Functional Connectivity Bias Of The Hippocampus In Suicidal Depressed Patients During Resting State

Objective To explore the anomalous activities of hippocampus that shown with functional connectivity in suicidal depressed patients by resting-state functional magnetic resonance imaging(fMRI).Method Functional magnetic resonance imaging was performed in subjects of 76 major depressive disorder(MDD)patients which include 43 patients with a history of suicide attempt(suicidal depression patients,SD)and 33 patients without suicide attempt(non-suicidal depression patients,NSD),and 44 healthy controls(HC)underwent fMRI equally.By researching the functional connectivity between hippocampus and whole brain,we explored the differences of the hippocampal functional connectivity between three groups.The source of the subjects in the group of SD and NSD was the depression patients in the psychiatric outpatient department and inpatient department of the First Affiliated Hospital of Chongqing Medical University.The subjects of the control group were recruited as the volunteers,and the method used in the experiment was cross-sectional study.Results SD relative controls showed decreased functional connectivity between the left hippocampus and the right angular gyrus,and same consequences showed between the right hippocampus and both the left inferior temporal gyrus and left inferior occipital gyrus.The result of SD compared with NSD demonstrated the increased functional connectivity between the left hippocampus and left rectus gyrus,but no group difference was found between the right hippocampus and the other brain regions.Reduced functional connectivity was found between the left hippocampus and both the right middle frontal gyrus and left superior frontal gyrus in NSD vs.HC,which the right hippocampus showed lessened functional connectivity with the left inferior temporal gyrus,right middle frontal gyrus and its' orbital part,and right angular gyrus.Conclusion: Abnormal functional relationships between the left hippocampus and some cortial regions in frontal lobe may underlie the biomarkers of MDD with suicidality,and that perhaps contribute to disturbances of cognition and behavior in MDD.