Abstract
Each saccadic eye movement modifies the retinal coordinates of visual objects. Despite the constant changes in retinal inputs, we perceive the visual world as stable. Visual stability is probed in the laboratory by asking participants to perform saccades to targets that are displaced during movement execution and measuring their perception of those displacements. Correct performance depends on an accurate spatiotopic representation of object positions and thus can be used as an index of spatiotopic processing. Displacing targets during the execution of the movement also leads to oculomotor plasticity: artificial undershoots caused by stepping the target forwards tend to be followed by larger-amplitude saccades, while artificial undershoots caused by stepping the target backwards tend to be followed by smaller-amplitude saccades. Performance on the spatiotopic task is inversely related to oculomotor plasticity: the better participants are at aligning pre- to post-saccadic retinal coordinates on a spatiotopic map, the less their saccade amplitudes change from trial to trial. However, variations of performance in the spatiotopic task were not always mirrored by variations in oculomotor plasticity. For example, performance on the spatiotopic task can be enhanced by inserting a temporal blank between saccade offset and displaced target appearance, but results suggest that the blank does not interfere with plasticity, suggesting that constructing spatiotopic representations across eye movements and oculomotor plasticity depend on only partially overlapping processes.
Meeting abstract presented at VSS 2014