An electrophysiological and anatomical study of afferents reaching the cerebellar uvula in the rabbit.

Stimulation of a medial region of the cerebellar uvula cortex produces sympathetically mediated cardiovascular effects in the decerebrate rabbit. In the present study the afferents to this cerebellar area have been determined using electrophysiological and neuroanatomical methods. Field potentials of prevalent mossy origin evoked by single-shock stimulation of different peripheral nerves have been recorded from sublobules IXa and IXb. No response to vagus and aortic nerves stimulation has been found. A modulation of Purkinje cell discharge following natural vestibular stimulation has been found. A modulation of Purkinje cell discharge following natural vestibular stimulation has been recorded from sublobules IXb and IXc. The retrograde transport of horseradish peroxidase from the uvula cortex has revealed a widespread afferent input to this cerebellar region arising from brain stem reticular and sensory nuclei. On the basis of the results obtained, together with the results of experiments performed in conscious rabbits, contained in the following paper (Bradley, Ghelarducci, La Noce & Spyer, 1990), it is suggested that the uvula participates in co-ordination of the visceral and somatic components of the alerting reaction in the rabbit.