Olivia Ipwanshek^1,2 (), Karsten Babin², Paul L Gribble^1,2,3,4, Jody C Culham^1,2,3; ¹Department of Psychology, Western University, Canada, ²Centre for Brain and Mind, Western University, Canada, ³Neuroscience Program, Western University, Canada, ⁴Department of Physiology & Pharmacology, Western University, Canada

Virtual reality (VR) offers a unique opportunity to investigate how the brain integrates vision and action, as it allows the visual representation of the body to be manipulated in ways otherwise impossible in the real world. A central theoretical question is how the appearance of one’s own hand shapes the planning and control of movement. We used a 3D VR reaching task to investigate how seeing a right or left virtual hand affects motor performance when controlling a KINARM robotic device with either the dominant (right) or non-dominant (left) arm. Right-handed participants (n=36) performed centre-out reaches while wearing a VR headset calibrated to match the physical space of the robot, allowing for the independent manipulation of the physical controlling arm (right or left) and the virtual hand seen (right or left). This design created match and mismatch conditions that allowed us to disentangle the effects of the seen hand from the acting hand in motor control. Trajectory analyses revealed that when participants controlled the robot with their dominant right arm, seeing it visually represented as a left hand produced significantly greater curvature error than seeing a right hand. Notably, this effect did not occur for the non-dominant left arm, which showed comparable performance regardless of virtual hand identity. These findings suggest that accurate visual representation of the right/dominant arm may be particularly important for precise motor control, and that visuomotor mismatch selectively disrupts performance when it involves the right/dominant limb. More broadly, this work demonstrates how VR can be leveraged to investigate the contributions of vision to motor control and may have applications for motor rehabilitation, as in mirror-therapy treatments for stroke and phantom-limb pain.

Acknowledgements: Natural Sciences and Engineering Council of Canada Discovery grant (04271-2022-RGPIN)