Fearful faces evoke a larger C1 than happy faces in executive attention task: an event-related potential study

Neural responses to negatively valenced stimuli such as fear are enhanced relative to positive or neutral stimuli, reflecting an emotional negativity bias. In the present study, high time resolution event related potential (ERP) techniques were used, to investigate whether C1, the earliest visually evoked potential, is modulated by emotional valence in the executive attention network. Subjects were instructed to respond to the expression of the face, while ignoring the content of word, in an emotional face-word Stroop task. We demonstrated modulation of C1 in response to fearful faces versus happy faces. The differentiation between detection of fearful and happy faces emerged at 60-90ms after the stimulus onset at the posterior electrode sites, and this early differentiation occurred regardless of whether the subject had viewed a congruent or incongruent trials (i.e., happy face with fear label or vice versa). The present results indicate that faces with a fearful expression capture processing resources at an early sensory processing stage.