Bilateral distribution of projections neurons directed to orbitofrontal cortices. Coronal sections through the prefrontal cortex showing labeled neurons in ipsilateral (ipsi) and contralateral (contra) hemispheres after infection of tracers in three cases. Rostral to caudal sections are shown from left to right (case AF), and top to bottom (cases BCb and AM). (Top)The injection of HRP was in area OPro (A, B, black area) and labeled neurons are seen in layers II-III (blue dots) and layers V and VI (red dots); (Left)Injection of fast blue was in area OPro (C), blue area). (Right)Injection of HRP was in the rostral part of area 11 (not shown). Dotted lines through the cortex in the coronal sections show the bottom of layer IV. Architectonic areas indicated by letters include: OPAll, orbital periallocortex; OPro, orbital proisocortex. Other architectonic areas are indicated by numbers. Abbreviations: A, arcuate sulcus; Cg, cingulate sulcus; LF, lateral fissure; LO, lateral orbital sulcus; MO, medial orbital sulcus; P, principal sulcus.