XIII Modification of Vestibular Sensitivity in the Rat

Abstract

The spontaneous activity response reflects the effects of rotation following experiential and organismic changes in a fashion similar to the more traditional physiological indices. In addition, the vestibular apparatus is definitely implicated in mediating the activity changes. The behavioral measure thus appears to provide a valid and sensitive test of the effects of vestibular stimulation in the rat. The relationship of the activity decrement produced by rotation in intact animals to what is termed "motion sickness" in other species is of considerable interest. While the lack of a criterion end point such as vomiting precludes direct comparison, the disruption of behavior might well be considered as a manifestation of sickness in the rat. Vestibular stimulation is reported to produce an activity decline prior to vomiting in squirrel monkeys and dogs. If well-known anti-motion sickness drugs can be shown to modify the rat''s response to rotation, this behavioral index might provide a 1st step for rapid initial screening of assessment of new drugs in lower animals. It may also provide a useful measure in experiments dealing with the basic functions of the vestibular system.