Purkinje Cell Activity During Suppression of Voluntary Eye Movements in Rhesus Macaques

Conscious control of actions helps us to reach our goals by suppressing responses to distracting external stimuli. The cerebellum has been suggested to complement cerebral control of inhibition of targeted movements (conscious control), though by what means, remains unclear. By measuring Purkinje cell (PC) responses during antisaccades, we show that the cerebellum not only plays a role in the execution of eye movements, but also in during the volitional inhibition thereof. We found that simple spike (SS) modulation during instruction and execution of prosaccades and antisaccades was prominent in PCs of both medial and lateral cerebellum, showing distinct, time-ordered sequences, but each with different sensitivities for execution and trial-history. SS activity in both regions modulated bidirectionally, with both facilitation (increasing SS firing) and suppression (decreasing SS firing) PCs showing firing-rate changes associated with instruction and execution, respectively. These findings show that different cerebellar regions can contribute to behavioral control and inhibition, but with different propensities, enriching the cerebellar machinery in executive control.