Functional Connectivity Of Affective Network In Patients With Postpartum Depression:a Resting-state FMRI Study

Objective:Postpartum depression（PPD）is a kind of mental disorder with anxiety and depression as the main symptoms after delivery.Some severe cases may have a tendency to self-harm,suicide or infanticide,and also have serious negative impacts on their families and offsprings.However,its neuropathological mechanism has not been fully appreciated.Depression studies using the amygdala（AMYG）and subanterior anterior cingulate cortex（sgACC）as the main node of emotional network（AN）found that patients with major depressive disorder（MDD）existed extensive functional connectivity（FC）abnormalities in the brain regions of AN,and PPD as a subtype of MDD,it is unclear whether abnormal FC also exists in the brain regions associated with emotion in PPD patients.Resting-state functional magnetic resonance imaging（rs-fMRI）was used to inquire into the affective network（AN）of patients with PPD in this work.And we can observe the abnormal functional connectivity（FC）of patients with PPD and its results of correlation analysis with EPDS scores,and to explore the possible neuropathological mechanism of abnormal connection of the functional brain region regulated by AN in PPD.Methods:A total of 23 patients with PPD（PPD group）and 28 healthy postpartum women（control group）were examined using rs-fMRI,and the Edinburgh Postpartum Depression Scale（EPDS）was used as a screening tool for PPD.Based on Matlab platform,DPABI,SPM and REST software packages were used to process rs-fMRI data.As two critical nodes of AN,AMYG and sgACC were selected as the regions of interest（ROI）to analyze the differences of functional connectivity strength（FCS）of two regions from other brain regions between two groups,followed by Pearson correlation analysis on the abnormal FCS value and EPDS score in PPD group.Results:1.A total of 23 PPD patients and 28 healthy postpartum women were included in this study.There was no significant difference between the PPD group and the control group in terms of age,years of education,employment status,delivery status,and delivery mode（P>0.05）,but the EPDS score of PPD patients was significantly higher than those of healthy postpartum women,and the difference between the two groups was statistically significant（t=17.39,P<0.001）.2.Compared to the control group,the patients in PPD group showed the areas of significantly weakened FC with left AMYG were right superior frontal gyrus（orbital）,left medial orbitofrontal cortex and right precentral gyrus（P<0.05）,and the area of significantly enhanced FC were right precuneus and left superior parietal lobule（P<0.05）.The areas of significantly weakened FC with right AMYG were right superior frontal gyrus（orbital）,right superior frontal gyrus,left hippocampus,bilateral inferior temporal gyrus,Cerebelum_8R and Cerebelum_6L（P<0.05）,and the area of significantly enhanced FC were right superior temporal pole and right inferior frontal gyrus（pars opercular）（P<0.05）.3.Compared to the control group,the patients in PPD group showed the areas of significantly enhanced FC with left sgACC were bilateral midcingulate area,left thalamus,left superior temporal gyrus,retrosplenial cortex,right supplementary motor area and left calcarine cortex（P<0.05）,and no FC attenuates statistically significant areas（P>0.05）.The areas of significantly enhanced FC with right sgACC were bilateral midcingulate area,left precuneus,left supramarginal gyrus,left lingual gyrus,right supplementary motor area and left calcarine cortex（P<0.05）,and the area of significantly weakened FC were Cerebelum_6R and Cerebelum_45L（P<0.05）.4.In PPD group,the reduced FCS between left AMYG and left medial orbitofrontal cortex was negatively correlated with EPDS scores（r=-0.62,P=0.02）.Conclusions:1.Patients with PPD have dysfunctional connectivity of AN in multiple brain regions,and the abnormal connection of the functional brain region regulated by AN may play an important role in the neuropathological mechanism of PPD.2.In PPD group,the weaker FCS between left amygdala and left medial orbitofrontal cortex is,the more severe depression,which may provide an effective mechanism-based biomarker underlying PPD.