Functional Magnetic Resonance Imaging Study Of Characteristics Of Brain Function And Structure In Early Parkinson’s Disease

[Objective] Using resting-state functional magnetic resonance imaging(Rs-fMRI), voxel-based morphometry(VBM) method and automatic segmentation technique,we explored differences of regional brain spontaneous activity and brain morphology in resting state in early Parkinson’s disease (PD) patients vs healthy participants.The purpose was to investigate the neural pathological mechanism of PD patients with multiple system involvement.[Methods] 29 participants diagnosed with early Parkinson’s disease (Hoehn-Yahr stage were 0-2) and 30 healthy controls(HC) who were matched in age,gender and education level were recruited.Resting-state functional MRI and three-dimensional brain structure scans were performed on all participants. Regional homogeneity (ReHo),amplitude of low frequency fluctuation(ALFF) and resting-state functionnal connectivity(rsFC) approachs were applied to preprocess the fMRI datasets.ALFF can evaluate the whole activity of the synchronicity in local brain regions.ReHo can evaluate the same time of area between tissue in a sequence of consistency.rsFC can evaluate the characteristics of functional connectivity of region interest (ROI) was connnected with other relative brain regions.Using voxel-based morphometry (VBM)method in combination with automatic segmentation technique to analysis the distribution characteristics of changes in whole brain morphology in early Parkinson’s disease participants. We analysed the results statistically by REST and SPSS 17.0 software.For Rs-fMRI and VBM data between groups we adopted the method by which was based on voxel two sample t-test with REST software.Using the partial correlation analysis to observe the UPDRS score and different brain regions of early Parkinson’s disease patients(age,gender,education level as the convariant).Both the differences of data were expressed by the international generic statistical parametric mapping. Using FIRST tool to segment every subcortical gray matter structure, and campaire the volume of the two groups should used the two sample ’t ’test by SPSS 17.0 software, then use the partial correlation analysis to observe the UPDRS score and different brain regions of early Parkinson’s disease patients(age, gender, education level as the control factors).[Results]1 FIRST analysis:In the subcortical gray matter structures,only the volume of right putamen was reduced(.P<0.05),and was no correlated with UPDRS score.2 VBM analysis:The grey matter volume differences of the two groups was showed in the statistical parametric mapping by AlphaSim correction (.P<0.005, cluster siaze≥12. as the threshold). Compared with the HC group, grey matter volume in PD group widely reduced in the bilateral superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus,parahippocampal gyrus and cerebellum posterior lobe; right primary motor cortex; paracentral lobule,superior temporal gyrus, middle temporal gyrus, posterior cingulate gyrus, inferior parietal lobule, cerebellum anterior lobe; left superior parietal lobule, precuneus, cuneus, lingual gyrus and amygdala.increased in the left cerebellum posterior lobe.These different brain regions were no correlated with UPDRS score.3 ALFF analysis:The mALFF value differences of the two groups was showed in the statistical parametric mapping by AlphaSim correction (P<0.005, cluster size ^26. as the threshold). Compared with the HC group,mALFF in PD group decreased in the bilateral postcentral gyrus, posterior cingulate gyrus, middle occipital gyrus and cerebellum posterior lobe;left primary motor cortex, fusiform gyrus, inferior occipital gyrus, cuneus, lingual gyrus,;right superior parietal lobule; increased in the bilateral insula, right putamen and the right cerebellum anterior lobe.The left cuneus was negatively correlated with UPDRS score.4 ReHo analysis:The ReHo value differences of the two groups was showed in the statistical parametric mapping by AlphaSim correction(P<0.01, cluster size≥40. as the threshold). Compared with the HC group, the average activation strength of these regional in PD group decreased in the bilateral primary motor cortex, supplementary motor cortex, postcentral gyrus and anterior cingulate gyrus;left middle frontal gyrus, middle occipital gyrus and precuneus;increased in the left insula and right middle temporal gyrus.These different brain regions were no correlated with UPDRS score.5 rsFC analysis:The rsFC value differences of the two groups was showed in the statistical parametric mapping by AlphaSim correction(P<0.01, cluster size≥40. as the threshold). ①When the bilateral putamen as the regions of interest,compared with the HC group,PD group exhibited decreased rsFCs in left and right putamen; the bilateral anterior cingulate gyrus, inferior frontal gyrus;left middle frontal gyrus and superior temporal gyrus;increased rsFCs in the bilateral primary motor cortex, postcentral gyrus and left medial frontal gyrus.②When the bilateral amygdala as the regions of interest,compared with the HC group,PD group exhibited decreased rsFCs in the bilateral putamen, anterior cingulate gyrus;right precentral gyrus, insula and prefrontal cortex; left subcallosal gyrus,globus pallidus, increased rsFCs in the bilateral superior parietal lobule,middle occipital gyrus and precuneus right supplementary motor cortex, inferior temporal gyrus; left cuneus, lingual gyrus, inferior occipital gyrus.The left globus pallidus and right putamen were negatively correlated with UPDRS score.The right supplementary motor cortex and insula were postive correlated with UPDRS score.[Conclusion] Brain funcion and morphology change can be reflected effectively through Resting-state fMRI(ReHo,ALFF,rsFC),VBM and automatic segmentation technique. Meanwhile, they are more helpful to explore the damage of neural circuits and brain functional network in Parkinson’s disease.The early PD patients designated by Hoehn-Yahr stage had a wide range of the loss of brain neurons function and gray matter atrophy. Dysfunction and abnormal structure in the putamen,motor cortex,PCC and cerebellum may contributed to the neuropathology of dyskinesia in PD. Dysfunction and abnormal structure in the prefrontal lobe,parietal lobe,temporal lobe,occipital lobe, cuneus,lingual gyrus,cerebellum,cingulate cortex and amygdala were closely related to the hearing reduction,memory deterioration,defective vision,cognitive impairments and abnormal emotion behaviors in PD patients. The imaging characteristics of wide Dysfunction and abnormal structure was conformed to the the complex neural pathological mechanism of PD patients with multiple system involvement.