internal_granular_layer - Synonyms for internal_granular_layer

Examples of "internal_granular_layer"
2>internal granular layer is focally indistinct and is occupied by large ganglion cells
The external granular layer of the cerebral cortex is commonly known as layer II. It should not be confused with the internal granular layer of the cerebral cortex (commonly known as layer IV).
The internal granular layer of the cortex, also commonly referred to as the granular layer of the cortex, is the layer IV in the subdivision of the mammalian cortex into 6 layers. The adjective internal is used in opposition to the external granular layer of the cortex.
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).
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.
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 ganglion cells densely distributed with some granule cells interspersed; the external granular layer (II) is denser and broader; cell layers are more distinct; the abundance of cells is somewhat greater.
The fourth, fifth and sixth layers, or the Internal Granular layer, Internal Pyramidal layer, and Polymorphic or Multiform layer respectively, are formed during mouse E11.5 to E14.5. Included in these layers are stellates, radial glia, and pyramidal neurons. Layer six is adjacent to the ventricular zone. During the production of these layers, transcription factors TBR1 and OTX1 are expressed along with CTIP2, or corticoneuronal zinc finger protein.
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
Brodmann area 6 is a cytoarchitecturally defined portion of the frontal lobe of the guenon. Brodmann-1909 regarded it as topographically and cytoarchitecturally homologous to the human agranular frontal area 6 and noted that, in the monkey, area 4 is larger than area 6, whereas, in the human, area 6 is larger than area 4. Distinctive features (Brodmann-1905): It is thick relative to other cortical areas; the transition from cortex to subcortical white matter is gradual; cell layers are indistinct; and the internal granular layer (IV) is absent.
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).
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 multiform layer (VI) is very thin (Brodmann-1905). Note that Brodmann later divided this area into two areas, area 24 of Brodmann-1909 and area 25 of Brodmann-1909 (Brodmann-1909).
Agranular insula is a portion of the cerebral cortex defined on the basis of internal structure in the human, the macaque, the rat, and the mouse. Classified as allocortex (periallocortex), it is in primates distinguished from adjacent neocortex (proisocortex) by absence of the external granular layer (II) and of the internal granular layer (IV). It occupies the anterior part of the insula, the posterior portion of the orbital gyri and the medial part of the temporal pole. In rodents it is located on the ventrolateral surface of the cortex rostrally, between the piriform area ventrally and the gustatory area or the visceral area (granular insular cortex) dorsally.
Granular insular cortex (or visceral area) refers to a portion of the cerebral cortex defined on the basis of internal structure in the human and macaque, the rat, and the mouse. Classified as neocortex, it is in primates distinguished from adjacent allocortex (periallocortex) by the presence of granular layers – external granular layer (II) and internal granular layer (IV) – and by differentiation of the external pyramidal layer (III) into sublayers. In primates it occupies the posterior part of the insula. In rodents it is located on the lateral surface of the cortex rostrally, dorsal to the gustatory area or, more caudally, dorsal to the agranular insula.
Brodmann area 11 is a subdivision of the frontal lobe of the guenon monkey defined on the basis of cytoarchitecture (Brodmann-1905). Distinctive features: area 11 lacks an internal granular layer (IV); larger pyramidal cells of sublayer 3b of the external pyramidal layer (III) merge with a denser self-contained collection of cells in the internal pyramidal layer (V); similar to area 10 of Brodmann-1909 is the presence in the multiform layer (VI) of trains of cells oriented parallel to the cortical surface separated by acellular fiber bundles; a thick molecular layer (I); a relatively narrow overall cortical thickness; and a gradual transition from the multiform layer (VI) to the subcortical white matter.
Brodmann area 22 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous to the superior temporal area 22 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): compared to Brodmann area 21-1909 the cortical thickness of area 22 is greater; cell density is reduced overall and the internal granular layer (IV) is even less developed with fewer cells; there is no detectable boundary between the internal pyramidal layer (V) and the multiform layer (VI); as in area 21, the ganglion cells of layer V are numerous and are arrayed adjacent to its boundary with layer IV, but they are plumper and more pyramidal in shape; the polymorphic cells of the multiform layer (VI) become gradually more numerous as one goes deeper and gives way to a wide sublayer 6b of fusiform cells as one approaches the boundary of the cortex with the subcortical white matter.
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 pyramidal 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.
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. Distinctive features (Brodmann-1905): the cortex is unusually thick; the layers are not distinct; the cells are relatively sparsely distributed; giant pyramidal (Betz) cells are present in the internal pyramidal layer (V); lack of an internal granular layer (IV) such that the boundary between the external pyramidal layer (III) and the internal pyramidal layer (V) is indistinct; lack of a distinct external granular layer (II); a gradual transition from the multiform layer (VI) to the subcortical white matter.
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 cortex is relatively thin; smaller cells predominate; the cell density of the multiform layer (VI) is great, producing a distinct boundary with the subcortical white matter; the internal granular layer (IV) is rather well developed; the internal pyramidal layer (V) contains a dense population of round, medium-sized ganglion cells concentrated at the border with layer IV; layers V and VI are narrow with a distinct mutual boundary.
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.
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 molecular layer (I) is wider; the pyramidal cells of sublayer 3b of the external pyramidal layer (III) are larger; the internal granular layer (IV) is less developed and contains fewer cells; ganglion cells of the internal pyramidal layer (V) are larger, rounder, and densely arrayed adjacent to layer IV; the boundary between layer V and the multiform layer (VI) is indistinct; and layer VI is wider and has no sublayers.