The olivocerebellar system differentially encodes the effect sensory events exert on behavior

Inferior olive neurons convey information about sensorimotor events via climbing fibers to the cerebellum, but their functional significance remains unclear. We directly imaged, with two-photon microscopy, climbing fiber axonal terminals in the cerebellum during a task that successively exposed mice to a force perturbation, a movement instruction and reward; each followed by multiple modes of motor activity. Climbing fiber activations by the sensory events were either generic or informative about the consequences the encoded event has on behavior. The number of informative cells and the information strength are regulated by event modality and functional complexity of the cell’s activity. We observed an additional, previously unreported activation of climbing fibers: they carried probabilistic information on the behavioral context during idle waiting periods preceding stimulus presentation. Our findings reveal properties of olivary neurons that are key for defining their function in the cerebellum-dependent control of behavior. They suggest that the inferior olive flexibly instructs the cerebellum of any process that may shape an animal’s action.