The term area 45 of Walker refers to a subdivision of the frontal lobe of the macaque (Macaca) defined on the basis of cytoarchitecture. It is distinguished from area 8 of Walker by large pyramidal cells in layers 3 and 5, the "absence of marked striations and its narrowness. In places the cortex… is quite thin, and the large cells of the third layer are at times arranged in clumps." Walker regarded the most likely cytoarchitectural homologue in the human to be area 45 of Brodmann (human) ( Walker-1940 ).