[Brain functional connectivity in depression during emotion processing].

Cognitive and emotional dysfunction in depressed patients has been broadly researched. However, the physiological mechanism of the emotional impairment is still obscure. In this study, according to the ethical principles and the procedures of informed consent, we enrolled 16 depression patients and 16 normal subjects in a "learning-judgment" cognitive task. Emotional faces were chosen and used as the visual stimuli, while the subjects' scalp electroencephalographs (EEG) were recorded. We calculated the coherences of the event-related EEG signals between different functional brain regions and used the repeated measure analysis of variance (ANOVA) to analyze the coherences. The results revealed, (1) The depressed patients had a significantly lower inter-hemisphere coherence than did the normal controls at frontal sites across all EEG basic rhythms; (2) The inter-hemispheric coherence of EEG beta activity was significantly correlated with the emotional processing during 1-200 ms after stimulus onset, and the synchronicity with the negative emotion stimulus was higher than that with neutral and positive stimuli; (3) The main effect of race was found at delta and theta bands at about 401-600 ms after stimulus onset. Moreover, the connectivity of inter-hemisphere for own-race stimulus was stronger than that for other-race stimulus.