Visuomotor process in movement correction: role of internal feedback loop

This study examined the role of the internal feedback loop in movement correction during interceptive actions when what the performers expect to happen changes quickly. Eleven participants performed an interceptive task with a moving target under two conditions [Brief (8 m/s) or Long (4 m/s)]. We manipulated the probability of these target conditions to induce movement correction (20-80, 50-50, and 80-20%) and delivered transcranial magnetic stimulation before movement initiation to disrupt the prediction of the movement consequence in the supplementary motor area of the cerebral cortex. In the 20% probability condition, which requires movement correction, the transcranial magnetic stimulation pulse had a significant adverse effect on the temporal error in the Brief condition, but not in the Long condition. The present results indicate that the internal feedback loop is crucial for movement correction for relatively brief interceptions.