EEG DYNAMICS DURING EMOTIONAL FACE PERCEPTION UNDER THE VARIABLE PRESENTATION TIME: AN ERP STUDY

Abstract

The face is one of the most significant elements of non-verbal communication, which allows humans to quickly get various types of information about a specific person. Therefore, understanding facial expressions is crucial for normal social interaction, as it lets us determine the emotional states and intentions of other people. The purpose of this study was to investigate the influence of the time factor on the happy and fearful facial expression processing, reflected in the structure and components of event-related potentials (ERPs). Accordingly, two parallel examinations were conducted with stimulus presentation periods of 500 ms and 100 ms. For the obtained data, two separate analyses (for happy and fearful faces) of the averaged ERP curves corresponding to different stimulus exposure periods were executed. The initial stages of processing (EPN, P3) demonstrated that the difference in the structure and amplitude characteristics of the ERP curve was not that significant, but it demonstrated an increase in attentional resources involvement and a strengthening of the primary emotional analysis. Later ERP components (N400, LPP) showed a more compelling difference, that reflected the complexity of semantic decoding, subsequent conscious evaluation, and processes related to decision-making. Thus, reducing the time of image display from 500 ms to 100 ms created the expected difficulties for the perception and processing of emotional facial expressions and was not sufficient for the normal course of these processes.