Reorganization of the brain’s default mode network in patients with Parkinson’s disease: resting-state fMRI-based analysis of individual components

Abstract

Resting-state functional magnetic resonance imaging (rs-fMRI) enables evaluation of low-frequency oscillations (0.01–0.1 Hz) of the BOLD-signal, which are related to changes in the hemodynamics parameters, thereby making possible to determine indirectly the spontaneous neuronal activity of various areas of the brain at rest . We conducted an rs-fMRI study in groups of healthy volunteers and patients with Parkinson’s disease (PD). Out of the spectrum of resting neural networks of the brain, the brain’s default mode network (DMN) was selected, and changes in the neuronal activity pattern of the network in PD patients were evaluated. Compared to the norm, PD was found to be characterized by a decrease in the activity of the right inferior parietal lobe (i.e. in the area incorporated into DMN and involved in visual-spatial perception) and, on the contrary, an increase in the spontaneous neuronal activity of DMN in the medial segments of the right superior frontal gyrus, right and left angular gyri, and anterosuperior and posteroinferior parts of the left and right precuneus. The detected changes in the neuronal activity, regarded as a manifestation of the neuroplasticity phenomenon,may potentially serve as biomarkers of a neurodegenerative process in PD.