Biology subjects

Tretyakova, V.

Publications and source records attributed to Tretyakova, V..

3 recordsLinked to original sources

bioRxiv2025

ABERRANT NEURAL ADAPTATION TO EXPECTED UNCERTAINTY IN ADULTS WITH AUTISM SPECTRUM DISORDER

The ability to adjust brain resources to manage expected uncertainty is hypothesized to be impaired in autism spectrum disorder (ASD), though the evidence remains limited. To investigate this, we studied 29 neurotypical (NT) and 29 high-functioning adults with ASD performing a probabilistic two-alternative value-based task while undergoing magnetoencephalography (MEG) and pupillometry. The task comprised five sequential blocks with stable reward probabilities (70%:30%), but varying stimulus pairs and reward values, enabling assessment of behavioral and neural adaptation to expected uncertainty. We analyzed a hit rate of advantageous choices, response times, and computational measures of prior belief strength and precision. To examine cortical activation during decision-making, we used MEG source reconstruction to quantify -{beta} oscillation suppression in decision-relevant cortical regions within the pre-decision time window. Linear mixed models assessed trial-by-trial effects. Behaviorally, ASD participants exhibited lower overall belief precision but intact probabilistic rule generalization, showing gradual performance improvement and strengthening of prior beliefs across blocks. However, unlike NT individuals, they did not show progressive downscaling of neural activation during decision-making or reduction in neural response to feedback signals as performance improved. Furthermore, on a trial-by-trial basis, increased belief precision in ASD was not associated with reduced cortical activation, a pattern observed in NT individuals. These findings suggest an atypically rigid and enhanced allocation of neural resources to advantageous decisions in individuals with ASD - although they, as NT individuals, rationally judge such decisions as optimal. This pattern may reflect an aversive response to the irreducible uncertainty inherent in probabilistic decision-making.

neuroscience↗

bioRxiv2024

Newly Acquired Word-Action Associations Trigger Auditory Cortex Activation During Movement Preparation: Implications for Hebbian Plasticity in Action Words Learning

Hebbian learning is believed to play a key role in acquisition of action words. However, this biological mechanism requires activation of the neural assemblies representing a word form and a corresponding movement to repeatedly overlap in time. In reality, though, these associated events could be separated by seconds. In the current MEG study, we examined trial-and-error learning of associations between novel auditory pseudowords and movements of specific body parts. We aimed to explore how the brain bridges the temporal gap between the transient activity evoked by auditory input and the preparatory motor activation before the corresponding movement. To address this, we compared learning-induced changes in neuromagnetic responses locked to the onset of the stimulus and to the onset of the movement. As learning progressed, both types of neural responses showed sustained enhancement during the delay period between the auditory pseudoword and the required movement. Cortical sources of this learning-induced increase were localized bilaterally in the lateral and medial temporal cortices. Notably, the learning effect was significantly stronger when measured time-locked to the movement onset, rather than to the pseudoword onset. This suggests that, after the pseudoword-movement associations were reliably acquired, the non-primary auditory cortex was reactivated in sync with the preparation of the upcoming movement. Such reactivation likely served to bring together in time the representations of the correct action and the preceding auditory cue. This temporal alignment could enable Hebbian learning, leading to long-lasting synaptic changes in temporally correlated neural assemblies.

neuroscience↗

bioRxiv2022

Learning of new associations invokes a major change in modulations of cortical beta oscillations in human adults

Large-scale cortical beta ({beta}) oscillations have been implicated in the learning processes but their exact role is debated. We explored the dynamics of {beta}-oscillations while 25 adult participants learned, through trial and error, novel associations between four auditory pseudowords and movements of four body extremities. We used MEG to evaluate learninginduced changes in beta modulation accompanying cue-triggered movements. Our findings showed that spatial-temporal characteristics of movement-related {beta}-oscillations underwent a major transition as learning proceeded. Early in learning, suppression of {beta}-power in multiple cortical areas occurred long before movement initiation and sustained throughout the whole behavioral trial. As learning advanced and task performance reached asymptote, {beta}suppression was replaced by a widespread and prolonged rise in {beta}-power. The {beta}-power rise started shortly after the initiation of correct motor response and mainly comprised the prefrontal and medial temporal regions of the left hemisphere. This post-decision {beta}-power predicted trial-by-trial response times (RT) at both stages of learning (before and after the rules become familiar) but in opposite ways. When a subject started to acquire associative rules and gradually improved task performance, a decrease in RT was correlated with the increase in the post-decision {beta}-band power. Repeatedly correct implementation of the learned rules reversed this correlation in the opposite direction with faster (more confident) responses associated with the weaker post-decision {beta}-band synchronization. Our findings suggest that maximal beta activity is pertinent to a distinct stage of learning and may serve to strengthen the newly learned association in a distributed memory network.

neuroscience↗