Selective influence of auditory distractors on motor cortex excitability

The diversion of attention from a primary goal by irrelevant events is known as attention capture, and is often followed by a directed action. The hypothesis that corticospinal excitability is modulated by attention capture was tested using transcranial magnetic stimulation. Participants watched a video while sounds were intermittently presented. Motor evoked potentials (MEPs) were elicited in each hand using transcranial magnetic stimulation 1 s after sound onset. MEP amplitudes were assessed as a function of hand (dominant, nondominant), sound location (ipsilateral or contralateral to hand location), and sound sample valence (negative, neutral, positive). Results showed that MEP amplitudes increased during sound presentation, but only for the dominant hand. There were no effects of location or emotional valence. The selective modulation of the dominant hand motor cortex may indicate that auditory events can prime the preferred hand for action.