Objective:To explore the microstructural abnormalities of white matter and the possible pathogenesis in major depressive disorder, by tract-based spatial statistics (TBSS) and voxel-based morphometry techniques (VBM).Methods:Twenty middle-aged female participants diagnosed with first-episode major depressive disorder according to ICD-10and fifteen normal controls matched for age, gender, and education were assessed using24-item Hamilton Depression Rating Scale(HAMD), HAMD scores were requested≥35in patients and<8in controls. Diffusion tensor imaging and Three-dimension T1weighted imaging was performed in all subjects by the German Siemens Magnetom Trio Tim3.0T MR Scanner. The DTI data were analyzed using tract-based spatial statistics(TBSS), and the high-resolution structural images were analyzed using voxel-based morphometry (VBM). The FA values and white matter volume between the patients and controls were compared by two sample t test.Results:Compared with normal controls, FA values were significantly decreased in the white matter of the left prefrontal cortex、left internal capsule and the right precuneus(P<0.005,cluster>40).The VBM results showed that comparing with normal controls, white matter volume was significantly decreased in the deep white matter of the bilateral frontal(P<0.05,cluster>100).Conclusion:Middle-aged、first-episode major depressive disorder patients showed significantly decreased FA values in the white matter of the left prefrontal cortex、left internal capsule and the right precuneus and white matter volume in the deep white matter of the bilateral frontal comparing with normal controls. FA values decreased in the white matter of the right precuneus suggested microstructural abnormalities of default mode network(DMN).The present results support the hypothesis that altered white matter integrity, especially in the prefrontal-subcortical neural circuit, may contribute to the neuropathology of MDD. |