Event-related desynchronization (ERD) patterns to emotion-related feedback stimuli

Event-related desynchronization (ERD) of alpha components was studied in 14 healthy right handed subjects in an affective task. In the present study positive and negative emotions were operationalized by winning and losing certain amounts of money in a gambling situation while measuring ERD to positive and negative feedback stimuli. All the subjects demonstrated comparable (i.e. statistically not separated) intensities of positive and negative affect of self-report data. The obtained results suggest that ERD can be used as an indicator of localized brain activation in affective tasks. As it was evidenced by ERD analyses, the left and right frontal lobes participated in valence discrimination. The predicted relative left frontal activation to the positive feedback stimuli and right frontal activation to the negative feedback stimuli was supported. This effect was restricted to the upper (i.e. 10-12 Hz) alpha band. These findings are evidence in favour of specific role of frontal hemispheric asymmetries in valence discrimination. It is concluded that ERD seems to be able to evidence relatively small differences in emotion processing and appears to be a suitable method with which to study emotion.