Abstract
Virtual reality tasks are advantageous for training (e.g., risk reduction) and investigating fundamental sensorimotor control problems (e.g., visuomotor adaptation). However, performing goal-directed movements in virtual environments can involve visual feedback delays and reduce limb representations (e.g., whole-limb vs. virtual hand). While previous work aimed to understand visuo-proprioceptive weighting in virtual environments, the current study was designed to understand the influence of pointing in virtual vs. real environments on sensorimotor control processes. Participants performed reaching movements in two conditions: directly seeing their hand or virtually using a cursor that represented their index fingertip's position. Visual feedback of the hand or cursor was provided during movement planning only or during movement planning and online control. Performance was quantified using efficiency (bits/second) calculated using amplitude, effective target width, and movement time. Overall, pointing with vision of the limb was significantly more efficient than pointing with vision of the cursor in both the planning only and planning and online control conditions. Further, the increase in efficiency between the cursor and the limb conditions was significantly greater in the planning and online control condition compared to the planning only condition. The findings suggest that representing the limb using a virtual object (i.e., a cursor) can reduce the efficiency of upper-limb movements. Moreover, additional reductions in efficiency can be attributed to delays between the visual cursor representation of the limb and the actual limb location online. Overall, this work replicates and extends previous findings that movement in virtual environments differs from movement in real environments.
