Music as a scaffold for listening to speech: Better neural phase-locking to song than speech

Rhythmically Modulating Neural Entrainment during Exposure to Regularities Influences Statistical Learning

The ability to discover regularities in the environment, such as syllable patterns in speech, is known as statistical learning. Previous studies have shown that statistical learning is accompanied by neural entrainment, in which neural activity temporally aligns with repeating patterns over time. However, it is unclear whether these rhythmic neural dynamics play a functional role in statistical learning or whether they largely reflect the downstream consequences of learning, such as the enhanced perception of learned words in speech. To better understand this issue, we manipulated participants' neural entrainment during statistical learning using continuous rhythmic visual stimulation. Participants were exposed to a speech stream of repeating nonsense words while viewing either (1) a visual stimulus with a "congruent" rhythm that aligned with the word structure, (2) a visual stimulus with an incongruent rhythm, or (3) a static visual stimulus. Statistical learning was subsequently measured using both an explicit and implicit test. Participants in the congruent condition showed a significant increase in neural entrainment over auditory regions at the relevant word frequency, over and above effects of passive volume conduction, indicating that visual stimulation successfully altered neural entrainment within relevant neural substrates. Critically, during the subsequent implicit test, participants in the congruent condition showed an enhanced ability to predict upcoming syllables and stronger neural phase synchronization to component words, suggesting that they had gained greater sensitivity to the statistical structure of the speech stream relative to the incongruent and static groups. This learning benefit could not be attributed to strategic processes, as participants were largely unaware of the contingencies between the visual stimulation and embedded words. These results indicate that manipulating neural entrainment during exposure to regularities influences statistical learning outcomes, suggesting that neural entrainment may functionally contribute to statistical learning. Our findings encourage future studies using non-invasive brain stimulation methods to further understand the role of entrainment in statistical learning.

Enhancing autism spectrum disorder classification in children through the integration of traditional statistics and classical machine learning techniques in EEG analysis

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder hallmarked by challenges in social communication, limited interests, and repetitive, stereotyped movements and behaviors. Numerous research efforts have indicated that individuals with ASD exhibit distinct brain connectivity patterns compared to control groups. However, these investigations, often constrained by small sample sizes, have led to inconsistent results, suggesting both heightened and diminished long-range connectivity within ASD populations. To bolster our analysis and enhance their reliability, we conducted a retrospective study using two different connectivity metrics and employed both traditional statistical methods and machine learning techniques. The concurrent use of statistical analysis and classical machine learning techniques advanced our understanding of model predictions derived from the spectral or connectivity attributes of a subject's EEG signal, while also verifying these predictions. Significantly, the utilization of machine learning methodologies empowered us to identify a unique subgroup of correctly classified children with ASD, defined by the analyzed EEG features. This improved approach is expected to contribute significantly to the existing body of knowledge on ASD and potentially guide personalized treatment strategies.

Domain-general but not speech-specific auditory duration perception predicts pseudoword reading in adults

Associations between reading performance and duration perception have been found both for domain-general and speech-specific duration perception. However, research seems limited to children and, critically, the predictive value of the two duration perception modalities has not been compared so far. In the present study we compared the weight of domain-general (comparison of time intervals defined by beeps) vs. speech-specific duration perception (pre-attentive EEG responses to consonants with different durations) as statistical predictors of reading in a sample of 46 neurotypical adults (18-43 years old) with 13 years of schooling on average. Reading included word and pseudoword decoding, as well as reading comprehension. We ran one regression model with domain-general and speech-specific duration perception as predictors for each of the three reading skills. Pseudoword decoding was the only reading skill that was significantly predicted by duration perception, and this happened for domain-general duration perception only. A complementary analysis adding 26 typically developing and 24 dyslexic adults to the main sample (n = 96 in total) showed the same pattern of results in dyslexics, but not in added controls. Our findings strengthen the idea that duration perception is important to phonological encoding and its use in grapheme-to-phoneme conversion, given that only pseudoword decoding was predicted by the interval comparison task. The irrelevance of speech-specific duration perception tones down the possibility that accurately perceiving the length of speech sounds is crucial to skilled reading.

Developmental changes in the categorization of speech and song

Music and language are two fundamental forms of human communication. Many studies examine the development of music- and language-specific knowledge, but few studies compare how listeners know they are listening to music or language. Although we readily differentiate these domains, how we distinguish music and language-and especially speech and song- is not obvious. In two studies, we asked how listeners categorize speech and song. Study 1 used online survey data to illustrate that 4- to 17-year-olds and adults have verbalizable distinctions for speech and song. At all ages, listeners described speech and song differences based on acoustic features, but compared with older children, 4- to 7-year-olds more often used volume to describe differences, suggesting that they are still learning to identify the features most useful for differentiating speech from song. Study 2 used a perceptual categorization task to demonstrate that 4-8-year-olds and adults readily categorize speech and song, but this ability improves with age especially for identifying song. Despite generally rating song as more speech-like, 4- and 6-year-olds rated ambiguous speech-song stimuli as more song-like than 8-year-olds and adults. Four acoustic features predicted song ratings: F0 instability, utterance duration, harmonicity, and spectral flux. However, 4- and 6-year-olds' song ratings were better predicted by F0 instability than by harmonicity and utterance duration. These studies characterize how children develop conceptual and perceptual understandings of speech and song and suggest that children under age 8 are still learning what features are important for categorizing utterances as speech or song. RESEARCH HIGHLIGHTS: Children and adults conceptually and perceptually categorize speech and song from age 4. Listeners use F0 instability, harmonicity, spectral flux, and utterance duration to determine whether vocal stimuli sound like song. Acoustic cue weighting changes with age, becoming adult-like at age 8 for perceptual categorization and at age 12 for conceptual differentiation. Young children are still learning to categorize speech and song, which leaves open the possibility that music- and language-specific skills are not so domain-specific.

Infant-directed song potentiates infants' selective attention to adults' mouths over the first year of life

The mechanisms by which infant-directed (ID) speech and song support language development in infancy are poorly understood, with most prior investigations focused on the auditory components of these signals. However, the visual components of ID communication are also of fundamental importance for language learning: over the first year of life, infants' visual attention to caregivers' faces during ID speech switches from a focus on the eyes to a focus on the mouth, which provides synchronous visual cues that support speech and language development. Caregivers' facial displays during ID song are highly effective for sustaining infants' attention. Here we investigate if ID song specifically enhances infants' attention to caregivers' mouths. 299 typically developing infants watched clips of female actors engaging them with ID song and speech longitudinally at six time points from 3 to 12 months of age while eye-tracking data was collected. Infants' mouth-looking significantly increased over the first year of life with a significantly greater increase during ID song versus speech. This difference was early-emerging (evident in the first 6 months of age) and sustained over the first year. Follow-up analyses indicated specific properties inherent to ID song (e.g., slower tempo, reduced rhythmic variability) in part contribute to infants' increased mouth-looking, with effects increasing with age. The exaggerated and expressive facial features that naturally accompany ID song may make it a particularly effective context for modulating infants' visual attention and supporting speech and language development in both typically developing infants and those with or at risk for communication challenges. A video abstract of this article can be viewed at https://youtu.be/SZ8xQW8h93A. RESEARCH HIGHLIGHTS: Infants' visual attention to adults' mouths during infant-directed speech has been found to support speech and language development. Infant-directed (ID) song promotes mouth-looking by infants to a greater extent than does ID speech across the first year of life. Features characteristic of ID song such as slower tempo, increased rhythmicity, increased audiovisual synchrony, and increased positive affect, all increase infants' attention to the mouth. The effects of song on infants' attention to the mouth are more prominent during the second half of the first year of life.

Brief Report: Telehealth Music-Enhanced Reciprocal Imitation Training in Autism: A Single-Subject Feasibility Study of a Virtual Parent Coaching Intervention

PURPOSE

Telehealth delivery increases accessibility of parent-mediated interventions that teach parents skills and support autistic children's social communication. Reciprocal Imitation Training (RIT), an evidence-based Naturalistic Developmental Behavioral Intervention (NDBI) focused on imitation skills, a common difficulty in autism, holds promise for telehealth-based parent training. Imitation is also a core component of musical play during childhood and the affordances of musical play/song naturally shape parent-child interactions. We evaluate the feasibility of a music-based, telehealth adaptation of RIT-music-enhanced RIT (tele-meRIT)-as a novel format for coaching parents in NDBI strategies.

METHODS

This single-subject, multiple baseline design study included 4 autistic children (32-53 months old) and their mothers. Parent-child dyads were recorded during 10-min free play probes at baseline, weekly tele-meRIT sessions, and one-week and one-month follow-up. Probes were coded for parents' RIT implementation fidelity, parent vocal musicality, and children's rate of spontaneous imitation.

RESULTS

No parent demonstrated implementation fidelity during baseline. All parents increased their use of RIT strategies, met fidelity by the end of treatment, and maintained fidelity at follow-up. Parent vocal musicality also increased from baseline. Intervention did not consistently increase children's imitation skills. A post-intervention evaluation survey indicated high parent satisfaction with tele-meRIT and perceived benefits to their children's social and play skills more broadly.

CONCLUSION

Implementing tele-meRIT is feasible. Although tele-meRIT additionally involved coaching in incorporating rhythmicity and song into play interactions, parents achieved fidelity in the RIT principles, suggesting one avenue by which music can be integrated within evidence-based parent-mediated NDBIs.

Neurophysiological time course of timbre-induced music-like perception

Traditionally, pitch variation in a sound stream has been integral to music identity. We attempt to expand music's definition, by demonstrating that the neural code for musicality is independent of pitch encoding. That is, pitchless sound streams can still induce music-like perception and a neurophysiological hierarchy similar to pitched melodies. Previous work reported that neural processing of sounds with no-pitch, fixed-pitch, and irregular-pitch (melodic) patterns, exhibits a right-lateralized hierarchical shift, with pitchless sounds favorably processed in Heschl's gyrus (HG), ascending laterally to nonprimary auditory areas for fixed-pitch and even more laterally for melodic patterns. The objective of this EEG study was to assess whether sound encoding maintains a similar hierarchical profile when musical perception is driven by timbre irregularities in the absence of pitch changes. Individuals listened to repetitions of three musical and three nonmusical sound-streams. The nonmusical streams were comprised of seven 200-ms segments of white, pink, or brown noise, separated by silent gaps. Musical streams were created similarly, but with all three noise types combined in a unique order within each stream to induce timbre variations and music-like perception. Subjects classified the sound streams as musical or nonmusical. Musical processing exhibited right dominant α power enhancement, followed by a lateralized increase in θ phase-locking and spectral power. The θ phase-locking was stronger in musicians than in nonmusicians. The lateralization of activity suggests higher-level auditory processing. Our findings validate the existence of a hierarchical shift, traditionally observed with pitched-melodic perception, underscoring that musicality can be achieved with timbre irregularities alone.NEW & NOTEWORTHY EEG induced by streams of pitchless noise segments varying in timbre were classified as music-like and exhibited a right-lateralized hierarchy in processing similar to pitched melodic processing. This study provides evidence that the neural-code of musicality is independent of pitch encoding. The results have implications for understanding music processing in individuals with degraded pitch perception, such as in cochlear-implant listeners, as well as the role of nonpitched sounds in the induction of music-like perceptual states.

Neural Entrainment to Musical Pulse in Naturalistic Music Is Preserved in Aging: Implications for Music-Based Interventions

Neural entrainment to musical rhythm is thought to underlie the perception and production of music. In aging populations, the strength of neural entrainment to rhythm has been found to be attenuated, particularly during attentive listening to auditory streams. However, previous studies on neural entrainment to rhythm and aging have often employed artificial auditory rhythms or limited pieces of recorded, naturalistic music, failing to account for the diversity of rhythmic structures found in natural music. As part of larger project assessing a novel music-based intervention for healthy aging, we investigated neural entrainment to musical rhythms in the electroencephalogram (EEG) while participants listened to self-selected musical recordings across a sample of younger and older adults. We specifically measured neural entrainment to the level of musical pulse-quantified here as the phase-locking value (PLV)-after normalizing the PLVs to each musical recording's detected pulse frequency. As predicted, we observed strong neural phase-locking to musical pulse, and to the sub-harmonic and harmonic levels of musical meter. Overall, PLVs were not significantly different between older and younger adults. This preserved neural entrainment to musical pulse and rhythm could support the design of music-based interventions that aim to modulate endogenous brain activity via self-selected music for healthy cognitive aging.

Theta Band (4-8 Hz) Oscillations Reflect Online Processing of Rhythm in Speech Production

How speech prosody is processed in the brain during language production remains an unsolved issue. The present work used the phrase-recall paradigm to analyze brain oscillation underpinning rhythmic processing in speech production. Participants were told to recall target speeches aloud consisting of verb-noun pairings with a common (e.g., [2+2], the numbers in brackets represent the number of syllables) or uncommon (e.g., [1+3]) rhythmic pattern. Target speeches were preceded by rhythmic musical patterns, either congruent or incongruent, created by using pure tones at various temporal intervals. Electroencephalogram signals were recorded throughout the experiment. Behavioral results in 2+2 target speeches showed a rhythmic priming effect when comparing congruent and incongruent conditions. Cerebral-acoustic coherence analysis showed that neural activities synchronized with the rhythmic patterns of primes. Furthermore, target phrases that had congruent rhythmic patterns with a prime rhythm were associated with increased theta-band (4-8 Hz) activity in the time window of 400-800 ms in both the 2+2 and 1+3 target conditions. These findings suggest that rhythmic patterns can be processed online. Neural activities synchronize with the rhythmic input and speakers create an abstract rhythmic pattern before and during articulation in speech production.

Neural synchronization is strongest to the spectral flux of slow music and depends on familiarity and beat salience

Neural activity in the auditory system synchronizes to sound rhythms, and brain–environment synchronization is thought to be fundamental to successful auditory perception. Sound rhythms are often operationalized in terms of the sound’s amplitude envelope. We hypothesized that – especially for music – the envelope might not best capture the complex spectro-temporal fluctuations that give rise to beat perception and synchronized neural activity. This study investigated (1) neural synchronization to different musical features, (2) tempo-dependence of neural synchronization, and (3) dependence of synchronization on familiarity, enjoyment, and ease of beat perception. In this electroencephalography study, 37 human participants listened to tempo-modulated music (1–4 Hz). Independent of whether the analysis approach was based on temporal response functions (TRFs) or reliable components analysis (RCA), the spectral flux of music – as opposed to the amplitude envelope – evoked strongest neural synchronization. Moreover, music with slower beat rates, high familiarity, and easy-to-perceive beats elicited the strongest neural response. Our results demonstrate the importance of spectro-temporal fluctuations in music for driving neural synchronization, and highlight its sensitivity to musical tempo, familiarity, and beat salience.

When we listen to a melody, the activity of our neurons synchronizes to the music: in fact, it is likely that the closer the match, the better we can perceive the piece. However, it remains unclear exactly which musical features our brain cells synchronize to. Previous studies, which have often used ‘simplified’ music, have highlighted that the amplitude envelope (how the intensity of the sounds changes over time) could be involved in this phenomenon, alongside factors such as musical training, attention, familiarity with the piece or even enjoyment. Whether differences in neural synchronization could explain why musical tastes vary between people is also still a matter of debate.

In their study, Weineck et al. aim to better understand what drives neuronal synchronization to music. A technique known as electroencephalography was used to record brain activity in 37 volunteers listening to instrumental music whose tempo ranged from 60 to 240 beats per minute. The tunes varied across an array of features such as familiarity, enjoyment and how easy the beat was to perceive. Two different approaches were then used to calculate neural synchronization, which yielded converging results.

The analyses revealed that three types of factors were associated with a strong neural synchronization. First, amongst the various cadences, a tempo of 60-120 beats per minute elicited the strongest match with neuronal activity. Interestingly, this beat is commonly found in Western pop music, is usually preferred by listeners, and often matches spontaneous body rhythms such as walking pace. Second, synchronization was linked to variations in pitch and sound quality (known as ‘spectral flux’) rather than in the amplitude envelope. And finally, familiarity and perceived beat saliency – but not enjoyment or musical expertise – were connected to stronger synchronization.

These findings help to better understand how our brains allow us to perceive and connect with music. The work conducted by Weineck et al. should help other researchers to investigate this field; in particular, it shows how important it is to consider spectral flux rather than amplitude envelope in experiments that use actual music.

Neural Tracking in Infancy Predicts Language Development in Children With and Without Family History of Autism

During speech processing, neural activity in non-autistic adults and infants tracks the speech envelope. Recent research in adults indicates that this neural tracking relates to linguistic knowledge and may be reduced in autism. Such reduced tracking, if present already in infancy, could impede language development. In the current study, we focused on children with a family history of autism, who often show a delay in first language acquisition. We investigated whether differences in tracking of sung nursery rhymes during infancy relate to language development and autism symptoms in childhood. We assessed speech-brain coherence at either 10 or 14 months of age in a total of 22 infants with high likelihood of autism due to family history and 19 infants without family history of autism. We analyzed the relationship between speech-brain coherence in these infants and their vocabulary at 24 months as well as autism symptoms at 36 months. Our results showed significant speech-brain coherence in the 10- and 14-month-old infants. We found no evidence for a relationship between speech-brain coherence and later autism symptoms. Importantly, speech-brain coherence in the stressed syllable rate (1-3 Hz) predicted later vocabulary. Follow-up analyses showed evidence for a relationship between tracking and vocabulary only in 10-month-olds but not in 14-month-olds and indicated possible differences between the likelihood groups. Thus, early tracking of sung nursery rhymes is related to language development in childhood.

Integrating music-based interventions with Gamma-frequency stimulation: Implications for healthy ageing

In recent years, music-based interventions (MBIs) have risen in popularity as a non-invasive, sustainable form of care for treating dementia-related disorders, such as Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD). Despite their clinical potential, evidence regarding the efficacy of MBIs on patient outcomes is mixed. Recently, a line of related research has begun to investigate the clinical impact of non-invasive Gamma-frequency (e.g., 40 Hz) sensory stimulation on dementia. Current work, using non-human-animal models of AD, suggests that non-invasive Gamma-frequency stimulation can remediate multiple pathophysiologies of dementia at the molecular, cellular and neural-systems scales, and, importantly, improve cognitive functioning. These findings suggest that the efficacy of MBIs could, in theory, be enhanced by incorporating Gamma-frequency stimulation into current MBI protocols. In the current review, we propose a novel clinical framework for non-invasively treating dementia-related disorders that combines previous MBIs with current approaches employing Gamma-frequency sensory stimulation. We theorize that combining MBIs with Gamma-frequency stimulation could increase the therapeutic power of MBIs by simultaneously targeting multiple biomarkers of dementia, restoring neural activity that underlies learning and memory (e.g., Gamma-frequency neural activity, Theta-Gamma coupling), and actively engaging auditory and reward networks in the brain to promote behavioural change.

Familiarity modulates neural tracking of sung and spoken utterances

Music is often described in the laboratory and in the classroom as a beneficial tool for memory encoding and retention, with a particularly strong effect when words are sung to familiar compared to unfamiliar melodies. However, the neural mechanisms underlying this memory benefit, especially for benefits related to familiar music are not well understood. The current study examined whether neural tracking of the slow syllable rhythms of speech and song is modulated by melody familiarity. Participants became familiar with twelve novel melodies over four days prior to MEG testing. Neural tracking of the same utterances spoken and sung revealed greater cerebro-acoustic phase coherence for sung compared to spoken utterances, but did not show an effect of familiar melody when stimuli were grouped by their assigned (trained) familiarity. However, when participant's subjective ratings of perceived familiarity were used to group stimuli, a large effect of familiarity was observed. This effect was not specific to song, as it was observed in both sung and spoken utterances. Exploratory analyses revealed some in-session learning of unfamiliar and spoken utterances, with increased neural tracking for untrained stimuli by the end of the MEG testing session. Our results indicate that top-down factors like familiarity are strong modulators of neural tracking for music and language. Participants' neural tracking was related to their perception of familiarity, which was likely driven by a combination of effects from repeated listening, stimulus-specific melodic simplicity, and individual differences. Beyond simply the acoustic features of music, top-down factors built into the music listening experience, like repetition and familiarity, play a large role in the way we attend to and encode information presented in a musical context.

On the Role of Neural Oscillations Across Timescales in Speech and Music Processing

This mini review is aimed at a clinician-scientist seeking to understand the role of oscillations in neural processing and their functional relevance in speech and music perception. We present an overview of neural oscillations, methods used to study them, and their functional relevance with respect to music processing, aging, hearing loss, and disorders affecting speech and language. We first review the oscillatory frequency bands and their associations with speech and music processing. Next we describe commonly used metrics for quantifying neural oscillations, briefly touching upon the still-debated mechanisms underpinning oscillatory alignment. Following this, we highlight key findings from research on neural oscillations in speech and music perception, as well as contributions of this work to our understanding of disordered perception in clinical populations. Finally, we conclude with a look toward the future of oscillatory research in speech and music perception, including promising methods and potential avenues for future work. We note that the intention of this mini review is not to systematically review all literature on cortical tracking of speech and music. Rather, we seek to provide the clinician-scientist with foundational information that can be used to evaluate and design research studies targeting the functional role of oscillations in speech and music processing in typical and clinical populations.

Acceptable Noise Levels and Preferred Signal-to-noise Ratios for Speech and Music

OBJECTIVES

The objective of this study was to evaluate the influence of music versus speech on a listener's signal-to-noise ratio (SNR) preferences when listening in a noise background. SNR preferences were quantified using acceptable noise level (ANL) and preferred SNR metrics. The measurement paradigm for ANL allows the listener to adjust the level of background noise while listening to the target at their most comfortable loudness level. A higher ANL indicates less tolerance for noise and a lower ANL indicates high tolerance for noise. The preferred SNR is simply the SNR the listener prefers when attending to a target in a fixed-amount (level) of background noise. In contrast to the ANL, the listener does not have control over the noise. Rather, they are only able to manipulate the target level. The first aim of the study was to determine if listeners' tolerances for noise, quantified using the ANL, when listening to music is different from that when listening to speech. The second aim of the study was to determine if listeners' tolerances for noise, quantified using their preferred SNR, when listening to music is different from that when listening to speech. The third aim of the study was to quantify the relationship between ANL and preferred SNR.

DESIGN

Ninety-nine normal-hearing, native-English speakers participated in this study. The ANL and preferred SNR were measured for speech and music targets. Music targets included two variations (with lyrics and without lyrics) of the song "Rocky Top." Measurements were made in the sound field at 0° azimuth, 1.5 m from a loud speaker. For both ANL and preferred SNR, targets were presented in 12-talker babble noise. The level of the noise was adjusted by the listener during ANL measurement but was fixed in level during the preferred SNR measurement (75 dB A). Repeated-measures analysis of variance was performed to identify any significant effect of target on the ANL and preferred SNR. Correlation analysis was performed to evaluate the relationship between ANL and preferred SNR.

RESULTS

Findings demonstrate a significant effect of target on ANL and preferred SNR. ANLs were highest for speech (mean = 7.2 dB), followed by music with lyrics (6.1 dB), and music without lyrics (2.5 dB). Preferred SNRs were highest for music with lyrics (mean = 2.3 dB), followed by speech (1.2 dB), and music without lyrics (-0.1 dB). A listener's ANL for a given target was strongly correlated with their ANL for a different target (the same was true for preferred SNR); however, ANL for a given target was not a statistically significant predictor of preferred SNR for the same target.

CONCLUSIONS

When listening in a background of noise, the listener's tolerance for noise depends on the target to which they are attending, whether music or speech. This dependence is especially evident for ANL measures, and less so for preferred SNR measures. Despite differences in ANL and preferred SNR across targets, a listener's ANL and preferred SNR for one target predicts their ANL and preferred SNR, respectively, for a different target. The lack of correlation between ANL and preferred SNR suggests different mechanisms underly these listener-preference metrics.

Envelope reconstruction of speech and music highlights stronger tracking of speech at low frequencies

The human brain tracks amplitude fluctuations of both speech and music, which reflects acoustic processing in addition to the encoding of higher-order features and one's cognitive state. Comparing neural tracking of speech and music envelopes can elucidate stimulus-general mechanisms, but direct comparisons are confounded by differences in their envelope spectra. Here, we use a novel method of frequency-constrained reconstruction of stimulus envelopes using EEG recorded during passive listening. We expected to see music reconstruction match speech in a narrow range of frequencies, but instead we found that speech was reconstructed better than music for all frequencies we examined. Additionally, models trained on all stimulus types performed as well or better than the stimulus-specific models at higher modulation frequencies, suggesting a common neural mechanism for tracking speech and music. However, speech envelope tracking at low frequencies, below 1 Hz, was associated with increased weighting over parietal channels, which was not present for the other stimuli. Our results highlight the importance of low-frequency speech tracking and suggest an origin from speech-specific processing in the brain.

Stronger connectivity and higher extraversion protect against stress-related deterioration of cognitive functions

Here we attempted to define the relationship between: EEG activity, personality and coping during lockdown. We were in a unique situation since the COVID-19 outbreak interrupted our independent longitudinal study. We already collected a significant amount of data before lockdown. During lockdown, a subgroup of participants willingly continued their engagement in the study. These circumstances provided us with an opportunity to examine the relationship between personality/cognition and brain rhythms in individuals who continued their engagement during lockdown compared to control data collected well before pandemic. The testing consisted of a one-time assessment of personality dimensions and two sessions of EEG recording and deductive reasoning task. Participants were divided into groups based on the time they completed the second session: before or during the COVID-19 outbreak ‘Pre-pandemic Controls’ and ‘Pandemics’, respectively. The Pandemics were characterized by a higher extraversion and stronger connectivity, compared to Pre-pandemic Controls. Furthermore, the Pandemics improved their cognitive performance under long-term stress as compared to the Pre-Pandemic Controls matched for personality traits to the Pandemics. The Pandemics were also characterized by increased EEG connectivity during lockdown. We posit that stronger EEG connectivity and higher extraversion could act as a defense mechanism against stress-related deterioration of cognitive functions.

Enhanced Memory for Vocal Melodies in Autism Spectrum Disorder and Williams Syndrome

Adults and children with typical development (TD) remember vocal melodies (without lyrics) better than instrumental melodies, which is attributed to the biological and social significance of human vocalizations. Here we asked whether children with autism spectrum disorder (ASD), who have persistent difficulties with communication and social interaction, and adolescents and adults with Williams syndrome (WS), who are highly sociable, even indiscriminately friendly, exhibit a memory advantage for vocal melodies like that observed in individuals with TD. We tested 26 children with ASD, 26 adolescents and adults with WS of similar mental age, and 26 children with TD on their memory for vocal and instrumental (piano, marimba) melodies. After exposing them to 12 unfamiliar folk melodies with different timbres, we required them to indicate whether each of 24 melodies (half heard previously) was old (heard before) or new (not heard before) during an unexpected recognition test. Although the groups successfully distinguished the old from the new melodies, they differed in overall memory. Nevertheless, they exhibited a comparable advantage for vocal melodies. In short, individuals with ASD and WS show enhanced processing of socially significant auditory signals in the context of music. LAY SUMMARY: Typically developing children and adults remember vocal melodies better than instrumental melodies. In this study, we found that children with Autistic Spectrum Disorder, who have severe social processing deficits, and children and adults with Williams syndrome, who are highly sociable, exhibit comparable memory advantages for vocal melodies. The results have implications for musical interventions with these populations.

Mental operations in rhythm: Motor-to-sensory transformation mediates imagined singing

What enables the mental activities of thinking verbally or humming in our mind? We hypothesized that the interaction between motor and sensory systems induces speech and melodic mental representations, and this motor-to-sensory transformation forms the neural basis that enables our verbal thinking and covert singing. Analogous with the neural entrainment to auditory stimuli, participants imagined singing lyrics of well-known songs rhythmically while their neural electromagnetic signals were recorded using magnetoencephalography (MEG). We found that when participants imagined singing the same song in similar durations across trials, the delta frequency band (1–3 Hz, similar to the rhythm of the songs) showed more consistent phase coherence across trials. This neural phase tracking of imagined singing was observed in a frontal-parietal-temporal network: the proposed motor-to-sensory transformation pathway, including the inferior frontal gyrus (IFG), insula (INS), premotor area, intra-parietal sulcus (IPS), temporal-parietal junction (TPJ), primary auditory cortex (Heschl’s gyrus [HG]), and superior temporal gyrus (STG) and sulcus (STS). These results suggest that neural responses can entrain the rhythm of mental activity. Moreover, the theta-band (4–8 Hz) phase coherence was localized in the auditory cortices. The mu (9–12 Hz) and beta (17–20 Hz) bands were observed in the right-lateralized sensorimotor systems that were consistent with the singing context. The gamma band was broadly manifested in the observed network. The coherent and frequency-specific activations in the motor-to-sensory transformation network mediate the internal construction of perceptual representations and form the foundation of neural computations for mental operations.

What enables our mental activities for thinking verbally or humming in our mind? Using an imagined singing paradigm with magnetoencephalography recordings, this study shows that neural oscillations in the motor-to-sensory transformation network tracked inner speech and covert singing.

Music as a coevolved system for social bonding

Why do humans make music? Theories of the evolution of musicality have focused mainly on the value of music for specific adaptive contexts such as mate selection, parental care, coalition signaling, and group cohesion. Synthesizing and extending previous proposals, we argue that social bonding is an overarching function that unifies all of these theories, and that musicality enabled social bonding at larger scales than grooming and other bonding mechanisms available in ancestral primate societies. We combine cross-disciplinary evidence from archaeology, anthropology, biology, musicology, psychology, and neuroscience into a unified framework that accounts for the biological and cultural evolution of music. We argue that the evolution of musicality involves gene-culture coevolution, through which proto-musical behaviors that initially arose and spread as cultural inventions had feedback effects on biological evolution due to their impact on social bonding. We emphasize the deep links between production, perception, prediction, and social reward arising from repetition, synchronization, and harmonization of rhythms and pitches, and summarize empirical evidence for these links at the levels of brain networks, physiological mechanisms, and behaviors across cultures and across species. Finally, we address potential criticisms and make testable predictions for future research, including neurobiological bases of musicality and relationships between human music, language, animal song, and other domains. The music and social bonding (MSB) hypothesis provides the most comprehensive theory to date of the biological and cultural evolution of music.

Advances in the Neurocognition of Music and Language

Neurocomparative music and language research has seen major advances over the past two decades. The goal of this Special Issue “Advances in the Neurocognition of Music and Language” was to showcase the multiple neural analogies between musical and linguistic information processing, their entwined organization in human perception and cognition and to infer the applicability of the combined knowledge in pedagogy and therapy. Here, we summarize the main insights provided by the contributions and integrate them into current frameworks of rhythm processing, neuronal entrainment, predictive coding and cognitive control.