Abstract
Numerous studies on visuomotor control (reaching and pointing) have implicitly assumed that there is a single eye-centered representation of target location for planning movements. However, visual information about target location enters our brains through two eyes which are horizontally separated and therefore provide disparate location information. In this study, we explored whether information about target location from the two eyes is actively transformed into a common eye-centered representation for reach space or whether the eye which encodes target location matters. We dissociated the location of targets presented to the two eyes by having seven subjects pointing to a distant central target while fixating on various (near) horizontally displaced, peripherally viewed targets,, a) with the right eye only or b) left eye only. We measured the final pointing positions of the fingertip in space. When pointing to peripheral viewed targets, subjects tend to overshoot the position of the target depending on its position relative to gaze. During viewing with each eye, this gaze-dependent pattern of overshoot errors depended on target location relative to each eye independently. These results suggest that the information about target location from the two eyes is not actively transformed into a single common target representation.
Support provided by NSERC, Canada