Abstract
The use of motor imagery for rehabilitation assumes that it is a simulation of overt movement. Recent evidence suggests otherwise, as unlike overt movement, motor imagery cannot update internal models which are crucial for predicting and improving movement outcomes. This may be because motor imagery lacks explicit knowledge of errors, key to updating internal models. To explore this, we exposed participants to a prism environment that shifted vision leftwards. All groups initially completed 20 physical reach-and-point trials, immediately followed by 230 more physical pointing trials [physical practice (PP, n = 22)], 230 imagined pointing movements [motor imagery (MI, n = 7)], 230 trials of an unrelated task [control (n = 22)] or went straight to the post-test (i.e., no pointing trials) [physical practice none (PP-None, n = 22)]. If motor imagery requires explicit knowledge of errors to update internal models, we hypothesized that MI would show aftereffects (pointing in the opposite direction of the prism shift), similar to PP, and unlike control and PP-None. Preliminary results show significant aftereffects in all groups (PP = 4.73° ± 0.27°; MI = 2.49° ± 0.48°; CTRL = 2.54° ± 0.27°; PP-None = 3.11° ± 0.27°) but no significant differences between the MI, control, and PP-None groups at post-test. Our results suggest that even with explicit knowledge of errors, motor imagery cannot update internal models like overt movement. These findings amplify the need to better understand motor imagery-based learning to ensure its appropriate application in rehabilitation.
