Study On Functional Connectivity Between Right Fronto-insular And Whole Brain In Patients With Different Motor Subtypes Of Parkinson’s Disease

Background: Parkinson’s disease(PD)can be divided into akinetic-rigid PD(AR-PD)and tremor dominant PD(TD-PD)according to its different motor symptoms.Patients with AR-PD are more prone to cognitive decline and depressive symptoms than patients with TD-PD.It has been previously discovered that primary depression is related to changes in the functions and effective connections of the triple-brain network of the default mode network(DMN),the central executive network(CEN)and the salience network(SN).The right fronto-insular cortex(rFIC),as a key node of SN,plays a critical role in the switching between the DMN and CEN,and participates in cognitive and emotional processing.This study is intended to test the hypothesis that AR-PD patients have alteration in the functional connectivity between rFIC and triple-brain network when compared with TD-PD patients healthy controls(HCs)at resting-state.METHODS: 23 AR-PD patients,21 TD-PD patients,and 18age-matched normal controls(HCs)were included in the study.Allsubjects underwent resting-state functional MRI(RS-fMRI)data acquisition and neuropsychological scale measurements.The resting-state functional connectivity(rs-FC)method with rFIC as the region of interest was used to study the patterns of functional connectivity among the three groups.Results: compared with TD-PD group,the functional connectivities between rFIC and the right insula and bilateral anterior cingulate gyrus were decreased in the AR-PD group.When compared with HCs,AR-PD group have decreased connectivities between rFIC and bilateral insula,anterior cingulate gyrus,central anterior gyrus and the right medial frontal gyrus.TD-PD group show decreased functional connectivities between rFIC and left insula and bilateral anterior cingulate gyrus when compared with HCs,and the FC value of rFIC-left insula in TD-PD group was positively correlated with HAMD score.Conclusion: There are decrased FC between rFIC and multiple brain regions in both groups of PD patients compared with HCs,and AR-PD group involves more extensive brain regions,involving SN and CEN.When compared with TD-PD group,the AR-PD group shows decreased FC regions with rFIC located in SN.The decreased FC between rFIC and the other nodes of SN as well as CEN may be a potential factor for AR-PD patients prone to develop cognitive decline and depressive symptoms.