Emotional face processing: An ERP study on visual selective attention of emotional faces presented subliminally and supraliminally

Faces are considered as important stimuli in neuroscience research. Indeed, many studies have brought to bear significant evidence of special treatment of emotional faces in brain processing. Moreover, these findings have favored the development of several models that highlight the brain areas involved in face perception. One example is Haxby model (2000). The aim of this study is to assess the effect of selective attention (target and non target condition) to emotional faces presented subliminally and supraliminally with an ERP study. Three components (N170, P2 and P300) have been analyzed for four emotions (happy, neutral, fearful and angry). The results showed strong evidence in favor of presentation and selective attention effects on the three components analyzed, suggesting cognitive resources as strongly influencing the emotional face brain processing. As suggested by spatial attention studies on emotional faces processing (e.g. Carlson et al., 2009), emotional faces are supposed to enhance selective attention effects. Moreover, an effect of different emotional expressions on early ERP components suggest quickly brain processing of emotional faces. A source localization analysis confirmed the findings of previous studies, namely the activation of the amygdala for the processing of emotional expressions (in line with the Haxby model, 2000) which is more consistent in the case of fearful faces (as supported by Ledoux, 2000). Moreover, a behavioral study brought evidences for a preferential treatment of positive faces compared to negatives ones in terms of accuracy and reaction times, it is suggested that a predominance of positive emotions in normal contexts may partly explain this effect (Leppänen and Hietanen, 2004). In general, our study confirmed emotional faces as special kinds of stimuli, influencing our cognitive resources in both conscious and unconscious presentations. Moreover, evidence of a large and specific neural substrate for emotional expressions treatment has been found with a particularity for fearful faces in the amygdala activation (as supported by Ledoux, 2000)