Abstract
Recent behavioural evidence suggests that perceptual processes are altered as one engages in goal-directed actions. For example, when an individual is presented with an audio-visual illusion (Shams et al., 2000, Andersen et al., 2004) during the high velocity portions of an upper limb reach, they are more accurate in their perception of visual stimuli (Tremblay and Nguyen, 2010). In the present study, we sought to determine if this altered perception of the audio-visual illusion at high limb velocities could be explained by engagement in visuomotor regulation processes. Fifteen participants performed rapid upper-limb reaching movements to a 30 cm target in two room light conditions (vision, no-vision). The audio-visual illusion was presented 0, 100, and 200 ms relative to movement onset and in a control/ resting condition. Analysis of the control conditions confirmed the presence of the illusion. Also, similar to previous observations, participants were more accurate in their perception of visual stimuli when their limb traveled at high limb velocity. Interestingly, this trend was not apparent when the room lights were turned off. Analysis of endpoint error and movement trajectories also revealed that trials with no vision of the limb were characterized by higher endpoint error, and a more preplanned mode of control (Heath, 2005). Altogether these results support the idea that altered perception of audiovisual stimuli during goal-directed action is associated with visuomotor regulation processes.Acknowledgments: Nserc, ORF, CFI