Term Name: | Brodmann (1909) area 4 |
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Synonyms: | area 4 of Brodmann (guenon), area 4 of Brodmann-1909, area gigantopyramidalis, B09-4, Brodmann (1909) area 4, Brodmann area 4, gigantopyramidal |
Definition: | 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. |
Ontology: | Uberon Ontology [UBERON:0013535] |