Resting-state Functional Connectivity Of Insular In Bipolar Patients During A Depressive Episode

Objective: To explore the mechanism of functional connectivity abnormalities in insular lobe in patients with bipolar disorder by resting state functional magnetic resonance imaging(fMRI).The results were compared with those of similar studies in order to find out the brain regions of functional connectivity abnormalities related to the diagnosis and differential diagnosis.Methods: According to the diagnostic criteria of DSM-V,26 patients with bipolar disorder and 29 healthy controls were enrolled in the study.Data preprocessing(motion correction,normalization,spatial smoothing et al.)and functional connectivity was carried out by using DPARSF which was based on MATLAB.The regions of interest(ROIs)were defined by three sub-regions of the insular: dAIC,vAIC and PIC as well.The functional connectivity analysis of the whole brain was analized with MIN coordinates of the ROIS by using REST.The result was evaluated using two-sample test,and then corrected with AlphaSim,p<0.01.Finally,the difference between the patients with bipolar disorder and healthy controls was obtained.We explored the relationship between HAMD and Z-score of FC.Results: 1.In both the bipolar depression group and the healthy control group,25 cases had been individually recruited.2.Compared with healthy controls,bipolar depressive patients with abnormal functional connectivity of insular included following brain regions: LvAIC-right frontal gyrus,right inferior frontal gyrus;RvAIC-right occipital middle,precuneus,left postcentral gyrus;LdAIC-left lingual gyrus,right fusiform gyrus;RdAIC-left fusiform gyrus,left lingual back,right precentral gyrus;LPIC-right cingulate gyrus,right inferior frontal gyrus and right precuneus.3.Correlation Analysis indicated following findings: the circadian rhythm factor in the HAMD was negatively correlated with the functional connectivity strength of LvAIC-right frontal gyrus.The functional connectivity strength of LPIC-right precuneus was positively related to hysteresis factor.The age of onset was positively correlated to the functional connectivity intensity of RvAIC-left postcentral gyrus.And the duration was positively correlated to the functional connectivity intensity of both LdAIC-left lingual gyrus,and LPIC-right precunealis.Conclusion:(1)The decreased functional connectivity between insular and fro ntal gyrus,inferior frontal gyrus,precuneus,lingual gyrus,cingulate gyrus,cing ulate gyrus in bipolar depression might be associated with cognitive decline a nd emotion regularion dysfunction of bipolar depression.Abnormal functional c onnectivity of frontal gyrus may be related to circadian rhythm disorders and a bnormal functional connectivity of fusiform may lead to disorder of emotion re cognition.(2)Interrelated but different features of each sub region suggesting t hat the regional functional connectivity of insula help to integrate cognitive pro cess,emotional reactions,sensory and motor function in different systems.Insu la is a key node between those systems and the key node of the abnormal fun ction and interaction among BD patients.