Explicit and incidental facial expression processing: An fMRI study

Considerable evidence indicates that processing facial expression involves both subcortical (amygdala and basal ganglia) and cortical (occipito-tempor al, orbitofrontal, and prefrontal cortex) structures. However, the specific ity of these regions for single types of emotions and for the cognitive dem ands of expression processing, is still unclear. This functional magnetic r esonance imaging (fMRI) study investigated the neural correlates of inciden tal and explicit processing of the emotional content of faces expressing ei ther disgust or happiness. Subjects were examined while they were viewing n eutral, disgusted, or happy faces., The incidental task required subjects t o decide about face gender, the explicit task to decide about face expressi on. In the control task subjects were requested to detect a white square in a greyscale mosaic stimulus. Results showed that the left inferior frontal cortex and the bilateral occipito-temporal junction responded equally to a ll face conditions. Several cortical and subcortical regions were modulated by task type, and by facial expression. Right neostriatum. and left amygda la were activated when subjects made explicit judgements of disgust, bilate ral orbitofrontal cortex when they made judgement of happiness, and right f rontal and insular cortex when they made judgements about any emotion. (C) 2001 Academic Press.