RPPW 2021: Neural entrainment underlies beat-based, but ... expectations in rhythm (Bouwer et al.)
This is a prerecorded video for a talk presented at the Rhythm Production and Perception Workshop 2021, held at RITMO Centre for Interdisciplinary Studies in Rhythm, Time, and Motion, University of Oslo, 22-25 June, 2021.
https://www.uio.no/ritmo/english/news...
Title: Neural entrainment underlies beat-based, but not pattern-based temporal expectations in rhythm
Authors: Fleur L. Bouwer, Johannes J. Fahrenfort and Heleen A. Slagter
Abstract: The brain continuously forms expectations about the timing of incoming information to optimize sensory processing. Such temporal expectations can be studied exceptionally well in musical rhythm, which can contain multiple types of structure that elicit temporal expectations. Rhythms often contain both a regular beat (eliciting “beat-based” expectations), and predictable patterns of absolute temporal intervals (eliciting “pattern-based” expectations). While beat-based expectations are thought to result from entrainment of low-frequency cortical oscillations to rhythmic input (Haegens & Zion Golumbic, 2018), it is unclear whether entrainment also underlies pattern-based expectations (Bouwer, Honing, & Slagter, 2020; Rimmele, Morillon, Poeppel, & Arnal, 2018). Here, we examined behavioral responses and EEG activity in silent periods following rhythmic sound sequences that allowed for beat-based or pattern-based expectations, or had random timing. In Experiment 1 (32 participants), we obtained ratings of how well probe tones presented at various times in the silence fitted the previous rhythm. While beat-based expectations affected fitness ratings for at least two beat-cycles, the effects of pattern-based expectations subsided after the expected time point in the silence. The effects of both beat-based and pattern-based expectations correlated with musical experience. In Experiment 2 (27 participants), using EEG, we found a CNV following the final tones of pattern-based and random sequences, but not beat-based sequences, suggesting that climbing neuronal activity may specifically reflect pattern-based expectations. Moreover, using a frequency tagging approach, we found enhanced power at the beat frequency for beat-based sequences not only during listening, but also during the silence, confirming a theoretical prediction of entrainment models. For pattern-based sequences, we observed enhanced power at pattern-related frequencies only during listening, but not during the silence. An additional analysis of the EEG data using multi scale entropy (MSE) as an index of signal regularity (Kloosterman, Kosciessa, Lindenberger, Fahrenfort, & Garrett, 2020) confirmed that the beat-based sequences elicited the most regular signal in the silence period. Finally, we show that multivariate pattern decoding may be a useful time-resolved alternative to spectral analyses in probing temporal expectations with EEG. Taken together, our findings suggest different mechanisms for expectations based on a regular beat and a rhythmic pattern, with the former but not the latter relying on neural entrainment.