Medial premotor cortex as a potential reservoir of reward expectancy signals influencing the primate frontoparietal network.

Reward expectancy plays an important role in modulating cortical activity associated with motivation, selection, and preparation of subsequent goal-directed movements. However, it is unclear how it is represented in the primate frontoparietal cortex in a form that is separable from activity for motor execution. Here, using common marmosets performing a classical conditioning task with auditory cues, we conducted wide-field one-photon calcium imaging of frontoparietal and auditory cortices while recording orofacial and body movements. Reward expectancy that was separable from licking, eye movement, and hand movement was represented in the medial part of the dorsorostral premotor cortex (mPMdr), but not the central part. Granger causality analysis revealed information flows from mPMdr to widespread frontoparietal areas beyond its functional subnetwork, specifically during the delay period before reward delivery. Our results suggest that in non-human primates, mPMdr serves to retain reward expectancy to modulate the frontoparietal network for subsequent movements.