Purkinje cell-specific knockout of the protein phosphatase PP2B impairs potetiation and cerebellar motor learning.Raising cytosolic Cl(-) in cerebellar granule cells affects their excitability and vestibulo-ocular learning.Climbing fiber input shapes reciprocity of Purkinje cell firing.Synaptic inhibition of Purkinje cells mediates consolidation of vestibulo-cerebellar motor learning.Genetic dissection of the function of hindbrain axonal commissures.