First, the ICD + group showed reduced “continue-to-gamble” activity in right inferior frontal gyrus and subthalamic nucleus. These patients did not differ in risk-taking attitude during sequential gambling from 13 patients without impulse control disorder (ICD - group), but they displayed differences in gambling-related activity in cortico-subcortical brain areas supporting inhibitory control. 13 patients had an impulse control disorder (ICD + group). During a gambling round, patients repeatedly decided between the option to continue with gambling and accumulate more monetary reward under increasing risk or the option to bank the current balance and start a new round. Patients performed a sequential gambling task while being ON and OFF their regular dopaminergic treatment. To address this question, we mapped task-related brain activity with whole-brain functional magnetic resonance imaging at 3 Tesla in 26 patients with Parkinson’s disease.
It is unclear how dopaminergic medication affects the neural networks that contribute to withholding inappropriate actions. Dopaminergic treatment may impair the ability to suppress impulsive behaviours in patients with Parkinson's disease, triggering impulse control disorders.