The term area 12 of Walker refers to a subdivision of the frontal lobe in the macaque (Macaca) defined on the basis of cytoarchitecture. Located at the frontal pole, it is characterized by a thin third layer, a "feeble" fourth, internal granular layer, and thick undifferentiated fifth and sixth layers. Walker regarded the most likely cytoarchitectural homologue in the human to be area 12 of Brodmann (human); he did not regard it has homologous to area 12 of Brodmann (guenon) ( Walker-1940 ).