Severity of depressive symptoms and oscillatory responses to emotional facial expressions

Abstract

We studies the differences in oscillatory responses to emotional facial expressions in 40 subjects with different severity of depressive symptoms (19 men and 21 women) aged 18-30 years. In subjects with low severity of depressive symptoms (group 2), the perception of happy facial expressions was marked by lower delta synchronization as compared with angry and neutral expressions; in subjects with high severity of depressive chronization as compared with angry and neutral expression; in subjects with high severity of depressive symptoms (group 1), the perception of happy faces was marked by higher delta synchronization. Since an increase in delta oscillations is usually observed in aversive conditions, we suggest that happy facial expressions are perceived as negative stimuli by the subjects of group 1. The perception of angry facial expressions was accompanied by alpha band desynchronization in Group 2 and by alpha synchronization in Group 1. Basing on Klimesch's theory, this effect suggests that the subjects of group 1 are initially set up for the perception of negative emotional information. The effect of emotional stimulus category was significant in group 2, but not significant in group 1, which is an evidence of disorders in the recognition of emotional information in depression-prone individuals.