The term area 13 of Walker refers to a subdivision of the frontal lobe of the macaque (Macaca) defined on the basis of cytoarchitecture. Compared to area 11 of Walker, it is a "fairly wide cortex" with a fainter fourth layer, internal granular layer, and "more loosely arranged" cells. Compared to area 12 of Walker, the fifth and sixth layers are wider. Walker did not recognize a cytoarchitectural homologue in the human as defined in Brodmann-1909 ( Walker-1940 ).