THE CEREBELLUM AND LEARNED RAPID RESPONSES

JAMES WILLIAM LUSSIER, Fordham University

Abstract

The study investigated the possibility that the cerebellum initiates learned movements in response to sensory events. This idea contrasts with traditional thought wherein the cerebellum is concerned with the mechanics of making coordinated movements and contributes to behavior only after movements initiated elsewhere in the brain have begun.^ Surgical lesions were made in the audiovisual receiving area of the cerebellar cortex of 16 of 32 male albino rats which had previously been trained to perform two tasks for food reinforcement. During the discrimination task, the rat was required to lift rapidly either the left or the right paw, depending upon which of two auditory stimuli were presented. During the white noise task, a third auditory stimulus was presented on all trials and a lift of either paw was sufficient for reinforcement.^ Lesioned rats showed increased reaction times during performance of both tasks. Performance was not affected equivalently, however, for the two tasks. Firstly, the increased reaction times were temporary for the white noise task, disappearing by the third postsurgical session, while they were enduring for the discrimination task, showing no diminishment across the seven postsurgical sessions. Secondly, only rats which were trained at least 30 sessions showed increased reaction times during both tasks. Rats which received fewer sessions showed increased reaction times only for the white noise task. Thirdly, among the control rats, reaction times during the discrimination phase of a session were highly predictive of the reaction times which were found during the white noise phase of the same session. Among the lesioned animals, the relationship between performances of the two tasks within a session was entirely disrupted.^ The pattern of the results was consistent with a theory in which the cerebellum learns to rapidly initiate movements on the basis of the existing sensory context. The results were not consistent with theories in which cerebellar activity does not begin until movement is occurring nor with those in which the cerebellar contribution is determined by the motoric form of the movement. ^

Subject Area

Physiological psychology

Recommended Citation

LUSSIER, JAMES WILLIAM, "THE CEREBELLUM AND LEARNED RAPID RESPONSES" (1982). ETD Collection for Fordham University. AAI8219250.
http://fordham.bepress.com/dissertations/AAI8219250

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