AbstractHow sensory information is processed during goal directed reaches is affected by the modality of the target (Sober and Sabes, 2005). For example, when planning reaches to visual targets, visual information contributes more to the motor plan than proprioception. In contrast, proprioceptive information is weighted more for movements toward proprioceptive targets (e.g., body positions). These target modality-dependent weighting mechanisms influence movement errors, kinematics, and the cortical treatment of sensory information (Sarlegna and Sainburg 2007, Blouin et al., 2014); however, it is presently unknown if these processes have an effect on multisensory perception during action. Twelve participants performed reaching movements to a 30 cm target defined by either a light emitting diode (i.e., visual target) or the index fingertip of the non-reaching hand (i.e., proprioceptive target). Audiovisual stimuli known to induce illusions (Shams et al., 2000; Andersen et al., 2004) were presented at 0 ms, 100 ms, and 200 ms relative to movement onset. After each trial, participants reported the number of visual events they perceived. Similar to previous studies, for the visual target, it was found that participant's perception of visual events was better if the illusion was presented at 0 ms and 100 ms compared to the 200 ms. These time-points corresponded to high velocity portions of the limb movement (see: Tremblay and Nguyen 2010). In contrast, there was no significant modulation of audiovisual perception for reaches performed to proprioceptive targets. These results support the idea that context dependent multisensory processes influence audiovisual perception during action.
Acknowledgments: NSERC, CAMPUS FRANCE