OBSERVATIONS ON THE CENTRAL CONTROL OF SHIVERING AND OF HEAT REGULATION IN THE RABBIT

Abstract

In a series of experiments on the localization of the central control of shivering in the rabbit, the brain stem was transected at various levels, and the shivering capacity tested shortly thereafter. Shivering still occurred after complete transection about 2 mm. above the calamus scriptorius, although there is evidence that after transection through or below the diencephalon, the threshold for this reflex is raised. At about the level of the calamus typical shivering was replaced by a form of muscular response less integrated, less generalized, and less intense, in the form of clonic spasms and inco-ordinated tremors. It would seem that the intensity of muscular response to cooling is diminished gradually as the medulla oblongata is progressively sectioned. There is no abrupt disappearance of shivering. Inasmuch as decerebrate rigidity is similarly affected by successive cuts through the medulla, the possibility of a relation between these phenomena is of interest. Gains in body temperature due to shivering occurred in many of the animals, indicating that, with most of the brain stem functionally removed, some vestige of the heat regulating mechanism was still present. The bearing of this on the question of a diencephalic center for heat regulation is discussed.