Kess Folco¹, Hannah Block¹; ¹Indiana University Bloomington

Perceiving distance is a vital component of everyday behavior, involved in actions such as reaching for a water bottle or crossing a busy road. The final neural construct of distance for actions is often an integrated multisensory representation including information from visual, proprioceptive, and motor (e.g. efference copy) systems, weighted by factors such as task goals and information reliability. These systems are also influenced by learning and experience. To test how inter-system transfer and learning changes sensory representation, participants performed target-directed reaches using a KINARM EndPoint robotic manipulandum while tracking eye movements. The task was to reproduce distances provided either visually or proprioceptively before and after adapting to a force perturbation that reduced the amount of force needed to reach the target. Preliminary results (n=7) suggest that assistive force (proprioceptive perturbation) during reaches caused a change in distance representations for both proprioceptive and visual systems. Specifically, proprioceptive distances were perceived as shorter and visual distances were perceived as longer, indicating the multisensory implications of unisensory perturbations. This effect was greater for inter-system distances, where the distance was provided to the hand but reproduced with the eye, or vice versa. In addition, continuous kinematic data from gaze and hand behavior during adaptation suggested this shift in distance perception may be related changes in gaze-hand coupling. Specifically, gaze typically leads reach trajectories, but following assistive force perturbations, gaze leads reach less. There was also a trend suggesting that people who shifted gaze-hand coupling the most saw more universal reductions in distance perception, regardless of sensory modality, across all types of reproductions. Together, these results emphasize the necessity of considering the impact that inter-system transfer may have on perception, particularly when sensory paradigms require an output behavior (e.g. button press or eye movement), which is then used to interpret the internal system.