Largely segregated parietofrontal connections linking rostral intraparietal cortex (areas AIP and VIP) and the ventral premotor cortex (areas F5 and F4)

Two functionally different cortical areas are located in the rostral part o f the intraparietal sulcus (IP): the ventral intraparietal area (VIP), alon g the fundus of the sulcus, and the anterior intraparietal area (AIP), rost ral in the lateral bank. VIP and AIP have functional properties comparable to those of the ventral premotor areas, F4 and F5, respectively. The aim of this study was to establish whether these intraparietal and premotor areas have direct and specific anatomical connections. Neural tracers were injec ted in F4, F5, and AIP in three macaque monkeys. The results showed that F4 and F5 are targets of strong projections from VIP and AIP, respectively, a nd that the linkage between F5 and AIP is highly selective. These data supp ort the notion that parietofrontal connections selectively link areas displ aying similar functional properties and form largely segregated anatomical circuits, Each of these circuits is possibly dedicated to specific aspects of sensorimotor transformations. In particular, the AIP-F5 circuit should p lay a crucial role in visuomotor transformation for grasping, the VIP-F4 ci rcuit is possibly involved in peripersonal space coding for movement.