Motion parallax from microscopic head movements during visual fixation
The purpose of this study was to investigate the contribution of the vestibular system to postural control during monocular vision using binaural-bipolar galvanic vestibular stimulation (GVS). Four visual (both eyes, dominant eye, non-dominant eye, and no vision) conditions were tested during GVS in five healthy subjects while focusing on a target placed in front of them. GVS evoked similar upper body postural sway during both monocular and no vision conditions that were significantly greater to those during binocular vision. Changes in ground reaction forces to the anode side followed that same trend, although data for vision with the dominant eye were not significantly different from that for binocular vision. These data suggest an increase in the weighting of vestibular afferent information during monocular vision for standing postural control.