Objective: To investigate the functional neural basis of decision-making in PD-ICD subjects using a modified version of the Iowa Gambling Task (IGT) paradigm.

Background: Impulse Control Disorders (ICD) is a frequent and severe psychiatric complication in Parkinson’s disease (PD)1 whose physiopathology is poorly understood2

Methods: 18 PD-ICD patients, 17 PD non-ICD patients and 18 healthy controls (HC) matched for age, gender and education, underwent functional MRI (fMRI) scanning while performing a modified version of the IGT using a block experimental design. The task was divided in 3 sections: response to positive, negative and mixed feedback. Whole-brain, Region- of-Interest (ROI) and multivariate functional connectivity analyses were performed.

Results: The PD-ICD group showed increased activation across the 3 conditions compared to HC in prefrontal cortex (PFC) (bilateral frontal superior medial gyrus, left middle frontal gyrus and left mid-orbitofrontal cortex), motor regions (bilateral pre-supplementary area), left middle temporal gyrus, parietal cortex (left inferior and superior giri) and bilateral putamen. Compared to PD non-ICD, PD-ICD patients showed enhanced activation in left inferior parietal cortex, right precuneus and bilateral putamen. Time course analyses revealed a Group by Condition interaction in the left and right insula, and right inferior frontal gyrus, where PD-ICD patients had lower activation in the mixed feedback condition than the other groups. Group differences in functional connectivity with the striatum were observed. Relative to HC, PD-ICD patients had stronger coupling with the bilateral dorsolateral PFC, and PD non-ICD patients had stronger connectivity with the orbitofrontal cortex/ventromedial PFC.

Conclusions: PD-ICD patients show altered activation of the cortex (insula and inferior frontal gyrus) and abnormal functional connectivity (striatum-PFC regions) in structures involved in risk and uncertainty during reward-based decision-making. Differences in the response to mixed feedback decision could be associated with a difficulty of acquisition of probabilistic contingencies in the learning phase in comparison to a non ICD population.

References:

1. Weintraub D, Koester J, Potenza MN et al. Impulse Control Disorders in Parkinson´s Disease: a cross sectional study of 3090 participants. Arch Neurol 2010;67:589-95
2. Voon V, Pessiglione M, Brezing C et al. Mechanisms underlying dopamine-mediated reward bias in compulsive behaviors. Neuron 2010; 65: 135

« Back to 2017 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/neural-correlates-underlying-reward-processing-and-decision-making-in-impulse-control-disorder-in-parkinsons-disease/