4 research outputs found
Functional correlates of response inhibition in impulse control disorders in Parkinson’s disease
Impulse control disorder is a prevalent side-effect of Parkinson’s disease (PD) medication, with a strong negative
impact on the quality of life of those affected. Although impulsivity has classically been associated with response
inhibition deficits, previous evidence from PD patients with impulse control disorder (ICD) has not revealed
behavioral dysfunction in response inhibition. In this study, 18 PD patients with ICD, 17 PD patients without this
complication, and 15 healthy controls performed a version of the conditional Stop Signal Task during functional
magnetic resonance imaging. Whole-brain contrasts, regions of interest, and functional connectivity analyses
were conducted. Our aim was to investigate the neural underpinnings of two aspects of response inhibition:
proactive inhibition, inhibition that has been prepared beforehand, and restrained inhibition, inhibition of an
invalid inhibitory tendency. We observed that, in respect to the other two groups, PD patients with ICD exhibited
hyperactivation of the stopping network bilaterally while performing proactive inhibition. When engaged in
restrained inhibition, they showed hyperactivation of the left inferior frontal gyrus, an area linked to action
monitoring. Restrained inhibition also resulted in changes to the functional co-activation between inhibitory
regions and left inferior parietal cortex and right supramarginal gyrus. Our findings indicate that PD patients
with ICD completed the inhibition task correctly, showing altered engagement of inhibitory and attentional
areas. During proactive inhibition they showed bilateral hyperactivation of two inhibitory regions, while during
restrained inhibition they showed additional involvement of attentional areas responsible for alerting and
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