Gamma oscillation in brain connectivity in emotion recognition by Granger causality

Recent studies have applied Granger causality to electroencephalography (EEG) in event-related paradigms. This study aimed to explore the causal modulation of gamma band in response to emotional face. The EEGs during emotional face search task were recorded from 13 normal subjects (6 males and 7 females). We utilized granger causality to establish a causal model of different brain areas under different rhythms. Thus, we concluded: 1) Negative emotion face induced larger causal value than positive one. 2) The causal modulation happened mainly at 30~50HZ. 3) During 300~600ms after stimulus onset, the brain regions were more active when negative emotion faces were processed than positive ones. 4) In low gamma band, negative emotion faces aroused more leads to participate in the modulation.