RECEIVING AREAS OF THE TACTILE, AUDITORY, AND VISUAL SYSTEMS IN THE CEREBELLUM

Abstract

By determining the loci of evoked electrical responses it is shown in cats that distinct areas of the cerebellar cortex receive nerve impulses which originate in tactile, auditory and visual receptors. The tactile receiving areas are 3 in number (1) in each lateral half of the anterior lobe and a few adjacent folia topographically distinct regions are related to different parts of the ipsilateral body surface; (2) and (3) in both paramedian lobules impulses are received from tactile receptors of the feet of both sides. The auditory and visual areas are essentially conterminous and occupy chiefly the lobulus simplex and tuber vermis. The authors carried out an abundance of control expts. the results of which leave no doubt as to the origins of the effective stimuli, e.g., the cerebellar responses to a flash of light are clearly evoked by activation of retinal elements, not by excitation of thermal receptors or reflex activation of proprioceptors in the region of the orbit. While no serious attempts were made to determine the exact pathways travelled by impulses from the 3 classes of exteroceptors stimulated, evidence is presented to show that in no case does the pathway include a relay to the cerebral cortex; that neither the tactile nor the auditory pathways extend above the level of the inferior colliculi; and that the impulses of cochlear origin pass through or close to the inferior colliculi. This study most emphatically suggests that cerebellar functions are modified by tactile, auditory, and visual stimuli as well as by impulses emanating from proprioceptors and from the cerebral cortex.