Linking brain activity during sequential gambling to impulse control in Parkinson's disease

Area of Science:

• Neuroscience
• Neurology
• Psychiatry

Background:

• Dopaminergic medication for Parkinson's disease (PD) is linked to impulse control disorders (ICDs).
• The neural mechanisms underlying this link, specifically how dopamine affects inhibitory control networks, remain unclear.
• Understanding these mechanisms is crucial for managing PD treatment side effects.

Purpose of the Study:

• To investigate how dopaminergic medication affects neural networks involved in suppressing impulsive behaviors in Parkinson's disease patients.
• To compare brain activity during a gambling task in patients with and without impulse control disorders (ICDs), both on and off dopaminergic treatment.

Main Methods:

• Whole-brain functional magnetic resonance imaging (fMRI) at 3 Tesla was used.
• 26 Parkinson's disease patients performed a sequential gambling task ON and OFF dopaminergic treatment.
• Patients were categorized into impulse control disorder (ICD+) and no impulse control disorder (ICD-) groups.

Main Results:

• ICD+ patients showed reduced "continue-to-gamble" activity in the right inferior frontal gyrus and subthalamic nucleus.
• Risk attitude correlated with neural activity in the subthalamic nucleus and striatum in ICD- patients only.
• Dopaminergic therapy reduced functional connectivity between the inferior frontal gyrus and subthalamic nucleus in ICD+ patients and altered striatal responses.

Conclusions:

• Medication-independent and medication-related neural differences contribute to ICD emergence in Parkinson's disease patients on dopamine therapy.
• Altered activity in cortico-subcortical circuits involved in inhibitory control may predispose PD patients to ICDs.
• Findings highlight the impact of dopaminergic therapy on neural networks and impulse control in Parkinson's disease.