Biology subjects

Kornysheva, K.

Publications and source records attributed to Kornysheva, K..

9 recordsLinked to original sources

bioRxiv2026

Cortico-cerebellar beta-band dynamics predict flexible motor timing

Flexible motor control requires that movements adapt to changing temporal contexts. Here, we test whether flexible timing is driven by context-dependent encoding across cortico-cerebellar circuits and how neural dynamics within these circuits enable accurate performance. To overcome the signal-to-noise limitations of conventional electro- and magnetoencephalography, we recorded whole-head neural dynamics using optically pumped magnetometer arrays (OPM-MEG). Participants learned a context-dependent task, executing manual button presses at time intervals 800 ms (T1) and 1,600 ms (T2), respectively, to avoid a periocular air puff, which was associated with an implicit conditioned eyeblink. We found that the motor cortex contralateral to the hand and bilateral cerebellar lobule VI dynamically encoded these intervals through beta-band (13-30 Hz) event-related desynchronisation (ERD) that precisely scaled with T1 and T2. The cerebellar trial-by-trial latency of the beta-band ERD predicted the timing of explicit manual actions. Finally, partial directed coherence revealed that baseline bidirectional beta-band coupling across the network transiently weakened from the ipsilateral cerebellum to the contralateral motor cortex during finger movement execution. Our findings show that cortico-cerebellar coupling functions as a gating mechanism and suggest that cerebellar circuits modulate cortical motor activity for flexible, accurate motor timing.

neuroscience↗

bioRxiv2026

Developmental coordination disorder affects the pre-ordering of sequential movements

Research suggests that motor difficulties in Developmental Coordination Disorder (DCD) are related to altered motor sequence planning, but it is unclear which mechanisms are affected, particularly in adults. This study addresses that gap by examining how the order of upcoming movements during the planning of skilled typing sequences affects motor production in adults with DCD. Previous monkey neurophysiology and behavioural findings in humans have shown that elements of a sequence are pre-ordered prior to execution, known as competitive queuing (CQ). CQ quality is predictive of subsequent performance, with skilled performers, those with fewer errors, having a larger position-dependent difference. DCD (N=28) and control participants (N=54) performed two 4-element finger sequences from memory in a delayed sequence production task over 3 sessions. Probe trials, which involved participants performing a single press after the Go Cue, assessed motor planning at each sequence position by measuring reaction time (RT) and error rate. We found that adults with DCD had a higher error rate and were slower to initiate and perform correct sequences. In terms of planning, the DCD group showed reduced preordering of sequence elements. Whilst the DCD group had a higher error rate on a working memory task, this was not correlated with the degree of pre-ordering of presses of the upcoming sequence. These findings suggest that disrupted motor sequence planning in DCD is characterised specifically by a failure to pre-order movements during the retrieval of sequences from memory. Additionally, motor sequence pre-ordering deficits in DCD are independent of general working memory impairments. These results extend prior evidence from motor imagery paradigms, demonstrating that internal modelling deficits are evident during the execution of motor plans. HighlightsO_LIAdults with DCD show diminished pre-ordering of sequential movements during planning. C_LIO_LIThe DCD group were slower to initiate and perform correct sequences from memory. C_LIO_LIMotor sequence planning is distinct from working memory performance. C_LIO_LIThis provides evidence for the IMD hypothesis in a skilled sequential task. C_LI

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bioRxiv2026

A domain-general neural signature of serial order memory across action and perception

Remembering events in the correct order, and generating ordered sequences of actions, are fundamental abilities across species. Behavioral studies, and theoretical work, raise the possibility that the brain represents serial order by a domain-general neural code, following the principle of Competitive Queuing. However, direct neurophysiological evidence for Competitive Queuing exists only in the motor domain. When humans and non-human primates prepare for a series of movements, several of the upcoming movements are represented in parallel, with their representational strength reflecting ordinal position in the sequence. We test the generalizability of this so-called primacy gradient across motor sequences and memorized auditory sequences. Using a multivariate decoding approach, Experiment 1 replicated the presence of a Competitive Queuing primacy gradient in magnetoencephalography (MEG) data of young healthy adults (n = 23) when they prepared a sequence of finger movements from memory. Importantly, we observed a similar primacy gradient when participants anticipated a sequence of tones they had learned before, in the absence of any movement. In Experiment 2 (n = 23; naive cohort), we rule out the possibility that this primacy gradient in auditory memory is explained by any learnt association between tones and movements, or by MEG signal fluctuations that are unrelated to discrete sequential events. In sum, we find a similar neural signature of serial order coding when humans prepare a sequence of movements, and when they anticipate a sequence of sounds. This lends support to the generalizability of Competitive Queuing.

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bioRxiv2025

Distributed neural dynamics underlie the shift from movement preparation to execution

Dissociating the neural mechanisms of movement preparation from those of execution across the brain is fundamental to understanding motor control. Invasive recordings in primary motor cortex (M1) indicate that shared neural populations support both phases by unfolding within orthogonal subspaces or "manifolds", yet whether and how these dynamics evolve across the broader set of brain regions involved in memory-guided skilled action remains poorly understood. Here, we used magnetoencephalography (MEG) data obtained during a memoryguided delayed finger-sequence task to track fast population dynamics across M1, premotor cortices, and the hippocampus. Linear discriminant analysis decoding of sequence-specific preparatory and execution patterns revealed a transition from preparation to execution patterns across all regions prior to movement onset. Importantly, the onset of execution exhibited region-specific timing, with M1 shifting last,[~] 100 ms before the first button press, consistent with the established cortical motor hierarchy. Low-dimensional trajectories showed that preparatory and execution states occupied distinct manifolds, yet were not fully orthogonal, suggesting partial overlap in tuning. MEG dynamics were dominated by peri-movement phase activity in the primary motor and premotor regions. Nevertheless, above-chance sequence decoding was recoverable from all motor and premotor regions during execution and in M1 during preparation. The state shift and the decoding accuracy were driven by distributed modulations across multiple frequency bands, indicating that full-band population dynamics carry richer information than band-limited features alone. These results demonstrate that non-invasive MEG can resolve continuous, hierarchical neural state transitions in the human brain in the context of memory-guided movement control. They offer mechanistic insight into distributed motor-related brain dynamics and support developing brain-computer-interfaces that incorporate signals from multiple brain regions beyond the primary motor cortex.

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bioRxiv2024

Ramping dissociates motor and cognitive sequences in the parietal and prefrontal cortices

Humans complete different types of sequences as a part of everyday life. These sequences can be divided into two important categories: those that are abstract, in which the steps unfold according to a rule at super-second to minute time scale, and those that are motor, defined solely by individual movements and their order which unfold at the sub-second to second timescale. For example, the sequence of making spaghetti consists of abstract tasks (preparing the sauce and cooking the noodles) and nested motor actions (stir pasta water). Previous work shows neural activity increases (ramps) in the rostrolateral prefrontal (RLPFC) during abstract sequence execution (Desrochers et al., 2015, 2019). During motor sequence production, activity occurs in regions of the prefrontal cortex (Yewbrey et al., 2023). However, it remains unknown if ramping is a signature of motor sequence production as well or solely an attribute of abstract sequence monitoring and execution. We tested the hypothesis that significant ramping activity occurs during motor sequence production in the RLPFC. Contrary to our hypothesis, we did not observe significant ramping activity in the RLPFC during motor sequence production, but we found significant ramping activity in bilateral inferior parietal cortex, in regions distinct from those observed during an abstract sequence task. Our results suggest different prefrontal-parietal circuitry may underlie abstract versus motor sequence execution.

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bioRxiv2024

The hippocampus pre-orders movements for skilled action sequences

Plasticity in the subcortical motor basal ganglia-thalamo-cerebellar network plays a key role in the acquisition and control of long-term memory for new procedural skills, from the formation of population trajectories controlling trained motor skills in the striatum to the adaptation of sensorimotor maps in the cerebellum. However, recent findings demonstrate the involvement of a wider cortical and subcortical brain network in the consolidation and control of well-trained actions, including an area traditionally associated with declarative memory - the hippocampus. Here, we probe which role these subcortical areas play in skilled motor sequence control, from sequence feature selection during planning to their integration during sequence execution. An fMRI dataset collected after participants learnt to produce four finger sequences entirely from memory with high accuracy over several days was examined for both changes in BOLD activity and their informational content in subcortical regions of interest. Although there was a widespread activity increase in effector-related striatal, thalamic and cerebellar regions, the associated activity did not contain information on the motor sequence identity. In contrast, hippocampal activity increased during planning and predicted the order of the upcoming sequence of movements. Our findings show that the hippocampus pre-orders movements for skilled action sequences, thus contributing to the higher-order control of skilled movements. These findings challenge the traditional taxonomy of episodic and procedural memory and carry implications for the rehabilitation of individuals with neurodegenerative disorders.

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bioRxiv2022

Cortical patterns shift from sequence feature separation during planning to integration during motor execution

Performing sequences of movements from memory and adapting them to changing task demands is a hallmark of skilled human behaviour, from handwriting to playing a musical instrument. Prior studies showed a fine-grained tuning of cortical primary motor, premotor, and parietal regions to motor sequences - from the low-level specification of individual movements to high-level sequence features like sequence order and timing. However, it is not known how tuning in these regions unfolds dynamically across planning and execution. To address this, we trained 24 healthy right-handed participants to produce four five-element finger press sequences with a particular finger order and timing structure in a delayed sequence production paradigm entirely from memory. Local cortical fMRI patterns during preparation and production phases were extracted from separate No-Go and Go trials, respectively, to tease out activity related to these peri-movement phases. During sequence planning, premotor and parietal areas increased tuning to movement order and timing, irrespective of their combinations. In contrast, patterns reflecting the unique integration of sequence features emerged in these regions during execution only, alongside timing-specific tuning in the ventral premotor, supplementary motor, and superior parietal areas. This was in line with the participants behavioural transfer of trained timing, but not of order to new sequence feature combinations. Our findings suggest a general neural state shift from high-level feature separation to low-level feature integration within cortical regions for movement execution. Recompiling sequence features trial-by-trial during planning may enable flexible last-minute adjustment before movement initiation.

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bioRxiv2020

Competitive state of actions during planning predicts sequence execution accuracy.

Humans can learn and retrieve novel skilled movement sequences from memory, yet the content and structure of sequence planning are not well understood. Previous computational and neurophysiological work suggests that actions in a sequence are planned as parallel graded activations and selected for output through competition (competitive queuing; CQ). However, the relevance of CQ during planning to sequence fluency and accuracy, as opposed to sequence timing, is unclear. To resolve this question, we assessed the competitive state of constituent actions behaviourally during sequence preparation. In three separate multi-session experiments, 55 healthy participants were trained to retrieve and produce 4-finger sequences with particular timing from long-term memory. In addition to sequence production, we evaluated reaction time (RT) and error rate increase to constituent action probes at several points during the preparation period. Our results demonstrate that longer preparation time produces a steeper CQ activation and selection gradient between adjacent sequence elements, whilst no effect was found for sequence speed or temporal structure. Further, participants with a steeper CQ gradient tended to produce correct sequences faster and with a higher temporal accuracy. In a computational model, we hypothesize that the CQ gradient during planning is driven by the width of acquired positional tuning of each sequential item, independently of timing. Our results suggest that competitive activation during sequence planning is established gradually during sequence planning and predicts sequence fluency and accuracy, rather than the speed or temporal structure of the motor sequence. HighlightsO_LIPre-ordering of actions during sequence planning can be assessed behaviourally C_LIO_LICompetitive gradient reflects sequence preparedness and skill, but not speed or timing C_LIO_LIGradient is retrieved rapidly and revealed during automatic action selection C_LIO_LIPositional tuning of actions boosts the competitive gradient during planning C_LI

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bioRxiv2018

Neural competitive queuing of ordinal structure underlies skilled sequential action

The fluent retrieval and production of movement sequences is essential for a variety of daily activities such as speech, tool-use, musical and athletic performance, but the neural mechanisms underlying sequence planning remain elusive. Here, participants learned sequences of finger presses with different timings and different finger orders, and reproduced them in a magneto-encephalography (MEG) scanner. We classified the MEG patterns immediately preceding each press in the sequence, and examined their dynamics over the production of the whole sequence. Our results confirm a role for the competitive queuing of upcoming action representations in the production of learned motor sequences, extending previous computational and non-human primate recording studies to non-invasive measures in humans. In addition, we show that competitive queuing does not simply reflect specific motor actions, but representations of higher-level sequential order that generalise across different motor sequences. Finally, we show that the quality of competitive queuing predicts participants production accuracy, and originates from parahippocampal and cerebellar sources. These results suggest that the brain learns and produces multiple behavioural sequences by flexibly combining representations of specific actions with more abstract, parallel representations of sequential structure.

neuroscience↗