Entraining the Brain: Applications to Language Research and Links to Musical Entrainment

Clayton’s paper provides a clear and accessible summary of the significance of entrainment for music making, and for human behaviour in general. He notes the central role of metrical structure in musical entrainment, the possible role of oscillatory neural activity, and the core notion of phase alignment. Here I show how these same factors are central to speech processing by the human brain. I argue that entrainment to metrical structure is core to linguistic as well as musical human behaviour. I illustrate this view using entrainment data from developmental dyslexia. The core role of entrainment in efficient speech processing suggests that language difficulties in childhood may benefit from music-based remediation that focuses on multi-modal rhythmic entrainment. Alignment of linguistic and musical metrical structure seems likely to be fundamental to successful remediation

Neural entrainment to the beat in multiple frequency bands in 6-7-year-old children

Entrainment to periodic acoustic stimuli has been found to relate both to the auditory and motor cortices, and it could be influenced by the maturity of these brain regions. However, existing research in this topic provides data about different oscillatory brain activities in different age groups with different musical background. In order to obtain a more coherent picture and examine early manifestations of entrainment, we assessed brain oscillations at multiple time scales (beta: 15-25 Hz, gamma: 28-48 Hz) and in steady state evoked potentials (SS-EPs in short) in 6-7-year-old children with no musical background right at the start of primary school before they learnt to read. Our goal was to exclude the effect of music training and reading, since previous studies have shown that sensorimotor entrainment (movement synchronization to the beat) is related to musical and reading abilities. We found evidence for endogenous anticipatory processing in the gamma band related to meter perception, and stimulus-related frequency specific responses. However, we did not find evidence for an interaction between auditory and motor networks, which suggests that endogenous mechanisms related to auditory processing may mature earlier than those that underlie motor actions, such as sensorimotor synchronization

Got rhythm? Better inhibitory control is linked with more consistent drumming and enhanced neural tracking of the musical beat in adult percussionists and nonpercussionists

Musical rhythm engages motor and reward circuitry that is important for cognitive control, and there is evidence for enhanced inhibitory control in musicians. We recently revealed an inhibitory control advantage in percussionists compared with vocalists, highlighting the potential importance of rhythmic expertise in mediating this advantage. Previous research has shown that better inhibitory control is associated with less variable performance in simple sensorimotor synchronization tasks; however, this relationship has not been examined through the lens of rhythmic expertise. We hypothesize that the development of rhythm skills strengthens inhibitory control in two ways: by fine-tuning motor networks through the precise coordination of movements “in time” and by activating reward-based mechanisms, such as predictive processing and conflict monitoring, which are involved in tracking temporal structure in music. Here, we assess adult percussionists and nonpercussionists on inhibitory control, selective attention, basic drumming skills (self-paced, paced, and continuation drumming), and cortical evoked responses to an auditory stimulus presented on versus off the beat of music. Consistent with our hypotheses, we find that better inhibitory control is correlated with more consistent drumming and enhanced neural tracking of the musical beat. Drumming variability and the neural index of beat alignment each contribute unique predictive power to a regression model, explaining 57% of variance in inhibitory control. These outcomes present the first evidence that enhanced inhibitory control in musicians may be mediated by rhythmic expertise and provide a foundation for future research investigating the potential for rhythm-based training to strengthen cognitive function

Étude de la modularité de la synchronisation à la pulsation musicale : synchronisation sensorimotrice dans l’amusie congénitale

À l’écoute de musique, la plupart des gens ressentent naturellement l’envie de bouger au rythme de celle-ci. Bien que cette activité puisse paraitre anodine, la capacité à émettre un mouvement en synchronie avec une pulsation rythmique (ou le beat en anglais) repose sur l’interaction d’un ensemble de mécanismes complexes. L’habileté à percevoir la pulsation dans la musique, et à pouvoir prédire l’occurrence des temps marquant celle-ci, serait entre autres possible grâce à un mécanisme d’entrainement. La spécificité des processus d’entrainement à la pulsation musicale demeure cependant débattue. Afin de mieux cerner la modularité de l’entrainement au beat musical, le travail de recherche présenté dans cette thèse avait pour objectif de caractériser, chez des individus présentant une amusie congénitale, la capacité à se synchroniser à la musique, au chant et à la parole. L’amusie congénitale est un trouble d’origine neurodéveloppementale qui affecte, selon le cas, l’habileté à percevoir dans la musique les fines variations mélodiques ou la capacité à percevoir et à se synchroniser au beat. L’étude 1 visait d’abord à déterminer l’influence d’une amusie congénitale affectant le traitement des hauteurs sur la perception et la synchronisation au beat. Les résultats ont mis en évidence, dans 50 % des cas, une faible capacité à se synchroniser avec le beat de séquences rythmiques contenant ou non des variations mélodiques. Néanmoins, des cas de dissociation claire ont pu être identifiés. Ainsi, bien que dans la majorité des cas une perception des variations de hauteurs déficiente semble s’accompagner d’une capacité réduite à percevoir la pulsation musicale et s’y synchroniser, ces deux habiletés peuvent également se trouver atteintes de façon isolée. Cette dissociation se constate d’ailleurs chez les individus ayant pris part aux études subséquentes de la thèse, qui ne parviennent pas à synchroniser un mouvement simple avec le beat, tout en demeurant dans les limites de la norme à une épreuve mesurant la perception des hauteurs en contexte mélodique. Les études 2 et 3 ont été élaborées dans le but d’investiguer la modularité de l’entrainement à la pulsation musicale en regard d’hypothèses suggérant que ce mécanisme soit plutôt partagé avec d’autres domaines tels que le langage. L’étude 2 avait pour objectif de tester l’implication des processus d’entrainement au beat musical dans la synchronisation à la parole. Pour se faire, un groupe d’individus ayant une amusie congénitale touchant la synchronisation au beat et des participants neurotypiques appariés ont complété une tâche de synchronisation motrice sur des extraits de chant et de parole. Les participants devaient taper du doigt la pulsation rythmique perçue dans des phrases chantées, dites avec un rythme régulier (comparable à du rap), et énoncées de manière naturelle (rythme irrégulier). Dans ces trois conditions, les individus atteints d’amusie sont moins bien parvenus à se synchroniser, comparativement aux participants contrôles. Ce résultat suggère l’existence d’un mécanisme d’entrainement commun à la parole et à la musique. Enfin, dans l’étude 3, nous avons testé une hypothèse selon laquelle la capacité d’imitation vocale et la synchronisation au beat reposeraient en partie sur un mécanisme commun de couplage sensorimoteur. Dans cette étude, des participants ayant une difficulté à se synchroniser au beat, ainsi que des participants contrôles appariés, ont chanté une mélodie connue avec et sans paroles, d’abord de mémoire, ensuite par imitation d’un modèle, et enfin en synchronie avec le modèle et avec un métronome. Les résultats de cette étude montrent, en premier lieu, que la capacité des participants ayant un trouble de la synchronisation au beat à chanter avec justesse est comparable à la population générale. Certains participants ont tout de même pu être identifiés comme étant de mauvais chanteurs. Cependant, nous n’avons pas pu mettre en évidence d’association claire entre la justesse du chant et l’habileté à se synchroniser à une pulsation rythmique. En revanche, la faible habileté à se synchroniser au beat était généralisée à la difficulté à se synchroniser par le chant. Dans l’ensemble, les résultats de la thèse suggèrent que, dans les cas d’amusie congénitale étudiés, la capacité à produire un mouvement synchronisé à la musique émergerait d’un mécanisme plus général d’entrainement permettant la synchronisation à d’autres stimuli auditifs, y compris la parole.Music naturally compels most individuals to engage in rhythmic behaviors. We can think of someone tapping his foot or nodding his head to the beat of music. Synchronizing a movement to the beat may seem simple at first, but it is a complex behavior. At least, someone needs to be able to extract the beat and predict the timing of upcoming beats. This ability to couple movement and music could be achieved through entrainment. The specificity of beat-based entrainment to music is, however, debated. This thesis aimed to assess sensorimotor synchronization to music, singing, and speech in congenital amusia, in order to test the specificity of entrainment mechanism to musical beat. Congenital amusia refers to a neurodevelopmental disorder that can affect, depending on cases, pitch perception (pitch-based amusia) or beat perception (beat-based amusia). In the first study, individuals with pitch-based amusia were tested on their ability to perceive and to produce musical beat. The results indicated that about fifty percent of pitch-based amusic participants had associated deficits in beat production and beat perception. Still, cases of dissociation, with spared ability to synchronize to and perceive musical beat, were also identified. Therefore, findings highlight a connection between melody and rhythm processing in most cases of pitchbased amusia, although it is possible for these domains to be selectively impaired. Concurrently, cases of beat-based amusia, included in Study 2 and Study 3, had a specific impairment in their ability to synchronize a simple movement with musical beat, while performing within the normal range on a standardized measure of pitch perception. Study 2 and Study 3 had the objective to test hypotheses regarding the domain specificity of beat-based entrainment. In Study 2, entrainment to speech and music was compared in participants with beat-based amusia. Participants had to align taps to the perceived regularity in the rhythm of naturally spoken, regularly spoken (similar to rap music), and sung sentences. It was found that the amusic participants synchronized less accurately in all conditions. This result suggests that a general entrainment mechanism could maybe drive sensorimotor synchronisation to speech and music. In Study 3, we assessed the hypothesis according to which vocal imitation and beatbased synchronisation could share a common sensorimotor coupling mechanism. Here, participants had to sing a familiar song from memory, after hearing a model, with the model, and with a metronome. First, results from this study indicate that vocal-pitch abilities are similar to the general population in beat-based amusia, when singing from memory. Cases of poor-pitch singing could still be identified among amusic participants. However, no clear association between synchronization to beat and vocal-pitch abilities was found. Nonetheless, results from synchronous singing and singing with a metronome mirrored results from tapping tasks, indicating a lowered ability to synchronize with the beat across contexts in beat-based amusia. Overall, by investigating sensorimotor synchronization to music and singing in congenital amusia, this thesis work provides new evidence that sensorimotor synchronization to musical beat may be built on a domain-general entrainment mechanism that could be involved with auditory stimuli that are not beat-based, like speech

Working Memory and Auditory Imagery Predict Sensorimotor Synchronisation With Expressively Timed Music

Sensorimotor synchronisation (SMS) is prevalent and readily studied in musical settings, as most people are able to perceive and synchronise with a beat (e.g., by finger tapping). We took an individual differences approach to understanding SMS to real music characterised by expressive timing (i.e., fluctuating beat regularity). Given the dynamic nature of SMS, we hypothesised that individual differences in working memory and auditory imagery—both fluid cognitive processes—would predict SMS at two levels: (1) mean absolute asynchrony (a measure of synchronisation error) and (2) anticipatory timing (i.e., predicting, rather than reacting to beat intervals). In Experiment 1, participants completed two working memory tasks, four auditory imagery tasks, and an SMS-tapping task. Hierarchical regression models were used to predict SMS performance, with results showing dissociations among imagery types in relation to mean absolute asynchrony, and evidence of a role for working memory in anticipatory timing. In Experiment 2, a new sample of participants completed an expressive timing perception task to examine the role of imagery in perception without action. Results suggest that imagery vividness is important for perceiving and control is important for synchronising with irregular but ecologically valid musical time series. Working memory is implicated in synchronising by anticipating events in the series

Get in Sync: Entrainment Mechanisms and Individual Characteristics Associated with Scripted-Sentence Learning in Aphasia

Script training is a well-established treatment for aphasia, but its mechanisms of action are not well understood, and it remains unclear which people with aphasia (PWA) benefit from it most. Understanding both treatment mechanisms and individual characteristics leading to scripted-sentence learning can improve treatment implementation and personalization. This dissertation investigates mechanisms and individual characteristics associated with scripted-sentence learning via a protocol adapted for Spanish-speaking PWA. A hypothesized mechanism of action in script training is speech entrainment, the unison production of sentences by patient and clinician. Entrainment relies on integrating rhythmic features, but it is unclear how these features facilitate scripted-sentence learning. Therefore, aim 1 examined the effects of speech entrainment to two types of rhythmic-enhanced sentences on scripted-sentence learning: word-stress aligned beats, which should support lexical retrieval, and metronomic beats, which should enhance memorization via chunking. In addition, identifying individual characteristics associated with scripted sentence learning can improve treatment personalization. Therefore, aim 2 examined behavioral characteristics (language, attention, and rhythmic processing) and cortical tracking (the coupling of neural oscillations and rhythmic speech properties) and their association with scripted-sentence learning. Fourteen Spanish-speaking PWA participated in a five-session learning paradigm using three conditions: word-stress aligned, metronomic, and control (no beats). Aim 1 analyses showed significant improvements over time across conditions, demonstrating successful scripted-sentence learning. Rhythmic-enhanced conditions engendered greater learning compared to the control condition, indicating that rhythmic features of speech entrainment are a key active ingredient for learning scripted sentences. The two rhythmic-enhanced conditions did not differ over time in terms of learning response, suggesting that both rhythmic manipulations may facilitate scripted-sentence learning. In aim 2 analyses, participants with more severe aphasia showed higher scripted-sentence learning estimates given that they started at a lower learning intercept and benefited more from the support that speech entrainment provides when learning highly formulaic language. More severely impaired PWA also showed lower cortical tracking, indicating lower perception of rhythmic speech properties. Lastly, attentional deficits and most rhythmic processing measures were not strongly associated with scripted-sentence learning. Finally, this is the first study to examine scripted-sentence learning in Spanish-speaking PWA, demonstrating cross-linguistic benefits of script training interventions

Genome-wide association study of musical beat synchronization demonstrates high polygenicity

Moving in synchrony to the beat is a fundamental component of musicality. Here we conducted a genome-wide association study to identify common genetic variants associated with beat synchronization in 606,825 individuals. Beat synchronization exhibited a highly polygenic architecture, with 69 loci reaching genome-wide significance (P < 5 × 10−8) and single-nucleotide-polymorphism-based heritability (on the liability scale) of 13%–16%. Heritability was enriched for genes expressed in brain tissues and for fetal and adult brain-specific gene regulatory elements, underscoring the role of central-nervous-system-expressed genes linked to the genetic basis of the trait. We performed validations of the self-report phenotype (through separate experiments) and of the genome-wide association study (polygenic scores for beat synchronization were associated with patients algorithmically classified as musicians in medical records of a separate biobank). Genetic correlations with breathing function, motor function, processing speed and chronotype suggest shared genetic architecture with beat synchronization and provide avenues for new phenotypic and genetic explorations