Event-Related Brain Oscillations Changes in Major Depressive Disorder Patients During Emotional Face Recognition

Major depressive disorder (MDD) is a disorder with multiple impairments, among which emotion disorder is the most main one. Nowadays, evoked activity (EA), such as event-related potential (ERP), has mostly been studied for MDD, but induced activity (IA) analysis is still lacking. In this paper, EA, IA and event-related spectral perturbation (ERSP) were studied and compared between MDD patients and healthy controls (HC). Electroencephalogram (EEG) of 26 healthy controls and 21 MDD patients were recorded during three different facial expression (positive, neutral, negative) recognition tasks. Two phases of task execution process were studied, the early stage (0-200 ms after stimuli), and the late stage (200-500 ms after stimuli). ERSP, EA index and IA index of θ (4-7 Hz), α (8-13 Hz) and β (14-30 Hz) frequency bands were calculated and compared between two groups for two phases, respectively. In the early stage, the results indicated a decreased IA in α band in MDD compared to HC in frontal and parieto-occipital areas during neutral and negative face recognition. During the late stage, reduced IA and lower ERSP were also observed in α band in frontal and parieto-occipital areas in MDD during neutral and negative face recognition. Moreover, IA in θ band in MDD was lower than HC during negative face recognition. The findings reflected the abnormality of negative emotion processing in MDD, which could help to interpret the neural mechanism of depression.