Pathological gambling in Parkinson's disease: Subthalamic oscillations during economics decisions

Abstract

Pathological gambling develops in up to 8% of patients with Parkinson's disease. Although the pathophysiology of gambling remains unclear, several findings argue for a dysfunction in the basal ganglia circuits. To clarify the role of the subthalamic nucleus in pathological gambling, we studied its activity during economics decisions. We analyzed local field potentials recorded from deep brain stimulation electrodes in the subthalamic nucleus while parkinsonian patients with (n = 8) and without (n = 9) pathological gambling engaged in an economics decision-making task comprising conflictual trials (involving possible risk-taking) and non conflictual trials. In all parkinsonian patients, subthalamic low frequencies (2-12 Hz) increased during economics decisions. Whereas, in patients without gambling, low-frequency oscillations exhibited a similar pattern during conflictual and non conflictual stimuli, in those with gambling, low-frequency activity increased significantly more during conflictual than during non conflictual stimuli. The specific low-frequency oscillatory pattern recorded in patients with Parkinson's disease who gamble could reflect a subthalamic dysfunction that makes their decisional threshold highly sensitive to risky options. When parkinsonian patients process stimuli related to an economics task, low-frequency subthalamic activity increases. This task-related change suggests that the cognitive-affective system that drives economics decisional processes includes the subthalamic nucleus. The specific subthalamic neuronal activity during conflictual decisions in patients with pathological gambling supports the idea that the subthalamic nucleus is involved in behavioral strategies and in the pathophysiology of gambling.

Subthalamic involvement in monetary reward and its dysfunction in parkinsonian gamblers

“…5 Our previous findings on the preparation of economics decision in parkinsonian patients with PG showed a subthalamic dysfunction that makes their decisional threshold highly sensitive to risky options. 3 In this study, we extend these results, suggesting that STN activity is also affected by reward and that PG could be related to a reward circuit disorder.…”

“…Then, to obtain the mean frequency band power in conflictual and non-conflictual task conditions during the two task phases (black screen, feedback) for each type of feedback (risky positive, risky negative, non-risky positive, non-risky negative), we applied the Hilbert transform. 3 For behavioural analyses, the economics strategy each patient used during task performance was evaluated by calculating the sum of risky choices in conflictual trials. Differences between economics strategies in patients with and without PG were tested in a one-way analysis of variance (ANOVA) using PG ( presence, absence) as between factor.…”

Human Subthalamic Nucleus Theta and Beta Oscillations Entrain Neuronal Firing During Sensorimotor Conflict

“…Both sites demonstrate conflict-related increases in theta-band activity (Cavanagh et al 2011, 2012; Cohen and Cavanagh 2011; Fumagalli et al 2011; Brittain et al 2012; Zavala et al 2013, 2014; Cohen and van Gaal 2014), altered theta-band activity has been associated with impulse control disorders (Cavanagh et al 2011; Rodriguez-Oroz et al 2011; Rosa et al 2013), and mPFC theta oscillations drive those of the STN during conflict (Zavala et al 2014). Furthermore, previous studies suggest that STN DBS both alters activity in the mPFC (Ballanger et al 2009) and reverses the relation between mPFC theta oscillations and conflict-induced slowing (Cavanagh et al 2011).…”

Toward sophisticated basal ganglia neuromodulation: Review on basal ganglia deep brain stimulation

“…Deficits in aversive-driven learning related to the inability of striatal DA to encode negative-prediction errors may also explain why depression and gambling is much more prevalent in PD (Rosa et al, 2013). …”