Corticomotor excitability changes during mirrored or asynergistic wrist movements.

The current study used transcranial magnetic stimulation (TMS) of the right primary motor cortex (M1) during bimanual contractions to examine facilitatory and inhibitory influences on the contralateral, target extensor carpi radialis muscle (ECR) during changes in the task demands of the ipsilateral (task) ECR. The bimanual contractions were either mirrored (isometric wrist extension bilaterally) or more difficult asynergistic (asymmetric [wrist extension paired with wrist radial deviation]) contractions. TMS-induced motor evoked potentials (MEPs) and cortical silent periods (CSPs) were recorded during the execution of visually guided ramp and hold tasks.