Biology subjects

Dotov, D.

Publications and source records attributed to Dotov, D..

5 recordsLinked to original sources

bioRxiv2026

Optimal coupling and task-specificity when learning rhythmic synchronization with a tool with varying levels of predictability and controllability

Sensorimotor learning and tool use involve synchronizing with external dynamics. Many everyday tools possess nonlinear hidden dynamics. Here we investigate how learning to synchronize with the complex dynamics of a tool depends on the degree of predictability and reciprocal coupling between user and tool. We introduce the concept of optimal coupling to measure adaptive user-tool coordination. Groups of participants practiced tracking an auditory stimulus in three conditions: 1) the tool was non-interactive and produced a periodic stimulus, 2) non-interactive and unstable stimulus, and 3) unstable but interactive stimulus which was coupled weakly to the participants movements and thus afforded control. Learning, retention, and transfer to visual modality were assessed using unpracticed test stimuli. Directional effective coupling was quantified using transfer entropy. Results showed that learning tended to be task-specific and there was no transfer to the visual modality. Interactive unstable practice exhibited some retention and generalization. We found a convergent reorganization of coupling during practice with the interactive unstable tool: stimulus-to-human coupling started high and decreased while human-to-stimulus coupling started low and increased. This suggests that embodiment of personalized rehabilitation technologies brings optimal reciprocal coupling in which sensorimotor-tool control is consistent with the minimal intervention principle postulated for within-body control.

neuroscience↗

bioRxiv2026

Effects of delay and amplification of auditory feedback for walking: anticipation, variability, and frequency adaptation.

When we walk, our footsteps generate rich acoustic information about foot timing, dragging, loading rate, etc. The role of self-generated or endogenous auditory feedback for gait control remains underexplored. We investigated how delay and amplification of self-produced footstep sounds modulate gait. Thirty healthy young adults walked overground while receiving real-time lateralized playback of the sound produced by their feet. Amplified auditory feedback (AAF) was delivered with no, shorter, or longer delay, and either at full or half amplification. Cortical hemodynamic responses were recorded concurrently in prefrontal and temporal regions of interest (ROI) with mobile functional near-infrared spectroscopy (fNIRS). Spatiotemporal gait parameters were analyzed as change relative to baseline. We found that amplification without delay reduced variability by almost 10%, consistent with strengthened sensorimotor coupling via enhanced perceptual access to foot-ground interaction dynamics. Delay increased cadence instead of reducing it. At the level of hemodynamic response, the ROI containing the superior temporal gyrus (STG) exhibited an increase during walking relative to quiet standing, especially in the condition with no delay and full amplification. To explain the effects of amplification and delay on gait timing, we offer two alternative models, one using anticipatory dynamic systems and the other Bayesian predictive processing.

neuroscience↗

bioRxiv2025

Manifold properties in the macaque medial premotor cortex during switching from attending to tapping to a metronome

Animals synchronize their movements with external rhythms to coordinate perception and action, but the neural population mechanisms that allow them to attend and then initiate and sustain these rhythms remain unclear. Using high-density recordings from the medial premotor cortex (MPC) of two macaque monkeys, we investigated neural dynamics during an attend-then-synchronize tapping task with visual metronomes. We found low-dimensional neural manifolds that capture neural population trajectories. During the attention phase, trajectories exhibited increasing amplitude and oscillatory modulation along successive stimuli, consistent with a resonant-like mechanism. Transition to tapping was marked by a reliable shift into a distinct manifold subspace, enabling accurate decoding of the switch in behavior. In addition, large amplitude and oscillatory indices were higher in successful tapping synchronization trials than in incorrect ones. These findings demonstrate that macaque MPC activity evolves along smooth, low-dimensional trajectories whose geometry governs different perceptual and motor aspects of tapping synchronization.

animal behavior and cognition↗

bioRxiv2025

Variance spectrum scaling analysis for high-dimensional coordination in human movement

Coordinated movement has been essential to our evolution as a species but its study has been limited by ideas largely developed for one-dimensional data. The field is poised for a change by high-density recording tools and the popularity of data sharing. New ideas are needed to revive classical theoretical questions such as the organization of the highly redundant biomechanical degrees of freedom and the optimal distribution of variability for efficiency and adaptiveness. Methods have been focused on increasing dimensions: making inferences from one or few measured dimensions about the properties of a higher dimensional system. The opposite problem is to record 100+ kinematic degrees of freedom and make inferences about properties of the embedded manifold. We present an approach to quantify the smoothness and degree to which the manifold is distributed among embedding dimensions. The principal components of embedding dimensions are rank-ordered by variance. The power-law scaling exponent of this variance spectrum is a function of the smoothness and dimensionality of the embedded manifold. It defines a threshold value beyond which the manifold becomes non-differentiable. We verified this approach by showing that the Kuramoto model close to global synchronization in the upper critical end of the coupling parameter obeys the threshold. Next, we tested if the scaling exponent was sensitive to participants gait impairment in a full-body motion capture dataset containing short gait trials. Variance scaling was highest in the healthy individuals, followed by osteoarthritis patients after hip-replacement, and lastly, the same patients pre-surgery. Thinking about manifold dimensionality, smoothness, and scaling could inform classic problems in movement science and exploration of the biomechanics of full-body action.

neuroscience↗

bioRxiv2021

Collective dynamics support group drumming, reduce variability, and stabilize tempo drift

Humans are social animals who engage in a variety of collective activities requiring coordinated action. Among these, music is a defining and ancient aspect of human sociality. Human social interaction has largely been addressed in dyadic paradigms and it is yet to be determined whether the ensuing conclusions generalize to larger groups. Studied more extensively in nonhuman animal behaviour, the presence of multiple agents engaged in the same task space creates different constraints and possibilities than in simpler dyadic interactions. We addressed whether collective dynamics play a role in human circle drumming. The task was to synchronize in a group with an initial reference pattern and then maintain synchronization after it was muted. We varied the number of drummers, from solo to dyad, quartet, and octet. The observed lower variability, lack of speeding up, smoother individual dynamics, and leader-less inter-personal coordination indicated that stability increased as group size increased, a sort of temporal wisdom of crowds. We propose a hybrid continuous-discrete Kuramoto model for emergent group synchronization with pulse-based coupling that exhibits a mean field positive feedback loop. This research suggests that collective phenomena are among the factors that play a role in social cognition.

animal behavior and cognition↗