A dissociation between visual and motor workspace inhibits generalization of visuomotor adaptation across the limbs

摘要

We have previously shown that the pattern of interlimb transfer following visuomotor adaptation depends on whether the two arms share task-space at a given workspace location: When the two arms adapted to a novel visuomotor rotation in unshared, lateral workspaces, transfer of movement direction information occurred symmetrically (i.e., from dominant to nondominant arm, and vice versa). When the two arms shared the same task-space, however, transfer of the same information became asymmetric (i.e., only from dominant to nondominant arm). In the present study, I investigated the effect of a conflict between visual and proprioceptive information of task-space on the pattern of interlimb transfer, by dissociating visual and motor workspaces. I hypothesized that the pattern of interlimb transfer would be determined by the way the motor control system uses available sensory information, and predicted that depending on whether the system relied more on vision or proprioception, transfer would occur either symmetrically or asymmetrically. Surprisingly, the results indicated that despite substantial adaptation to a novel visuomotor rotation, no transfer occurred across the arms when the visual and motor workspaces were dissociated in space. Based on this finding, I suggest that when a conflict exists between visual and proprioceptive information with respect to the sharing of the given task-space by the two arms, it interferes with executive decisions made by the motor control system in determining hand dominance at a given workspace, which results in a lack of transfer across the arms.