Resting-state Magnetic Resonance Imaging Study Of Hippocampal Functional Connectivity In Depressed Patients With Suicidal Ideation

BackgroundSuicide is an important public health problem in todays society.There is a very close relationship between suicidal ideation and suicidal behavior,and the intervention of suicidal ideation is an important measure to prevent suicidal behavior.Patients with depression are more likely to develop suicidal ideation and suicidal behavior.At present,the research on depression with suicide is increasing.Related research on suicidal behavior suggests that the hippocampus plays an important role in depression with suicidal behavior,but there are few researches on suicidal ideation in the hippocampus,which need to be further discussed.ObjectivesThe purpose of this study is to explore the spontaneous function of hippocampus in patients with suicide ideational depression,and to analyze the difference of the abnormal function connection network of hippocampus if there is any abnormality in the hippocampus.MethodsA total of 49 patients with depression were included according to the Diagnostic and Statistical Manual of Mental Disorders-IV(DSM-IV)Diagnostic criteria for "depression",including 29 depressive patients with suicidal ideation and 20 depressive patients without suicidal ideation,as well as 33 healthy controls.Age,gender,education level and Hamilton Depression Scale(HAMD-17)scores of all subjects were collected.Course of disease and Hamilton Anxiety Scale(HAMA)of depression group with and without suicidal ideation.The data of all subjects were collected by resting functional Magnetic Resonance Imaging(fMRI).The Mean Amplitude of Low Frequency Fluctuations(mALFF)of the whole brain was obtained by analyzing the magnetic resonance data under REST plus(www.restfmri.net)analysis software.First,one-way ANOVA was used to compare the differences among the three groups,and then the pairwise comparison of independent sample t-test was used to obtain significant differences in brain regions.Finally,we use the different hippocampal region as the seed region to analyze the functional connectivity(FC)based on the seed region.ResultsThere was no significant difference in age,sex and education level among the three groups.There were significant statistical differences in HAMD scores among the three groups.There were significant differences in the course of depression and HAMA scores between the group with suicidal ideation and the group without suicidal ideation.In the resting state,compared with the normal control group,the mALFF values of left inferior temporal gyrus,right hippocampus and right medial superior frontal gyrus were significant difference in depressive patients with suicidal ideation.The results of the functional connection based on the abnormal right hippocampus as the seed region showed that: compared with the normal control group,the connection intensity between the right hippocampus and the right middle temporal gyrus,the right inferior temporal gyrus,the left middle temporal gyrus,the left inferior temporal gyrus,the left inferior parietal angular gyrus and the left superior parietal gyrus in the suicidal depression group was significantly lower than that in the normal control group.ConclusionsThis study suggests that the increase of mALFF in hippocampus and the decrease of functional connections between the brain areas and hippocampus may be related to the pathogenesis of depression with suicidal ideation.