Functional connectivity bias of the hippocampus in suicidal depressed patients during resting state

Abstract:

Objective：To explore the functional connectivity bias of the hippocampus in suicidal depressed patients by resting-state functional magnetic resonance imaging（Rs-fMRI）. Methods：Functional magnetic resonance imaging（fMRI） was performed on 76 patients with major depressive disorder（MDD），of which 43 patients were with suicide attempt history（suicidal depression，SD） and 33 patients without（non-suicidal depression，NSD），and 44 healthy controls（HC）. The differences of the hippocampal functional con－nectivity among the three groups were explored by researching the functional connectivity between hippocampus and the whole brain. The subjects in the SD group and NSD group were the depression patients admitted into the Psychiatric Department of the First Affiliated Hospital of Chongqing Medical University，while the subjects of the control group were recruited as the volunteers. The method used in the experiment was cross-sectional study. Results：Compared with the HC group，the SD group had decreased func－tional connectivity between the left hippocampus and the right angular gyrus，as well as that between the right hippocampus and the left inferior temporal gyrus or left inferior occipital gyrus respectively. Compared with the NSD group，the SD group demonstrated the increased functional connectivity between the left hippocampus and left rectus gyrus，but the same functional connectivity between the right hippocampus and the other brain regions. Compared with the HC group，the NSD group showed the reduced functional connec－tivity between the left hippocampus and the right middle frontal gyrus or left superior frontal gyrus respectively，as well as that be－tween the right hippocampus and the left inferior temporal gyrus，right middle frontal gyrus and its orbital part，or right angular gyrus respectively. Conclusion：The abnormal functional connectivity between the left hippocampus and some cortial regions in frontal lobe may underlie the biomarkers of MDD with suicidal activity，which perhaps contributes to the disturbances in cogni－tion and behavior in MDD.