Investigating Implicit and Explicit Contributions to Dual Visuomotor Adaptation

Abstract

The ability to seamlessly switch between different visuomotor mappings is critical for effective interactions in a dynamic environment. This experiment aimed to establish the implicit (unconscious) and explicit (conscious strategy) contributions to adapting one's reaches to two small visuomotor mappings simultaneously (dual visuomotor adaptation). 59 right-handed participants were divided into two groups: a Dual adaptation group and a Single adaptation group. The Dual group trained to reach when cursor feedback was rotated (i) 20° clockwise (CW) relative to hand motion when a target was displayed in the left visual workspace and (ii) 20° counterclockwise (CCW) relative to hand motion when a target was displayed in the right visual workspace. The Single group trained to reach with just one 20° cursor distortion (CW or CCW) regardless of visual workspace. Results revealed that while all participants adapted their reaches to the distorted cursor feedback, those who reached with a Single CCW cursor distortion demonstrated significantly greater visuomotor adaptation in comparison to those who reached with a Single CW cursor distortion or with two opposing cursor distortions (Dual group). For all groups, visuomotor adaptation arose implicitly. However, the Dual group demonstrated significantly less implicit adaptation than participants who trained with a Single CW distortion even after additional reach training trials. Together, these results indicate a role for implicit processes in simultaneously updating one's reaches to two small visuomotor mappings.