Biology subjects

Jacoby, N.

Publications and source records attributed to Jacoby, N..

11 recordsLinked to original sources

bioRxiv2026

Neural categorisation of rhythm in human newborns

Music is ubiquitous across cultures, and humans engage in social interactions through music from early in life. A cornerstone of these interactions is rhythm categorisation, allowing the sheer diversity of rhythmic inputs to be mapped onto internal rhythm categories. The pervasiveness of certain rhythm categories across cultures suggests that rhythm categorisation may be partially rooted in neurobiological predispositions constraining the internal representations of rhythm. However, this view appears to conflict with the diversity of music practices across cultures, which points to a role of experience in rhythm categorisation. To assess the relative contributions of neurobiological predispositions and experience, we tested 0- to 3-day-old newborns, capitalising on their minimal postnatal experience with music. Using electroencephalography (EEG), we recorded, in newborns and adults, brain responses to drum sounds whose pattern of relative interval duration ranged from isochronous to long-short rhythms (1:1 - 2:1 interval ratio). Results indicate significant categorisation in newborns's neural responses, with a representational structure that correlate with those of adults, yet with a greater degree of differentiation across rhythms. These findings reveal neurobiological predispositions enabling rhythm categorisation to be present at birth and further shaped across the lifespan, highlighting the evolutionary roots and plasticity supporting this human cultural practice.

neuroscience↗

bioRxiv2025

Categorical rhythmic priors in macaques

Rhythmic ability is a universal aspect of human cultures and sets the basis for musical rhythm perception and synchronization. While humans can synchronize movements to complex rhythms, it is unclear whether this capability extends to our primate ancestors. In this study, we explore whether primates can synchronize to complex rhythms and acquire rhythmic representations with generalizability akin to humans. Using controlled behavioral experiments, we provide evidence that monkeys not only can synchronize to short-long or long-short rhythms but also learn representations that generalize across a wide range of rhythm ratios and total durations. These results indicate ability to flexibly represent ratios within a relative timing framework is not exclusive to humans, but it is also present in monkeys. In addition, the produced intervals show a bias towards rhythmic categories. Notably, in an iterative tapping task, macaques and humans showed large priors for isochrony and integer ratios (2:1, 3:1). These results demonstrate a common biological foundation for rhythm synchronization in primates, extending our understanding of the shared cognitive mechanisms between primates and humans, and highlight the enormous potential of using monkeys to study the neurophysiological basis of complex rhythm perception.

neuroscience↗

bioRxiv2025

Flexible tapping synchronization in macaques: dynamic switching of timing strategies within rhythmic sequences

The ability to synchronize bodily movements with regular auditory rhythm across a broad range of tempos underlies humans capacity for playing music and dancing. This capability is prevalent across human cultures but relatively uncommon among non-human species. Recent research indicates that monkeys can predictively synchronize to regular, isochronous metronomes, exhibiting a preference for visual rather than auditory sequences. In this study, we trained macaques to perform a visual synchronization tapping task, testing their synchronization abilities over a wide tempo range and characterizing their precision and accuracy in timing intervals throughout rhythmic sequences. Additionally, we investigated whether the macaques employed priors or error correction strategies to maintain synchrony with the metronome. Our findings demonstrate that, following sufficient training, macaques exhibit a remarkable capability to synchronize across diverse tempos. Through an inference model analysis, we identified two distinct timing control strategies used by the macaques: an initial strong regression-to-the-mean effect transitioning dynamically into a more precise error correction approach at their preferred tempo. These results provide compelling evidence that primates possess sophisticated rhythmic timing mechanisms, effectively leveraging internal and external cues to regulate their tapping behavior according to task demands. NEW & NOTEWORTHYWe trained macaques in a visual synchronization tapping task and using an inference model we found that they are highly precise and accurate in their rhythmic performance. The model also captured a dynamic switch in behavior. At the beginning of the task, the monkeys used their prior knowledge about the interval statistics and then switched to an error correction mechanism to generate intervals depending on the previously produced duration.

neuroscience↗

bioRxiv2024

Revealing rhythm categorization in human brain activity

Humans across cultures show an outstanding capacity to perceive, learn, and produce musical rhythms. These skills rely on mapping the infinite space of possible rhythmic sensory inputs onto a finite set of internal rhythm categories. What are the brain processes underlying rhythm categorization? We used electroencephalography (EEG) to measure brain activity as human participants listened to a continuum of rhythmic sequences characterized by repeating patterns of two inter-onset intervals. Using frequency and representational similarity analyses, we show that brain activity does not merely track the temporal structure of rhythmic inputs, but, instead, automatically produces categorical representation of rhythms. Surprisingly, despite this automaticity, these rhythm categories do not arise in the earliest stages of the ascending auditory pathway, but show strong similarity between implicit neural and overt behavioral responses. Together, these results and methodological advances constitute a critical step towards understanding the biological roots and diversity of musical behaviors across cultures.

neuroscience↗

bioRxiv2023

Musical pitch has multiple psychological geometries

Pitch perception is central for both speech and music, and the representation of musical pitch has intrigued scholars for centuries. In his seminal work, Roger Shepard proposed a series of increasingly complex geometrical models to approximate the psychological representation of pitch, most famously the pitch helix which is often used in textbooks. The pitch helix represents the logarithmic scaling of the periodicity of tones and the similarity between tones separated by an octave. However, support for geometrical models of musical pitch derives from studies that are small-scale and sometimes contradictory. Moreover, research suggests that the representation of pitch is influenced by task context and expertise raising the question of whether any single integrated geometric approximation is sufficient. Using multi-dimensional scaling analysis, we revisit this problem through nine experiments involving participants with varied levels of musical expertise (N = 592) and paradigms covering both perception and production, as well as implicit and explicit measures of perceptual similarity. We show that, depending on task and musical experience, the best geometrical approximation can exhibit an array of structures ranging from linear to double-helical structures, providing strong evidence that a simple helical model, or in fact any fixed geometrical model, cannot explain the data. To explain these large variations, we then show that they can be captured by different reweightings of a small set of perceptual factors suggesting a composite representation. These findings highlight the importance of examining diverse tasks and populations to address the classic question of how perceptual representations are organized.

neuroscience↗

bioRxiv2022

Reshaping musical consonance with timbral manipulations and massive online experiments

The phenomenon of musical consonance is an essential feature in diverse musical styles. The traditional belief, supported by centuries of Western music theory and psychological studies, is that consonance derives from simple ( harmonic) frequency ratios between tones. Here we show through massive large-scale behavioral experiments (235,440 judgments) that harmonic consonance preferences can be deeply reshaped by timbral manipulations, even as far as to induce preferences for inharmonic intervals. We show how such effects may have shaped the cultural evolution of diverse scale systems ranging from the gamelans slendro scale to the tuning of Western mean-tone and equal-tempered scales. Through computational modeling we show that these timbral manipulations elegantly dissociate competing psychoacoustic mechanisms underlying consonance, and we derive an updated computational model combining liking of harmonicity, disliking of fast beats (roughness), and liking of slow beats. Altogether, this work showcases how large-scale behavioral experiments can inform classical questions in auditory perception. Author summary"We reveal effects of timbre on consonance perception that motivate a new understanding of the evolution of musical scales."

neuroscience↗

bioRxiv2022

Studying the Effect of Oral Transmission on Melodic Structure using Online Iterated Singing Experiments

Since generations, singing and speech have been mainly transmitted orally. How does oral transmission shape the evolution of music? Here, we developed a method for conducting online transmission experiments, in which sung melodies are passed from one singer to the next. We show that cognitive and motor constraints play a profound role in the emergence of melodic structure. Specifically, initially random tones develop into more structured systems that increasingly reuse and combine fewer elements, making melodies easier to learn and transmit over time. We discuss how our findings are compatible with melodic universals found in most human cultures and culturally specific characteristics of participants previous musical exposure. Overall, our method efficiently automates online singing experiments while enabling large-scale data collection using standard computers available to everyone. We see great potential in further extending this work to increase the efficiency, scalability, and diversity of research on cultural evolution and cognitive science.

neuroscience↗

bioRxiv2021

REPP: A robust cross-platform solution for online sensorimotor synchronization experiments

Sensorimotor synchronization (SMS), the rhythmic coordination of perception and action, is a fundamental human skill that supports many behaviors, from daily repetitive routines to the most complex behavioural coordination, including music and dance (Repp 2005; Repp & Su, 2013). Research on SMS has been mostly conducted in the laboratory using finger tapping paradigms, where participants typically tap with their index finger to a rhythmic sequence of auditory stimuli. However, these experiments require equipment with high temporal fidelity to capture the asynchronies between the time of the tap and the corresponding cue event. Thus, SMS is particularly challenging to study with online research, where variability in participants hardware and software can introduce uncontrolled latency and jitter into recordings. Here we present REPP (Rhythm ExPeriment Platform), a novel technology for measuring SMS in online experiments that can work efficiently using the built-in microphone and speakers of standard laptop computers. The audio stimulus (e.g., a metronome or a music excerpt) is played through the speakers and the resulting signal is recorded along with participants responses in a single channel. The resulting recording is then analyzed using signal processing techniques to extract and align timing cues with high temporal accuracy. In this paper, we validate REPP through a series of calibration and behavioural experiments. We demonstrate that our technology achieves high temporal accuracy (latency and jitter within 2 ms on average), high test-retest reliability both in the laboratory (r = .87) and online (r = .80), and high concurrent validity (r = .94). We also show that REPP is fully automated and customizable, enabling researchers to monitor experiments in real time and to implement a wide variety of SMS paradigms. We discuss methods for ensuring high recruiting efficiency and data quality, including pre-screening tests and automatic procedures for quality monitoring. REPP can therefore open new avenues for research on SMS that would be nearly impossible in the laboratory, reducing experimental costs while massively increasing the reach, scalability and speed of data collection.

neuroscience↗

bioRxiv2020

Impaired online error-correction disrupts synchronization to external events in autism

Autism is a developmental disorder characterized by impaired social skills and accompanied by motor and perceptual atypicalities. Its etiology is an open question, partly due to the diverse range of associated difficulties. Based on recent observations that individuals with autism are slow in updating perceptual priors, we now hypothesized that motor updating is also slow. Slow motor updating is expected to hamper the ability to synchronize to external events, since asynchronies are corrected sluggishly. Since sensorimotor synchronization is important for social bonding and cooperation, its impairment is expected to impair social skills. To test this hypothesis, we measured paced finger tapping to a metronome in neurotypical, ASD, and dyslexia groups. Dyslexia was assessed as a control group with a non-social neurodevelopmental atypicality. Only the ASD group showed reduced sensorimotor synchronization. Trial-by-trial computational modelling revealed that their ability to form controlled motor responses and to maintain reliable temporal representations was adequate. Only their rate of error-correction was slow and was correlated with the severity of their social difficulties. Taken together, these findings suggest that slow updating in autism contributes to both sloppy sensorimotor performance and difficulties in forming social bonds. SignificanceThe prevalence of autism diagnosis has increased immensely is the last decades. Yet its etiology remains a challenge, partly since the functional relations between characteristic social difficulties, perceptual and motor atypicalities are not understood. Using trial-by-trial computational modelling, we show that a single deficit underlies the poor synchronization of individuals with autism in both static and changing environments. Slow updating, leading to slow online error correction of motor plans, has an immense explanatory power explaining both difficulties in sensorimotor synchronization, and social impairments.

neuroscience↗

bioRxiv2019

Unravelling the genetic architecture of musical rhythm

Moving in synchrony to the beat is a fundamental component of musicality. Here, we conducted a genome-wide association study (GWAS) to identify common genetic variants associated with beat synchronization in 606,825 individuals. Beat synchronization exhibited a highly polygenic architecture, with sixty-nine loci reaching genome-wide significance (p<5x10-8) and SNP-based heritability (on the liability scale) of 13%-16%. Heritability was enriched for genes expressed in brain tissues, and for fetal and adult brain-specific gene regulatory elements, underscoring the role of central nervous system-expressed genes linked to the genetic basis of the trait. We performed validations of the self-report phenotype (through internet-based experiments) and of the GWAS (polygenic scores for beat synchronization were associated with patients algorithmically classified as musicians in medical records of a separate biobank). Genetic correlations with breathing function, motor function, processing speed, and chronotype suggest shared genetic architecture with beat synchronization and provide avenues for new phenotypic and genetic explorations.

genetics↗

bioRxiv2019

Analysis of task-based functional MRI data preprocessed with fMRIPrep

Functional magnetic resonance imaging (fMRI) is a standard tool to investigate the neural correlates of cognition. fMRI noninvasively measures brain activity, allowing identification of patterns evoked by tasks performed during scanning. Despite the long history of this technique, the idiosyncrasies of each dataset have led to the use of ad-hoc preprocessing protocols customized for nearly every different study. This approach is time-consuming, error-prone, and unsuitable for combining datasets from many sources. Here we showcase fMRIPrep (http://fmriprep.org), a robust tool to prepare human fMRI data for statistical analysis. This software instrument addresses the reproducibility concerns of the established protocols for fMRI preprocessing. By leveraging the Brain Imaging Data Structure (BIDS) to standardize both the input datasets --MRI data as stored by the scanner-- and the outputs --data ready for modeling and analysis--, fMRIPrep is capable of preprocessing a diversity of datasets without manual intervention. In support of the growing popularity of fMRIPrep, this protocol describes how to integrate the tool in a task-based fMRI investigation workflow.

bioinformatics↗