Investigating Oscillatory Activity in Cerebral Cortex during Affective Picture Processing

Emotion plays an important role in people's life. Previous studies have revealed that the characteristics of high frequency bands of Electroencephalogram (EEG) have shown good performance in emotion recognition. However, there is a lack of clear and unified conclusions about which brain regions to select for feature extraction. In this study, pleasant, neutral, unpleasant and scrambled pictures selected from International Affective Picture System (IAPS) were presented to subjects. In order to improve the spatial resolution, source estimation algorithm was used to reconstruct the cortical response in the processing of affective pictures. Oscillation activities of different frequency bands in the key brain regions were studied in cerebral cortex. The results showed that the activation of the brain was the weakest under scrambled condition. Referring to neutral condition, the energy of Alpha, Beta and Gamma bands under pleasant condition increased significantly in the bilateral middle temporal gyrus, middle frontal gyrus and prefrontal gyrus, while the energy of Alpha and Beta bands under unpleasant condition decreased significantly in the left middle occipital gyrus and bilateral middle temporal gyrus. These results provide a scientific basis for the selection of electrodes and frequency bands in emotion recognition based on EEG signals.