Information processing in major depression: The ERP connection

This study combined a number of literatures in order to test hypotheses about mood-congruent memory biases in normals and depressives while seeking to integrate theories about psychological and neuropsychological views of information processing anomalies seen in major depressives. Specifically, it examined: (1) Relationship of depression and anxiety to P300 and N200 amplitude using a more complex task than has typically been used in ERP studies of depression; (2) ERPs to further our understanding of mood-congruent memory bias seen in major depressives and controls; (3) Scalp topography in order to assess generalized reductions in amplitude over right parietal or left frontal scalp sites in depressives and to investigate a possible relationship between right frontal and left parietal ERP activity and depression; (4) Sensitivity of N200 and P300 to emotional valence in both word and face stimuli. No main effect for group differences emerged. Support for a positive recognition bias in controls and a lack of this bias in depressives was found. A generalized reduction in N200 recorded over the right parietal region was found in depressives. Finally, the sensitivity of P300 to stimulus valence was confirmed. The implications of these findings for depression and emotional valence are discussed.