Architectonic maps of the orbitofrontal cortex

Top: Architectonic maps of the orbitofrontal cortex in humans (A) and macaque monkeys (B), and lateral frontal cortex in rats (C). Bottom: ventral views of a human (A) and monkey (B) brain; lateral view of a rat brain (C). The “granular” areas appear in blue; agranular areas in green; allocortical areas in yellow. Note that the “granular” prefrontal cortex dominates the frontal lobe of primates. Abbreviations: AON, anterior olfactory “nucleus”; Fr2, second frontal area; I, insula; LO, lateral orbital area; M1, primary motor area; Par, parietal cortex; Pir, Piriform cortex; l, lateral; m, medial; o, orbital; r, rostral; c, caudal; i, inferior; p, posterior; s, sulcal; v, ventral. a has two meanings: in Ia, it means agranular; in 13a, it distinguishes that area from area 13b. Architectonics from Öngür et al.