Delayed attentional disengagement from sad face: a study of alpha rhythm by event-related desynchronization.

This study investigated the influence of different emotional facial cues on the detection of subsequent visual digit targets presented after various cue-target intervals (CTIs). Behavioral results indicated that, compared to neutral faces, happy faces facilitated the response to subsequent tasks only after a short CTI (17 ms), while sad faces would slow or inhibit the processing of following tasks after different CTIs (17, 350, 1000, and 1500 ms). Event-related desynchronization of alpha rhythm (α-ERD) showed that the left frontal and parietal cortical areas were more prominently activated by emotional faces than by neutral ones. In particular, happy faces induced more activity in left frontal lobes, starting from the beginning of CTI (post-cue 0~400 ms), while sad faces induced stronger and longer activation during the middle of CTI (post-cue 400~800 ms). Such a later a-ERD in left frontal area suggested that the attentional disengagement was slowed by sad faces.