Enhanced Visual Processing When Reaching for Targets Presented Near the Hands
33.308, Sunday, 18-May, 8:30 am - 12:30 pm, Jacaranda Hall
Karolina Beben1, Liana Brown1; 1Psychology, Trent University
Placing a hand near a target seems to influence how it is processed. One possible explanation for near-hand effects is that bimodal neuron recruitment contributes to a more robust representation of targets appearing near the hands in comparison to targets far from the hands. Neurophysiological studies have shown that near-hand targets recruit visual-tactile bimodal cells, and that the response of these cells varies with the distance between the target and nearby hand. The purpose of the current study is to determine if the representation of target location for reaching is influenced by the presence of the hand near the target. Participants reached for targets that appeared either near or far from (1) the participant’s invisible resting left hand or (2) a visual cue (absence of left-hand). We predicted that if hand-proximity effects arise from the recruitment of visual-tactile bimodal cells then participants should reach for targets more quickly and with greater accuracy and precision when the hand is in the workspace, and that these measures should vary with the distance between the hand and target. Right-hand reaching movements were tracked using a motion tracker to measure movement timing, end-point accuracy and precision. Our results showed that when the resting hand was present there was a reduction in spatial error, error variability, and movement time when compared to the no-hand condition. Likewise, these measures varied significantly with the distance between the target and hand. Overall, these results suggest that the visual representation of the target is enhanced through the recruitment of multisensory resources when the target appears near but not far from the hand.