The cerebellum controls complex, coordinated and rapid movements, a
function requiring precise timing abilities. However, the network
mechanisms that underlie the temporal organization of activity in the
cerebellum are largely unexplored, because in vivo recordings have usually
targeted single units. Here, we use tetrode and multi-site recordings to
demonstrate that Purkinje cell activity is synchronized by a
high-frequency (~200 Hz) population oscillation. We combine pharmacological
experiments and modeling to show how the recurrent inhibitory connections
between Purkinje cells are sufficient to generate these oscillations. A
key feature of these oscillations is a fixed population frequency that is
independent of the firing rates of the individual cells. Convergence in
the deep cerebellar nuclei of Purkinje cell activity, synchronized by
these oscillations, likely organizes temporally the cerebellar output.