Climbing fibre modification of cerebellar Purkinje cell responses to parallel fibre inputs

Electrical stimulation has been used to activate, separately and independently, the climbing fibre inputs to Purkinje cells of the cat cerebellum. The effects of climbing fibre impulses on Purkinje cell discharges evoked by parallel fibre stimulation has been examined. It was found that impulses in the climbing fibre could block or reduce, in a graded manner, the Purkinje cell response to parallel fibre inputs. It has previously been shown that climbing a fibre inputs do not suppress the antidromic spike response of the Purkinje cell to cerebellar white matter stimulation. This suggests that the climbing fibre impulses modify the Purkinje cell response to parallel fibre inputs by reducing the excitatory action of parallel fibre impulses on the Purkinje cell.