Figure 2.

Coronal sections (left side), two-dimensional unfolded map, and lateral, medial, and orbital views (right side) of the Macaca mulatta brain indicating the architectonic divisions of the frontal cortex. In the unfolded map, vertical lines correspond to the position of the coronal sections from rostral (+42) to caudal (+25) in mm from the posterior commissure. Layer IV is delineated with a continuous line while the white matter boundary is represented with dashed lines in the coronal section schematic drawings. Dashed lines in the unfolded map represent the frontal sulci. cc, corpus callosum; cg, cingular gyrus; FO/FPO, frontal operculum; ia, inferior ramus of the arcuate sulcus; Iag, insular agranular cortex; Idg, insular disgranular cortex; lo, lateral orbital sulcus; mo, medial orbital sulcus; olf, olfactory area; p, sulcus principalis; PAll, frontal periallocortical area; Pro, frontal proisocortical area; ro, rostral sulcus; sa, superior ramus of the arcuate sulcus.