Connectional subdivisions reflect neuronal features of the various sectors of the macaque ventrolateral prefrontal cortex

Previous neuroanatomical tracing studies on monkey ventrolateral prefrontal cortex (VLPFC) suggest the existence of a rostro-caudal organization, in which caudal and middle areas are mainly involved in controlling oculomotor and skeletomotor behaviors, respectively, while rostral ones in more abstract operations (Gerbella et al. 2017). A recent study (Rozzi et al. 2023) demonstrated that this region, as a whole, processes contextual information relevant for action guidance. To address whether there are potential functional differences within specific VLPFC areas, we employed Demixed Principal Component (dPCA) and decoding analyses to investigate neural activity recorded in distinct VLPFC sectors during the execution of different behavioral tasks: a passive task, in which the monkey had simply to observe static images, and an active Go/NoGo task in which monkeys had to perform or withhold an object-related hand action based on different instructive cues.The results show that: 1) neural activity in the caudo-ventral areas, in particular caudal area 12r, is more modulated during the visual passive task; 2) these areas are also strongly engaged during the initial phases of the Go/NoGo task, in which cues and objects are presented; 3) areas of the intermediate VLPFC, in particular area 46v, are more active during the final phases of the Go/NoGo task, i.e. during action execution or witholding; 4) the different VLPF sectors, especially caudal area 12r and intermediate area 46v, host neurons encoding the type of performed task. Altogether, our findings indicate that the various VLPFC areas exhibit phase- and task-dependent differential involvement in task-relevant information coding.