SCAPPS location:London (Ontario, CA) date:16-18 October 2014
When aiming to a visual illusion, bias is influenced by the amount and type of visual information available. In the present experiment, visual information was manipulated while the participants performed goal-directed hand movements with or without proprioceptive perturbation. The effect of muscle tendon vibration (TV) was investigated on both the preferred and non-preferred hands of left- and right-handers.We expected the influence of vision on the TV effect to be stronger on the right hands of both left- and right-handers. As well, we hypothesized that the non-preferred hands of both groups would be more susceptible to the proprioceptive illusion effects. The results showed that TV effects were stronger on the proprioceptively guided non-preferred hand in both left- and right-handers (20% amplitude reduction versus 15.9% on preferred hand). Interestingly, the impact of vision (i.e., larger illusion effects in fixation than in saccade condition) was seen on the right hand of both handedness groups. Interestingly, left-handers also showed this difference in the left (preferred) hand (fixation: 17.1%; saccade: 14.7%). These results indicate that both hand/hemisphere specializations and also hand preference contribute to the observed effects. Although some of the effects were similar in left- and right handers, the vibration effects were larger in the non-preferred hands, and the right hand/left hemisphere system made use of visual input when provided the opportunity. It appears that lifelong visuomotor training results in an advantage of the left (preferred) hand of left handers for using visual information to suppress illusory bias. These results confirm that some hand/hemisphere specializations are independent of hand preference. They highlight the flexibility of the visuo-manual control system based on the constraints imposed by the task demands and the available information.