Paper presented at the Rhythm Production and Perception Workshop, Amsterdam, Netherlands
Title: Functional dissociation between delta and beta oscillations for rhythmic entrainment
Authors: Andrew Chang, Alexandra Rice, Dan Bosnyak & Laurel J. Trainor
Abstract: The phase of delta band (1 – 3 Hz) and the induced power of beta band (15 – 25 Hz) oscillations in auditory cortex reflect neural mechanisms involved in predicting the onset timing of the next beat during rhythmic entrainment, and the coupling strength between these them is positively associated with the accuracy of temporal prediction. Following dynamic attending theory, we hypothesized that the delta activity reflects an oscillatory time frame, and the beta activity reflects dynamic temporal attention. Together, the alignment between these two represents temporal expectations. We recorded EEG while participants passively listened to an isochronous auditory tone sequence (IOI 500 ms; 2 Hz). In different conditions, tones with deviant pitch occurred pseudorandomly on either 10% or 20% of trials.. We expected the deviant pitches to trigger involuntary bottom-up changes in attention, with stronger effects the rarer the deviants, but that the steady IOI would provide a predictable oscillatory time frame. The results of 16 participants showed that the delta phase and induced beta power both entrained to 2 Hz in standard trials. Consistent with our hypothesis, on deviant trials, the induced power in low-beta band (15 – 20 Hz) was larger on deviant than standard trials, and stronger the rarer the deviants (10% vs. 20%). Conversely, the delta phase remained unchanged between standard and deviant trials. Furthermore, the delta-beta coupling strength decreased on deviant compared to standard trials, consistent with the influence of attention on beta band power but not delta band phase.