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DOI: 10.1055/s-0032-1301619
A Resting-State fMRI Analysis to Reveal Changes in Functional Connectivity Patterns of the DLPFC in Patients with Parkinson’s Disease
Introduction: The characteristic motor symptoms in Parkinson’s disease (PD) are often accompanied by cognitive, emotional and motivational deficits, which are modulated by dysfunctions of the fronto-striatal loops. The dorsolateral prefrontal cortex (DLPFC) is known to be involved in executive functioning. While activations of the DLPFC during executive tasks are well described, the impact of resting state functional connectivity (FC) of the DLPFC on cognitive changes remains to be specified. In a first step, changes in FC of the DLPFC in PD patients are determined. Methods: We examined 53 PD patients and 16 age-matched control subjects. Subjects were scanned at rest. The FC analysis was based on the common seed-region approach. Two general linear models (respectively for the left and right hemisphere) were specified for each subject modelling time series of the DLPFC and two additional covariates (averaged signal over white matter and cerebrospinal fluid compartments). Finally regression coefficients were compared on group level.
Fig. 1: Statistical maps showing significant differences in functional connectivity with the DLPFC (punc<0.001) between PD patients and controls. Panel A: statistical t-map (PD>CON) using correlation coefficients with the left DLPFC. Panel B: statistical t-map (PD>CON) using correlation coefficients with the right DLPFC. Subpanels in the top-right corner of each panel show group specific parameter estimates and 90% confidence intervalls at the locations with maximal group differences.
Results: Statistical comparisons (PD>CON) between the correlation coefficients of the PD patient group and the control group showed two significant bilateral clusters in the cerebellum (punc<0.001). Beta estimates at the peak locations (subpanels in Fig.1 A and B) revealed a strong negative correlation with the DLPFC region in the control group and a much smaller negative correlation in the patient group. Reversed statistical comparisons (PD<CON) showed no relevant differences at this statistical level (punc<0.001). Conclusions: Our preliminary results point toward an impaired resting state FC of the DLPFC in PD patients. FC differences between patients and controls were found in the cerebellum, probably in the region of the dentate nucleus, known to be anatomically connected with the DLPFC. Further analyses will deal with the relevance of altered FC for cognitive functioning by dissecting the data according to available behavioral data.