Neurophysiological Correlates of Motion Sickness: Role of Vestibulocerebellum and 'Vomiting Center' Reanalyzed,

Unexpected findings were obtained regarding 1 the role of nodulus and uvula of the vestibulocerebellum in vestibular-induced vomiting and 2 the existence of a readily identifiable, discretely localized vomiting center. Sinusoidal electrical stimulation of the vestibular labyrinths of decerebrate cats could produce vomiting and related activity similar to that observed motion sickness. These symptoms occurred in animals with lesions of the posterior cerebellar vermis that included the nodulus and uvula, indicating, by analogy, that these structures are not essential for the development of many symptoms of motion sickness in intact animals. In a second series of experiments, electrical stimulation of the brainstem was used in an attempt to localize a vomiting center to a restricted anatomical region. Vomiting proved difficult to produce a vomiting center, stimulation of which evoked readily reproducible results, could not be identified.