Cerebellar learning, fast and slow
Climbing fiber (CF) inputs to cerebellar Purkinje cells (PCs) encode sensorimotor and reward-related instructive signals that are utilized to learn and refine goal-directed behaviors. However, it remains unclear how these instructive signals evolve during the acquisition and refinement phases of learning, whether they target the same PCs, and whether different brain-wide pathways drive functionally distinct populations of CFs.
In this project, we used 2-photon calcium imaging to record CF inputs to PCs chronically over weeks while head-fixed mice learned to perform a visuomotor integration task (slow learning). Once mice were experts, we probed fast, adaptive learning by altering the gain between object translation and wheel movement.
Our results suggest that instructive CF signals define functionally distinct cerebellar regions: inputs to some cerebellar regions primarily receive sensorimotor instruction and mediates the slow acquisition of goal-directed behaviors, while inputs to other regions preferentially receive reward-related instruction that can guide fast adaptation to dynamic environmental contexts. We are exploring whether this regional functional specialization may result from the differential brain-wide circuits driving distinct populations of presynaptic olivary neurons.