Biology subjects

Martynova, O.

Publications and source records attributed to Martynova, O..

16 recordsLinked to original sources

bioRxiv2025

Novelty, category and orientation tuning for printed characters: a magnetoencephalography study with fast periodic visual stimulation

Letter recognition is assumed to involve several levels of analysis, including coarse tuning for category and novelty and more fine tuning, related to letter orientation. We employed an oddball fast periodic visual stimulation (FPVS) paradigm with magnetoencephalography (Elekta VectorView, 306 sensors) to study neural discrimination responses in the source space. Using contrasts between native letters and foreign letters, digits, or inverted native letters, we aimed to isolate the neural responses to visual novelty, category, and orientation during character analysis. The study was conducted with a cohort of 25 adults. The response topography demonstrated bilateral organization, including language-related brain regions as ventral occipitotemporal cortex, inferior parietal cortex and middle temporal areas. Comparing conditions, we revealed right lateralized parietal clusters, associated with novelty tuning, and left lateralized occipitotemporal clusters exhibiting higher activity for letters among digits discrimination, supporting the role of this area in letter processing. No distinct spatial patterns specific to orientation tuning were observed in comparison to novelty and category tuning. We proposed that expertise-dependent orientation-specific tuning mechanisms may operate within an embedded, spatially overlapping with coarse tuning neural framework, characterized by special spatiotemporal patterns.

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bioRxiv2024

The heart rate dynamics and antioxidant capacity under cognitive load in Obsessive-Compulsive disorder

The research of the oxidants-antioxidants homeostasis and its connection to autonomic nervous system (ANS) dysfunction in patients with obsessive-compulsive disorder (OCD) is a relatively uncharted field of study. We recruited 31 patients diagnosed with OCD and 29 healthy volunteers to analyze their saliva antioxidant capacity before and after a three-block behavioral task with cognitive and emotional load, during which we assessed heart rate (HR) and heart rate variability (HRV) patterns. We found that the OCD group had a significantly lower antioxidant capacity (AOC) and showed no increase in AOC after the cognitive task as compared with healthy volunteers. The notable negative correlation between HR and AOC changes led us to select two subgroups inside the OCD and control group: one with high HR and another with low HR. The AOC changes for OCD and healthy participants with high HR were similar, while OCD sub-group with low HR exhibited significantly different changes in AOC compared with the control group. Although HRV did not show a correlation with AOC, the OCD group demonstrated substantially higher increase of very low frequencies (VLF) of HRV during the cognitive task performance and significantly elevated low frequency powers of HRV expressed in normal units (LFnu). OCD sub-group with lower HR exhibited higher LFnu compared to both the patient and the control group with high HR. Our findings imply that OCD patients with elevated sympathetic tone of ANS reflected by initially increased HR show more adaptive AOC to cognitive load

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bioRxiv2024

Rapid Semantic Processing: An MEG Study of Narrative Text Reading

Research has shown that semantic analysis occurs at early stages of word processing (less than 200 ms). While traditional studies have focused on isolated words/sentences, our research explores rapid semantic processing during reading stories using event-related potentials and magnetoencephalography. We employed the rapid serial visual presentation paradigm to present texts word by word. Each word presentation lasted 150 ms, enhancing rapid semantic processing. We computed semantic dissimilarity (SD) values for each word and categorized them into quartiles to investigate their effect on brain responses. Our analysis revealed significant ERP differences within early time windows (120-132 ms). Two distinct clusters were identified: positive in the right occipital region and negative in the left temporal region. In both clusters less pronounced responses were registered for words with lowest SD which corresponds to theories of predictive coding. These findings broaden our understanding of rapid semantic processing and suggest new methodology.

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bioRxiv2023

Increased error rate and delayed response to negative emotional stimuli in antisaccade task in obsessive-compulsive disorder

Ample evidence links impaired inhibitory control, attentional distortions, emotional dysregulation, and obsessive-compulsive disorder (OCD). However, it remains unclear what underlies the deficit that triggers the OCD cycle. The present study used an antisaccade paradigm with emotional stimuli to compare eye movement patterns reflecting inhibitory control and attention switching in OCD and healthy control groups. Thirty-two patients with OCD and thirty healthy controls performed the antisaccade task with neutral, positive, and negative visual images. The groups differed significantly in the number of errors to negative stimuli. The latency of correct antisaccades varied between valences in OCD group when negative and neutral stimuli served as target ones. The OCD group showed more errors to negative stimuli than the control group and they also performed antisaccades more slowly to negative and neutral stimuli than positive ones. Other patterns, including mean velocity of correct antisaccades and anticipatory saccades, did not differ between groups. The mean velocity of correct antisaccades was higher for negative and positive stimuli than for neutral stimuli; however, there were more anticipatory saccades for neutral stimuli than for negative and positive stimuli in both groups. The peak velocity parameter did not show any differences either between groups or between valences. The findings support a hypothesis that an attentional bias towards threatening stimuli interferes with inhibitory control in OCD.

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bioRxiv2023

Top-down Modulation of Brain Responses in Spelling Error Recognition

The task being undertaken can influence orthographic, phonological and semantic processes. In linguistic research, two tasks are most often used: a task requiring a decision in relation to the presented word and a passive reading task which does not require a decision regarding the presented word. The results of studies using these different tasks are not always consistent. This study aimed to explore brain responses associated with the process of recognition of spelling errors, as well as the influence of the task on this process. Event-related potentials (ERPs) were recorded in 40 adults during an orthographic decision task to determine correctly spelled words and words written with errors that did not change the phonology and during the passive reading. During spelling recognition, the early stages up to 100 ms after the stimulus were automatic and did not depend on the requirements of the task. The amplitude of the N1 component (90-160 ms) was greater in the orthographic decision task, but did not depend on the correct spelling of the word. Late word recognition after 350-500 ms was task dependent, but spelling effects were similar across the two tasks: misspelled words evoked an increase in the amplitude of the N400 component related to lexical and semantic processing regardless of the task. In addition, the orthographic decision task modulated spelling effects, this was reflected in an increase in the amplitude of the P2 component (180-260 ms) for correctly spelled words compared with misspelled words. Thus, our results show that spelling recognition involves general lexico-semantic processes independent of the task. Simultaneously, the orthographic decision task modulates the spelling-specific processes necessary to quickly detect conflicts between orthographic and phonological representations of words in memory. HighlightsO_LIThe influence of task on the recognition of correct spelling of words was studied C_LIO_LISublexical stages during spelling recognition are task-independent C_LIO_LIThe amplitude of the P1, N1 and P600 components is not sensitive to the spelling of words C_LIO_LIThe orthographic decision task modulates the spelling processes at 180-260 ms C_LIO_LISpelling recognition modulates the N400 component regardless of the task C_LI

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bioRxiv2023

Electrophysiological signatures of spelling sensitivity development from primary school age to adulthood

Recognizing spelling errors is important for correct writing and reading, and develops over an extended period. The neural bases of the development of orthographic sensitivity remain poorly understood. We investigated event-related potentials (ERPs) associated with spelling error recognition when performing the orthographic decision task with correctly spelled and misspelled words in children aged 8-10 years old, early adolescents aged 11-14 years old, and adults. Spelling processing in adults included an early stage associated with the initial recognition of conflict between orthography and phonology (reflected in the N400 time window) and a later stage (reflected in the P600 time window) related to re-checking the spelling. In children 8-10 years old, there were no differences in ERPs to correct and misspelled words; in addition, their behavioral scores were worse than those of early adolescents, implying that the ability to quickly recognize the correct spelling is just beginning to develop at this age. In early adolescents, spelling recognition was reflected only at the later stage, corresponding to the P600 component. At the behavioral level, they were worse than adults at recognizing misspelled words. Our data suggest that orthographic sensitivity can develop beyond 14 years.

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bioRxiv2022

Frequency Effects on Spelling Error Recognition: An ERP Study

Spelling errors are ubiquitous in all writing systems. Most studies exploring spelling errors focused on the phonological plausibility of errors. However, unlike typical pseudohomophones, spelling errors occur in naturally produced written language with variable frequencies. We investigated the time course of recognition of the most frequent orthographic errors in Russian (error in an unstressed vowel at the root) and the effect of word frequency on this process. During ERP recording, 26 native Russian speakers silently read high-frequency correctly spelled words, low-frequency correctly spelled words, high-frequency words with errors, and low-frequency words with errors. The amplitude of P200 was more positive for correctly spelled words than for misspelled words and did not depend on the frequency of the words. Word frequency affected spelling recognition in the later stages of word processing (350-700 ms): high-frequency misspelled words elicited a greater P300 than high-frequency correctly spelled words, and low-frequency misspelled words elicited a greater N400 than low-frequency correctly spelled words. We observe spelling effects in the same time window for both the P300 and N400, which may reflect temporal overlap between mainly categorization processes based on orthographic properties for high-frequency words and phonological processes for low-frequency words. We concluded that two independent pathways can be active simultaneously during spelling recognition: one reflects mainly orthographic processing of high-frequency words and the other is the phonological processing of low-frequency words. Our findings suggest that these pathways are associated with different ERP components. Therefore, our results complement existing reading models and demonstrate that the neuronal underpinnings of spelling error recognition during reading depend on word frequency.

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bioRxiv2021

A Toolbox and Crowdsourcing Platform for Automatic Labeling of Independent Components in Electroencephalography (ALICE)

Independent Component Analysis (ICA) is a conventional approach to exclude non-brain signals such as eye-movements and muscle artifacts from electroencephalography (EEG). Due to other possible EEG contaminations, a rejection of independent components (ICs) is usually performed in semiautomatic mode and requires experts involvement. Noteworthy, as also revealed by our study, experts opinion about the nature of a component often disagrees highlighting the need to develop a robust and sustainable automatic system for EEG ICs classification. The current article presents a toolbox and crowdsourcing platform for Automatic Labeling of Independent Components in Electroencephalography (ALICE) available via link http://alice.adase.org/. The ALICE toolbox aims to build a sustainable algorithm not only to remove artifacts but also to find specific patterns in EEG signals using ICA decomposition based on accumulated experts knowledge. The difference from previous toolboxes is that the ALICE project will accumulate different benchmarks based on crowdsourced visual labeling of ICs collected from publicly available and in-house EEG recordings. The choice of labeling is based on estimation of IC time-series, IC amplitude topography and spectral power distribution. The platform allows supervised ML model training and re-training on available data subsamples for better performance in specific tasks (i.e. movement artifact detection in healthy or autistic children). Also, current research implements the novel strategy for consentient labeling of ICs by several experts. The provided baseline model shows that it can be used not only for detection of noisy IC but also for automatic identifications of components related to the functional brain oscillations such as alpha and mu-rhythm. The ALICE project implies the creation and constant replenishment of the IC database, which will be used for continuous improvement of ML algorithms for automatic labeling and extraction of non-brain signals from EEG. The toolbox and current dataset are open-source and freely available to the researcher community.

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bioRxiv2020

The ages of zone of proximal development for retrospective time assessment and anticipation of time event

We aimed to investigate the ability of children aged 5-14 years old (preschoolers, primary schoolers, and preteens) to assess and anticipate time intervals. 287 Russian children aged 5-14 years old and 26 adults of control group participated in our study. The neuropsychological assessment, Wechsler Intelligence Scale for Children and a battery of time-related tests were applied. All groups of children overestimated the events duration, although the accuracy of the second estimations increased among the participants aged 6-8 years after a prompt was offered. A zone of proximal development for time anticipation task was detected for children aged 9-11 years, when the prompt could significantly improve the accuracy of time perception. The participants overestimated the duration of both upcoming and past events, with the degree of overestimation being found to be negatively correlated with age. Further, a higher degree of accuracy in terms of time estimation was found to be correlated with higher scores on the attention and memory tests, and accuracy of time anticipation was associated with scores of praxis test.

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bioRxiv2020

The Laplacian eigenmaps dimensionality reduction of fMRI data for discovering stimulus-induced changes in the resting-state brain activity

The resting brain at wakefulness is active even in the absence of goal-directed behavior or salient stimuli. However, patterns of this resting-state (RS) activity can undergo alterations following exposure to meaningful stimuli. This study aimed to develop an unbiased method to detect such changes in the RS activity after exposure to emotionally meaningful stimuli. For this purpose, we used functional magnetic resonance imaging (fMRI) of RS brain activity before and after the acquisition and extinction of experimental conditioned fear. A group of healthy volunteers participated in three fMRI sessions: a RS before fear conditioning, a fear extinction session, and a RS immediately after fear extinction. The fear-conditioning paradigm consisted of three neutral visual stimuli paired with a partial reinforcement by a mild electric current. We used both linear and non-linear dimensionality reduction approaches to distinguish between the initial RS and the RS after stimuli exposure. The principal component analysis (PCA) as a linear dimensionality reduction method did not differentiate these states. Using the non-linear Laplacian eigenmaps manifold learning method, we were able to show significant differences between the two RSs at the level of individual participants. This detection was further improved by smoothing the BOLD signal with the wavelet multiresolution analysis. The developed method can improve the discrimination of functional states collected in longitudinal fMRI studies.

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bioRxiv2020

Reproducible correlations of corpus callosum and cingulum generalized fractional anisotropy with anxiety ratings in healthy participants

Diffusion tensor imaging revealed that trait anxiety predicts the microstructural properties of fiber tracts between the anterior cingulate cortex, prefrontal cortex, and amygdala. However, the whole-brain structural connectivity has been rarely reported in the non-clinical populations with marginal deviations in trait anxiety and substantial changes in state anxiety. This work is aimed to assess the correlation of state and trait anxiety inventory (STAI) scores and their one-day deviation with white matter connectivity at the whole-brain scale. 64-direction diffusion-weighted images were collected in 25 participants without prior complaints of excess anxiety and/or clinical history of anxiety disorders. The self-reported ranking of STAI was collected twice with 24-hour interval: one day before and several minutes before the MRI scanning. A correlation analysis between the generalized fractional anisotropy (GFA) and the STAI ratings was performed for all regions of the brain. According to the diffusion connectometry, the most reproducible positive correlation of GFA and anxiety scores was observed for corpus callosum. For both days of psychological assessment, the left cingulum GFA correlated negatively with State anxiety ratings, while the right cingulum GFA was strongly associated with Trait anxiety. Our results suggest that the density of the corpus callosum and bilateral cingulum tracts are associated with the individual level of anxiety.

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bioRxiv2020

PERCEPTION OF NON-VERBAL PROSODY IN CHILDREN WITH ASD

Paralinguistic features of the speaker, such as prosody, temp, loudness, and dynamics, are an important marker of a persons emotional state. The deficit of processing of emotional prosody could be preferably associated with the impairments in individuals with ASDs social behavior. The following two groups of children participated in our study: 30 preschoolers from 4 to 6 years old in the target group (39.1 {+/-} 6.4 scores by Childhood Autism Rating Scale), 24 preschoolers of the control group from 4 to 6 years in the control group. The prosody stimuli were the combination of syllables, said with intonations of "joy," "angry," "sadness," "fear," and "calm." Fast Fourier transform (FFT) is used to analyze power spectrum density (PSD). The resulting normalized spectrum was integrated over unit width intervals in the range of interest (2 to 20 Hz with a step in 1Hz). Children with ASD, similarly to TD children, showed the most pronounced differenced of EEG in response to prosodics of fear and anger. The significant groups differences in PSD were detected for sad and joy intonations. Indexes of EEG differences between pleasure and painful intonations were significantly higher in the control group than children with ASD and between sadness and calm or joy and calm intonations. This paper makes up two main contributions: In general, we obtained that children with ASD have less response to a human voices emotional intonation. The physical characteristics of stimuli are more critical than a sign of emotions. The effect of EEG spectral power has hemisphere specialization in the healthy control group, but not in ASD children. Since spectral power for negative emotions in the target group is higher, we proposed that ASD children worse recognize positive emotions than negative emotions.

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bioRxiv2020

Implicit auditory perception of local and global irregularities in passive listening condition

The auditory system detects differences in sounds at an implicit level, but data on this difference might not be sufficient to make explicit discrimination. The biomarkers of implicit auditory memory of ambiguous stimuli could shed light on unconscious auditory processing and implicit auditory learning. Mismatch negativity (MMN) and P3a, components of event-related potentials (ERPs) reflecting stimuli discrimination without direct attention, were previously detected in response to the local (short-term) irregularity in the auditory sequence even in an unconscious state. At the same time, P3b was elicited only in case of direct attention in response to the global (long-term) irregularity. In this study, we applied the local-global auditory paradigm to obtain possible electrophysiological signatures of implicit detection of hardly distinguishable auditory stimuli. ERPs were recorded from 20 healthy volunteers during active discrimination of deviant sounds in the old-ball sequence and passive listening of the same sounds in the sequence with local-global irregularity. The discrimination task consisted of two blocks with different deviant sounds targeted to respond. The sound discrimination accuracy was at an average of 40 %, implying the difficulty of explicit sound recognition. Comparing ERPs to standard and deviant sounds, we found posterior negativity in ERP around 450-600 ms in response to targeted deviant sounds. MMN was significant only in response to non-target deviants. In the passive local-global paradigm, we observed an anterior positivity (284-412 ms), compatible with P3a, in response to a violation of local regularity. Violation of global regularity elicited an anterior negative response (228-586 ms), resembling the N400 component of ERPs. Importantly, the other indexes of auditory discrimination, such as MMN and P3b, were insignificant in ERPs to both regularity violations. The observed P3a and N400 components of ERPs may reflect prediction error signals in the implicit perception of sound patterns even if behavioral recognition was poor. HighlightsO_LIProcessing of hardly distinguishable harmonic tones differs from processing of complex patterns, which consist of these tones C_LIO_LIImplicit perception of local and global irregularities differs C_LIO_LIIn passive listening, local irregularity elicits frontal positivity that is associated with an involuntary switch of attention C_LIO_LIIn passive listening, global irregularity elicits late negativity that might reflect prediction error signals C_LI

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bioRxiv2019

Variance and Scale-Free Properties of Resting-State BOLD Signal Alter after Fear Memory Acquisition and Extinction

Previous studies showed differences in brain dynamics during rest and different tasks. We aimed to find changes of variance and scale-free properties of blood oxygenation level-dependent (BOLD) signal between resting-state sessions before and after fear learning and fear memory extinction in twenty-three healthy right-handed volunteers. During a 1-hour break between MRI-scanning, subjects passed through fear extinction procedure, followed by Pavlovian fear conditioning with weak electrical stimulation. After preprocessing, we extracted the average time course of BOLD signal from 245 regions of interest (ROI) taken from the resting-state functional atlas. The variance of the BOLD signal in and Hurst exponent (H), which reflects the scale-free dynamic, were compared in resting states before after fear learning. Six ROIs showed a significant difference in H after fear extinction, including areas from the fear and memory networks. In consistency with the previous results, H decreased during fear extinction but then increased higher than before, specifically in areas related to fear extinction network, whereas the other ROIs restored H to the initial level. The BOLD signal variance showed distinct behavior: the variance in subcortical regions increased permanently, while cortical areas demonstrated a decreasing variance during fear extinction and the reverse growth in resting state after fear extinction. A limited number of ROIs showed both changes in H and the variance. Our results suggest that the variability and scale-free properties of the BOLD signal are sensitive indicators of the residual brain activity related to the recent experience.

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bioRxiv2019

Longitudinal Changes of Resting-State Functional Connectivity of Amygdala Following Fear Learning and Extinction

Altered functional connectivity of the amygdala has been observed in a resting state immediately after fear learning, even one day after aversive exposure. The persistence of increased resting-state functional connectivity (rsFC) of the amygdala has been a critical finding in patients with stress and anxiety disorders. However, longitudinal changes in amygdala rsFC have rarely been explored in healthy participants. To address this issue, we studied the rsFC of the amygdala in two groups of healthy volunteers. The control group participated in three fMRI scanning sessions of their resting state at the first visit, one day, and one week later. The experimental group participated in three fMRI sessions on the first day: a resting state before fear conditioning, a fear extinction session, and a resting state immediately after fear extinction. Furthermore, this group experienced scanning after one day and week. The fear-conditioning paradigm consisted of visual stimuli with a distinct rate of partial reinforcement by electric shock. During the extinction, we presented the same stimuli in another sequence without aversive pairing. In the control group, rsFC maps were statistically similar between sessions for the left and right amygdala. However, in the experimental group, the increased rsFC mainly of the left amygdala was observed after extinction, one day, and one week. The between-group comparison also demonstrated an increase in the left amygdala rsFC in the experimental group. Our results indicate that functional connections of the left amygdala influenced by fear learning may persist for several hours and days in the human brain.

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bioRxiv2018

Lateral Asymmetry in Weekly Reproducibility of Resting State Amygdala Functional Connectivity

Abnormal functional connectivity of the amygdala with several other brain regions has been observed in patients with higher anxiety or post-traumatic stress disorder, both in a resting state and threatening conditions. However, findings on the specific connections of the amygdala might be varied due to temporal and individual fluctuations in the resting state functional connectivity (rsFC) of the amygdala and its lateral asymmetry, as well as possible variability in anxiety among healthy subjects. We studied reproducibility of rsFC data for the right and left amygdala, obtained by functional magnetic resonance imaging twice in a one-week interval in 20 healthy volunteers with low to moderate anxiety. We found resting-state amygdala network, which included not only areas involved in the emotion circuit, but regions of the default mode network (DMN) associated with memory and other brain areas involved in motor inhibition and emotion suppression. The amygdala network was stable in time and within subjects, but between-session reproducibility was asymmetrical for the right and left amygdala rsFC. The right amygdala had more significant connections with DMN regions and the right ventrolateral prefrontal cortex. The rsFC values of the right amygdala were more sustained across the week than the left amygdala rsFC. Our results support a hypothesis of functional lateralization of the amygdala. The left amygdala is more responsible for the conscious processing of threats, which may produce more variable rsFC; the right amygdala rsFC is more stable due to its greater engagement in continuous automatic evaluation of stimuli.\n\nHighlightsO_LIAmygdala resting state network included areas of emotion circuit and motor control\nC_LIO_LIDuring rest amygdala was functionally connected with areas of default mode network\nC_LIO_LIFunctional connectivity of the right amygdala was more sustained across the week\nC_LIO_LIFunctional connections of amygdala network were more stable in the right hemisphere\nC_LI

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