Oscillatory responses to reward processing in borderline personality disorder
Objectives. Previous electrophysiological studies have confirmed impaired reward processing in patients with BPD. However, it is not clear which aspects of reward processing are affected and which brain regions are involved. The present study investigated both evoked and induced event-related oscillations (EROs) to feedback events (thought to represent different aspects of feedback processing), and used source localization (sLORETA) to assess activity in two areas known to contribute to reward processing, the dorsomedial prefrontal/anterior cingulate cortex (dmPFC/ACC) and the orbitofrontal cortex (OFC). Methods. Eighteen patients with BPD and 22 healthy controls performed a gambling task, while 64-channel electroencephalographic activity was recorded. Evoked and induced theta and high-beta band EROs as well as activity in the two regions of interest were investigated depending on the valence and magnitude of feedback events. Results. Theta-band responses to negative feedback were reduced in BPD, an effect that involved only evoked responses and the dmPFC/ ACC region, and was associated with trait impulsivity in patients. sLORETA analyses revealed disturbed evoked responses depending on feedback magnitude in the theta (OFC) and high-beta (dmPFC/ACC and OFC) frequency range. Conclusions. The results indicate multiple dysfunctions of feedback processing in patients with BPD, implicating several distinct subsets of reward-processing mechanisms.