Purkinje cell responses in the anterior cerebellar vermis during Pavlovian fear conditioning in the rabbit.

Extracellular single-unit recordings of Purkinje cells in the anterior cerebellar vermis (ACV) of the rabbit found evidence of short-latency (20-30 ms) differential responses to discriminatively-conditioned auditory stimuli during Pavlovian fear conditioning procedures. These differential unit responses appeared to be a function of learning as differential ACV Purkinje cell responses were not observed in naive (untrained) animals. Some of these evoked neurophysiological responses were also correlated with the behavioral conditioned autonomic response. (CAR); a conditioned bradycardiac response. These electrophysiological data, coupled with previous lesion results, suggest that the ACV is part of an important neural circuit for Pavlovian conditioned bradycardia.