Abstract
Background: Changes in motivational processing may play a role in weight gain and other non-motor side effects in Parkinson's disease (PD) patients treated with deep brain stimulation of the subthalamic nucleus. Objective/hypothesis: We aimed to assess changes in aversive and appetitive motivational activation using modulation of the acoustic blink reflex (ABR) by rewarding and aversive stimuli.
Methods: ABR elicited during the viewing of erotic, food, aversive and neutral pictures was recorded in 11 off-medicated patients with the subthalamic stimulation switched ON and OFF, and in 11 control subjects. Results: ABR to erotic stimuli was larger in patients in the ON compared to the OFF condition and controls (P < 0.01).
Aversive stimuli caused a larger increase in the ABR in patients with the ON condition than in controls (P < 0.05). Additionally, we found a negative correlation of the ABR magnitude to food pictures in the ON condition with weight gain following subthalamic stimulation (P < 0.01, after adjustment to OFF condition).
Conclusions: Our results suggest that subthalamic stimulation affects motivational processing. Subthalamic stimulation may disturb appetitive engagement by erotic cues and increase aversive activation in PD patients.
Additionally, postoperative weight gain may be related to changes in the processing of food cues due to subthalamic stimulation.