A Resting-state FMRI Study Of Brain Local Consistency And Functional Connectivity In Patients With Parkinson's Disease And Depression

Part1: Alterations in regional homogeneity of resting state brain activity in Parkinson's disease patients with depressionObjective: Depression is the most common psychiatric symptoms in Parkinson's disease(PD).It can appear in the early stage of Parkinson's disease,or even before the appearance of movement disorders,and accompany the whole course of the disease.However,the pathogenesis of depressed Parkinson's disease(DPD)is still unclear,so this study used the resting state fMRI to investigate the changes of regional homogeneity(ReHo)in DPD and their relationship with major depressive disorder(MDD),and to further explore the pathophysiological mechanism of DPD.Methods: A total of 42 PD patients without depression,20 PD patients with depression,20 major depressive disorder patients and 47 well-matched healthy controls were scanned with resting-state functional magnetic resonance imaging for ReHo analysis.The MMSE,Unified Parkinson's Disease Rating Scale(UPDRS-?)scores and course of the disease were used to assess the clinical symptom,then the correlations between abnormal brain regions and clinical data were explored.Results:(1)The main effect of Parkinson's disease: PD group showed higher ReHo in left ventrolateral prefrontal cortex and right precuneus,but lower ReHo in bilateral supplementary motor area and left angular gyrus;(2)The main effect of depression: the depression group had increased ReHo in bilateral cerebellum,and decreased ReHo in left posterior cingulate gyrus,left postcentral gyrus,left supplementary motor area,right dorsolateral prefrontal cortex,right precentral gyrus,right inferior parietal gyrus and right calcarine;(3)Interactive effect of PD and depression: interactive brain areas included bilateral middle frontal gyrus,left inferior orbitofrontal cortex and supramarginal gyrus;(4)The main effect of depression: the ReHo of the brain regions,including left dorsolateral prefrontal cortex,right inferior parietal gyrus,had significant negative correlation with HAMD scores.There was a significant positive correlation between the ReHo value of right calcarine and the HAMD score in DPD group,while there was no significant correlation between the ReHo value and the HAMD score in the MDD group.Interactive effects of PD and depression: there was a significant negative correlation between the ReHo value of the bilateral middle frontal gyrus,left inferior orbitofrontal cortex and the HAMD score in the MDD group.Conclusion: PD patients with depression have abnormal brain function,and the pathogenesis of depression is not consistent with MDD.So DPD is not simply an overlay of PD and major depressive disorder.Part2: Functional connectivity analysis of amygdala in Parkinson's disease patients with depressionObjective: The amygdala is an important node which is associated with the generation,expression and experience of negative emotions.,and its interaction with other areas of the cortex and subcortical,plays an important role in emotional regulation.This study selected amygdala from emotion network,then used functional connectivity analysis to explore changes of the amygdala function connection in Parkinson's disease with depression and to further explore the pathophysiological mechanism of DPD.Methods: A total of 42 PD patients without depression,20 PD patients with depression,20 major depressive disorder patients and 47 well-matched healthy controls collected in Nanjing Medical University affiliated Brain Hospital outpatient clinic from June 2017 to October 2017 were scanned with resting-state functional magnetic resonance imaging for functional connectivity analysis.The MMSE,Unified Parkinson's Disease Rating Scale(UPDRS-?)scores and course of the disease were used to assess the clinical symptom,then the correlations between abnormal brain regions and clinical data were explored.Results:(1)The change of FC in the left amygdala: under the main effect of Parkinson's disease,the functional connection between the left amygdala and the left superior temporal gyrus,middle temporal gyrus was weakened;under the main effect of depression,the depression group had decreased FC between the left amygdala and the left frontal gyrus,the right inferior parietal gyrus and amygdala;under the interactive effect of PD and depression,interactive brain areas included right orbitofrontal cortex and posterior cingulum cortex;(2)there were no changes of FC in the right amygdala.(3)Interactive effect of PD and depression: the FC value between the left amygdala and the right orbitofrontal cortex in MDD had a significant negative correlation with HAMD scores,had significant negative correlation with HAMD scores.Conclusion: Based on the amygdala,we found the abnormal functional connectivity of the corticolimbic network in DPD.We also found that the pathogenesis of the depression in DPD maybe overlapped with the pathogenesis of MDD,but it is not a simple overlay of PD and major depressive disorder.Though,these results acquired within this small sample still need further validation in future studies.