Autonomic and somatic responses evoked by stimulation of the cerebellar uvula in the conscious rabbit.

The present study has investigated the effects of electrical stimulation of the cerebellar posterior cortex in the conscious rabbit. Stimulation of lobule IX (the uvula) elicited an increase in mean arterial blood pressure and heart rate, accompanied by EEG desynchronization, pupillary dilatation and a specific motor reaction, consisting of pricking of the ears, neck stiffening and running movements. Stimulation of lobule VIII was ineffective in evoking equivalent responses. The administration of barbiturates reversed the cardiovascular response to uvula stimulation, producing a fall in mean arterial pressure. The characteristics of the pattern of responses obtained, together with the anatomical and electrophysical observations provided in the preceding paper (Bradley, Ghelarducci, La Noce, Paton, Spyer & Withington-Wray, 1990), suggest a possible involvement of uvula cortex in the expression of the alerting reaction in the rabbit.