Using a rapid serial visual presentation paradigm, we previously showed that the average amplitudes of six event-related potential (ERP) components were affected by different categories of emotional faces. In the current study, we investigated the six discriminating components on a single-trial level to clarify whether the amplitude difference between experimental conditions results from a difference in the real variability of single-trial amplitudes or from latency jitter across trials. It is found that there were consistent amplitude differences in the single-trial P1, N170, VPP, N3, and P3 components, demonstrating that a substantial proportion of the average amplitude differences can be explained by the pure variability in amplitudes on a single-trial basis between experimental conditions. These single-trial results verified the three-stage scheme of facial expression processing beyond multitrial ERP averaging, and showed the three processing stages of "fear popup", "emotional/unemotional discrimination", and "complete separation" based on the single-trial ERP dynamics.
We investigated the reappraisal and the time course of negative emotion regulation by performing event-related potential (ERP) recordings. We found that negative pictures elicited more positive P2 and late positivity potential (LPP) deflections than neutral pictures. This effect occurred between 150-2000 ms post-stimulus. Compared to the emotion maintaining condition, the emotion enhancing condition was associated with higher arousal ratings and displayed increased P2 and LPP amplitudes. The decrease condition was also associated with reduced picture-induced arousal; however, it led to increased P2 and LPP amplitudes. Furthermore, when compared with the maintain condition, both the enhancing and decrease conditions significantly enhanced LPP in the early stage (350-750 ms). Compared to previous studies using western subjects, the negative emotion LPP effects of the present study were shorter in duration and the decrease-emotion condition elicited larger LPPs.
