Effects of cerebellar lesions and stimulation on the shivering tremor

Abstract

Shivering responses to cold have been studied in 21 cats subjected to lesions or stimulation of the cerebellum. Reluctance gauges taped to the extremity were used to sense accelerations produced by the tremor. Shivering of normal pattern was recorded within hours after total extirpation of the cerebellum and up to 4 weeks after surgery. Cats with lesions restricted to the anterior lobe also demonstrated apparently normal rhythm shivering. Comparison of regularity, amplitude, and rate of limb tremor in cats with a hemicerebellectomy, or lesions of one dentate, interpositus, or fastigial nucleus failed to reveal significant differences between the two sides of the body. Single shock or repetitive stimulation of medial cerebellar sites through indwelling electrodes primarily caused suppression of the amplitude of an ongoing tremor, but only at thresholds well above those needed to cause clonic or tonic movements of the limb. It is concluded that the presence of the cerebellum is not requisite for initiation and maintenance of shivering and that this organ has little regulatory effect on the rhythmicity of shivering.