Electrophysiological evidence of temporal preparation driven by rhythms in audition.

Reaction speed to respond to an auditory target stimulus is enhanced when it is presented at a moment matching the temporal structure of a preceding regular rhythm (Sanabria et al., 2011). However, the electrophysiological correlates of this behavioural enhancement remain unknown. In the present study, participants' performed a simple auditory reaction time task in which a regular rhythm with either a fast (400 ms interval between the tones making the rhythm) or a slow (900 ms interval between the tones making the rhythm) was presented prior to the target. The target tone could be presented, with the same probability, 400 ms or 900 ms after the offset of the rhythmic sequence. The behavioural results showed that the fastest responses were obtained when the target appeared in synchrony with the preceding rhythm (e.g., the target was presented 900 ms after the slow rhythm). This behavioural benefit was accompanied by amplitude modulations of the N1 potential and the P2 potential, both related to the processing of the auditory target. Crucially, these electrophysiological modulations were obtained in both the fast and the slow rhythm conditions. The current research demonstrates that rhythms with different paces can drive temporal preparation exogenously, affecting early and late stages of auditory neural processing.