Uberon 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.;
Uberon synonym : area 4 of Brodmann; giant pyramidal area; Brodmann area 4; B09-4; area gigantopyramidalis; Brodmann area 4, gigantopyramidal; Brodmann's area 4; area 4 of Brodmann-1909;
Uberon related term : area 4 of Brodmann (guenon); BA4;
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.