Manipulation-specific activity in motor and somatosensory cortex as mice handle food

Food-handling offers unique yet largely unexplored opportunities to investigate how cortical activity relates to forelimb movements in a natural, ethologically essential, and kinematically rich form of manual dexterity. To determine these relationships, we recorded spiking activity in mouse forelimb M1 and S1 and tongue/jaw M1. Activity in all areas was strongly modulated in close association with discrete active manipulation events that occurred intermittently as mice fed. Each areas activity was also partly distinct in its overall timing and phasic/tonic temporal profile, attributable to area-specific composition of activity classes. Forelimb position could be accurately predicted from activity in all three regions. These results thus establish that cortical activity during food-handling is manipulation-specific, distributed, and broadly similar across multiple cortical areas, while also exhibiting area- and submovement-specific relationships with the fast kinematic hallmarks of this form of complex, free-object-handling manual dexterity.