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Brain Imaging Behav. 2015 Sep;9(3):619-38. doi: 10.1007/s11682-014-9317-9.

Task-rest modulation of basal ganglia connectivity in mild to moderate Parkinson's disease.

Author information

1
Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Road, Stanford, CA, 94305-5723, USA. evamoe@stanford.edu.
2
Neuroscience Program, SRI International, Menlo Park, CA, 94025, USA. evamoe@stanford.edu.
3
Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, 401 Quarry Road, Stanford, CA, 94305-5723, USA.
4
Neuroscience Program, SRI International, Menlo Park, CA, 94025, USA.
5
Valley Parkinson Clinic, Los Gatos, CA, 95032, USA.
6
Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA, 94305, USA.

Abstract

Parkinson's disease (PD) is associated with abnormal synchronization in basal ganglia-thalamo-cortical loops. We tested whether early PD patients without demonstrable cognitive impairment exhibit abnormal modulation of functional connectivity at rest, while engaged in a task, or both. PD and healthy controls underwent two functional MRI scans: a resting-state scan and a Stroop Match-to-Sample task scan. Rest-task modulation of basal ganglia (BG) connectivity was tested using seed-to-voxel connectivity analysis with task and rest time series as conditions. Despite substantial overlap of BG-cortical connectivity patterns in both groups, connectivity differences between groups had clinical and behavioral correlates. During rest, stronger putamen-medial parietal and pallidum-occipital connectivity in PD than controls was associated with worse task performance and more severe PD symptoms suggesting that abnormalities in resting-state connectivity denote neural network dedifferentiation. During the executive task, PD patients showed weaker BG-cortical connectivity than controls, i.e., between caudate-supramarginal gyrus and pallidum-inferior prefrontal regions, that was related to more severe PD symptoms and worse task performance. Yet, task processing also evoked stronger striatal-cortical connectivity, specifically between caudate-prefrontal, caudate-precuneus, and putamen-motor/premotor regions in PD relative to controls, which was related to less severe PD symptoms and better performance on the Stroop task. Thus, stronger task-evoked striatal connectivity in PD demonstrated compensatory neural network enhancement to meet task demands and improve performance levels. fMRI-based network analysis revealed that despite resting-state BG network compromise in PD, BG connectivity to prefrontal, premotor, and precuneus regions can be adequately invoked during executive control demands enabling near normal task performance.

KEYWORDS:

Cognitive control; Neural compensation; Parkinson’s disease; Response switching; Task-related and resting-state functional connectivity; fMRI

PMID:
25280970
PMCID:
PMC4385510
DOI:
10.1007/s11682-014-9317-9
[Indexed for MEDLINE]
Free PMC Article

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