Adaptive plasticity in vestibular influences on cardiovascular control

Data collected in both human subjects and animal models indicate that the v estibular system influences the control of blood pressure. In animals, peri pheral vestibular lesions diminish the capacity to rapidly and accurately m ake cardiovascular adjustments to changes in posture. Thus, one role of ves tibulo-cardiovascular influences is to elicit changes in blood distribution in the body so that stable blood pressure is maintained during movement. H owever, deficits in correcting blood pressure following vestibular lesions diminish over time, and are less severe when non-labyrinthine sensory cues regarding body position in space are provided. These observations show that pathways that mediate vestibulo-sympathetic reflexes can be subject to pla stic changes. This review considers the adaptive plasticity in cardiovascul ar responses elicited by the central vestibular system. Recent data indicat e that the posterior cerebellar vermis may play an important role in adapta tion of these responses, such that ablation of the posterior vermis impairs recovery of orthostatic tolerance following subsequent vestibular lesions. Furthermore, recent experiments suggest that non-labyrinthine inputs to th e central vestibular system may be important in controlling blood pressure during movement, particularly following vestibular dysfunction. A number of sensory inputs appear to be integrated to produce cardiovascular adjustmen ts during changes in posture. Although loss of any one of these inputs does not induce lability in blood pressure, it is likely that maximal blood pre ssure stability is achieved by the integration of a variety of sensory cues signaling body position in space. (C) 2000 Elsevier Science Inc.