| This study investigated the influence of different emotional facial stimuli on the detection of subsequent visual digit target presented at various cue-target intervals (CTIs). The behavioral results showed that, the reaction times to subsequent task were significantly reduced as the CTI increased. Happy emotional information accelerated or facilitated the subsequent detection during the 17 ms CTI condition, while sad emotional information appeared to slow down or inhibit the processing of next stimulus during both short and long CTIs (17, 350, 1000, and 1500 ms) conditions. Analysis on the event-related potential (ERP) during the 1500 ms CTI condition indicated that, emotional faces evoked larger P1 amplitude than neutral faces, and sad faces evoked larger P3 amplitude than happy ones; while no significant differences evoked by subsequent digit targets were observed. Further, event-related (de-)synchronization (ERS/ERD) of the alpha rhythm activity during the 1500 ms interval was examined. Results showed that the frontal and parietal cortical areas were more heavily activated by emotional materials compared to neutral ones. The difference was that, in comparison with neutral faces, happy faces induced more activity in left frontal lobes, starting from the beginning of CTI (post-cue 0~400 ms), while sad faces induced such higher activation during the middle of CTI (post-cue 400~800 ms). In conclusion, a former stimulus would show different effects on the identification of the subsequent visual target and discrepancy in the time course, which depends on its emotional types. Happy faces momentarily accelerate or facilitate the processing of following targets, while sad emotional information would inhibit or interfere with the subsequent visual tasks in a long-lasting way. This negative effect might be due to that, negative stimuli may occupy more attentional resources, or the attentional control during attentional disengagement was primed in a later period. |
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