Parallel electrophysiological and prefrontal hemodynamic alterations during stroop task performance in major depressive disorder: a simultaneous EEG-fNIRS study.

INTRODUCTION: Major depressive disorder (MDD) is associated with executive-control deficits, yet the simultaneous electrophysiological and hemodynamic correlates of Stroop-task performance remain incompletely characterized. This study investigated parallel neural and prefrontal hemodynamic alterations during cognitive conflict processing using simultaneous electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). METHODS: Twenty-two patients with MDD and twenty-one healthy controls completed a color-word Stroop task while EEG and fNIRS were recorded simultaneously. Behavioral performance, stimulus-locked event-related potential (ERP) components, oscillatory activity, and prefrontal region-of-interest (ROI) hemoglobin responses were analyzed using group × condition mixed-design analysis of variance. RESULTS: Compared with healthy controls, patients with MDD showed impaired behavioral performance together with altered ERP components, oscillatory activity, and prefrontal hemoglobin responses during Stroop-task performance, indicating concurrent electrophysiological and hemodynamic abnormalities associated with executive-control dysfunction. DISCUSSION: These findings support the presence of parallel task-related electrophysiological and prefrontal hemodynamic alterations in MDD during cognitive conflict processing. Larger prospective studies incorporating trial-level reliability metrics, channel-wise fNIRS analyses, and clinical covariates are warranted to further validate these observations.