Common and distinct neural responses during direct and incidental processing of multiple facial emotions.

Whether common or distinct neural systems underpin perception of different emotions and the degree to which these systems are automatically engaged during emotional perception are unresolved. We performed an event-related fMRI experiment in which subjects viewed morphed emotional faces displaying low or high intensities of disgust, fear, happiness, or sadness under two task conditions. The amygdala and fusiform cortex responded to high-intensity expressions of all emotions, independent of task. Right superior temporal sulcus showed an additive effect of the emotion-directed task and high-intensity emotion. Ventromedial prefrontal and somatosensory cortices, regions implicated in providing representations of somatic states, showed enhanced activity during explicit emotional judgments. We failed to find predicted differences between emotions. The results suggest that amygdala contributes to task-independent perceptual processing of a range of emotions. We interpret ventromedial prefrontal and somatosensory cortex activations as evidence that these regions contribute to explicit emotion processing through linking emotion perception with representations of somatic states previously engendered by emotions.