Biology subjects

Bares, M.

Publications and source records attributed to Bares, M..

3 recordsLinked to original sources

bioRxiv2026

EEG connectivity changes in early response to antidepressant treatment

ObjectiveFinding indicators of early response to antidepressant treatment in EEG signals recorded from patients suffering from major depressive disorder. MethodsFunctional brain connectivity networks based on weighted imaginary coherence and weighted imaginary mean phase coherence were computed for 176 patients for 6 different EEG frequency bands. Cross-hemispheric connectivity (CH) and lateral asymmetry (LA) were estimated from these networks based on EEG signals recorded before the beginning of treatment (V is1) and one week after the start of the treatment (V is2). Repeated measures ANOVA was used to check for statistically significant changes in connectivity based on these measures at V is2 w.r.t. V is1. Post-hoc analysis was performed with multiple pairwise comparison tests to determine which group means were significantly different. ResultsIt was found that CHV is2 was significantly reduced w.r.t. CHV is1 in the {beta}1 [12.5 - 17.5 Hz] frequency band for the responders to treatment. Also, LAV is2 was significantly increased w.r.t. LAV is1 in the {beta}1 frequency band for the responders. No such significant changes were observed for the non-responders. Brain networks constructed using both weighted imaginary coherence and weighted imaginary mean phase coherence were found to exhibit these results. For the CH connectivity changes, binarized networks and for the LA connectivity changes, weighted networks were found to be more reliable. ConclusionsResponders were found to show a reduction in cross-hemispheric connectivity and an increase in lateral asymmetry, both in the {beta}1 band while no such change was observed for the non-responders. SignificanceDecrease in cross-hemispheric connectivity and increase in lateral asymmetry in the {beta}1 band may represent candidate neurophysiological indicators of early treatment response, but they require independent replication before any clinical application can be considered.

neuroscience↗

bioRxiv2026

Graph-Based EEG Symmetry Features from the Temporal Lobe as Markers of Antidepressant Treatment Response

Major Depressive Disorder (MDD) is a mental disorder that affects millions globally and has highly individualized responses to antidepressant treatment. Identifying objective early markers that can distinguish responders from non-responders remains a critical challenge in personalized psychiatry. In this study, we investigate the role of brain symmetry in EEG-derived functional connectivity as a potential early marker of treatment response. Using resting-state EEG recordings from 176 patients diagnosed with MDD at baseline (Visit 1) and after one week of treatment (Visit 2), we construct graph-based representations of functional connectivity and define region-wise and electrode-wise temporal-lobe symmetry features. We focus on symmetry change scores (Visit 2 - Visit 1) across typical EEG frequency bands in both weighted and binary forms. Statistical analyses reveal a consistent group-level pattern in the and {beta} bands: responders show negative symmetry change scores, whereas non-responders show relative stability or weakly positive change scores. The contrast is strongest in the {beta}1 band and is more pronounced for binary symmetry metrics, while the band shows the same direction with slightly weaker significance. Physiologically, these opposite trajectories are consistent with a treatment-related shift toward more lateralized temporal-lobe network organization in responders and a more bilateral coupling pattern in nonresponders; however, these neurophysiological interpretations remain hypothesis-generating given the resting-state design and the absence of direct behavioral or task-based validation. To quantify whether temporal symmetry change scores contain reproducible discriminative signal under strict validation, we benchmark the proposed features in a supervised classification pipeline using repeated nested cross-validation. The best-performing configuration achieved a median out-of-sample AUC of 0.690 with a 95% bootstrap confidence interval of [0.611, 0.711], indicating modest but reproducible separability. Overall, temporal-lobe symmetry change features provide interpretable candidate markers of early antidepressant-related neurophysiological change that may complement existing EEG predictors in future multi-marker models, but they are not yet sufficient for standalone clinical decision support and require external validation in independent cohorts.

neuroscience↗

bioRxiv2021

Electrophysiological correlates of proactive and reactive inhibition in a modified visual Go/NoGo task

Impulse control is crucial for everyday functioning in modern society. People with borderline personality disorder (BPD) suffer from impulse control impairment. According to the theory of dual mechanisms of control, motor impulse control can be divided into proactive and reactive modes. Proactive inhibition is involved before an event that might require inhibitory control. Reactive inhibition is initiated after the occurrence of an event that requires inhibitory control. Few studies have focused on proactive inhibition in relation to impaired impulse control, moreover electrophysiological evidence is scarce. Therefore, in the search for electrophysiological correlates of proactive and reactive inhibitions, we assessed event-related potentials elicited during a modified emotionally neutral visual Go/NoGo task in 28 clinically impulsive BPD patients and 35 healthy control (HC) subjects. In both groups, proactive inhibition was associated with enhanced late prestimulus activity and a suppressed poststimulus N2 component. In both groups, reactive inhibition was associated with enhanced poststimulus N2 and P3 components. We found no electrophysiological differences between HC subjects and BPD patients and both groups performed similarly in the task. Hence, the clinically observed impulse control impairment in BPD might act through different mechanisms other than altered inhibitory control in an emotionally neutral task.

neuroscience↗