Perceptual surprise aides inhibitory motor control.

Abstract

Neurophysiological studies of cortico-motor excitability have shown that unexpected sounds are followed by motor inhibition. In a recent study, Leiva, Parmentier, Elchlepp, and Verbruggen (2015) derived a prediction from these findings: unexpected, task-irrelevant sounds should increase the ability to withhold motor responses in a Go/NoGo task. Contrary to that prediction, they found that playing unexpected sounds before NoGo-stimuli decreased the likelihood of successful motor inhibition. However, we here argue that the relative timing of unexpected events relative to NoGo-related motor activity is key. Cortico-motor inhibition can be found only until ∼150 ms after the onset of unexpected sounds. Therefore, since Leiva et al. (2015) placed their sounds 200 ms prior to NoGo-stimuli, the inhibitory influence of unexpected sounds may have fully abated before the critical inhibitory period. Consequently, we here repeated their study, with 1 key change: task-irrelevant sounds were presented 50 ms after NoGo-stimulus onset, which ensures that cortico-motor inhibition takes place when motor inhibition is needed. Across 4 experiments, this changed timing produced the results predicted by the previous cortico-motor suppression findings: More responses were successfully withheld after unexpected sounds. These data provide new evidence for the fact that unexpected events can engage an inhibitory control process and benefit motor inhibition. (PsycINFO Database Record