Synchronous spiking of cerebellar Purkinje cells during control of movements

The ability of the brain to accurately control a movement depends on the cerebellum. Yet, how the cerebellar neurons encode information relevant for this control remains poorly understood. The computations that are performed in the cerebellar cortex are transmitted to its nuclei via Purkinje cells (P cells), which are inhibitory neurons. However, if the spiking activity within P cell populations were temporally synchronized, that inhibition would entrain nucleus neurons, making them fire. Do P cells transmit information by synchronously timing their spikes? We simultaneously recorded from multiple P cells while marmosets performed saccadic eye movements, and organized the neurons into populations that shared a complex spike response to error. Before movement onset, this population of P cells increased their simple spike activity with a magnitude that depended on the velocity of the upcoming saccade, and then sharply reduced their activity below baseline at saccade onset. During deceleration, the spikes became temporally aligned within the population. Thus, the P cells relied on disinhibition, combined with spike synchronization, to convey to the nucleus when to decelerate and potentially stop the movement.