An Examination of Executive Dysfunction Associated with Frontostriatal Circuitry in Parkinson's Disease

Abstract

Parkinson's disease (PD) is a neurodegenerative movement disorder presenting with subcortical pathology and characterized by motor deficits. However, as is frequently reported in the literature, patients with PD can also exhibit cognitive and behavioral (i.e., nonmotor) impairments, cognitive executive deficits and depression being the most prominent. Considerable attention has addressed the role that disruption to frontostriatal circuitry can play in mediating nonmotor dysfunction in PD. The three nonmotor frontostriatal circuits, which connect frontal cortical regions to the basal ganglia, originate from the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), and orbitofrontal cortex (OFC). The objective of the current study was to use our understanding of frontostriatal circuit function (via literature review) to categorize neuropsychological measures of cognitive and behavioral executive functions by circuit. To our knowledge, such an approach has not been previously attempted in the study of executive dysfunction in PD. Neuropsychological measures of executive functions and self-report behavioral inventories, categorized by circuit function, were administered to 32 nondemented patients with Parkinson's disease (NDPD) and to 29 demographically matched, healthy normal control participants (NC). Our findings revealed significant group differences for each circuit, with the PD group performing worse than the NC group. Among the patients with PD, indices of impairment were greater for tasks associated with DLPFC function than with OFC function. Further, only an index of DLPFC test performance was demonstrated to significantly discriminate individuals with and without PD. In conclusion, our findings suggest that nondemented patients with PD exhibit greater impairment on neuropsychological measures associated with DLPFC than with ACC or OFC circuit function.

Low dopamine striatal D2 receptors are associated with prefrontal metabolism in obese subjects: Possible contributing factors

“…It is possible that the functions of the prefrontal cortex that contribute to obesity are the ones sensitive to DA modulation via striatal prefrontal pathways (Robbins, 2007;Zgaljardic et al, 2006).…”

“…Indeed abnormalities in prefrontal metabolism and impairment in executive function have been documented in a wide range of disorders including those with dopaminergic involvement such as drug addiction, schizophrenia, Parkinson's disease and ADHD (Volkow et al, 1993b;Gur et al, 2000;Robbins, 2007;Zgaljardic et al, 2006).…”

Effects of cognitive task on gait initiation in Parkinson disease: Evidence of motor prioritization?

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The Unique and Combined Effects of Apathy and Depression on Cognition in Parkinson’s Disease

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