Temporal dynamics of neural activity in macaque frontal cortex assessed with large-scale recordings

The cortical network controlling the arm and hand when grasping objects consists of several areas in parietal and frontal cortex. Recently, more anterior prefrontal areas have also been implicated in object grasping, but their exact role is currently unclear. To investigate the neuronal encoding of objects during grasping in these prefrontal regions and their relation with other cortical areas of the grasping network, we performed large-scale recordings (more than 2000 responsive sites) in frontal cortex of monkeys during a saccade-reach-grasp task. When an object appeared in peripheral vision, the first burst of activity emerged in prearcuate areas (the FEF and area 45B), followed by dorsal and ventral premotor cortex, and a buildup of activity in primary motor cortex. After the saccade, prearcuate activity remained elevated while primary motor and premotor activity rose in anticipation of the upcoming arm and hand movement. Remarkably, a large number of premotor and prearcuate sites responded when the object appeared in peripheral vision and remained active when the object came into foveal vision. Thus, prearcuate and premotor areas continuously encode object information when directing gaze and grasping objects.