EP 45. Emotional valence and arousal gradient along the anterior–posterior axis within the subthalamic nucleus in Parkinson’s disease

Abstract

Introduction Changes in emotional processes have been reported after deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson’s disease (PD). The STN DBS increased activity of the aversive motivational system: the fearful stimuli were experienced as more salient with the DBS switched on. The STN is organized into a dorsolateral motor, a central associative, and a ventromedial limbic territories and clinical effects of STN DBS seem to depend on the position of the active electrode contact within the STN in a manner that reflects the functional organization and connectivity of the STN. Objectives Considering the functional organization of the STN, we aimed to analyze the relationship between changes in subjective emotional experience to pictures presenting fearful stimuli and the active electrode contact position within the STN. Patients and methods Twenty off-medicated PD patients (all men, aged 58.4 ± (SD)6 years, disease duration 15 ± 4 years, 2.3 ± 1 years after implantation) viewed series of 84 pictures depicting primary rewarding, aversive fearful or neutral stimuli and performed ratings according to emotional valence (from 1 to 9, ranging from unpleasant to pleasant) and arousal (from 1 to 9, ranging from calm to excited) in DBS switched ON- and OFF-conditions. To localize the active electrode contact position, both the preoperative 3T T2-weighted MR (T2W) images visualizing the STN and the postoperative 1.5T T1W images displaying the susceptibility artifact of the permanent DBS electrode were automatically co-registered with the frame-based preoperative 1.5T T1W images into one stereotactic space using software for neurosurgical planning. The active electrode contact position in the STN was reconstructed based on the location of the susceptibility artifact of the permanent DBS electrode. Furthermore, each STN was manually delineated and fitted onto the STN reference model by Morel. The relationship between the affective ratings to aversive stimuli including the ON vs. OFF differences to the active contact positions in was assessed using linear models. Results In the DBS ON-condition, patients attributed lower valence scores compared with the OFF-condition (P Conclusions Our results confirm previous observations STN DBS affects emotional processing related to aversive stimuli. They further suggest emotional valence and arousal are processed separately at this subcortical level and their representations are organized along the anterior–posterior axis in the STN. Supported by Grant GACR 16-13323S and PRVOUK P26/LF1/4.