title: Altered network efficiency in major depressive disorder.
abstract: BACKGROUND
  Major depressive disorder (MDD) is associated with dysfunction between cognitive control and affective processing system. However, little is known about alterations of the nodal and edge efficiency in abnormal systems of MDD patients. We used two independent datasets and two different structural templates to investigate the alterations of the nodal and edge efficiency of whole-brain functional networks of MDD.
  
  
  METHODS
  Forty-two MDD and forty-two age, education-matched controls were selected to investigate network efficiency abnormalities of the MDD patients' cortical and subcortical regions, as well as the disrupted functional connectivity between these regions, from the perspective of network topological architectures. In addition, another dataset, which included thirty MDD patients and thirty controls, was also investigated using the same method.
  
  
  RESULTS
  Results showed that MDD group demonstrated significant increase in the local efficiency, although not change of global efficiency. In addition, nodal efficiency was found to increase in affective processing regions (i.e., amygdale, thalamus, hippocampus), but decrease in cognitive control related regions, which included dorsolateral prefrontal cortex and anterior cingulate cortex. The edge efficiency was found to increase, involving both connectivity between thalamus and limbic system regions and connectivity between hippocampus and regions (i.e., amygdala, thalamus). More important, result was replicated within independent datasets for the first and different structural templates for another.
  
  
  CONCLUSIONS
  Our results indicated that MDD was associated with disrupted functional connectivity networks between cognitive control and affective processing systems. The findings might shed light on the pathological mechanism of depression and provide potential biomarkers for clinic treatment of depression.
authors.affiliation: College of Computer and Information Science, Southwest University, Chongqing, 400715, China.|College of Electronic and Information Engineering, Southwest University, Chongqing, 400715, China.|School of Computer Science, Sichuan University of Science and Engineering, Sichuan, Zigong, 643000, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Ye
authors.affiliation: College of Computer and Information Science, Southwest University, Chongqing, 400715, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Qing
authors.affiliation: School of Computer Science, Sichuan University of Science and Engineering, Sichuan, Zigong, 643000, China. zhangk@uestc.edu.cn.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: College of Computer and Information Science, Southwest University, Chongqing, 400715, China. liugy@swu.edu.cn.|College of Electronic and Information Engineering, Southwest University, Chongqing, 400715, China. liugy@swu.edu.cn.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Liu
mesh_terms: D000328:Adult; D000679:Amygdala / Q000473:pathology; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008032:Limbic System / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D013788:Thalamus / Q000473:pathology
keywords: Cognitive control system; Functional magnetic resonance imaging; Major depressive disorder; Network efficiency; Network topology