title: Anatomical and functional brain abnormalities in unmedicated major depressive disorder.
abstract: BACKGROUND
  Using magnetic resonance imaging (MRI) and resting-state functional magnetic resonance imaging (rsfMRI) to explore the mechanism of brain structure and function in unmedicated patients with major depressive disorder (MDD).
  
  
  METHODS
  Fifty patients with MDD and 50 matched healthy control participants free of psychotropic medication underwent high-resolution structural and rsfMRI scanning. Optimized diffeomorphic anatomical registration through exponentiated lie algebra and the Data Processing Assistant for rsfMRI were used to find potential differences in gray-matter volume (GMV) and regional homogeneity (ReHo) between the two groups. A Pearson correlation model was used to analyze associations of morphometric and functional changes with clinical symptoms.
  
  
  RESULTS
  Compared to healthy controls, patients with MDD showed significant GMV increase in the left posterior cingulate gyrus and GMV decrease in the left lingual gyrus (P<0.001, uncorrected). In ReHo analysis, values were significantly increased in the left precuneus and decreased in the left putamen (P<0.001, uncorrected) in patients with MDD compared to healthy controls. There was no overlap between anatomical and functional changes. Linear correlation suggested no significant correlation between mean GMV values within regions with anatomical abnormality and ReHo values in regions with functional abnormality in the patient group. These changes were not significantly correlated with symptom severity.
  
  
  CONCLUSIONS
  Our study suggests a dissociation pattern of brain regions with anatomical and functional alterations in unmedicated patients with MDD, especially with regard to GMV and ReHo.
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.affiliation: Chengdu First People's Hospital, Chengdu, People's Republic of China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Ma
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Mingli
authors.initials: M
authors.lastname: Li
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Dong Feng Mao Jian Hospital, Shiyan, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Huang
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Liansheng
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: Psychiatric Laboratory and Department of Psychiatry, Sichuan University, Chengdu, People's Republic of China ; National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Ma
keywords: functional magnetic resonance imaging; gray-matter volume; major depressive disorder; regional homogeneity