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

Resting-state functional magnetic resonance imaging (rs-fMRI)enables evaluation of low-frequency oscillations (0.010.1 Hz)of the BOLD-signal, which are related to changes in the hemodynamicsparameters, thereby making possible to determineindirectly the spontaneous neuronal activity of various areas ofthe brain at rest . We conducted an rs-fMRI study in groups ofhealthy volunteers and patients with Parkinsons disease (PD).Out of the spectrum of resting neural networks of the brain, thebrains default mode network (DMN) was selected, and changesin the neuronal activity pattern of the network in PD patientswere evaluated. Compared to the norm, PD was found to becharacterized by a decrease in the activity of the right inferior parietallobe (i.e. in the area incorporated into DMN and involvedin visual-spatial perception) and, on the contrary, an increase inthe spontaneous neuronal activity of DMN in the medial segmentsof the right superior frontal gyrus, right and left angulargyri, and anterosuperior and posteroinferior parts of the left andright precuneus. The detected changes in the neuronal activity,regarded as a manifestation of the neuroplasticity phenomenon,may potentially serve as biomarkers of a neurodegenerative processin PD.