nucleus and the dorsal-medial portions
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    Falx cerebelli

    Falx cerebelli

    The falx cerebelli is a small triangular process of dura mater, received into the posterior cerebellar notch. Its base is attached, above, to the under and back part of the tentorium cerebelli; its posterior margin, to the lower division of the vertical crest on the inner surface of the occipital bone. As it descends, it sometimes divides into two smaller folds, which are lost on the sides of the foramen magnum. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Inferior temporal gyrus

    Inferior temporal gyrus

    The inferior temporal gyrus is placed below the middle temporal sulcus, and is connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface of the temporal lobe, where it is limited by the inferior sulcus. This region is one of the higher levels of the ventral stream of visual processing, associated with the representation of complex object features, such as global shape. It may also be involved in face perception.
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    Interthalamic adhesion

    Interthalamic adhesion

    The medial surface of the thalamus constitutes the upper part of the lateral wall of the third ventricle, and is connected to the corresponding surface of the opposite thalamus by a flattened gray band, the Interthalamic adhesion (massa intermedia, middle commissure, gray commissure). In non-human mammals it is a large structure. In humans this mass averages about 1 cm in length in its antero-posterior diameter. It sometimes consists of two parts and occasionally is absent. The interthalamic adhesion is found in 70-80% of humans. It is present more often in females and larger than in males by an average of 53 percent. When absent in development, no noticeable deficit has been observed. It contains nerve cells and nerve fibers; a few of the latter may cross the middle line, but most of them pass toward the middle line and then curve laterally on the same side. It is still uncertain whether the interthalamic adhesion contains fibers that cross the mid-line and for this reason it is inappropriate to call it a commissure. In 1889, a Portuguese anatomist by the name of Macedo examined 215 brains, showing that male humans are approximately twice as likely to lack an interthalamic
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    Septum pellucidum

    Septum pellucidum

    The septum pellucidum (also called the septum lucidum), and not to be confused with the medial septum, is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the fornix. The septum pellucidum actually consists of two layers or laminae of both white and gray matter, called the laminae septi pellucidi. During fetal development there is a space between the two laminae called the cavum septum pellucidum which, in ninety per cent of cases, disappears during infancy. The cavum is occasionally referred to as the fifth ventricle but the term has lost favor in recent years, as the space is usually not continuous with the ventricular system. Indeed fifth ventricle has been used for other purposes in recent years. The septum pellucidum is located in the midline of the brain, between the two cerebral hemispheres. It is attached inferior to the corpus callosum, the large collection of nerve fibers that connect the two cerebral hemispheres. It is attached to the anterior part of the fornix, and on either side of the structure are the two lateral ventricles. The septum
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    Brodmann area 15

    Brodmann Area 15 is one of Brodmann's subdivisions of the cerebral cortex in the brain. Area 15 was defined by Brodmann in the guenon monkey, but he found no equivalent structure in humans. However, functional imaging experiments have found structures that may be homologous. Area 15 is located in the part of the insula nearest the temporal lobe and part of the anterior temporal lobe facing the insula. It is buried in the Sylvian Fissure and thus not visible on the surface of the brain without dissection. Area 15, like all Brodmann areas, is defined on the basis of cytoarchitecture of the region of cortex. The cortex in area 15 is thinner than in the rest of the insula and temporal lobe. The molecular layer (I) is unusually wide; the external granular layer (II) and the external pyramidal layer (III) are less dense, and the internal granular layer (IV) is totally absent, so that the medium-sized pyramidal cells of layer III and the internal pyramidal layer (V) merge with a few isolated granular cells scattered at their boundary. The multiform layer (VI) divides into a more densely cellular outer sublayer (VIa) and a less dense inner sublayer (VIb). As in Brodmann area 14, the
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    159
    Brodmann area 30

    Brodmann area 30

    Brodmann area 30, also known as agranular retrolimbic area 30, is a subdivision of the cytoarchitecturally defined retrosplenial region of the cerebral cortex. In the human it is located in the isthmus of cingulate gyrus. Cytoarchitecturally it is bounded internally by the granular retrolimbic area 29, dorsally by the ventral posterior cingulate area 23 and ventrolaterally by the ectorhinal area 36 (Brodmann-1909).
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    Brodmann area 36

    Brodmann area 36

    Ectorhinal area 36 is a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. With its medial boundary corresponding approximately to the rhinal sulcus it is located primarily in the fusiform gyrus. Cytoarchitecturally it is bounded laterally and caudally by the inferior temporal area 20, medially by the perirhinal area 35 and rostrally by the temporopolar area 38 (H) (Brodmann-1909). Together with Brodmann area 35, it comprises the perirhinal cortex.
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    Cingulate sulcus

    Cingulate sulcus

    The cingulate sulcus is a sulcus (brain fold) on the medial wall of the cerebral cortex. The frontal and parietal lobes are separated by the cingulate sulcus from the cingulate gyrus.
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    Cranial nerve nucleus

    Cranial nerve nucleus

    A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with. All the nuclei except that of the IV nerve supply nerves of the same side of the body. Just as grey matter in the ventral (closer to front of a human) spinal cord tends to be efferent (motor) fibers, and the dorsal horn tends to contain afferent (sensory) neurons, nuclei in the brainstem are arranged in an analogous way. There are several cranial nerve nuclei (roman numeral refers to the cranial nerve number):
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    Frontopontine fibers

    Frontopontine fibers

    The frontopontine fibers are situated in the medial fifth of the base of the cerebral peduncles; they arise from the cells of the frontal lobe and end in the nuclei of the pons. The frontopontine tract (tractus frontopontinus) refers to the combination of the fibers. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Midbrain tectum

    Midbrain tectum

    The tectum (Latin: roof) is a region of the brain, specifically the dorsal part of the mesencephalon (midbrain). This is contrasted with the tegmentum, which refers to the region ventral to the ventricular system. The tectum is responsible for auditory and visual reflexes. It is derived in embryonic development from the alar plate of the neural tube. In adult humans, it only consists of the inferior and the superior colliculi. Both colliculi also have descending projections to the paramedian pontine reticular formation and spinal cord, and thus can be involved in responses to stimuli faster than cortical processing would allow. Collectively the colliculi are referred to as the corpora quadrigemina. The term "tectal plate" (or "quadrigeminal plate") is used to describe the junction of the gray and white matter in the embryo. (NeuroNames ancil-453)
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    Brodmann area 18

    Brodmann area 18

    Brodmann area 18, or BA18, is part of the occipital cortex in the human brain. It accounts for the bulk of the volume of the occipital lobe. It is known as a "Visual Association Area" and is responsible for the interpretation of images. This area is also known as parastriate area 18. It is a subdivision of the cytoarchitecturally defined occipital region of cerebral cortex. In the human it is located in parts of the cuneus, the lingual gyrus and the lateral occipital gyrus (H) of the occipital lobe. Cytoarchitecturally it is bounded on one side by the Brodmann area 17, from which it is distinguished by absence of a band of Gennari, and on the other by the peristriate area 19 (Brodmann-1909). Brodmann area 18 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is topographically and cytoarchitecturally homologous to parastriate area 18 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): a wide, dense internal granular cell layer (IV); a distinct sublayer 3b of closely packed large pyramidal cells positioned in the external pyramidal layer (III) directly above layer IV; an almost cell free, narrow internal pyramidal layer
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    Brodmann area 40

    Brodmann area 40

    Brodmann area 40, or BA40, is part of the parietal cortex in the human brain. The inferior part of BA40 is in the area of the supramarginal gyrus, which lies at the posterior end of the lateral fissure, in the inferior lateral part of the parietal lobe. It is bounded approximately by the intraparietal sulcus, the inferior postcentral sulcus, the posterior subcentral sulcus and the lateral sulcus. Cytoarchitecturally it is bounded caudally by the angular area 39 (H), rostrally and dorsally by the caudal postcentral area 2, and ventrally by the subcentral area 43 and the superior temporal area 22 (Brodmann-1909). Cytoarchitectonically defined subregions of rostral BA40/the supramarginal gyrus are PF, PFcm, PFm, PFop, and PFt. Area PF is the homologue to macaque area PF, part of the mirror neuron system, and active in humans during imitation. The supramarginal gyrus part of Brodmann area 40 is the region in the inferior parietal lobe that is involved in reading both in regards to meaning and phonology.
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    Posterior perforated substance

    Posterior perforated substance

    The depressed area between the crura is termed the interpeduncular fossa, and consists of a layer of gray matter, the posterior perforated substance, which is pierced by small apertures for the transmission of blood vessels; its lower part lies on the ventral aspect of the medial portions of the tegmenta, and contains a nucleus named the interpeduncular ganglion; its upper part assists in forming the floor of the third ventricle. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Terminal stria

    Terminal stria

    The stria terminalis (or terminal stria) is a structure in the brain consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus. Serving as a major output pathway of the amygdala, the stria terminalis runs from its corticomedial division to the ventral medial nucleus of the hypothalamus. The stria terminalis covers the thalamostriate vein, marking a line of separation between the thalamus and the caudate nucleus as seen upon gross dissection of the ventricles of the brain, viewed from the superior aspect. The stria terminalis extends from the region of the interventricular foramen to the temporal horn of the lateral ventricle, carrying fibers from the amygdala to the septal nuclei, hypothalamic, and thalamic areas of the brain. It also carries fibers projecting from these areas back to the amygdala. The activity of the bed nucleus of the stria terminalis correlates with anxiety in response to threat monitoring. It is thought to act as a relay site within the hypothalamic-pituitary-adrenal axis and regulate its activity in response to acute stress. It is also thought to promote behavioral inhibition in response to unfamiliar
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    Brain stem

    Brain stem

    In vertebrate anatomy the brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. It is usually described as including the medulla oblongata (myelencephalon), pons (part of metencephalon), and midbrain (mesencephalon). Less frequently, parts of the diencephalon are included. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves. Though small, this is an extremely important part of the brain as the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body pass through the brain stem. This includes the corticospinal tract (motor), the posterior column-medial lemniscus pathway (fine touch, vibration sensation and proprioception) and the spinothalamic tract (pain, temperature, itch and crude touch). The brain stem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle. The brain stem has many basic functions including heart rate, breathing, sleeping and eating. 1. Conduit
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    Brodmann area 16

    Brodmann area 16 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is a relatively undifferentiated cortical area that Brodmann regarded as part of the insula because of the relation of its innermost multiform layer (VI) with the claustrum (VICl). The laminar organization of cortex is almost totally lacking. The molecular layer (I) is wide as in area 15 of Brodmann-1905. The space between layer I and layer VI is composed of a mixture of pyramidal cells and spindle cells with no significant number of granule cells. Pyramidal cells clump in the outer part to form glomeruli similar to those seen in some of the primary olfactory areas (Brodmann-1905). This term also refers to an area known as peripaleocortical claustral - a cytoarchitecturally defined (agranular) portion of the insula at its rostral extreme where it approaches most closely the claustrum and the prepyriform area (Stephan-76).
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    Brodmann area 21

    Brodmann area 21

    Brodmann area 21, or BA21, is part of the temporal cortex in the human brain. The region encompasses most of the lateral temporal cortex, a region believed to play a part in auditory processing and language. Language function is left lateralized in most individuals. BA21 is superior to BA20 and inferior to BA40 and BA41. This area is also known as middle temporal area 21. It is a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. In the human it corresponds approximately to the middle temporal gyrus. It is bounded rostrally by the temporopolar area 38 (H), ventrally by the inferior temporal area 20, caudally by the occipitotemporal area 37 (H), and dorsally by the superior temporal area 22 (Brodmann-1909). Brodmann area 21 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous to the middle temporal area 21 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): Compared to area 20 of Brodmann-1909, the total cortical thickness of area 21 is greater, the granular cells are less abundant, and the boundary with the subcortical white matter is less distinct; the
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    Brodmann area 32

    Brodmann area 32

    The Brodmann area 32, also known in the human brain as the dorsal anterior cingulate area 32, refers to a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. In the human it forms an outer arc around the anterior cingulate gyrus. The cingulate sulcus defines approximately its inner boundary and the superior rostral sulcus (H) its ventral boundary; rostrally it extends almost to the margin of the frontal lobe. Cytoarchitecturally it is bounded internally by the ventral anterior cingulate area 24, externally by medial margins of the agranular frontal area 6, intermediate frontal area 8, granular frontal area 9, frontopolar area 10, and prefrontal area 11-1909. (Brodmann19-09). Dorsal region of anterior cingulate gyrus is associated with rational thought processes, most notably active during the Stroop task. In the guenon Brodmann area 32 is a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. This area was named 25 in Brodmann-1905 and labeled 25 in a figure contributed by Brodmann in Mauss-1908. In Brodmann-1909, however, the area was labeled 32 and the name "area 25" was attached to the area that has since been the
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    Brodmann area 38

    Brodmann area 38

    Brodmann area 38, also BA38 or temporopolar area 38 (H), is part of the temporal cortex in the human brain. BA 38 is at the anterior end of the temporal lobe, known as the temporal pole. BA38 is a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. It is located primarily in the most rostral portions of the superior temporal gyrus and the middle temporal gyrus. Cytoarchitecturally it is bounded caudally by the inferior temporal area 20, the middle temporal area 21, the superior temporal area 22 and the ectorhinal area 36 (Brodmann-1909). Cytoarchitectonic and chemoarchitectonic studies find that it contains at least seven subareas, one of which, "TG", is unique to humans. "The functional significance of this area TG is not known, but it may bind complex, highly processed perceptual inputs to visceral emotional responses." This area is among the earliest affected by Alzheimer's disease and the earliest involved at the start of temporal lobe seizures.
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    Cingulum

    Cingulum

    In neuroanatomy, the cingulum is a collection of white matter fibers projecting from the cingulate gyrus to the entorhinal cortex in the brain, allowing for communication between components of the limbic system. It forms the white matter core of the cingulate gyrus, following it from the subcallosal gyrus of the frontal lobe beneath the rostrum of corpus callosum to the parahippocampal gyrus and uncus of the temporal lobe. Cingulotomy, the surgical severing of the cingulum, is a form of psychosurgery used to treat depression and OCD.
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    Lateral ventricles

    Lateral ventricles

    The lateral ventricles are part of the ventricular system of the brain. Classified as part of the telencephalon, they are the largest of the ventricles. The lateral ventricles connect to the central third ventricle through the interventricular foramen of Monro. The volume of the lateral ventricles are known to increase with age. They are also enlarged in a number of neurological conditions and are on average larger in patients with schizophrenia, bipolar disorder, major depressive disorder and Alzheimer's disease. Each lateral ventricle has three horns: The body of the lateral ventricle is the central portion, just posterior to the frontal horn. The trigone of the lateral ventricle is a triangular area defined by the temporal horn inferiorly, the occipital horn posteriorly, and the body of the lateral ventricle anteriorly. The cella media is the central part of the lateral ventricle. Ependyma cover the inside of the lateral ventricles and are epithelial cells. The lateral ventricles, similarly to other parts of the ventricular system of the brain, develop from the central canal of the neural tube. Specifically, the lateral ventricles originate from the portion of the tube that is
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    Thalamus

    Thalamus

    The thalamus (from Greek θάλαμος, "inner chamber") is a midline symmetrical structure within the brains of vertebrates including humans, situated between the cerebral cortex and midbrain. Its function includes relaying sensory and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep, and alertness. The thalamus surrounds the third ventricle. It is the main product of the embryonic diencephalon. The thalamus is perched on top of the brainstem, near the center of the brain, with nerve fibers projecting out to the cerebral cortex in all directions. The medial surface of the thalamus constitutes the upper part of the lateral wall of the third ventricle, and is connected to the corresponding surface of the opposite thalamus by a flattened gray band, the Interthalamic adhesion. Both parts of this structure of the brain in the human are each about the size and shape of a walnut. These are about three centimetres in length, at the widest part 2.5 centimetres across and about 2 centimetres in height (the nut relative to an unshelled nut with the nut-shell join in the horizontal plane). The two halves of the thalamus are prominent bulb-shaped masses, about
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    Uncus

    Uncus

    The anterior extremity of the Parahippocampal gyrus is recurved in the form of a hook, the uncus, which is separated from the apex of the temporal lobe by a slight fissure, the incisura temporalis. Although superficially continuous with the hippocampal gyrus, the uncus forms morphologically a part of the rhinencephalon. The term uncus was coined by Felix Vicq d’Azyr (1748–1794). The part of the olfactory cortex that is on the temporal lobe covers the area of the uncus, which leads into the two significant clinical aspects of the uncus: uncinate fits and uncal herniations. The landmark that helps you find the amygdala during a coronal section of the brain. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    6.50
    2 votes
    178
    Brodmann area 24

    Brodmann area 24

    Brodmann area 24 is part of the anterior cingulate in the human brain. In the human this area is known as ventral anterior cingulate area 24, and it refers to a subdivision of the cytoarchitecturally defined cingulate cortex region of cerebral cortex (area cingularis anterior ventralis). It occupies most of the anterior cingulate gyrus in an arc around the genu of corpus callosum. Its outer border corresponds approximately to the cingulate sulcus. Cytoarchitecturally it is bounded internally by the pregenual area 33, externally by the dorsal anterior cingulate area 32, and caudally by the ventral posterior cingulate area 23 and the dorsal posterior cingulate area 31. Francis Crick, one of the discoverers of DNA, listed area 24 as the seat of free will because of its centrality in abulia and amotivational syndromes. In the guenon this area is referred to as area 24 of Brodmann-1905. It includes portions of the cingulate gyrus and the frontal lobe. The cortex is thin; it lacks the internal granular layer (IV) so that the densely distributed, plump pyramidal cells of sublayer 3b of the external pyramidal layer (III) merge with similar cells of the internal pyramidal layer (V); the
    4.75
    4 votes
    179

    Brodmann area 14

    Brodmann Area 14 is one of Brodmann's subdivisions of the cerebral cortex in the brain. It was defined by Brodmann in the guenon monkey . No equivalent structure exists in humans. Brodmann areas were defined based on cytoarchitecture rather than function. Area 14 differs most clearly from Brodmann area 13-1905 in that it lacks a distinct internal granular layer (IV). Other differences are a less distinct external granular layer (II), a widening of the relatively cell-free zone of the external pyramidal layer (III); cells in the internal pyramidal layer (V) are denser and rounded; and the cells of the multiform layer (VI) assume a more distinct tangential orientation Area 14 is believed to serve as association cortex for the visceral senses and olfaction along with Area 13. They also serve to aggregate autonomic information.
    5.33
    3 votes
    180
    Subcallosal area

    Subcallosal area

    The subcallosal area (parolfactory area of Broca) is a small triangular field on the medial surface of the hemisphere in front of the subcallosal gyrus, from which it is separated by the posterior parolfactory sulcus; it is continuous below with the olfactory trigone, and above and in front with the cingulate gyrus; it is limited anteriorly by the anterior parolfactory sulcus. The subcallosal area is also known as "Zuckerkandl's gyrus", for Emil Zuckerkandl. The parahippocampal gyrus, subcallosal area, and cingulate gyrus have been described together as the periarcheocortex. The "subcallosal area" and "parolfactory area" are considered equivalent in BrainInfo, but in Terminologia Anatomica they are considered distinct structures. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.33
    3 votes
    181
    Anterior proper fasciculus

    Anterior proper fasciculus

    Anterior proper fasciculus, fasciculus proprius, or fasiculus proprii (anterior basis bundle) is the remaining fibers of the anterior funiculus. It consists of This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    7.00
    1 votes
    182
    Brodmann area 26

    Brodmann area 26

    Brodmann area 26 is the name for a small part of the brain. In the human this area is called ectosplenial area 26. It is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. It is a narrow band located in the isthmus of cingulate gyrus adjacent to the fasciolar gyrus internally. It is bounded externally by the granular retrolimbic area 29 (Brodmann-1909). In the guenon Brodmann area 26 is a subdivision of the cerebral cortex defined on the basis of cytoarchitecture. The smallest of Brodmann's cortical areas in the monkey, it represents cortex that is less differentiated and smaller in monkey and human than in other species. Brodmann regarded it as topographically and cytoarchitecturally homologous to the combined human ectosplenial area 26, granular retrolimbic area 29 and agranular retrolimbic area 30 (Brodmann-1909). Distinctive features (Brodmann-1905): thin cortex; distinct but narrow layers.
    7.00
    1 votes
    183
    Edinger-Westphal nucleus

    Edinger-Westphal nucleus

    The Edinger–Westphal nucleus is the accessory parasympathetic cranial nerve nucleus of the oculomotor nerve (cranial nerve III), supplying the constricting muscles of the iris. Alternatively, the Edinger–Westphal nucleus is a term often used to refer to the adjacent population of non-preganglionic neurons that do not project to the ciliary ganglion, but rather project to the spinal cord, dorsal raphe nucleus, and lateral septal nuclei. Unlike the classical preganglionic Edinger–Westphal neurons that contain choline acetyltransferase, neurons of the non-preganglionic Edinger–Westphal nucleus contain various neuropeptides, such as Urocortin and cocaine- and amphetamine-regulated transcript. Previously, it had been proposed to rename this group of non-preganglionic, neuropeptide-containing neurons to perioculomotor subgriseal neuronal stream, abbreviated pIIISG. However, more recently, a final nomenclature has been determined. Preganglionic oculomotor neurons within the Edinger–Westphal nucleus shall be referred to as the EWpg, and the neuropeptide-containing neurons shall be known as the centrally-projecting Edinger Westphal nucleus, or EWcp. The paired nuclei are posterior to the
    7.00
    1 votes
    184
    Olfactory bulb

    Olfactory bulb

    The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors. In most vertebrates, the olfactory bulb is the most rostral (forward) part of the brain. In humans, however, the olfactory bulb is on the inferior (bottom) side of the brain. The olfactory bulb is supported and protected by the cribriform plate of the ethmoid bone, which in mammals separates it from the olfactory epithelium, and which is perforated by olfactory nerve axons. The bulb is divided into two distinct structures: the main olfactory bulb and the accessory olfactory bulb. The main olfactory bulb has a multi-layered cellular architecture. In order from surface to the center the layers are The olfactory bulb transmits smell information from the nose to the brain, and is thus necessary for a proper sense of smell. As a neural circuit, the glomerular layer receives direct input from olfactory nerves, made up of the axons from approximately ten million olfactory receptor neurons in the olfactory mucosa, a region of the nasal cavity. The ends of the axons cluster in spherical structures known as glomeruli such that each glomerulus receives input primarily from olfactory
    7.00
    1 votes
    185
    Pons

    Pons

    The pons (pronounced /ˈpɔnz/) is a structure located on the brain stem, named after the Latin word for "bridge" or the 16th-century Italian anatomist and surgeon Costanzo Varolio (pons Varolii). It is cranial to the medulla oblongata, caudal to the midbrain, and ventral to the cerebellum. In humans and other bipeds, this means it is above the medulla, below the midbrain, and anterior to the cerebellum. This white matter includes tracts that conduct signals from the cerebrum down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus. The pons in humans measures about 2.5 cm in length. Most of it appears as a broad anterior bulge rostral to the medulla. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. They connect the cerebellum to the pons and midbrain. The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture. Within the pons is the pneumotaxic center, a nucleus in the pons that regulates the
    7.00
    1 votes
    186
    Brodmann area 10

    Brodmann area 10

    Brodmann area 10, or BA10 is the frontopolar part of the frontal cortex in the human brain. BA10 was originally defined in terms of cytoarchitectonic traits in autopsy brains; modern functional imaging research cannot directly identify these boundaries and the terms anterior prefrontal, rostral prefrontal cortex and frontopolar prefrontal cortex are used to refer to the area in the most anterior part of the frontal cortex that approximates to or principally covers BA10. BA10 is the largest cytoarchitectonic area in the human brain. It has been described as "one of the least well understood regions of the human brain". Present research suggests that it is involved in strategic processes in memory retrieval and executive function. During human evolution, the functions in this area resulted in its expansion relative to the rest of the brain. The volume of the human area 10 is 14 cm and 1.2% of brain volume. This is twice what would be expected in a hominoid with a human sized brain. For comparison the volume of bonobo area 10 is 2.8 cm3 and makes up only 0.74% of its brain. In each hemisphere, area 10 contains an estimated 250 million neurons. This area is a subdivision of the
    6.00
    2 votes
    187
    Brodmann area 5

    Brodmann area 5

    Brodmann area 5 is one of Brodmann's cytologically defined regions of the brain. It is involved in somatosensory processing and association. Brodmann area 5 is part of the parietal cortex in the human brain. It is situated immediately posterior to the primary somatosensory areas (Brodmann areas 3, 1, and 2), and anterior to Brodmann area 7. In guenon Brodmann area 5 is a subdivision of the parietal lobe defined on the basis of cytoarchitecture. It occupies primarily the superior parietal lobule. Brodmann-1909 considered it topologically and cytoarchitecturally homologous to the preparietal area 5 of the human. Distinctive features (Brodmann-1905): compared to area 4 of Brodmann-1909 area 5 has a thick self-contained internal granular layer (IV); lacks a distinct internal pyramidal layer (V); has a marked sublayer 3b of pyramidal cells in the external pyramidal layer (III); has a distinct boundary between the internal pyramidal layer (V) and the multiform layer (VI); and has ganglion cells in layer V beneath its boundary with layer IV that are separated from layer VI by a wide clear zone. In the macaque monkey the area PE corresponds to BA5.
    6.00
    2 votes
    188
    Lateral lemniscus

    Lateral lemniscus

    The lateral lemniscus is a tract of axons in the brainstem that carries information about sound from the cochlear nucleus to various brainstem nuclei and ultimately the contralateral inferior colliculus of the midbrain. Three distinct, primarily inhibitory, cellular groups are located interspersed within these fibers, and are thus named the nuclei of the lateral lemniscus. The brainstem nuclei include: Fibers leaving these brainstem nuclei ascending to the inferior colliculus rejoin the lateral lemniscus. In that sense, this is not a 'lemniscus' in the true sense of the word (second order, decussated sensory axons), as there is third (and out of the lateral superior olive, fourth) order information coming out of some of these brainstem nuclei. The lateral lemniscus is located where the cochlear nuclei and the pontine reticular formation (PRF) crossover. The PRF descends the reticulospinal tract where it innervates motor neurons and spinal interneurons. It is the main auditory tract in the brainstem that connects the superior olivary complex (SOC) with the inferior colliculus (IC). The dorsal cochlear nucleus (DCN) has input from the LL and output to the contralateral LL via the
    6.00
    2 votes
    189
    Median aperture

    Median aperture

    The median aperture ('"medial aperture," "Foramen of Magendie"') drains CSF from the fourth ventricle into the cisterna magna. The two other openings of the fourth ventricle are lateral apertures (foramina of Luschka), one on the left and one on the right, which drain cerebrospinal fluid into the cerebellopontine angle cistern. The median foramen on axial images is posterior to the pons and anterior to the caudal cerebellum. It is surrounded by the obex and gracile tubercles of the medulla, tela choroidea of the fourth ventricle and its choroid plexus, which is attached to the cerebellar vermis.]]. The Foramen of Magendie is named for François Magendie, who first described it.
    6.00
    2 votes
    190
    Midbrain tegmentum

    Midbrain tegmentum

    The midbrain tegmentum is the part of the midbrain extending from the substantia nigra to the cerebral aqueduct in a horizontal section of the midbrain. It forms the floor of the midbrain that surrounds the cerebral aqueduct.
    6.00
    2 votes
    191
    Nucleus raphe obscurus

    Nucleus raphe obscurus

    The nucleus raphes obscurus, despite the implications of its name, has some very specific functions and connections of afferent and efferent nature. The nucleus raphes obscurus projects to the cerebellar lobes VI and VII and to crus II along with the nucleus raphes pontis . This so called nucleus raphes obscurus has also been implicated in the modulation of the hypoglossal nerve. It has been observed that the ablation of this nucleus causes a change in the firing pattern in the XII nerve . In addition, the nucleus raphes obscurus mediates expiration via the effect of serotonin and depresses periodic synaptic potentials . It has also been shown that this nucleus stimulates gastrointestinal motor function; microinjections of 5-HT into the nucleus raphes obscurus increase gastric movement .
    6.00
    2 votes
    192
    Tuber cinereum

    Tuber cinereum

    The tuber cinereum is a hollow eminence of gray matter situated between the mammillary bodies and the optic chiasm. The tuber cinereum is part of the hypothalamus. Laterally it is continuous with the anterior perforated substances and anteriorly with a thin lamina, the lamina terminalis. The infundibulum, a hollow conical process, projects from the tuber cinereum. The infundibulum extends forward and down where it is attached to the posterior lobe of the pituitary gland. It houses the nuclei: The tuberomammillary nucleus (TMN) is the sole source of histamine in the brain. By its release of histamine, the tuberomamillary nucleus of the tuber cinereum helps to regulate the circadian cycle. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    6.00
    2 votes
    193
    Cingulate cortex

    Cingulate cortex

    The cingulate cortex is a part of the brain situated in the medial aspect of the cortex. It includes the cortex of the cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe. It receives inputs from the thalamus and the neocortex, and projects to the entorhinal cortex via the cingulum. It is an integral part of the limbic system, which is involved with emotion formation and processing, learning, and memory. The combination of these three functions makes the cingulate gyrus highly influential in linking behavioral outcomes to motivation (e.g. a certain action induced a positive emotional response, which results in learning). This role makes the cingulate cortex highly important in disorders such as depression and schizophrenia. It also plays a role in executive function and respiratory control. Cingulum means belt in Latin. The name was likely chosen because this cortex, in great part, surrounds the corpus callosum. Cingulate is an adjective (cingularis or cingulatus). The cingulate cortex is a part of the "grand lobe limbique" of Broca (1898) that
    5.00
    3 votes
    194
    Obex

    Obex

    The obex (from the Latin for barrier) is the point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord. The obex occurs in the caudal medulla. The decussating of sensory fibers happens at this point. Hemangioblastoma has been observed in this location. Neurological surgical intervention in the treatment of syringomyelia or hydromyelia may involve plugging the obex to prevent the transmission of cerebrospinal fluid to the central canal of the spinal cord.
    4.25
    4 votes
    195
    Arcuate nucleus

    Arcuate nucleus

    In the medulla oblongata, the arcuate nucleus is a group of neurons located on the anterior surface of the medullary pyramids. They receive fibers from the corticospinal tract and send their axons through the anterior external arcuate fibers and striae medullares to the cerebellum via the inferior cerebellar peduncle. Arcuate nuclei are capable of chemosensitivity and have a proven role in controlling respiratory frequency.
    5.50
    2 votes
    196
    Diencephalon

    Diencephalon

    The diencephalon ("interbrain") is the region of the vertebrate neural tube which gives rise to posterior forebrain structures. In development, the forebrain develops from the prosencephalon, the most anterior vesicle of the neural tube which later forms both the diencephalon and the telencephalon. In adults, the Diencephalon appears at the upper end of the brain stem, situated between the cerebrum and the brain stem. It is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus and the epithalamus. The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to posterior forebrain structures including the thalamus, hypothalamus, posterior portion of the pituitary gland, and pineal gland. The hypothalamus performs numerous vital functions, most of which relate directly or indirectly to the regulation of visceral activities by way of other brain regions and the autonomic nervous system.
    5.50
    2 votes
    197
    Arcuate nucleus

    Arcuate nucleus

    The arcuate nucleus (or infundibular nucleus) is an aggregation of neurons in the mediobasal hypothalamus, adjacent to the third ventricle and the median eminence. The arcuate nucleus includes several important populations of neurons, including: neuroendocrine neurons, centrally-projecting neurons, and others. The arcuate nucleus also contains a population of specialized ependymal cells, called tanycytes.
    6.00
    1 votes
    198
    Brodmann area 25

    Brodmann area 25

    Brodmann area 25 (BA25) is an area in the cerebral cortex of the brain and delineated based on its cytoarchitectonic characteristics. It is also called the subgenual area, area subgenualis or subgenual cingulate. It is the 25th "Brodmann area" defined by Korbinian Brodmann (thus its name). BA25 is located in the cingulate region as a narrow band in the caudal portion of the subcallosal area adjacent to the paraterminal gyrus. The posterior parolfactory sulcus separates the paraterminal gyrus from BA25. Rostrally it is bound by the prefrontal area 11 of Brodmann. Brodmann described this area as it is labeled now in 1909. Originally in 1905, Brodmann labeled the area as part of area 24. In 1909, he divided the area into area 24 and 25. This region is extremely rich in serotonin transporters and is considered as a governor for a vast network involving areas like hypothalamus and brain stem, which influences changes in appetite and sleep; the amygdala and insula, which affect the mood and anxiety; the hippocampus, which plays an important role in memory formation; and some parts of the frontal cortex responsible for self-esteem. The subcallosal cingulate gyrus which consists of BA25 as
    6.00
    1 votes
    199
    Hypothalamus

    Hypothalamus

    The hypothalamus (from Greek ὑπό = under and θάλαμος = room, chamber) is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland (hypophysis). The hypothalamus is located below the thalamus, just above the brain stem. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is roughly the size of an almond. The hypothalamus is responsible for certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes certain neurohormones, often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones. The hypothalamus controls body temperature, hunger, thirst, fatigue, sleep, and circadian cycles. The hypothalamus is a brain structure composed of distinct nuclei and less anatomically distinct areas. It is found in all vertebrate nervous systems. In mammals, the axons of magnocellular neurosecretory cells of the paraventricular nucleus and
    6.00
    1 votes
    200
    Anterior hypothalamic nucleus

    Anterior hypothalamic nucleus

    The anterior hypothalamic nucleus is a nucleus of the hypothalamus. Its function is thermoregulation (cooling) of the body. Damage or destruction of this nucleus causes hyperthermia. The anterior hypothalamus plays a role in regulating sleep. The anterior hypothalamic region is sometimes grouped with the preoptic area.
    5.00
    2 votes
    201
    Commissural fibers

    Commissural fibers

    The commissural fibers or transverse fibers connect the two hemispheres of the brain. They include: In contrast to commissural fibers, association fibers connect regions within the same hemisphere of the brain. Projection fibers connect the lobe to other parts of the brain and the spinal cord. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.00
    2 votes
    202
    Globus pallidus

    Globus pallidus

    The globus pallidus (Latin for "pale globe") also known as paleostriatum, is a sub-cortical structure of the brain. It is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system. The globus pallidus is a major component of the basal ganglia core along with the striatum and its direct target, the substantia nigra. The latter are made up of similar neuronal elements, have similar afferents from the dorsal striatum and have a similar synaptology; neither receives cortical afferents. The origin of the name is not established. It was known by Dejerine (1906) but not by Santiago Ramón y Cajal (1909–1911). As the elements in no way have the shape of a globe, Foix and Nicolesco (1925), the Vogts (1941), Crosby et al. (1962) followed by the Terminologia anatomica proposed the simpler term (neuter adjective) of pallidum ("pale"). For a long time the globus pallidus was linked to the putamen and termed the lentiform nucleus (nucleus lenticularis or lentiformis), a heterogeneous anatomical entity that is part of the striatum rather than the pallidum. The link with the substantia nigra pars reticulata was
    5.00
    2 votes
    203
    Orbitofrontal cortex

    Orbitofrontal cortex

    The orbitofrontal cortex (OFC) is a prefrontal cortex region in the frontal lobes in the brain which is involved in the cognitive processing of decision-making. In non-human primates it consists of the association cortex areas Brodmann area 11, 12 and 13; in humans it consists of Brodmann area 10, 11 and 47 Because of its functions in emotion and reward, the OFC is considered by some to be a part of the limbic system. The OFC anatomically is defined as the part of the prefrontal cortex that receives projections from the magnocellular, medial nucleus of the mediodorsal thalamus. It gets its name from its position immediately above the orbits in which the eyes are located. Considerable individual variability has been found in the OFC of both humans and non-human primates. A related area is found in rodents. The human OFC is among the least-understood regions of the human brain; but it has been proposed that the OFC is involved in sensory integration, in representing the affective value of reinforcers, and in decision-making and expectation. In particular, the OFC seems to be important in signaling the expected rewards/punishments of an action given the particular details of a
    5.00
    2 votes
    204
    Cerebral peduncle

    Cerebral peduncle

    Mainly, the three common areas that give rise to the cerebral peduncles are the cortex, the spinal cord and the cerebellum. The cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum. The region includes the midbrain tegmentum, crus cerebri and pretectum. By this definition, the cerebral peduncles are also known as the basis pedunculi, while the large ventral bundle of efferent fibers is referred to as the crus cerebri or the pes pedunculi. There are numerous nerve tracts located within this section of the brainstem. Of note, in the cerebral peduncular loop fibers from motor areas of the brain project to the cerebral peduncle and then project to various thalamic nuclei. Important fibers running through the cerebral peduncles include the corticospinal tract and the corticobulbar tract, among others. This area contains many nerve tracts conveying motor information to and from the brain to the rest of the body.
    4.50
    2 votes
    205
    Frontal lobe

    Frontal lobe

    The frontal lobe is an area in the brain of mammals, located at the front of each cerebral hemisphere and positioned anterior to (in front of) the parietal lobe and superior and anterior to the temporal lobes. It is separated from the parietal lobe by a space between tissues called the central sulcus, and from the temporal lobe by a deep fold called the lateral (Sylvian) sulcus. The precentral gyrus, forming the posterior border of the frontal lobe, contains the primary motor cortex, which controls voluntary movements of specific body parts. The frontal lobe contains most of the dopamine-sensitive neurons in the cerebral cortex. The dopamine system is associated with reward, attention, short-term memory tasks, planning, and motivation. Dopamine tends to limit and select sensory information arriving from the thalamus to the fore-brain. A report from the National Institute of Mental Health says a gene variant that reduces dopamine activity in the prefrontal cortex is related to poorer performance and inefficient functioning of that brain region during working memory tasks, and to slightly increased risk for schizophrenia. On the lateral surface of the human brain, the central sulcus
    4.50
    2 votes
    206
    Prosencephalon

    Prosencephalon

    In the anatomy of the brain of vertebrates, the prosencephalon (or forebrain) is the rostral-most (forward-most) portion of the brain. The prosencephalon, the mesencephalon (midbrain), and rhombencephalon (hindbrain) are the three primary portions of the brain during early development of the central nervous system. It controls body temperature, reproductive functions, eating, sleeping, and any display of emotions. At the five-vesicle stage, the prosencephalon separates into the diencephalon (prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum) and the telencephalon (cerebrum). The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia. By 5 weeks in utero, it is visible as a single portion toward the front of the fetus. At 8 weeks in utero, the prosencephalon splits into the left and right cerebral hemispheres. When the embryonic prosencephalon fails to divide the brain into two lobes, it results in a condition known as holoprosencephaly.
    4.50
    2 votes
    207
    Cerebellar vermis

    Cerebellar vermis

    The cerebellar vermis (Latin for worm) is located in the medial, cortico-nuclear zone of the cerebellum, residing in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways. The cerebellum develops in a rostro-caudal manner, with rostral regions in the midline giving rise to the vermis, and caudal regions developing into the cerebellar hemispheres. By 4 months gestation, the vermis becomes fully foliated, while development of the hemispheres lags by 30–60 days. Postnatally, proliferation and organization of the cellular components of the cerebellum continues, with completion of the foliation pattern by 7 months of life and final migration, proliferation, and arborization of cerebellar neurons by 20 months. Inspection of the posterior fossa is a common feature of prenatal ultrasound and is used primarily to determine whether excess
    5.00
    1 votes
    208
    External capsule

    External capsule

    The external capsule is a series of white matter fiber tracts in the brain. These fibers run between the most lateral (toward the side of the head) segment of the lentiform nucleus and the claustrum. The external capsule is a route for cholinergic fibers from the basal forebrain to the cerebral cortex. The external capsule eventually joins the internal capsule around the lenticular nucleus.
    5.00
    1 votes
    209
    Lateral proper fasciculus

    Lateral proper fasciculus

    The lateral proper fasciculus (lateral basis bundle) constitutes the remainder of the lateral column, and is continuous in front with the anterior proper fasciculus. It consists chiefly of intersegmental fibers which arise from cells in the gray substance, and, after a longer or shorter course, reënter the gray substance and ramify in it. Some of its fibers are, however, continued upward into the brain under the name of the medial longitudinal fasciculus. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.00
    1 votes
    210
    Parietoöccipital fissure

    Parietoöccipital fissure

    Only a small part of the Parietooccipital Fissure ( parieto-occipital sulcus or Parietoöccipital fissure) is seen on the lateral surface of the hemisphere, its chief part being on the medial surface. The lateral part of the parietooccipital fissure (Fig. 726) is situated about 5 centimeters (cm) in front of the occipital pole of the hemisphere, and measures about 1.25 cm. in length. The medial part of the parietooccipital fissure (Fig. 727) runs downward and forward as a deep cleft on the medial surface of the hemisphere, and joins the calcarine fissure below and behind the posterior end of the corpus callosum. In most cases it contains a submerged gyrus. It marks the boundary between the cuneus and precuneus, and also between the parietal and occipital lobes. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.00
    1 votes
    211
    Substantia innominata

    Substantia innominata

    The substantia innominata (literally "unnamed substance") of Meynert is a stratum in the human brain consisting partly of gray and partly of white substance, which lies below the anterior part of the thalamus and lentiform nucleus. The gross anatomical structure is called the anterior perforated substance because, to the naked eye, it appears to be perforated by many holes (which are actually blood vessels). It is part of the basal forebrain and includes the nucleus basalis. It consists of three layers, superior, middle, and inferior. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
    5.00
    1 votes
    212
    Cuneate nucleus

    Cuneate nucleus

    One of the dorsal column nuclei, the cuneate nucleus is a wedge-shaped nucleus in the closed part of the medulla oblongata. It contains cells that give rise to the cuneate tubercle, visible on the posterior aspect of the medulla. It lies laterally to the gracile nucleus and medial to the spinal trigeminal nucleus in the medulla. The cuneate nucleus is part of posterior column-medial lemniscus pathway, carrying fine touch and proprioceptive information from the upper body (above T6, except the face and ear - the information from the face and ear is carried by the primary sensory trigeminal nucleus) to the contralateral thalamus via the medial lemniscus. It receives direct input from the mechanoreceptors of the upper body as well as indirect input from them via the spinal cord. It is also subject to descending control from the central nervous system. It may be affected by vitamin E deficiency exhibiting neuroaxonal swelling.
    4.00
    2 votes
    213
    Pars opercularis

    Pars opercularis

    In the human brain the Pars opercularis (literally "the part that covers") is the part of the inferior frontal gyrus that lies between the inferior precentral sulcus and the ascending ramus of the lateral sulcus. It is called opercularis because it covers part of the insula. The pars opercularis together with the pars triangularis form Broca's area.
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    Brodmann area 20

    Brodmann area 20

    Brodmann area 20, or BA20, is part of the temporal cortex in the human brain. The region encompasses most of the ventral temporal cortex, a region believed to play a part in high-level visual processing and recognition memory. This area is also known as inferior temporal area 20, and it refers to a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. In the human it corresponds approximately to the inferior temporal gyrus. Cytoarchitecturally it is bounded medially by the ectorhinal area 36 (H), laterally by the middle temporal area 21, rostrally by the temporopolar area 38 (H) and caudally by the occipitotemporal area 37 (H) (Brodmann-1909). Brodmann area 20 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous to the inferior temporal area 20 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): area 20 is similar to area 19 of Brodmann-1909 in the relative abundance of small cell types relative to the number of larger pyramidal cells; a very dense, wide internal granular layer (IV) composed almost exclusively of granule cells, as in area 18 of Brodmann-1909;
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    Brodmann area 35

    Brodmann area 35

    Brodmann area 35, together with Brodmann area 36, is most frequently referred to as perirhinal cortex. This area is known as perirhinal area 35. It is a subdivision of the cytoarchitecturally defined hippocampal region of the cerebral cortex. In the human it is located along the rhinal sulcus. Cytoarchitectually it is bounded medially by the entorhinal area 28 and laterally by the ectorhinal area 36 (H). Brodmann found a cytoarchitecturally homologous area in the monkey (Cercopithecus), but it was so weakly developed that he omitted it from the cortical map of that species (Brodmann-1909).
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    Corona radiata

    Corona radiata

    In neuroanatomy, the corona radiata is a white matter sheet that continues ventrally as the internal capsule and dorsally as the centrum semiovale. This sheet of axons contains both descending and ascending axons that carry nearly all of the neural traffic from and to the cerebral cortex. The corona radiata is associated with the corticospinal tract, the corticopontine tract, and the corticobulbar tract.
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    Internal capsule

    Internal capsule

    The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the putamen and the globus pallidus. The internal capsule contains both ascending and descending axons. It consists of axonal fibres that run between the cerebral cortex and the pyramids of the medulla. The internal capsule is V-shaped when cut horizontally/transversely (the same plane as the brim of a top hat). When cut horizontally: Working anterior to posterior: Other fibers within the internal capsule The superior parts of both the anterior and posterior limbs and the genu of the internal capsule are supplied by the lenticulostriate arteries, which are branches off of the M1 segment of the middle cerebral artery. The inferior half of the anterior limb is supplied via the recurrent artery of Heubner, which is a branch of the anterior cerebral artery. The inferior half of the posterior limb is supplied by the anterior choroidal artery, which is a branch of the internal carotid artery. In summary, the blood supply of the internal capsule is Anterior limb: lenticulostriate branches of middle cerebral artery (superior half) & recurrent artery of Heubner off of the
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    Medial longitudinal fasciculus

    Medial longitudinal fasciculus

    The medial longitudinal fasciculus (MLF) is a pair of crossed fiber tracts (group of axons), one on each side of the brainstem. These bundles of axons are situated near the midline of the brainstem and are composed of both ascending and descending fibers that arise from a number of sources and terminate in different areas. The medial longitudinal fasciculus carries information about the direction that the eyes should move. It connects the cranial nerve nuclei III (Oculomotor nerve), IV (Trochlear nerve) and VI (Abducens nerve) together, and integrates movements directed by the gaze centers (frontal eye field) and information about head movement (from cranial nerve VIII, Vestibulocochlear nerve). It is an integral component of saccadic eye movements as well as vestibulo-ocular and optokinetic reflexes. It also carries the descending tectospinal tract and medial vestibulospinal tracts into the cervical spinal cord, and innervates some muscles of the neck and upper limbs. The descending MLF mainly arises from the medial Vestibular nucleus (VN) and is thought to be involved in the maintenance of gaze. This is achieved by inputs to the VN from Descending fibers can also arise from the
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    Medulla oblongata

    Medulla oblongata

    The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla. The medulla contains the cardiac, respiratory, vomiting and vasomotor centers and deals with autonomic, involuntary functions, such as breathing, heart rate and blood pressure. The medulla is often thought of as being in two parts: The region between the anterior median sulcus and the anterolateral sulcus is occupied by an elevation on either side known as the pyramid of medulla oblongata. This elevation is caused by the corticospinal tract. In the lower part of the medulla some of these fibers cross each other thus obliterating the anterior median fissure. This is known as the decussation of the pyramids. Some other fibers that originate from the anterior median fissure above the decussation of the pyramids and run laterally across the surface of the pons are known as the external arcuate fibers. The region between the anterolateral and posterolateral sulcus in the upper part of the medulla is marked by a swelling known as the Olivary body. It is caused by a large mass of gray matter known as the
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    Nucleus accumbens

    Nucleus accumbens

    The nucleus accumbens (NAcc), also known as the accumbens nucleus or as the nucleus accumbens septi (Latin for nucleus leaning against the septum or as The pleasure center)), is a collection of neurons and forms the main part of the ventral striatum. It is thought to play an important role in reward, pleasure, laughter, addiction, aggression, fear, and the placebo effect. Each half of the brain has one nucleus accumbens. It is located where the head of the caudate and the anterior portion of the putamen meet just lateral to the septum pellucidum. The nucleus accumbens and the olfactory tubercle collectively form the ventral striatum, which is part of the basal ganglia. The nucleus accumbens can be divided into two structures—the nucleus accumbens core and the nucleus accumbens shell. These structures have different morphology and function. The principal neuronal cell type found in the nucleus accumbens is the medium spiny neuron. The neurotransmitter produced by these neurons is gamma-aminobutyric acid (GABA), one of the main inhibitory neurotransmitters of the central nervous system. These neurons are also the main projection or output neurons of the nucleus accumbens. While 95%
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    Parietal lobe

    Parietal lobe

    The parietal lobe is a part of the brain positioned above (superior to) the occipital lobe and behind (posterior to) the frontal lobe. The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the dorsal stream of the visual system. This enables regions of the parietal cortex to map objects perceived visually into body coordinate positions. The name derives from the overlying parietal bone, which is named from the Latin paries-, wall. The parietal lobe is defined by three anatomical boundaries: The central sulcus separates the parietal lobe from the frontal lobe; the parieto-occipital sulcus separates the parietal and occipital lobes; the lateral sulcus (sylvian fissure) is the most lateral boundary, separating it from the temporal lobe; and the medial longitudinal fissure divides the two hemispheres. Immediately posterior to the central sulcus, and the most anterior part of the parietal lobe, is the postcentral gyrus (Brodmann area 3), the secondary somatosensory cortical area. Dividing this and the posterior parietal cortex is the postcentral sulcus. The
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    Primary auditory cortex

    Primary auditory cortex

    The primary auditory cortex is a region of the brain that processes sound and thereby contributes to our ability to hear. It is the first cortical region of the auditory pathway. Corresponding roughly with Brodmann areas 41 and 42 of the cerebral cortex, it is located on the temporal lobe, and performs the basics of hearing—pitch and volume. Besides receiving input from the ear and lower centers of the brain, the primary auditory cortex also transmits signals back to these areas. As with other primary sensory cortical areas, auditory sensations reach perception only if received and processed by a cortical area. Evidence for this comes from lesion studies in human patients who have sustained damage to cortical areas through tumors or strokes, or from animal experiments in which cortical areas were deactivated by surgical lesions or other methods. Damage to the Primary Auditory Cortex in humans leads to a loss of any awareness of sound, but an ability to react reflexively to sounds remains as there is a great deal of subcortical processing in the auditory brainstem and midbrain. Neurons in the auditory cortex are organized according to the frequency of sound to which they respond
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    Rhinencephalon

    Rhinencephalon

    In animal anatomy, the rhinencephalon is a part of the brain involved with olfaction. The term rhinencephalon has been used to describe different structures at different points in time. One definition includes the olfactory bulb, olfactory tract, anterior olfactory nucleus, anterior perforated substance, medial olfactory stria, lateral olfactory stria, parts of the amygdala and prepyriform area. Some references classify other areas of the brain related to perception of smell as rhinencephalon, but areas of the human brain that receive fibers strictly from the olfactory bulb are limited to those of the paleopallium. As such, the rhinencephalon includes the olfactory bulb, the olfactory tract, the olfactory tubercle and striae, the anterior olfactory nucleus and parts of the amygdala and the piriform cortex.
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    Trapezoid body

    Trapezoid body

    The trapezoid body is part of the auditory pathway. It is a bundle of fibers and cells in the pontine tegmentum. It consists of fibers arising from the ventral cochlear nucleus. A collection of nerve cells inside forms a trapezoid nucleus. The superior olivary nucleus is situated on the dorsal surface of the trapezoid body. Most nerve fibers pass directly from the superior olivary nuclei to the inferior colliculus. Axons leaving the ventral cochlear nucleus (VCN) form a broad pathway that crosses under the brain stem in the trapezoid body. A thin pathway, the intermediate acoustic stria, also leaves the VCN, merging with the trapezoid body close to the superior olivary complex, where many of its axons synapse. Axons leaving the dorsal cochlear nucleus (DCN) form the dorsal acoustic stria, which reaches primarily the contralateral dorsal nucleus of the lateral lemniscus and the central nucleus of the inferior colliculus.
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    Brodmann area 27

    Brodmann area 27

    Area 27 of Brodmann-1909 is a cytoarchitecturally defined cortical area that is a rostral part of the parahippocampal gyrus of the guenon (Brodmann-1909). It is commonly regarded as a synonym of presubiculum (Crosby-62).
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    Brodmann area 31

    Brodmann area 31

    Brodmann area 31, also known as dorsal posterior cingulate area 31, is a subdivision of the cytoarchitecturally defined cingulate region of the cerebral cortex. In the human it occupies portions of the posterior cingulate gyrus and medial aspect of the parietal lobe. Approximate boundaries are the cingulate sulcus dorsally and the parieto-occipital sulcus caudally. It partially surrounds the subparietal sulcus, the ventral continuation of the cingulate sulcus in the parietal lobe. Cytoarchitecturally it is bounded rostrally by the ventral anterior cingulate area 24, ventrally by the ventral posterior cingulate area 23, dorsally by the gigantopyramidal area 4 and preparietal area 5 and caudally by the superior parietal area 7 (H) (Brodmann-1909).
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    Brodmann area 9

    Brodmann area 9

    Brodmann area 9, or BA9, is part of the frontal cortex in the human brain. It contributes to the dorsolateral prefrontal cortex. The term Brodmann area 9 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. Brodmann-1909 regarded it on the whole as topographically and cytoarchitecturally homologous to the granular frontal area 9 and frontopolar area 10 in the human. Distinctive features (Brodmann-1905): Unlike Brodmann area 6-1909, area 9 has a distinct internal granular layer (IV); unlike Brodmann area 6 or Brodmann area 8-1909, its internal pyramdal layer (V) is divisible into two sublayers, an outer layer 5a of densely distributed medium-size ganglion cells that partially merges with layer IV, and an inner, clearer, cell-poor layer 5b; the pyramidal cells of sublayer 3b of the external pyramidal layer (III) are smaller and sparser in distribution; the external granular layer (II) is narrow, with small numbers of sparsely distributed granule cells. It is the medial prefrontal cortex.
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    Fourth ventricle

    Fourth ventricle

    The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle. The fourth ventricle extends from the cerebral aqueduct (aqueduct of Sylvius) to the obex, and is filled with cerebrospinal fluid (CSF). The fourth ventricle has a characteristic diamond shape in cross-sections of the human brain. It is located within the pons or in the upper part of the medulla. CSF entering the fourth ventricle through the cerebral aqueduct can exit to the subarachnoid space of the spinal cord through two lateral foramina of Luschka (singular: foramen of Luschka) and a single, midline foramen of Magendie (see List of human anatomical parts named after people). The fourth ventricle has a "roof" dorsally and a "floor" ventrally. The roof of the fourth ventricle is formed by the cerebellum (superior and inferior medullary vela), the floor by the rhomboid fossa, and the side "walls" formed by the cerebellar peduncles. Among the prominent features of the floor of the fourth ventricle are the: The fourth ventricle,
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    Hippocampus

    Hippocampus

    The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is closely associated with the cerebral cortex, and in primates is located in the medial temporal lobe, underneath the cortical surface. It contains two main interlocking parts: Ammon's horn and the dentate gyrus. In Alzheimer's disease, the hippocampus is one of the first regions of the brain to suffer damage; memory problems and disorientation appear among the first symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia—the inability to form or retain new memories. In rodents, the hippocampus has been studied extensively as part of a brain system responsible for spatial memory and navigation. Many neurons in the rat and mouse hippocampus respond as place cells: that is, they fire
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    Hypoglossal nucleus

    Hypoglossal nucleus

    The hypoglossal nucleus is a cranial nerve nucleus, and it extends the length of the medulla, and being a motor nucleus, is close to the midline. In the open medulla, it is visible as what is known as the hypoglossal trigone, a raised area (medial to the vagal trigone) protruding slightly into the fourth ventricle. In the closed medulla, the gracile and cuneate nuclei lie posteriorly, which means the nucleus is not as close to the back of the medulla as in the open medulla. It is, however, still close to the midline.
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    Interventricular foramina

    Interventricular foramina

    In the brain, the interventricular foramina (or foramina of Monro) are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. As channels, they allow cerebrospinal fluid (CSF) produced in the lateral ventricles to reach the third ventricle and then the rest of the brain's ventricular system. They also contain choroid plexus, a specialized CSF-producing structure, that is continuous with that of the lateral and third ventricles. The crescent-shaped interventricular foramina are located on the medial and inferior aspect of the lateral ventricles. Each foramen is bounded by the fornix and thalamus. The lumens of the foramina have a diameter of several millimeters. Inflammation, tumor, or other conditions that may occlude the foramina may lead to internal hydrocephalus. The foramina were named after the Scottish physician Alexander Monro, who first described the structures in his 1783 publication, Observations on the Structure and Functions of the Nervous System. They had previously been identified by the 17th century anatomist Raymond Vieussens.
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    Intraparietal sulcus

    Intraparietal sulcus

    The intraparietal sulcus (IPS) is located on the lateral surface of the parietal lobe, and consists of an oblique and a horizontal portion. The IPS contains a series of functionally distinct subregions that have been intensively investigated using both single cell neurophysiology in primates and human functional neuroimaging. Its principal functions are related to perceptual-motor coordination (for directing eye movements and reaching) and visual attention. The IPS is also thought to play a role in other functions, including processing symbolic numerical information, visuospatial working memory and interpreting the intent of others. Behavioral studies suggest that the IPS is associated with impairments of basic numerical magnitude processing and that there is a pattern of structural and functional alternations in the IPS and in the PFC in dyscalculia. Children with developmental dyscalculia were found to have less gray matter in the left IPS. Five regions of the intraparietal sulcus (IPS): anterior, lateral, ventral, caudal, and medial All of these areas have projections to the frontal lobe for executive control. Activity in the intraparietal sulcus has also been associated with
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    Medial longitudinal fissure

    Medial longitudinal fissure

    The great longitudinal fissure (or longitudinal cerebral fissure, or longitudinal fissure, or interhemispheric fissure) is the deep groove that separates the two hemispheres of the vertebrate brain. The falx cerebri, a dural brain covering, lies within the medial longitudinal fissure. The corpus callosum crosses the medial longitudinal fissure.
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    Median eminence

    Median eminence

    The median eminence is part of the inferior boundary for the hypothalamus part of the human brain. A small swelling on the tuber cinereum posterior to the infundibulum – atop the pituitary stalk – the median eminence lies in the area roughly bounded on its posterolateral region by the cerebral peduncles, and on its anterolateral region by the optic chiasm. The median eminence is one of the seven areas of the brain devoid of a blood–brain barrier. It is sometimes considered one of the circumventricular organs. The median eminence is a part of the hypothalamus from which regulatory hormones are released. It is of great physiological importance, as it is integral to the hypophyseal portal system, which connects the hypothalamus with the anterior lobe of the pituitary gland. Parvocellular neurons from the hypothalamus terminate in the median eminence of the hypothalamus. Specifically, it is in the median eminence that the secretions of the hypothalamus (releasing and inhibiting regulatory hormones, known as "hypophysiotropic hormones") collect before entering the portal system. Such hypophysiotropic hormones include: CRF (corticotropin releasing factor), GnRH (gonadotropin releasing
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    Metencephalon

    Metencephalon

    The metencephalon is a developmental categorization of portions of the central nervous system. The metencephalon is composed of the pons and the cerebellum; contains a portion of the fourth ventricle; and the trigeminal nerve (CN V), abducens nerve (CN VI), facial nerve (CN VII), and a portion of the vestibulocochlear nerve (CN VIII). The metencephalon develops from the higher/rostral half of the embryonic rhombencephalon, and is differentiated from the myelencephalon in the embryo by approximately 5 weeks of age. By the third month, the metencephalon differentiates into its two main structures, the pons and the cerebellum. The pons regulates breathing through particular nuclei that regulate the breathing center of the medulla oblongata. The cerebellum works to coordinate muscle movements, maintain posture, and integrate sensory information from the inner ear and proprioceptors in the muscles and joints. List of regions in the human brain
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    Nucleus raphe magnus

    Nucleus raphe magnus

    The nucleus raphes magnus, located directly rostral to the nucleus raphes obscurus, is afferently stimulated from axons in the spinal cord and cerebellum. This makes the nucleus raphes magnus a likely candidate for part of the motor system; however, it seems to participate in the endogenous analgesia system. Mounting evidence suggests that the nucleus raphes magnus plays an important role in homeostatic regulation . The nucleus raphes magnus receives descending afferents from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, parvocellular reticular nucleus and the prelimbic, infralimbic, medial and lateral precentral cortices . All of these brain areas influence the main function of the nucleus raphes magnus. The main function of the nucleus raphes magnus is mostly pain mediation; in fact it sends projections to the dorsal horn of the spinal cord to directly inhibit pain. The nucleus raphes magnus releases enkephalin when stimulated. The periaqueductal gray, the center of analgesia, sends efferent connections to the nucleus raphes magnus in when it is stimulated by opiates (endogenous or
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    Occipital lobe

    Occipital lobe

    The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1 (visual one). Human V1 is located on the medial side of the occipital lobe within the calcarine sulcus; the full extent of V1 often continues onto the posterior pole of the occipital lobe. V1 is often also called striate cortex because it can be identified by a large stripe of myelin, the Stria of Gennari. Visually driven regions outside V1 are called extrastriate cortex. There are many extrastriate regions, and these are specialized for different visual tasks, such as visuospatial processing, color discrimination and motion perception. The name derives from the overlying occipital bone, which is named from the Latin oc- + caput, "back of the head". The two occipital lobes are the smallest of four paired lobes in the human cerebral cortex. Located in the rearmost portion of the skull, the occipital lobes are part of the forebrain. The cortical lobes are not defined by any internal structural features, but rather by the bones of the skull that overlie them. Thus, the occipital lobe
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    Periaqueductal gray

    Periaqueductal gray

    Periaqueductal gray (PAG; also called the "central gray") is the gray matter located around the cerebral aqueduct within the tegmentum of the midbrain. It plays a role in the descending modulation of pain and in defensive behaviour. The ascending pain and temperature fibers of the spinothalamic tract also send information to the PAG via the spinomesencephalic tract (so-named because the fibers originate in the spine and terminate in the PAG, in the mesencephalon or midbrain). Stimulation of the periaqueductal gray matter of the midbrain activates enkephalin-releasing neurons that project to the raphe nuclei in the brainstem. 5-HT (serotonin) released from the raphe nuclei descends to the dorsal horn of the spinal cord where it forms excitatory connections with the "inhibitory interneurons" located in Laminae II (aka the substantia gelatinosa). When activated, these interneurons release either enkephalin or dynorphin (endogenous opioid neurotransmitters), which bind to mu opioid receptors on the axons of incoming C and A-delta fibers carrying pain signals from nociceptors activated in the periphery. The activation of the mu-opioid receptor inhibits the release of substance P from
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    Posterior nucleus of vagus nerve

    Posterior nucleus of vagus nerve

    The dorsal nucleus of the vagus nerve (or posterior motor nucleus of vagus) is a cranial nerve nucleus for the vagus nerve in the medulla that lies under the floor of the fourth ventricle. It mostly serves parasympathetic vagal functions in the gastrointestinal tract, lungs, and other thoracic and abdominal vagal innervations. The cell bodies for the preganglionic parasympathetic vagal neurons that innervate the heart reside in the nucleus ambiguus. Additional cell bodies are found in the nucleus ambiguus, which give rise to the branchial efferent motor fibers of the vagus nerve (CN X) terminating in the laryngeal, pharyngeal muscles, and musculus uvulae.
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    Rhomboid fossa

    Rhomboid fossa

    The anterior part of the fourth ventricle is named, from its shape, the rhomboid fossa, and its anterior wall, formed by the back of the pons and medulla oblongata, constitutes the floor of the fourth ventricle. It is covered by a thin layer of gray substance continuous with that of the medulla spinalis; superficial to this is a thin lamina of neuroglia which constitutes the ependyma of the ventricle and supports a layer of ciliated epithelium. The fossa consists of three parts, superior, intermediate, and inferior. The sulcus limitans forms the lateral boundary of the medial eminence. In the superior part of the rhomboid fossa it corresponds with the lateral limit of the fossa and presents a bluish-gray area, the locus cæruleus, which owes its color to an underlying patch of deeply pigmented nerve cells, termed the substantia ferruginea. At the level of the colliculus facialis the sulcus limitans widens into a flattened depression, the superior fovea, and in the inferior part of the fossa appears as a distinct dimple, the inferior fovea. Lateral to the foveæ is a rounded elevation named the area acustica, which extends into the lateral recess and there forms a feebly marked
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    Superior temporal gyrus

    Superior temporal gyrus

    The superior temporal gyrus is one of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear. The superior temporal gyrus is bounded by: The superior temporal gyrus contains several important structures of the brain, including: The superior temporal gyrus contains the primary auditory cortex, which is responsible for processing sounds. Specific sound frequencies map precisely onto the primary auditory cortex. This auditory (or tonotopic) map is similar to the homunculus map of the primary motor cortex. Some areas of the superior temporal gyrus are specialized for processing combinations of frequencies, and other areas are specialized for processing changes in amplitude or frequency. The superior temporal gyrus also includes the Wernicke's area, which (in most people) is located in the left hemisphere. It is the major area involved in the comprehension of language. The superior temporal gyrus (STG) is involved in auditory processing, including language, but also has been implicated as a critical structure in social cognition. ) The superior temporal gyrus has been involved in the perception
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    Supraoptic nucleus

    Supraoptic nucleus

    The supraoptic nucleus (SON) is a nucleus of magnocellular neurosecretory cells in the hypothalamus of the mammalian brain. The nucleus is situated at the base of the brain, adjacent to the optic chiasm. In humans, it contains about 3,000 neurons. The cell bodies produce a peptide hormone: anti-diuretic hormone. In the cell bodies, the hormones are packaged in large, membrane-bound vesicles which are transported down the axons to the nerve endings. The secretory granules are also stored in packets along the axon called Herring bodies. Similar magnocellular neurons are also found in the paraventricular nucleus. Each neuron in the nucleus has one long axon that projects to the posterior pituitary gland, where it gives rise to about 10,000 neurosecretory nerve terminals. The magnocellular neurons are electrically excitable: In response to afferent stimuli from other neurons, they generate action potentials which propagate down the axons. When an action potential invades a neurosecretory terminal, the terminal is depolarised, and calcium enters the terminal through voltage-gated channels. The calcium entry triggers the secretion of some of the vesicles by a process known as exocytosis.
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    Tela chorioidea of the third ventricle

    Tela chorioidea of the third ventricle

    The part of the choroid plexus in relation to the body of the ventricle forms the vascular fringed margin of a triangular process of pia mater, named the tela chorioidea of the third ventricle, and projects from under cover of the lateral edge of the fornix. Blood is supplied by branches from the superior cerebellar artery. This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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    Trochlear nucleus

    Trochlear nucleus

    The nucleus of the trochlear nerve is located in the midbrain, at the level of the inferior colliculus. It is a motor nucleus, so is located near the midline. Oddly, fibers from the trochlear nucleus cross over in the midbrain at the superior medullary velum and exit posteriorly, (this is the only cranial nerve to do so). The nerve then goes around the midbrain, and is visible coming out the sides.
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