Modification of Visual and Vestibular Control of Posture by Long-term Adaptation to Body-movement-yoked Visual Motion and Galvanic Vestibular Stimulation

Abstract

Human postural control is a multi-modal process with visual and vestibular information. Thus, postural sway is induced by visual motion as well as vestibular stimulation. The purpose of this study was to measure individual differences in weights on vision and vestibular senses to control posture, and to investigate if the individual weights could be modulated by long-term adaptation to visual motion or galvanic vestibular stimulation (GVS). GVS was applied through left and right mastoid processes (0.1-0.5mA, sinusoidal amplitude modulation). Both visual motion and GVS induced lateral (leftward-rightward) postural sway back and forth. Observers' body movement was measure by a force plate and a magnetic motion tracker. We measured observers' postural sway induced by visual motion or GVS before and after a 7-days adaptation task (n