Evoked cerebral cortex activity in the human brain in conditions of the active and passive perception of facial expressions.

Visual evoked potentials were recorded in the occipital, parietal, central, frontal, and posterior temporal areas of the cortex in 22 healthy right-handed subjects during passive observation and recognition of emotionally positive, negative, and neutral facial expressions. Recognition of emotions was associated with significantly higher levels of cortical activity than was passive observation; this was reflected as increases in the amplitudes of the negative waves N1, N2, and N3, along with decreases in the latencies of the N1, P2, and N2 waves. The latencies of the N3 and P3 waves, which are associated with the later stages of information processing, increased as compared with those recorded during passive observation. Dynamic mapping during the recognition of emotions demonstrated involvement of the anterocentral regions of the cortex of both hemispheres, while passive perception was associated only with right-sided activation of these areas. Analysis of evoked potentials by the principal components method showed an increase in the complexity of the structure of the N2 wave during recognition of the type of facial expression, and a component corresponding to the descending part of the N2 wave was identified, associated with the classification stage.