Individual differences in internal oscillator properties that impact perception and production of rhythms

Abstract

Auditory tasks such as understanding speech and making music rely on our ability to track those sounds and adjust our attention based on the temporal cues they contain. An entrainment approach proposes that internal oscillatory mechanisms underlie these abilities by synchronizing to rhythms in the external world. Here, we aimed to understand the factors that facilitate and impede rhythm processing by investigating the interplay between properties of external and internal rhythms. We focused on two key properties of an oscillator: its preferred rate, the default rate at which it oscillates in the absence of input; and flexibility, its ability to adapt to changes in rhythmic context. We hypothesized that flexibility would be diminished with advancing age. Experiment 1 was a two-session duration discrimination paradigm where we developed methods to estimate preferred rate and flexibility and assessed their reliability. Experiment 2 involved a shorter version of this paradigm and a paced tapping task with matched stimulus conditions, in addition to a spontaneous motor tempo (SMT), and two preferred perceptual tempo (PPT) tasks that measured motor and perceptual rate preferences, respectively. Preferred rates, estimated as the stimulus rates with best performance for each individual were showed harmonic relationship across sessions (Experiment 1), and were correlated with SMT (Experiment 2). Interestingly, estimates from motor tasks were slower than those from the perceptual task, and the degree of slowing was consistent for each individual. In order to challenge individuals’ flexibility, we maximized the differences in stimulus rates between consecutive trials in the duration discrimination and paced tapping tasks. As a result, performance in both tasks decreased, and performance on individual trials indicated a gravitation towards the stimulus rate presented on the preceding trial. Critically, flexibility, quantified as individuals’ ability to adapt to faster-than-previous rates, decreased with age. Overall, the findings support that an oscillatory system with domain-specific rate preferences underlies perception and production of rhythms, and that this system loses its ability to flexibly adapt to changes in the external rhythmic context in ageing.

Modeling rhythm perception and temporal adaptation: top-down influences on a gradually decaying oscillator

“…This behavior (complete entrainment decay) is more like a complete erasure of the oscillator's memory for the stimulus rate and is inconsistent with the base model's assumption of sustained oscillations within trials. Moreover, findings from the current experiment (Kaya et al, 2023) and previous literature show that responses on individual trials of perceptual (Wiener et al, 2014;Kim & Alais, 2021;Liberman et al, 2014;Jones & McAuley, 2005) and motor (Kaya & Henry, 2022;Motala et al, 2020) tasks reflect a gravitation toward the properties of the stimulus presented on the previous trial. We have suggested that these 'history effects' might stem from incomplete entrainment decay: the underlying oscillator sustains its oscillation at the previous trial's entrained rate to an extent, rather than fully decaying to its preferred rate.…”

“…Based on the prediction that detuning will affect an oscillator's ability to successfully synchronize to a stimulus rhythm, we quantified preferred rate as the stimulus rate with maximum duration-discrimination accuracy (Kaya et al, 2023). Here, we found that participants' preferred rate estimates corresponded either directly to their P0 parameter estimate or its integer-ratios, indicating improved accuracy at oscillators' preferred rate and its (sub)harmonics.…”

“…Here, we describe the task procedure, the derived measures, and methods for estimation of preferred rate and flexibility. Detailed information regarding participants, experimental procedure, apparatus and data cleaning are provided in (Kaya et al, 2023).…”

“…We assessed correlations between estimates across sessions using Pearson correlation for Wp and Wdecaybetween, and Spearman correlation for Wɸ, P0 and Wdecaywithin , whose random-order session distributions required nonparametric tests. Additionally, to assess harmonic relationships between the P0 estimates across sessions, we used the permutation test developed in a previous study (Kaya & Henry, 2022) and used for same purposes in the analyses of empirical estimates (Kaya et al, 2023) of preferred rate in the current study (see Empirical data section). We additionally clustered the P0 estimates based on their distance from the unity line, using cluster function in MATLAB, to further explore the estimates' harmonic correspondence across sessions.…”

“…Two main properties of an oscillator that determine how well it synchronizes to an external rhythm are 1) the rate at which it naturally oscillates in the absence of any input, its natural frequency (Pikovsky et al, 2003), referred to as 'preferred rate' here; and 2) its 'flexibility', which refers to how well it adapts to changes in the external rhythmic context. In previous studies, we developed methods to estimate these properties of the oscillators underlying perceptual (Kaya et al, 2023) and motor (Kaya & Henry, 2022) responses. Both preferred rate and flexibility estimates were reliable across multiple testing sessions but were slower for motor than perceptual tasks.…”