Event-related potentials for implicit, explicit, and empathic processing of emotional facial expressions

The current study examined how implicit, explicit, and empathic responses to emotional facial expressions influence event-related potentials (ERPs). Non-depressed and non-anxious human participants viewed happy, sad, and neutral emotional facial expressions while attempting to either identify the gender (implicit), identify the emotional expression (explicit), or empathize with the emotional expression (empathic). EEG data were recorded from 19 electrodes set
according to the international 10-20 system with analysis focusing on mean amplitudes for midline and bilateral frontal, central, and parietal electrodes. Midline analysis showed that the vertex positive potential (VPP; 140-200ms) amplitude was largest for sad faces across all electrodes regardless of condition. Global analysis showed that P3 (200-400ms) amplitudes in the expression recognition condition differed by hemisphere and electrode for sad and happy faces but not for neutral faces. Finally, the global analysis also showed that P3 amplitudes for all three emotional expressions in the empathize condition differed by hemisphere and electrode. The results suggest that the early perception of emotional expression across all manipulations is represented by increased midline amplitude of the VPP while processes such as expression recognition and empathizing with expressions are represented by differences in P3 amplitudes across hemispheres and electrodes.