The study of early emotion processing in the frontal area using a two-dipole source model

The present study explored early emotion processing in the frontal area using the two-dipole source model. The 21-channel recordings of event-related potentials (ERPs) produced by a pure tone were analyzed in order to assess information processing. In the test conditions, the pure tone followed the presentation of one of two unpleasant sounds to enhance anxiety. In the control condition, only the pure tone was presented. There were two groups of eight subjects, one with low scores for trait anxiety and one with high scores. The ERPs were separately averaged for the groups, as well as for the high- and low-anxiety sound and control session. A negative peak around 120 ms (C2) and a positive peak around 280 ms (C5) after stimulus onset were identified in all the sessions. The two-dipole source model was applied to these two components. In the C2 component, dipole sources were located in the left frontal area in the control sessions, and in the right frontal area in the high-anxiety sessions. This activation pattern was clearer in the group with low trait anxiety. In contrast, with the C5 component, lateralization of the dipole source in the frontal area was not seen. These findings suggest that the frontal area is involved in early emotion processing. A dual-stage model of emotion processing is therefore proposed.