Enhanced neural activity in response to dynamic facial expressions of emotion: an fMRI study.

Dynamic facial expressions of emotion constitute natural and powerful media of communication between individuals. However, little is known about the neural substrate underlying the processing of dynamic facial expressions of emotion. We depicted the brain areas by using fMRI with 22 right-handed healthy subjects. The facial expressions are dynamically morphed from neutral to fearful or happy expressions. Two types of control stimuli were presented: (i) static facial expressions, which provided sustained fearful or happy expressions, and (ii) dynamic mosaic images, which provided dynamic information with no facial features. Subjects passively viewed these stimuli. The left amygdala was highly activated in response to dynamic facial expressions relative to both control stimuli in the case of fearful expressions, but not in the case of happy expressions. The broad region of the occipital and temporal cortices, especially in the right hemisphere, which included the activation foci of the inferior occipital gyri, middle temporal gyri, and fusiform gyri, showed higher activation during viewing of the dynamic facial expressions than it did during the viewing of either control stimulus, common to both expressions. In the same manner, the right ventral premotor cortex was also activated. These results identify the neural substrate for enhanced emotional, perceptual/cognitive, and motor processing of dynamic facial expressions of emotion.