Affective Judgments of Faces Modulate Early Activity (∼160 ms) within the Fusiform Gyri

Functional neuroimaging studies have implicated the fusiform gyri (FG) in structural encoding of faces, while event-related potential (ERP) and magnetoen- cephalography studies have shown that such encoding occurs approximately 170 ms poststimulus. Behavioral and functional neuroimaging studies suggest that pro- cesses involved in face recognition may be strongly modulated by socially relevant information conveyed by faces. To test the hypothesis that affective informa- tion indeed modulates early stages of face processing, ERPs were recorded to individually assessed liked, neutral, and disliked faces and checkerboard-reversal stimuli. At the N170 latency, the cortical three-dimen- sional distribution of current density was computed in stereotactic space using a tomographic source local- ization technique. Mean activity was extracted from the FG, defined by structure-probability maps, and a meta-cluster delineated by the coordinates of the voxel with the strongest face-sensitive response from five published functional magnetic resonance imaging studies. In the FG, 160 ms poststimulus, liked faces elicited stronger activation than disliked and neutral faces and checkerboard-reversal stimuli. Further, confirming recent results, affect-modulated brain elec- trical activity started very early in the human brain (112 ms). These findings suggest that affective fea- tures conveyed by faces modulate structural face en- coding. Behavioral results from an independent study revealed that the stimuli were not biased toward par- ticular facial expressions and confirmed that liked faces were rated as more attractive. Increased FG ac- tivation for liked faces may thus be interpreted as reflecting enhanced attention due to their saliency.