Effects of Kindermusik training on infants’ rhythmic enculturation

Probing Beat Perception with Event-Related Potentials (ERPs) in Human Adults, Newborns, and Nonhuman Primates

The aim of this chapter is to give an overview of how the perception of rhythmic temporal regularity such as a regular beat in music can be studied in human adults, human newborns, and nonhuman primates using event-related brain potentials (ERPs). First, we discuss different aspects of temporal structure in general, and musical rhythm in particular, and we discuss the possible mechanisms underlying the perception of regularity (e.g., a beat) in rhythm. Additionally, we highlight the importance of dissociating beat perception from the perception of other types of structure in rhythm, such as predictable sequences of temporal intervals, ordinal structure, and rhythmic grouping. In the second section of the chapter, we start with a discussion of auditory ERPs elicited by infrequent and frequent sounds: ERP responses to regularity violations, such as mismatch negativity (MMN), N2b, and P3, as well as early sensory responses to sounds, such as P1 and N1, have been shown to be instrumental in probing beat perception. Subsequently, we discuss how beat perception can be probed by comparing ERP responses to sounds in regular and irregular sequences, and by comparing ERP responses to sounds in different metrical positions in a rhythm, such as on and off the beat or on strong and weak beats. Finally, we will discuss previous research that has used the aforementioned ERPs and paradigms to study beat perception in human adults, human newborns, and nonhuman primates. In doing so, we consider the possible pitfalls and prospects of the technique, as well as future perspectives.

Early social communication through music: State of the art and future perspectives

A growing body of research shows that the universal capacity for music perception and production emerges early in development. Possibly building on this predisposition, caregivers around the world often communicate with infants using songs or speech entailing song-like characteristics. This suggests that music might be one of the earliest developing and most accessible forms of interpersonal communication, providing a platform for studying early communicative behavior. However, little research has examined music in truly communicative contexts. The current work aims to facilitate the development of experimental approaches that rely on dynamic and naturalistic social interactions. We first review two longstanding lines of research that examine musical interactions by focusing either on the caregiver or the infant. These include defining the acoustic and non-acoustic features that characterize infant-directed (ID) music, as well as behavioral and neurophysiological research examining infants' processing of musical timing and pitch. Next, we review recent studies looking at early musical interactions holistically. This research focuses on how caregivers and infants interact using music to achieve co-regulation, mutual engagement, and increase affiliation and prosocial behavior. We conclude by discussing methodological, technological, and analytical advances that might empower a comprehensive study of musical communication in early childhood.

A Dynamical, Radically Embodied, and Ecological Theory of Rhythm Development

Musical rhythm abilities-the perception of and coordinated action to the rhythmic structure of music-undergo remarkable change over human development. In the current paper, we introduce a theoretical framework for modeling the development of musical rhythm. The framework, based on Neural Resonance Theory (NRT), explains rhythm development in terms of resonance and attunement, which are formalized using a general theory that includes non-linear resonance and Hebbian plasticity. First, we review the developmental literature on musical rhythm, highlighting several developmental processes related to rhythm perception and action. Next, we offer an exposition of Neural Resonance Theory and argue that elements of the theory are consistent with dynamical, radically embodied (i.e., non-representational) and ecological approaches to cognition and development. We then discuss how dynamical models, implemented as self-organizing networks of neural oscillations with Hebbian plasticity, predict key features of music development. We conclude by illustrating how the notions of dynamical embodiment, resonance, and attunement provide a conceptual language for characterizing musical rhythm development, and, when formalized in physiologically informed dynamical models, provide a theoretical framework for generating testable empirical predictions about musical rhythm development, such as the kinds of native and non-native rhythmic structures infants and children can learn, steady-state evoked potentials to native and non-native musical rhythms, and the effects of short-term (e.g., infant bouncing, infant music classes), long-term (e.g., perceptual narrowing to musical rhythm), and very-long term (e.g., music enculturation, musical training) learning on music perception-action.

Impact of Early Rhythmic Training on Language Acquisition and Electrophysiological Functioning Underlying Auditory Processing: Feasibility and Preliminary Findings in Typically Developing Infants

Previous evidence has shown that early auditory processing impacts later linguistic development, and targeted training implemented at early ages can enhance auditory processing skills, with better expected language development outcomes. This study focuses on typically developing infants and aims to test the feasibility and preliminary efficacy of music training based on active synchronization with complex musical rhythms on the linguistic outcomes and electrophysiological functioning underlying auditory processing. Fifteen infants participated in the training (RTr+) and were compared with two groups of infants not attending any structured activities during the same time frame (RTr−, N = 14). At pre- and post-training, expressive and receptive language skills were assessed using standardized tests, and auditory processing skills were characterized through an electrophysiological non-speech multi-feature paradigm. Results reveal that RTr+ infants showed significantly broader improvement in both expressive and receptive pre-language skills. Moreover, at post-training, they presented an electrophysiological pattern characterized by shorter latency of two peaks (N2* and P2), reflecting a neural change detection process: these shifts in latency go beyond those seen due to maturation alone. These results provide preliminary evidence on the efficacy of our training in improving early linguistic competences, and in modifying the neural underpinnings of auditory processing in infants.

Modulation of Theta Phase Synchrony during Syllable Processing as a Function of Interactive Acoustic Experience in Infancy

Plasticity, a prominent characteristic of the infant brain, supports formation of cortical representations as infants begin to interact with and adapt to environmental sensory events. Enhanced acoustic processing efficiency along with improved allocation of attentional resources at 7 months and establishment of well-defined phonemic maps at 9 months have been shown to be facilitated by early interactive acoustic experience (IAE). In this study, using an oddball paradigm and measures of theta phase synchrony at source level, we examined short- and long-term effects of nonspeech IAE on syllable processing. Results demonstrated that beyond maturation alone, IAE increased the efficiency of syllabic representation and discrimination, an effect that endured well beyond the immediate training period. As compared with naive controls, the IAE-trained group at 7, 9, and 18 months showed less theta phase synchrony for the standard syllable and at 7 and 18 months for the deviant syllable. The decreased theta phase synchrony exhibited by the trained group suggests more mature, efficient, acoustic processing, and thus, better cortical representation and discrimination of syllabic content. Further, the IAE modulatory effect observed on theta phase synchrony in left auditory cortex at 7 and 9 months was differentially associated with receptive and expressive language scores at 12 and 18 months of age.

Bouncing the network: A dynamical systems model of auditory-vestibular interactions underlying infants' perception of musical rhythm

Previous work suggests that auditory-vestibular interactions, which emerge during bodily movement to music, can influence the perception of musical rhythm. In a seminal study on the ontogeny of musical rhythm, Phillips-Silver and Trainor (2005) found that bouncing infants to an unaccented rhythm influenced infants' perceptual preferences for accented rhythms that matched the rate of bouncing. In the current study, we ask whether nascent, diffuse coupling between auditory and motor systems is sufficient to bootstrap short-term Hebbian plasticity in the auditory system and explain infants' preferences for accented rhythms thought to arise from auditory-vestibular interactions. First, we specify a nonlinear, dynamical system in which two oscillatory neural networks, representing developmentally nascent auditory and motor systems, interact through weak, non-specific coupling. The auditory network was equipped with short-term Hebbian plasticity, allowing the auditory network to tune its intrinsic resonant properties. Next, we simulate the effect of vestibular input (e.g., infant bouncing) on infants' perceptual preferences for accented rhythms. We found that simultaneous auditory-vestibular training shaped the model's response to musical rhythm, enhancing vestibular-related frequencies in auditory-network activity. Moreover, simultaneous auditory-vestibular training, relative to auditory- or vestibular-only training, facilitated short-term auditory plasticity in the model, producing stronger oscillator connections in the auditory network. Finally, when tested on a musical rhythm, models which received simultaneous auditory-vestibular training, but not models that received auditory- or vestibular-only training, resonated strongly at frequencies related to their "bouncing," a finding qualitatively similar to infants' preferences for accented rhythms that matched the rate of infant bouncing.

Melodic expectations in 5- and 6-year-old children

It has been argued that children implicitly acquire the rules relating to the structure of music in their environment using domain-general mechanisms such as statistical learning. Closely linked to statistical learning is the ability to form expectations about future events. Whether children as young as 5 years can make use of such internalized regularities to form expectations about the next note in a melody is still unclear. The possible effect of the home musical environment on the strength of musical expectations has also been under-explored. Using a newly developed melodic priming task that included melodies with either "expected" or "unexpected" endings according to rules of Western music theory, we tested 5- and 6-year-old children (N = 46). The stimuli in this task were constructed using the information dynamics of music (IDyOM) system, a probabilistic model estimating the level of "unexpectedness" of a note given the preceding context. Results showed that responses to expected versus unexpected tones were faster and more accurate, indicating that children have already formed robust melodic expectations at 5 years of age. Aspects of the home musical environment significantly predicted the strength of melodic expectations, suggesting that implicit musical learning may be influenced by the quantity of informal exposure to the surrounding musical environment.

Infant Movement Response to Auditory Rhythm

Rhythmic entrainment occurs when an auditory rhythm drives an internal movement oscillator, thus providing a continuous time reference that improves temporal and spatial movement parameters. Entrainment processes and outcomes are well known for adults, but research is lacking for infants who might benefit from diagnosis and treatment of irregular rhythms within biological, sensorimotor, cognitive, and social domains. The present study used a combination of inertial measurement units and custom-made software to determine the amount, tempo, and regularity of movement in 28 infants aged 6-10 months while they were exposed to silence, an irregular rhythmic cue, or a regular rhythmic cue with tempo changes. We also assessed changes in the infants' movement parameters following a one-week rhythm training protocol. While results revealed no significant effect of auditory condition on amount or tempo of movement, infant movement was significantly more regular when infants were exposed to 120 bpm (beats per minute) than to an irregular rhythmic cue or a 10% faster rhythmic cue (132 bpm). Infants showed no notable changes in movement amount, tempo, or regularity following one week of training involving auditory and physical rhythm. Overall, infants seem to engage in spontaneous movements with or without auditory rhythm but may not show tempo sensitivity through their movements. Increased movement regularity suggests that 120 bpm may be a preferred tempo for infants, at which they are more likely to demonstrate well-timed movements that may reflect interval entrainment. Infants' auditory-motor systems appear not to respond to a 1-week rhythm training protocol.

Musical playschool activities are linked to faster auditory development during preschool-age: a longitudinal ERP study

The influence of musical experience on brain development has been mostly studied in school-aged children with formal musical training while little is known about the possible effects of less formal musical activities typical for preschool-aged children (e.g., before the age of seven). In the current study, we investigated whether the amount of musical group activities is reflected in the maturation of neural sound discrimination from toddler to preschool-age. Specifically, we recorded event-related potentials longitudinally (84 recordings from 33 children) in a mismatch negativity (MMN) paradigm to different musically relevant sound changes at ages 2–3, 4–5 and 6–7 years from children who attended a musical playschool throughout the follow-up period and children with shorter attendance to the same playschool. In the first group, we found a gradual positive to negative shift in the polarities of the mismatch responses while the latter group showed little evidence of age-related changes in neural sound discrimination. The current study indicates that the maturation of sound encoding indexed by the MMN may be more protracted than once thought and provides first longitudinal evidence that even quite informal musical group activities facilitate the development of neural sound discrimination during early childhood.

Modeling infants' perceptual narrowing to musical rhythms: neural oscillation and Hebbian plasticity

Previous research suggests that infants' perception of musical rhythm is fine-tuned to culture-specific rhythmic structures over the first postnatal year of human life. To date, however, little is known about the neurobiological principles that may underlie this process. In the current study, we used a dynamical systems model featuring neural oscillation and Hebbian plasticity to simulate infants' perceptual learning of culture-specific musical rhythms. First, we demonstrate that oscillatory activity in an untrained network reflects the rhythmic structure of either a Western or a Balkan training rhythm in a veridical fashion. Next, during a period of unsupervised learning, we show that the network learns the rhythmic structure of either a Western or a Balkan training rhythm through the self-organization of network connections. Finally, we demonstrate that the learned connections affect the networks' response to violations to the metrical structure of native and nonnative rhythms, a pattern of findings that mirrors the behavioral data on infants' perceptual narrowing to musical rhythms.

Are We Doing More Than We Know? Possible Mechanisms of Response to Music Therapy

Due to advances in medical knowledge the population of older adults struggling with issues of aging like Alzheimer's disease (AD), Parkinson's disease (PD), and stroke is growing. There is a need for therapeutic interventions to provide adaptive strategies to sustain quality of life, decrease neurologic impairment, and maintain or slow cognitive decline and function due to degenerative neurologic diseases. Musical interventions with adults with cognitive impairments have received increased attention over the past few years, such as the value of personalized music listening in the iPod project for AD (1); music as a tool to decrease agitation and anxiety in dementia (2); and music to aid in episodic memory (3); Rhythmic Auditory Stimulation as rehabilitation for PD (4); and recently the potential of 40 Hz sensory brain stimulation with AD and PD (5, 6). These approaches indicate the expanding scope and efficacy of music therapy and the potential mechanisms involved. This paper explicates a four-level model of mechanisms of music response (7, 8) that may help understand current music therapy approaches and treatments and help focus future research. Each level will be illustrated with research and suggestions for research directions.

Rhythm and melody as social signals for infants

Infants typically experience music through social interactions with others. One such experience involves caregivers singing to infants while holding and bouncing them rhythmically. These highly social interactions shape infant music perception and may also influence social cognition and behavior. Moving in time with others-interpersonal synchrony-can direct infants' social preferences and prosocial behavior. Infants also show social preferences and selective prosociality toward singers of familiar, socially learned melodies. Here, we discuss recent studies of the influence of musical engagement on infant social cognition and behavior, highlighting the importance of rhythmic movement and socially relevant melodies.

Babies know bad dancing when they see it: Older but not younger infants discriminate between synchronous and asynchronous audiovisual musical displays

Movement to music is a universal human behavior, yet little is known about how observers perceive audiovisual synchrony in complex musical displays such as a person dancing to music, particularly during infancy and childhood. In the current study, we investigated how perception of musical audiovisual synchrony develops over the first year of life. We habituated infants to a video of a person dancing to music and subsequently presented videos in which the visual track was matched (synchronous) or mismatched (asynchronous) with the audio track. In a visual-only control condition, we presented the same visual stimuli with no sound. In Experiment 1, we found that older infants (8-12months) exhibited a novelty preference for the mismatched movie when both auditory information and visual information were available and showed no preference when only visual information was available. By contrast, younger infants (5-8months) in Experiment 2 did not discriminate matching stimuli from mismatching stimuli. This suggests that the ability to perceive musical audiovisual synchrony may develop during the second half of the first year of infancy.

Exaggeration of Language-Specific Rhythms in English and French Children's Songs

The available evidence indicates that the music of a culture reflects the speech rhythm of the prevailing language. The normalized pairwise variability index (nPVI) is a measure of durational contrast between successive events that can be applied to vowels in speech and to notes in music. Music-language parallels may have implications for the acquisition of language and music, but it is unclear whether native-language rhythms are reflected in children's songs. In general, children's songs exhibit greater rhythmic regularity than adults' songs, in line with their caregiving goals and frequent coordination with rhythmic movement. Accordingly, one might expect lower nPVI values (i.e., lower variability) for such songs regardless of culture. In addition to their caregiving goals, children's songs may serve an intuitive didactic function by modeling culturally relevant content and structure for music and language. One might therefore expect pronounced rhythmic parallels between children's songs and language of origin. To evaluate these predictions, we analyzed a corpus of 269 English and French songs from folk and children's music anthologies. As in prior work, nPVI values were significantly higher for English than for French children's songs. For folk songs (i.e., songs not for children), the difference in nPVI for English and French songs was small and in the expected direction but non-significant. We subsequently collected ratings from American and French monolingual and bilingual adults, who rated their familiarity with each song, how much they liked it, and whether or not they thought it was a children's song. Listeners gave higher familiarity and liking ratings to songs from their own culture, and they gave higher familiarity and preference ratings to children's songs than to other songs. Although higher child-directedness ratings were given to children's than to folk songs, French listeners drove this effect, and their ratings were uniquely predicted by nPVI. Together, these findings suggest that language-based rhythmic structures are evident in children's songs, and that listeners expect exaggerated language-based rhythms in children's songs. The implications of these findings for enculturation processes and for the acquisition of music and language are discussed.

Musical intervention enhances infants' neural processing of temporal structure in music and speech

Individuals with music training in early childhood show enhanced processing of musical sounds, an effect that generalizes to speech processing. However, the conclusions drawn from previous studies are limited due to the possible confounds of predisposition and other factors affecting musicians and nonmusicians. We used a randomized design to test the effects of a laboratory-controlled music intervention on young infants' neural processing of music and speech. Nine-month-old infants were randomly assigned to music (intervention) or play (control) activities for 12 sessions. The intervention targeted temporal structure learning using triple meter in music (e.g., waltz), which is difficult for infants, and it incorporated key characteristics of typical infant music classes to maximize learning (e.g., multimodal, social, and repetitive experiences). Controls had similar multimodal, social, repetitive play, but without music. Upon completion, infants' neural processing of temporal structure was tested in both music (tones in triple meter) and speech (foreign syllable structure). Infants' neural processing was quantified by the mismatch response (MMR) measured with a traditional oddball paradigm using magnetoencephalography (MEG). The intervention group exhibited significantly larger MMRs in response to music temporal structure violations in both auditory and prefrontal cortical regions. Identical results were obtained for temporal structure changes in speech. The intervention thus enhanced temporal structure processing not only in music, but also in speech, at 9 mo of age. We argue that the intervention enhanced infants' ability to extract temporal structure information and to predict future events in time, a skill affecting both music and speech processing.

Emotional experience in music fosters 18-month-olds' emotion-action understanding: a training study

We examine whether emotional experiences induced via music-making promote infants' use of emotional cues to predict others' action. Fifteen-month-olds were randomly assigned to participate in interactive emotion training either with or without musical engagement for three months. Both groups were then re-tested with two violation-of-expectation paradigms respectively assessing their sensitivity to some expressive features in music and understanding of the link between emotion and behaviour in simple action sequences. The infants who had participated in music, but not those who had not, were surprised by music-face inconsistent displays and were able to interpret an agent's action as guided by her expressed emotion. The findings suggest a privileged role of musical experience in prompting infants to form emotional representations, which support their understanding of the association between affective states and action.

Active Drumming Experience Increases Infants' Sensitivity to Audiovisual Synchrony during Observed Drumming Actions

In the current study, we examined the role of active experience on sensitivity to multisensory synchrony in six-month-old infants in a musical context. In the first of two experiments, we trained infants to produce a novel multimodal effect (i.e., a drum beat) and assessed the effects of this training, relative to no training, on their later perception of the synchrony between audio and visual presentation of the drumming action. In a second experiment, we then contrasted this active experience with the observation of drumming in order to test whether observation of the audiovisual effect was as effective for sensitivity to multimodal synchrony as active experience. Our results indicated that active experience provided a unique benefit above and beyond observational experience, providing insights on the embodied roots of (early) music perception and cognition.

Promises of formal and informal musical activities in advancing neurocognitive development throughout childhood

Adult musicians show superior neural sound discrimination when compared to nonmusicians. However, it is unclear whether these group differences reflect the effects of experience or preexisting neural enhancement in individuals who seek out musical training. Tracking how brain function matures over time in musically trained and nontrained children can shed light on this issue. Here, we review our recent longitudinal event-related potential (ERP) studies that examine how formal musical training and less formal musical activities influence the maturation of brain responses related to sound discrimination and auditory attention. These studies found that musically trained school-aged children and preschool-aged children attending a musical playschool show more rapid maturation of neural sound discrimination than their control peers. Importantly, we found no evidence for pretraining group differences. In a related cross-sectional study, we found ERP and behavioral evidence for improved executive functions and control over auditory novelty processing in musically trained school-aged children and adolescents. Taken together, these studies provide evidence for the causal role of formal musical training and less formal musical activities in shaping the development of important neural auditory skills and suggest transfer effects with domain-general implications.

A developmental study of the effect of music training on timed movements

When people clap to music, sing, play a musical instrument, or dance, they engage in temporal entrainment. We examined the effect of music training on the precision of temporal entrainment in 57 children aged 10–14 years (31 musicians, 26 non-musicians). Performance was examined for two tasks: self-paced finger tapping (discrete movements) and circle drawing (continuous movements). For each task, participants synchronized their movements with a steady pacing signal and then continued the movement at the same rate in the absence of the pacing signal. Analysis of movements during the continuation phase revealed that musicians were more accurate than non-musicians at finger tapping and, to a lesser extent, circle drawing. Performance on the finger-tapping task was positively associated with the number of years of formal music training, whereas performance on the circle-drawing task was positively associated with the age of participants. These results indicate that music training and maturation of the motor system reinforce distinct skills of timed movement.

Perceiving temporal regularity in music: the role of auditory event-related potentials (ERPs) in probing beat perception

The aim of this chapter is to give an overview of how the perception of a regular beat in music can be studied in humans adults, human newborns, and nonhuman primates using event-related brain potentials (ERPs). Next to a review of the recent literature on the perception of temporal regularity in music, we will discuss in how far ERPs, and especially the component called mismatch negativity (MMN), can be instrumental in probing beat perception. We conclude with a discussion on the pitfalls and prospects of using ERPs to probe the perception of a regular beat, in which we present possible constraints on stimulus design and discuss future perspectives.

Serial binary interval ratios improve rhythm reproduction

Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

Joint Drumming in Brazilian and German Preschool Children

As a core feature of musical rituals around the world, humans synchronize their movements to the pulse of a shared acoustic pattern—a behavior called rhythmic entrainment. The purpose of the present study was (a) to examine the development of rhythmic entrainment with a focus on the role of experience and (b) to follow one line of evidence concerning its adaptive function. We hypothesized (a) that children learn how to synchronize movements to sound during social interactions, where they experience this behavior as a convention of the surrounding culture’s practice, and (b) that rhythmic entrainment has an adaptive value by allowing several people to coordinate their actions, thereby creating group cohesion and ultimately promoting cooperativeness. We compared the spontaneous synchronization behavior of Brazilian and German preschool children during joint drumming with an experimenter, either vis-à-vis or separated by a curtain, versus drumming along a playback beat. Afterward, we measured the children’s prosocial tendencies toward the experimenter. We found that Brazilian children were more likely than German children to spontaneously synchronize their drumming in a social setting, even if the codrummer was hidden from view. According to hypothesis, the variation in individual synchronization accuracy between and within the two samples could be partly explained by differences in individual experience with active musical practice, as revealed by parental interviews. However, we found no differences in children’s prosocial tendencies depending on whether they just had drummed alone or together with the experimenter.

Does visual information influence infants' movement to music?

Humans are often exposed to music beginning at birth (or even before birth), yet the study of the development of musical abilities during infancy has only recently gained momentum. The goals of the present study were to determine whether young infants (ages four to seven months) spontaneously moved rhythmically in the presence of music, and whether the presence of visual information in addition to music would increase or decrease infants' movement. While nearly all infants moved in the presence of music, very few infants demonstrated rhythmic movement. Results revealed that, when visual information was present, and particularly when infants appeared to show focused attention toward the visual information, infants moved less than when only auditory information was present. The latter result is in agreement with most studies of sensory dominance in adults in which visual stimuli are dominant over auditory stimuli.

Critical period for acoustic preference in mice

Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a "critical period" for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their innate bias for silent shelter, which typically could not be altered in adulthood. Instead, exposing adult mice treated acutely with valproic acid or carrying a targeted deletion of the Nogo receptor (NgR(-/-)) unmasked a strong plasticity of preference consistent with a reopening of the critical period as seen in other systems. Imaging of cFos expression revealed a prominent neuronal activation in response to the exposed music in the prelimbic and infralimbic medial prefrontal cortex only under conditions of open plasticity. Neither behavioral changes nor selective medial prefrontal cortex activation was observed in response to pure tone exposure, indicating a music-specific effect. Open-field center crossings were increased concomitant with shifts in music preference, suggesting a potential anxiolytic effect. Thus, music may offer both a unique window into the emotional state of mice and a potentially efficient assay for molecular "brakes" on critical period plasticity common to sensory and higher order brain areas.

Auditory processing in high-functioning adolescents with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a pervasive developmental disorder including abnormalities in perceptual processing. We measure perception in a battery of tests across speech (filtering, phoneme categorization, multisensory integration) and music (pitch memory, meter categorization, harmonic priming). We found that compared to controls, the ASD group showed poorer filtering, less audio-visual integration, less specialization for native phonemic and metrical categories, and a higher instance of absolute pitch. No group differences were found in harmonic priming. Our results are discussed in a developmental framework where culture-specific knowledge acquired early compared to late in development is most impaired, perhaps because of early-accelerated brain growth in ASD. These results suggest that early auditory remediation is needed for good communication and social functioning.

Neural mechanisms of rhythm perception: current findings and future perspectives

Perception of temporal patterns is fundamental to normal hearing, speech, motor control, and music. Certain types of pattern understanding are unique to humans, such as musical rhythm. Although human responses to musical rhythm are universal, there is much we do not understand about how rhythm is processed in the brain. Here, I consider findings from research into basic timing mechanisms and models through to the neuroscience of rhythm and meter. A network of neural areas, including motor regions, is regularly implicated in basic timing as well as processing of musical rhythm. However, fractionating the specific roles of individual areas in this network has remained a challenge. Distinctions in activity patterns appear between "automatic" and "cognitively controlled" timing processes, but the perception of musical rhythm requires features of both automatic and controlled processes. In addition, many experimental manipulations rely on participants directing their attention toward or away from certain stimulus features, and measuring corresponding differences in neural activity. Many temporal features, however, are implicitly processed whether attended to or not, making it difficult to create controlled baseline conditions for experimental comparisons. The variety of stimuli, paradigms, and definitions can further complicate comparisons across domains or methodologies. Despite these challenges, the high level of interest and multitude of methodological approaches from different cognitive domains (including music, language, and motor learning) have yielded new insights and hold promise for future progress.

Becoming musically enculturated: effects of music classes for infants on brain and behavior

Musical enculturation is a complex, multifaceted process that includes the development of perceptual processing specialized for the pitch and rhythmic structures of the musical system in the culture, understanding of esthetic and expressive norms, and learning the pragmatic uses of music in different social situations. Here, we summarize the results of a study in which 6-month-old Western infants were randomly assigned to 6 months of either an active participatory music class or a class in which they experienced music passively while playing. Active music participation resulted in earlier enculturation to Western tonal pitch structure, larger and/or earlier brain responses to musical tones, and a more positive social trajectory. Furthermore, the data suggest that early exposure to cultural norms of musical expression leads to early preferences for those norms. We conclude that musical enculturation begins in infancy and that active participatory music making in a positive social setting accelerates enculturation.

Effects of perceptual experience on children's and adults' perception of unfamiliar rhythms

Rhythm and meter are fundamental components of music that are universal yet also culture specific. Although simple, isochronous meters are preferred and more readily discriminated than highly complex, nonisochronous meters, moderately complex nonisochronous meters do not pose a problem for listeners who are exposed to them from a young age. The present work uses a behavioral task to examine the ease with which listeners of various ages acquire knowledge of unfamiliar metrical structures from passive exposure. We examined perception of familiar (Western) rhythms with an isochronous meter and unfamiliar (Balkan) rhythms with a nonisochronous meter. We compared discrimination by American children (5 to 11 years) and adults before and after a 2-week period of at-home listening to nonisochronous meter music from Bulgaria. During the first session, listeners of all ages exhibited superior discrimination of isochronous than in nonisochronous melodies. Across sessions, this asymmetry declined for young children but not for older children and adults.

Active music classes in infancy enhance musical, communicative and social development

Previous studies suggest that musical training in children can positively affect various aspects of development. However, it remains unknown as to how early in development musical experience can have an effect, the nature of any such effects, and whether different types of music experience affect development differently. We found that random assignment to 6 months of active participatory musical experience beginning at 6 months of age accelerates acquisition of culture-specific knowledge of Western tonality in comparison to a similar amount of passive exposure to music. Furthermore, infants assigned to the active musical experience showed superior development of prelinguistic communicative gestures and social behaviour compared to infants assigned to the passive musical experience. These results indicate that (1) infants can engage in meaningful musical training when appropriate pedagogical approaches are used, (2) active musical participation in infancy enhances culture-specific musical acquisition, and (3) active musical participation in infancy impacts social and communication development.