ABSTRACT
Objective:To investigate the value of large-scale brain network research based on independent component analysis (ICA) in discovering the changes of intrinsic functional connections within and between resting-state networks (RSNs) in first-episode untreated adult patients with major depressive disorder (MDD).Methods:From January 2019 to June 2021, twenty-three patients with MDD (MDD group) and 30 healthy volunteers (HC group) matched with gender, age and years of education were selected. All participants underwent resting-state brain function imaging (rs-fMRI), and the MDD group completed the 17-item Hamilton depression scale(HAMD-17). The independent component analysis (ICA) method was used to analyze rs-fMRI data, and meaningful RSNs were obtained. SPM12 and Gift softwares were used to compare the strength of intrinsic functional connection within and between the RSNs of the MDD group and HC group, and the Pearson correlation analysis was conducted by IBM SPSS statistics 25.0 to evaluate the correlation between the functional connection strength and HAMD-17 scores in MDD group.Results:Compared with the HC group, intrinsic functional connection strength of medial prefrontal cortex (mPFC) (MNI: x, y, z=-6, 54, 25)in MDD group was significantly enhanced, while the intrinsic functional connection strength of the left angular gyrus (AG) (MNI: x, y, z=-48, -66, 21), the left precuneus (PCu) (MNI: x, y, z=-6, -63, 33), the left dorsolateral prefrontal cortex (dlPFC) (MNI: x, y, z=-36, 12, 51)and the right anterior insula (AI) (MNI: x, y, z=36, 21, 0)were significantly weakened. Compared with the HC group, functional connection strength between posterior default mode net work(pDMN) and anterior default mode network(aDMN) in MDD group was significantly weakened ( t=-2.206, P=0.032), and function connection strength between pDMN and left frontal parietal network(lFPN) was significantly strengthened ( t=2.318, P=0.025). In MDD group, intrinsic functional connection strength of mPFC and the functional connection strength of pDMN-lFPN were positively correlated with the HAMD-17 score ( r=0.524, P=0.010; r=0.441, P=0.035). Conclusion:Large-scale brain network study based on the ICA can find abnormal functional connections within and between RSNs in first-episode untreated adult patients with MDD, and provide objective imaging markers for the clinical diagnosis and treatment of MDD.