Objective To explore the functional connectivity characteristics and intensity of brain network in depression at rest.Methods Patients with major depressive disorder(MDD)and healthy controls(HCs)underwent resting state functional magnetic resonance imaging.The total brain degree centrality(DC)of the two groups was calculated to assess the functional connection strength.Support vector machine(SVM)method was used to investigate whether abnormal DC value can recognize MDD.Results A total of 26 patients and 37 controls were included in the analysis.Compared to HCs,MDD group showed decreased DC value in the left middle frontal gyrus(t=-4.98,P＜0.05,GRF corrected)and increased DC value in the right middle temporal gyrus(t=5.02,P＜0.05,GRF corrected),right parahippocampal gyrus(t=4.80,P＜0.05,GRF corrected),and right posterior cerebellar gyrus(t=4.98,P＜0.05,GRF corrected).Additionally,no significant correlations were found between abnormal DC values and clinical variables(i.e.,17-item Hamilton depression scale and Beck depression scale scores)in MDD group(P＞0.05).SVM analysis showed that decreased DC value in the left middle frontal gyrus might be used to distinguish MDD group from HCs with an accuracy of 84.13%,a specificity of 81.08%,and a sensitivity of 88.46%,the area under the operational characteristic curve is 0.87.Conclusions Altered DC values in the left middle frontal gyrus and right middle temporal gyrus,right parahippocampal gyrus,right posterior cerebellum may contribute to the pathophysiology of MDD.The change of functional connection strength of the left medial frontal gyrus may be helpful for the recognition of MDD.

BackgroundCurrently， the problem of depressed mood in college students is becoming more prominent. The experience of childhood maltreatment is a significant contributor to depression among college students. Although the association between the two has been confirmed， the specific psychosocial mechanisms underlying how childhood maltreatment affects college students' mental health remain insufficiently evidenced. ObjectiveTo explore the mediating role of emotion regulation difficulties in the relationship between childhood maltreatment and depression among college students， and to investigate the moderated effects of psychological resilience and family socioeconomic status， aiming to provide references for improving depressive symptoms in college students. MethodsOn 14 March 2024， a cluster sampling method was employed to recruit 751 college students from a university in Heilongjiang Province. Participants were assessed with Childhood Trauma Questionnaire （CTQ）， Difficulties in Emotion Regulation Scale （DERS）， Patients' Health Questionnaire Depression Scale-9 item （PHQ-9）， 10-item Connor-Davidson Resilience Scale （CD-RISC-10） and Family Socioeconomic Status Questionnaire. Pearson correlation analysis was adopted to examine the correlation between the scores of scales. Model 4 and model 7 in Process 4.2 were used to test the mediating effects of emotional regulation difficulties and the moderated effects of psychological resilience and family socioeconomic status. Results① A total of 712 （94.81%） valid questionnaires were collected. ② College students' CTQ score was positively correlated with DERS score and PHQ-9 score （r=0.296， 0.507， P<0.01）， and negatively correlated with CD-RISC-10 score and Family Socioeconomic Status Questionnaire score （r=-0.148， -0.229， P<0.01）. ③ The indirect effect value of difficulties in emotion regulation on the relationship between childhood maltreatment and depression was 0.091 （95% CI： 0.018~0.046）， accounting for 17.95% of the total effect. ④ The first half of the mediation model "childhood maltreatment → difficulties in emotion regulation → depression" （childhood maltreatment → difficulties in emotion regulation） was moderated by psychological resilience （β=-0.030， t=-6.147， 95% CI： -0.040~-0.020） and family socioeconomic status （β=-0.051， t=-3.929， 95% CI： -0.077~-0.026）. ConclusionChildhood maltreatment exerts both a direct effect on college students' depression and an indirect effect through emotion regulation difficulties. The childhood maltreatment → emotion regulation difficulties pathway in this mediation model is moderated by psychological resilience and family socioeconomic status. ［Funded by Qiqihar Medical University Graduate Student Innovation Fund Project （number， QYYCX2023-48）； Special Research Fund Project for Young Doctors of Qiqihar Academy of Medical Sciences （number， QMSI2021B-08）］