Steady state-evoked potentials of subjective beat perception in musical rhythms

Synchronization of movement to music is a seemingly universal human capacity that depends on sustained beat perception. Previous research has suggested that listener's conscious perception of the musical structure (e.g., beat and meter) might be reflected in neural responses that follow the frequency of the beat. However, the extent to which these neural responses directly reflect concurrent, listener-reported perception of musical beat versus stimulus-driven activity is understudied. We investigated whether steady state-evoked potentials (SSEPs), measured using electroencephalography (EEG), reflect conscious perception of beat by holding the stimulus constant while contextually manipulating listeners' perception and measuring perceptual responses on every trial. Listeners with minimal music training heard a musical excerpt that strongly supported one of two beat patterns (context phase), followed by a rhythm consistent with either beat pattern (ambiguous phase). During the final phase, listeners indicated whether or not a superimposed drum matched the perceived beat (probe phase). Participants were more likely to indicate that the probe matched the music when that probe matched the original context, suggesting an ability to maintain the beat percept through the ambiguous phase. Likewise, we observed that the spectral amplitude during the ambiguous phase was higher at frequencies that matched the beat of the preceding context. Exploratory analyses investigated whether EEG amplitude at the beat-related SSEPs (steady state-evoked potentials) predicted performance on the beat induction task on a single-trial basis, but were inconclusive. Our findings substantiate the claim that auditory SSEPs reflect conscious perception of musical beat and not just stimulus features.