AUTONOMIC HYPOTHALAMIC OUTBURSTS ELICITED BY CEREBELLAR STIMULATION

Abstract

Somatic and autonomic outbursts of sham rage were observed in the thalamic cat (1) during cerebellar stimulation or (2) immediately thereafter as a rebound effect. Histological controls showed that the rostral and central parts of the fastigial nuclei yielded sham rage outbursts during stimulation, whereas the rebound effects were elicited from midline fibers between the posterior parts of the roof nuclei and from the buried folia of tuber, pyramis and uvula. The cerebellar origin of these effects is shown by their abolition following histologically controlled destruction of the stimulated structures. Diencephal-ic centers are essential since the responses were abolished by rostral midbrain electrocoagulation. Anatomical and physiological evidence suggests that the cerebellar influence on diencephalic structures might be mediated over the ascending reticular formation.