Investigation of sensorimotor dysfunction in Parkinson disease by resting-state fMRI

Purpose: Functional MRI has played a fundamental role in Parkinson's disease(PD) study. In this paper, we performed an independent component analysis (ICA) based on functional networks to reveal the intricate variations on the morphology and functional properties of brain. Our analysis aims at discovering the differences between PD patients with sensorimotor function impairment and normal controls(NC), thus helping to understand the coordination neurological function degeneration in PD objectively. Method: We investigated the blood oxygen level dependent(BOLD) functional MRI obtained at a 3.0 T MRI scanner. 30 PD patients and 28 NC subjects underwent the scan in resting state. The signals of sensory and motor coordinative control areas in the sensorimotor, insula and cerebellum networks acquired by ICA(Independent Component Analysis)were applied to analyze the functional alterations. Specifically, intra-network analysis was performed with signals in local networks, and inter-network analysis was conducted by functional network connectivity (FNC) with signals across different networks. Two sample T test was carried out to detect the significant (p < 0.05, FDR p < 0.05) functional abnormality in PD patients. Conclusion: We identified an obvious increase in bilateral posterior insula, but decrease in bilateral cerebellum hemisphere, supplementary motor area(SMA) and precentral gyrus paracentral lobule of left postcentral gyrus. Besides, we found a significantly increased connection between independent component (IC) 13 which was located in right postcentral gyrus and cerebellum. Decreased connections were detected between sensory and motor cortex in sensorimotor network and between cerebellum and insula network by FNC analysis in PD patients as well. Discussion: Parkinson's disease derives from the degeneration of the dopaminergic neurons in substantia nigra, and results in decreased secretion of inhibitory neurotransmitter. The significant differences between PD and NC groups in our research maybe explain the clinical manifestations of prominent bradykinesia and multiple extrapyramidal symptoms.