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 shows that the frequency of the beat can be observed in the neural activity of the listener. However, the extent to which these neural responses reflect concurrent, conscious perception of musical beat versus stimulus-driven activity is a matter of debate. We investigated whether this kind of periodic brain activity, measured using electroencephalography (EEG), reflects perception of beat, by holding the stimulus constant while manipulating the listener’s perception. Listeners with minimal music training heard a musical excerpt that strongly supported one of two beat patterns (context), 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 corresponding to the beat of the preceding context, and the EEG amplitude at the beat-related frequency predicted performance on the beat induction task on a single-trial basis. Together, these findings provide evidence that auditory cortical activity reflects conscious perception of musical beat and not just stimulus features or effortful attention.