The term area 22 of Brodmann (guenon) refers to a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous to area 22 of Brodmann (human) ( Brodmann-1909 ). Distinctive features ( Brodmann-1905 ): compared to area 21 of Brodmann (guenon) 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.