HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Guerraz, M. Articles by Day, B. L. Search for Related Content PubMed PubMed Citation Articles by Guerraz, M. Articles by Day, B. L.

Expectation and the Vestibular Control of Balance

¹ Université du Sud Toulon–Var, France
² University College London

Recent experiments have shown that the visual channel of balance control is susceptible to cognitive influence. When a subject is aware that an upcoming visual disturbance is likely to arise from an external agent, that is, movement of the visual environment, rather than from self-motion, the whole-body response is suppressed. Here we ask whether this is a principle that generalizes to the vestibular channel of balance control. We studied the whole-body response to a pure vestibular perturbation produced by galvanic vestibular stimulation (GVS; 0.5 mA for 3 sec). In the first experiment, subjects stood with vision occluded while stimuli were delivered either by the subject himself (self-triggered) or by the experimenter. For the latter, the stimulus was delivered either without warning (unpredictable) or at a fixed interval following an auditory cue (predictable). Results showed that GVS evoked a whole-body response that was not affected by whether the stimulus was self-triggered, predictable, or unpredictable. The same results were obtained in a second experiment in which subjects had access to visual information during vestibular stimulation. We conclude that the vestibular-evoked balance response is automatic and immune to knowledge of the source of the perturbation and its timing. We suggest the reason for this difference between visual and vestibular channels stems from a difference in their natural abilities to signal self-motion. The vestibular system responds to acceleration of the head in space and therefore always signals self-motion. Visual flow, on the other hand, is ambiguous in that it signals object motion and eye motion, as well as self-motion.

This article has been cited by other articles:

				B. L. Day and M. Guerraz Feedforward versus feedback modulation of human vestibular-evoked balance responses by visual self-motion information J. Physiol., July 1, 2007; 582(1): 153 - 161. [Abstract] [Full Text] [PDF]