CIRCUS MOVEMENTS IN CATS FOLLOWING MIDBRAIN STIMULATION THROUGH CHRONICALLY IMPLANTED ELECTRODES

Abstract

Contraversive circling or turning of the head in cats was obtained following stimulation of the midbrain tegmentum adjacent to the periaqueductal gray matter, the midlateral and lateral tegmentum, and in a few instances from points within the periaqueductal gray matter. Ipsiversive phenomena were obtained from the medial tegmentum ventral to the periaqueductal gray matter. Complementary evidence was obtained from cats with electrolytic lesions involving the periaqueductal gray matter and adjacent tegmentum on one side only. These animals showed ipsiversive head turning or circling. Based on the present work and reports in the literature, the author delineates a lateral tegmental area extending from the midbrain through the medulla from which contraversive turning phenomena can be elicited and a ventromedial area throughout a similar extent from which ipsiversive turning phenomena can be elicited.