Functional Magnetic Resonance Imaging Of Brain In Patients With First-episode Untreated Depression Based On VBM And Resting

Objective:This study is to explore the changes of gray matter volume in patients with first-episode untreated depression by the voxel-based morphometry(VBM)method,and take the brain region with different gray matter volume as the seed point to analyze the strength of functional connection between the seed point and the whole brain.In additon,this study is to explore the association between brain structural and functional abnormalities of the first-episode untreated patients with depression,and to provide new clues for further understanding the occurrence and development mechanism of depression.Methods:30 patients with first-episode untreated depression and 22 healthy volunteers matched with age and sex were recruited from the Department of Neurology and Mental Health Clinic of the First Hospital of Jilin University.All patients meet the Diagnstic and Statistial Manal of Menal Disorders,the fifth edition(DSM-V)diagnostic criteria for depression.All patients were assessed by 17-item Hamilton Depression Rating Scale(HAMD),HAMD scores were requested≥7 in patients.Used the PHILPS 3.0T MRI scanner for sagittal three-dimensionl brain structre scans and resting-state functinal magnetic resonnce imaging scans.The brain structure images of the two groups were studied by the VBM method to explore the changes of gray matter volume in patients with first-episode untreated depression.Resulted statistical map used the Alpha Sim correction.The statistical threshold setting P < 0.05 and the minimum cluster size of 45 voxels,it was considered that the difference was statistically significant,thus the brain area of gray matter volume change was obtained.Taking the brain region of gray matter volume change as seed point,resting-state functional magnetic resonance imaging was used to explore the functional connection strength between the seed point and the whole brain.Resulted statistical map used the FWE correction.The statistical threhold setting P < 0.05 and the minium cluster size of 201 voxels,it was considered that the difference was statistically significant,so as to obtain the brain regions in which functional connectivity(FC)values were enhanced or weakened in patients with first-episode untreated depression.Results:1.After analyzing the basic data of 30 patients with depression and 22 healthy volunteers,we found that there were no significant difference in sex and age between the two groups.2.VBM analysis : Compared to healthy controls,the volume of gray matter in left middle tempral gyrus,right inslar lobe,left supeior occiptal gyrus and right dorsolteral supeior frontal gyrus were decresed in the first-episode untreated depression group(P<0.05,cluster size>45,Alpha Sim correction),no regions increased.3.Taking the right insular lobe as the seed point,it was found that the brain regions with enhanced functional connections in the first-episode untreated depression group were medial superior frontal gyrus and cuneate prefrontal lobe(P<0.05,cluster size>201,FWE correction),no regions weakened.Take the left middle temporal gyrus,left superior occiptal gyrus and right dorsolatral superior frontal gyrus as seed points respectively,no brain regions with enhanced or weakened functional connection were found in the first-episode untreated depression group.Conclusion:1.The brain regions with decreased gray matter volume in patients with first-episode untreated depression are mainly located in frontal lobe,temporal lobe,occipital lobe and insular lobe,indicating that the occurrence and development of depression is related to multiple brain regions.the interaction between different brain regions may be the key to the pathogenesis of depression.2.In the study of resting-state functioal magnetic resonance imaging,it is found that the brain areas with abnormal functional connectivty are an important part the default network,indicating the default network plays a significant role in the pathogenesis of depression.Meanwhile,the study is to provide new evidence for the hypothesis that there is a default network abnormality in the brain network of patients with depression.3.The brain regions with abnormal gray matter volume also have abnormal functional connectivity,indicating that there is a close relationship and interaction between brain structure and brain function in the pathogenesis of depression.