Rhythmic Sequences Research Articles

Temporal dynamics of uncertainty and prediction error in musical improvisation across different periods

Human improvisational acts contain an innate individuality, derived from one’s experiences based on epochal and cultural backgrounds. Musical improvisation, much like spontaneous speech, reveals intricate facets of the improviser’s state of mind and emotional character. However, the specific musical components that reveal such individuality remain largely unexplored. Within the framework of human statistical learning and predictive processing, this study examined the temporal dynamics of uncertainty and surprise (prediction error) in a piece of musical improvisation. This cognitive process reconciles the raw auditory cues, such as melody and rhythm, with the musical predictive models shaped by its prior experiences. This study employed the Hierarchical Bayesian Statistical Learning (HBSL) model to analyze a corpus of 456 Jazz improvisations, spanning 1905 to 2009, from 78 distinct Jazz musicians. The results indicated distinctive temporal patterns of surprise and uncertainty, especially in pitch and pitch-rhythm sequences, revealing era-specific features from the early 20th to the 21st centuries. Conversely, rhythm sequences exhibited a consistent degree of uncertainty across eras. Further, the acoustic properties remain unchanged across different periods. These findings highlight the importance of how temporal dynamics of surprise and uncertainty in improvisational music change over periods, profoundly influencing the distinctive methodologies artists adopt for improvisation in each era. Further, it is suggested that the development of improvisational music can be attributed to the adaptive statistical learning mechanisms. This study explores the period-specific characteristics in the temporal dynamics of improvisational music, emphasizing how artists adapt their methods to resonate with the cultural and emotional contexts of their times. Such shifts in improvisational ways offer a window into understanding how artists intuitively respond and adapt their craft to resonate with the cultural zeitgeist and the emotional landscapes of their respective times.

Rhythm Facilitates Auditory Working Memory via Beta-Band Encoding and Theta-Band Maintenance.

Rhythm, as a prominent characteristic of auditory experiences such as speech and music, is known to facilitate attention, yet its contribution to working memory (WM) remains unclear. Here, human participants temporarily retained a 12-tone sequence presented rhythmically or arrhythmically in WM and performed a pitch change-detection task. Behaviorally, while having comparable accuracy, rhythmic tone sequences showed a faster response time and lower response boundaries in decision-making. Electroencephalographic recordings revealed that rhythmic sequences elicited enhanced non-phase-locked beta-band (16 Hz-33 Hz) and theta-band (3 Hz-5 Hz) neural oscillations during sensory encoding and WM retention periods, respectively. Importantly, the two-stage neural signatures were correlated with each other and contributed to behavior. As beta-band and theta-band oscillations denote the engagement of motor systems and WM maintenance, respectively, our findings imply that rhythm facilitates auditory WM through intricate oscillation-based interactions between the motor and auditory systems that facilitate predictive attention to auditory sequences.

Entrainment echoes in the cerebellum

Evidence accumulates that the cerebellum's role in the brain is not restricted to motor functions. Rather, cerebellar activity seems to be crucial for a variety of tasks that rely on precise event timing and prediction. Due to its complex structure and importance in communication, human speech requires a particularly precise and predictive coordination of neural processes to be successfully comprehended. Recent studies proposed that the cerebellum is indeed a major contributor to speech processing, but how this contribution is achieved mechanistically remains poorly understood. The current study aimed to reveal a mechanism underlying cortico-cerebellar coordination and demonstrate its speech-specificity. In a reanalysis of magnetoencephalography data, we found that activity in the cerebellum aligned to rhythmic sequences of noise-vocoded speech, irrespective of its intelligibility. We then tested whether these "entrained" responses persist, and how they interact with other brain regions, when a rhythmic stimulus stopped and temporal predictions had to be updated. We found that only intelligible speech produced sustained rhythmic responses in the cerebellum. During this "entrainment echo," but not during rhythmic speech itself, cerebellar activity was coupled with that in the left inferior frontal gyrus, and specifically at rates corresponding to the preceding stimulus rhythm. This finding represents evidence for specific cerebellum-driven temporal predictions in speech processing and their relay to cortical regions.

How does musical rhythm influence grammatical processing at the neurophysiological level?

Numerous behavioral studies have demonstrated a rhythmic priming effect (RPE) on grammatical processing using grammaticality judgment tasks (GJT), where participants performed better following regular rhythmic sequences compared to baseline conditions or irregular rhythmic sequences (i.e. auditory rhythmic sequences with violated metrical structure). Only a few studies, however, have explored neurophysiological RPE in grammatical processing. Such neurophysiological investigations have been limited to GJT presented auditorily, have been primarily focused on the French- and German-speaking adult participants, and have rarely used baseline nonpriming conditions. The objective of the present study was to investigate neurophysiological correlates of the RPE in the GJT presented in visual modality. In the current study, we registered a 128-channel electroencephalogram while Russian-speaking adolescents performed a visual GJT, where each sentence was presented word by word in a self-paced manner. Before each experimental block, participants listened to regular rhythmic sequences, irregular rhythmic sequences, or silence. We observed that the late negativity in the event-related potential was larger for the ungrammatical condition compared to the grammatical condition only after the presentation of irregular rhythmic sequences. This effect, referred to as the N600 component in previous research, has been associated with increased cognitive complexity. In conclusion, results suggest that exposure to irregular rhythmic stimulation may lead to increased cognitive demand. This is attributed to the complexity associated with concurrently executing the GJT and managing rhythmic disruption, consequently increasing the strain on working memory resources.

The Early Work of Paul Fraisse: The Timing of ‘Spontaneous’ Rhythms

Abstract The article discusses Paul Fraisse’s early study of the timing of what he called ‘spontaneous’ rhythms, where people were required to perform a specified sequence of spaced taps on a response key without the times between the responses being controlled. Results come from his doctoral thesis, carried out under the supervision of Albert Michotte in Louvain/Leuven in Belgium between 1935 and 1937. In spite of the lack of timing instructions, responses were divided into ‘short times’ (around 200 ms), ‘long times’ (usually around 450 ms), and ‘pauses’ (the times between execution of consecutive rhythmic sequences). This division held over changes in the tap sequence, when different patterns of three, four, and five responses were produced. A later experiment varied total sequence duration, including the pauses, and the ratio of long to short times was approximately preserved even with marked changes in sequence duration, except at the slowest speed. Fraisse regarded the pause as having a different function from the short and long times. It changed only slightly when the pattern changed, but marked changes in the duration of the pause did not affect the pattern. Fraisse suggested it was a kind of separator, needed to maintain the rhythmic structure of the patterns, and used the idea of a temporal ‘Gestalt’ where the pause represented the ‘ground’ or ‘framework’ and the rhythmic sequence the ‘Figure ’.

Neural oscillations suggest periodicity encoding during auditory beat processing in the premature brain.

When exposed to rhythmic patterns with temporal regularity, adults exhibit an inherent ability to extract and anticipate an underlying sequence of regularly spaced beats, which is internally constructed, as beats are experienced even when no events occur at beat positions (e.g., in the case of rests). Perception of rhythm and synchronization to periodicity is indispensable for development of cognitive functions, social interaction, and adaptive behavior. We evaluated neural oscillatory activity in premature newborns (n=19, mean age, 32±2.59weeks gestational age) during exposure to an auditory rhythmic sequence, aiming to identify early traces of periodicity encoding and rhythm processing through entrainment of neural oscillations at this stage of neurodevelopment. The rhythmic sequence elicited a systematic modulation of alpha power, synchronized to expected beat locations coinciding with both tones and rests, and independent of whether the beat was preceded by tone or rest. In addition, the periodic alpha-band fluctuations reached maximal power slightly before the corresponding beat onset times. Together, our results show neural encoding of periodicity in the premature brain involving neural oscillations in the alpha range that are much faster than the beat tempo, through alignment of alpha power to the beat tempo, consistent with observations in adults on predictive processing of temporal regularities in auditory rhythms. RESEARCH HIGHLIGHTS: In response to the presented rhythmic pattern, systematic modulations of alpha power showed that the premature brain extracted the temporal regularity of the underlying beat. In contrast to evoked potentials, which are greatly reduced when there is no sounds event, the modulation of alpha power occurred for beats coinciding with both tones and rests in a predictive way. The findings provide the first evidence for the neural coding of periodicity in auditory rhythm perception before the age of term.

Spectral consistency in sound sequence affects perceptual accuracy in discriminating subdivided rhythmic patterns.

Musical compositions are distinguished by their unique rhythmic patterns, determined by subtle differences in how regular beats are subdivided. Precise perception of these subdivisions is essential for discerning nuances in rhythmic patterns. While musical rhythm typically comprises sound elements with a variety of timbres or spectral cues, the impact of such spectral variations on the perception of rhythmic patterns remains unclear. Here, we show that consistency in spectral cues affects perceptual accuracy in discriminating subdivided rhythmic patterns. We conducted online experiments using rhythmic sound sequences consisting of band-passed noise bursts to measure discrimination accuracy. Participants were asked to discriminate between a swing-like rhythm sequence, characterized by a 2:1 interval ratio, and its more or less exaggerated version. This task was also performed under two additional rhythm conditions: inversed-swing rhythm (1:2 ratio) and regular subdivision (1:1 ratio). The center frequency of the band noises was either held constant or alternated between two values. Our results revealed a significant decrease in discrimination accuracy when the center frequency was alternated, irrespective of the rhythm ratio condition. This suggests that rhythm perception is shaped by temporal structure and affected by spectral properties.

Electrophysiological Activity Associated with a Cross-Modal Anapaest Rhythm: Evidence for the Vestibular Syncopation Hypothesis

Abstract We report an experiment that tested the vestibular syncopation rhythm hypothesis, which holds that the rhythmic effect of syncopation is a form of vestibular reflexive/automated response to a postural perturbation, for example during locomotion. Electrophysiological signals were recorded from the cerebral cortex and cerebellum during processing of rhythmic sequences in a sample of experienced participants. Recordings were made using four different stimulus modalities, auditory, axial, vestibular and visual, under different rhythmic timing conditions, irregular, regular and syncopated/uncertain. Brain current activity was measured using a model with10-dipole source regions of interest in each of the participants, each modality, each timing condition, and for each beat within the bar of the rhythm. The cross-modal spectral power in the frontal electroencephalogram (EEG) and the cerebellar electrocerebellogram (ECeG) was also analysed. The results show that the brain activity increases from the irregular to the regular and then from the regular to the uncertain timing conditions. However, the vestibular modality induces the greatest total brain activity across the regions of interest and exhibits the highest sensitivity to the interaction of beat structure with the timing conditions in both source currents and spectral power. These data provide further evidence to support the primal role of the vestibular system in human processing of rhythm.

Encoding surprise by retinal ganglion cells.

The efficient coding hypothesis posits that early sensory neurons transmit maximal information about sensory stimuli, given internal constraints. A central prediction of this theory is that neurons should preferentially encode stimuli that are most surprising. Previous studies suggest this may be the case in early visual areas, where many neurons respond strongly to rare or surprising stimuli. For example, previous research showed that when presented with a rhythmic sequence of full-field flashes, many retinal ganglion cells (RGCs) respond strongly at the instance the flash sequence stops, and when another flash would be expected. This phenomenon is called the 'omitted stimulus response'. However, it is not known whether the responses of these cells varies in a graded way depending on the level of stimulus surprise. To investigate this, we presented retinal neurons with extended sequences of stochastic flashes. With this stimulus, the surprise associated with a particular flash/silence, could be quantified analytically, and varied in a graded manner depending on the previous sequences of flashes and silences. Interestingly, we found that RGC responses could be well explained by a simple normative model, which described how they optimally combined their prior expectations and recent stimulus history, so as to encode surprise. Further, much of the diversity in RGC responses could be explained by the model, due to the different prior expectations that different neurons had about the stimulus statistics. These results suggest that even as early as the retina many cells encode surprise, relative to their own, internally generated expectations.

Using isochrony, but not meter, to discriminate rhythmic sequences in rats (Rattus norvegicus).

Meter induction is a key process for rhythm perception. However, while some nonhuman animals readily detect temporal regularities and perceive beats in auditory sequences, there is no consistent evidence that they extract metrical structures. In the present experiment, we familiarized rats (Rattus norvegicus) to auditory rhythmic sequences that evoked a duple or a triple meter. We then tested their recognition of these familiar sequences when pitted against novel sequences that evoked no meter (isotonic), evoked a different meter (either duple or triple), or were nonmetrical (nonisochronous). The animals only discriminated isochronous from nonisochronous sequences. However, we found no evidence for meter induction, as the animals did not discriminate familiar from isotonic sequences or from sequences with a different meter. The findings suggest that, under a familiarization paradigm, the natural tendency of the animals is to focus on temporal rather than melodic changes to recognize rhythmic sequences. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Acquired amusia after a right middle cerebral artery infarction – a case study

ABSTRACT A 62-year-old musician—MM—developed amusia after a right middle-cerebral-artery infarction. Initially, MM showed melodic deficits while discriminating pitch-related differences in melodies, musical memory problems, and impaired sensitivity to tonal structures, but normal pitch discrimination and spectral resolution thresholds, and normal cognitive and language abilities. His rhythmic processing was intact when pitch variations were removed. After 3 months, MM showed a large improvement in his sensitivity to tonality, but persistent melodic deficits and a decline in perceiving the metric structure of rhythmic sequences. We also found visual cues aided melodic processing, which is novel and beneficial for future rehabilitation practice.

Diverse Time Encoding Strategies Within the Medial Premotor Areas of the Primate.

The measurement of time in the subsecond scale is critical for many sophisticated behaviors, yet its neural underpinnings are largely unknown. Recent neurophysiological experiments from our laboratory have shown that the neural activity in the medial premotor areas (MPC) of macaques can represent different aspects of temporal processing. During single interval categorization, we found that preSMA encodes a subjective category limit by reaching a peak of activity at a time that divides the set of test intervals into short and long. We also observed neural signals associated with the category selected by the subjects and the reward outcomes of the perceptual decision. On the other hand, we have studied the behavioral and neurophysiological basis of rhythmic timing. First, we have shown in different tapping tasks that macaques are able to produce predictively and accurately intervals that are cued by auditory or visual metronomes or when intervals are produced internally without sensory guidance. In addition, we found that the rhythmic timing mechanism in MPC is governed by different layers of neural clocks. Next, the instantaneous activity of single cells shows ramping activity that encodes the elapsed or remaining time for a tapping movement. In addition, we found MPC neurons that build neural sequences, forming dynamic patterns of activation that flexibly cover all the produced interval depending on the tapping tempo. This rhythmic neural clock resets on every interval providing an internal representation of pulse. Furthermore, the MPC cells show mixed selectivity, encoding not only elapsed time, but also the tempo of the tapping and the serial order element in the rhythmic sequence. Hence, MPC can map different task parameters, including the passage of time, using different cell populations. Finally, the projection of the time varying activity of MPC hundreds of cells into a low dimensional state space showed circular neural trajectories whose geometry represented the internal pulse and the tapping tempo. Overall, these findings support the notion that MPC is part of the core timing mechanism for both single interval and rhythmic timing, using neural clocks with different encoding principles, probably to flexibly encode and mix the timing representation with other task parameters.

EEG-based mental workload assessment in a simulated flight task using single-channel brain rhythm sequence

EEG-based mental workload assessment in a simulated flight task using single-channel brain rhythm sequence

Children With Developmental Language Disorder Show Deficits in the Production of Musical Rhythmic Groupings.

Children with developmental language disorder (DLD) show evidence of domain-general deficits in sequentially patterned motor skills. This study focuses on the production of rhythmically grouped sequences drawn from a music task, with the hypothesis that children with DLD will show a sequential pattern learning deficit that crosses language and action domains. Fifty-seven 4- to 5-year-old children (36 with DLD) drummed and clapped a developmentally appropriate musical rhythmic sequence 24 times (clapped 12 times, drummed 12 times). The accuracy of rhythmic events (markings of claps, drums, and pauses in a target sequence) was assessed through a modification of classic speech and language transcription procedures. The variability and prosodic structure of the rhythmic groupings were also measured. Children with DLD produced less accurate and more variable rhythmic groupings compared to their typically developing (TD) peers. While the final-position grouping of the sequence was especially vulnerable for all children, those with DLD included more co-occurring errors in initial and final groupings of the same rhythmic sequence. Both TD children and children with DLD were less accurate in the clapping than the drumming task. Neither rhythmic drumming nor clapping accuracy correlated with motor skill in either group of children. This study provides novel evidence of a manual rhythmic grouping deficit in DLD, one that is motivated by language-not motor or speech-factors. Cognitive abilities necessary to organize rhythmic events into higher order groupings are impaired across music and language in children with DLD. Rhythmic organization and sequencing may serve an important role in diagnosis and intervention in this population. https://doi.org/10.23641/asha.24158745.

Рsychoacoustic testing to assess the functional maturation of the central audiotory system

The age-appropriate development of the central auditory system is crucial for a child’s normal auditory and speech development. If there are any issues with this development, it can lead to central auditory processing disorders (APD) and problems with psychoverbal and general development. Psychoacoustic testing is an informative and accessible diagnostic tool for identifying signs of APD. This testing can be performed on children as young as four years old, provided there are normative data available for different age groups. The purpose of this study was to assess the functional state of the central auditory system using psychoacoustic methods in healthy children of different ages. Materials Methods. We examined 125 healthy full-term children between the ages of 4 and 17 years who had normal peripheral hearing and no speech, language, cognitive, or academic problems. The children were divided into five age groups: 4–5 years 11 months, 6–7 years 11 months, 8–9 years 11 months, 10–11 years 11 months, and 12 years and older. In addition to traditional audiological examinations, all children underwent tests to assess the functional state of the central parts of the auditory system, including tests for the perception of rhythmic sequences of stimuli, Random Gap Detection Test, monaural low redundant speech testing in quiet and in noise, alternating binaural speech testing, dichotic digits test, and a simplified version of the Russian matrix sentence test in noise (RUMatrix). The results showed that the tests used were sensitive to the functional state of various structures of the central auditory system, and signs of maturation in the “bottom-up” direction were demonstrated as the children grew older. The rate of evolutionary processes varied depending on the age group of the subjects. It was also shown that the morphofunctional development of the central auditory system is not completed by adolescence. Conclusion. These findings can be used to differentiate between the immaturity of the central auditory system, APD, and speech-language disorders of different types in children of different ages. Overall, this study emphasizes the importance of early detection and intervention for any issues related to the central auditory system in children.

Manual Rhythmic Sequencing Skills in Children With Childhood Apraxia of Speech.

Rhythm is one procedural mechanism that underlies language and motor skill acquisition and has been implicated in children with childhood apraxia of speech (CAS). The purpose of this study is to investigate manual rhythmic sequencing skills in children with a history of or current CAS (hx/CAS) compared to children with typical development (TD). Thirty-eight children (18 with hx/CAS, 20 with TD), ages 5;0-12;8 (years;months), from across the United States participated in an online study. Participants imitated two rhythms in two different conditions, clapping and tapping. We assessed overall accuracy, mean number of beats, pause marking, and rhythmic sequence variability using the Mann-Whitney U test. Effect sizes were calculated to examine the influence of coordinative complexity on performance. Compared to children with TD, children with hx/CAS marked fewer trials with a pause in both conditions of the easier rhythm and showed lower overall accuracy and more variable rhythmic sequences in both rhythms and conditions. The mean number of beats produced by children with hx/CAS and children with TD did not differ in three out of four rhythms/conditions. Unlike children with TD, children with hx/CAS showed little improvement from clapping to tapping across most dependent measures; reducing coordination demands did not improve performance in children with hx/CAS. We found that children with hx/CAS show manual rhythmic deficits that are similar to the deficits they display in speech. These findings provide support for a domain-general cognitive mechanisms account of the rhythmic deficits observed across linguistic and nonlinguistic tasks in children with hx/CAS. https://doi.org/10.23641/asha.24052821.

Investigating the impact of age on auditory short-term, long-term, and working memory

Cognitive aging is characterized by the gradual decline of a number of abilities, such as attention, executive functioning, and memory. Research on memory aging has reported age-related deficits in short-term (STM), long-term (LTM), and working memory (WM) and linked these to structural and functional changes in the brain that occur with aging. However, only a few studies have drawn direct comparisons between these memory subsystems in the auditory domain. In this study, we assessed auditory STM, LTM, and WM abilities of young (under 25 years of age) and older (over 60 years of age) adults using musical and numerical tasks. In addition, we measured musical training history and tested its modulating effects on auditory memory performance. Overall, we found that older adults underperformed in specific memory tasks, such as STM related to discrimination of rhythmic sequences, LTM associated with identification of novel musical sequences, and numerical WM. Furthermore, we observed a positive influence of musical training on certain memory tasks involving music. In conclusion, aging differentially affects several types of auditory memory, and in the case of specific musical memory tasks, a higher level of musical training provides significant advantages.

Neural substrates of top-down processing during perceptual duration-based timing and beat-based timing.

Temporal context is a crucial factor in timing. Previous studies have revealed that the timing of regular stimuli, such as isochronous beats or rhythmic sequences (termed beat-based timing), activated the basal ganglia, whereas the timing of single intervals or irregular stimuli (termed duration-based timing) activated the cerebellum. We conducted a functional magnetic resonance imaging (fMRI) experiment to determine whether top-down processing of perceptual duration-based and beat-based timings affected brain activation patterns. Our participants listened to auditory sequences containing both single intervals and isochronous beats and judged either the duration of the intervals or the tempo of the beats. Whole-brain analysis revealed that both duration judgments and tempo judgments activated similar areas, including the basal ganglia and cerebellum, with no significant difference in the activated regions between the two conditions. In addition, an analysis of the regions of interest revealed no significant differences between the activation levels measured for the two tasks in the basal ganglia as well as the cerebellum. These results suggested that a set of common brain areas were involved in top-down processing of both duration judgments and tempo judgments. Our findings indicate that perceptual duration-based timing and beat-based timing are driven by stimulus regularity irrespective of top-down processing.

Minimum description length for selection of models of musical rhythm

We apply the minimum description length (MDL) methodology from information theory in order to select mathematical models for musical rhythm. We consider six models proposed by David Temperley and mathematically formalize them, which allows for an MDL analysis. As a consequence, we find that two of the models are not suitable to apply this methodology, as their codification strategy does not represent all possible rhythm sequences. A slight modification of Temperley's hierarchical model provides an improvement in codification performance, robust across all the four corpora considered in the experiments: three classical corpora commonly used in music studies and one of tango songs recently released. Our study confirms the usefulness of the MDL approach to solve the classical trade-off between model complexity and its ability to fit the data.

EEG rhythm based emotion recognition using multivariate decomposition and ensemble machine learning classifier

Recently, electroencephalogram (EEG) signals have shown great potential to recognize human emotions. The goal of effective computing is to assist computers in understanding various types of emotions via human–computer interaction (HCI). Multichannel EEG signals are used to measure the electrical activity of the brain in space and time. Automated emotion recognition using multichannel EEG signals is an interesting area of cognitive neuroscience and affective computing research. This research proposes EEG multichannel rhythmic features and ensemble machine learning (EML) classifiers with leave-one-subject-out cross-validation (LOSOCV) for automatic emotion classification from multichannel EEG recordings. Multivariate fast iterative filtering (MvFIF) is used to assess the EEG rhythm sequences. EEG rhythms delta(δ), theta(θ), alpha(α), beta(β), and gamma(γ) are separated based on the mean frequency of the EEG rhythm sequence. Three Hjorth parameters and nine entropy features were extracted from multichannel EEG rhythms. Extracted features are selected using the minimum redundancy maximum relevance (mRMR) approach. The experimental design was performed on two emotional datasets (GAMEEMO and DREAMER). The validation showed that gamma rhythm multichannel features with EML-based subspace K-nearest neighbor (SS KNN) were as high as 93.5%–99.8%, achieving high classification accuracy. The comparisons of δ, θ, α, β, and γ rhythms with EML, support vector machine (SVM), and artificial neural network (ANN) were performed. we also analyzed multi-class emotions (HVHA, HVLA, LVHA, LVLA) with an ensemble-based bagging tree on gamma rhythm. It provides a novel solution for multichannel rhythm-specific features in EEG data analysis.