Acquisition of classically conditioned eyeblink response following bilateral lesions of flocculus and paraflocculus

Stimulation of regions of the cerebellar flocculus can elicit eyeblinks, but the relationship of this floccular eyeblink zone to eyeblink classical conditioning is unknown. In this experiment, New Zealand white rabbits received bilateral lesions of the flocculus and paraflocculus and were subsequently classically conditioned with tone and corneal airpuff on the left and then the right eye. All animals reached training criterion on both eyes, with the exception of one animal whose lesion included the superior cerebellar peduncle and who was unable to learn on the ipsilateral eye. The lesioned group was not significantly different from unlesioned controls in rate of acquisition or conditioned or unconditioned response amplitude. These results indicate that the flocculus and paraflocculus are not by themselves the essential site of plasticity for classical conditioning of the rabbit eyeblink response.