title: A significant risk factor for poststroke depression: the depression-related subnetwork.
abstract: BACKGROUND
  Despite being one of the direct causes of depression, whether stroke-induced neuroanatomical deterioration actually plays an important role in the onset of poststroke depression (PSD) is controversial. We assessed the structural basis of PSD, particularly with regard to white matter connectivity.
  
  
  METHODS
  We evaluated lesion index, fractional anisotropy (FA) reduction and brain structural networks and then analyzed whole brain voxel-based lesions and FA maps. To understand brain damage in the context of brain connectivity, we used a graph theoretical approach. We selected nodes whose degree correlated with the Hamilton Rating Scale for Depression score (p < 0.05, false discovery rate-corrected), after controlling for age, sex, years of education, lesion size, Mini Mental State Examination score and National Institutes of Health Stroke Scale score. We used Poisson regression with robust standard errors to assess the contribution of the identified network toward poststroke major depression.
  
  
  RESULTS
  We included 116 stroke patients in the study. Fourteen patients (12.1%) had diagnoses of major depression and 26 (22.4%) had mild depression. We found that lesions in the right insular cortex, left putamen and right superior longitudinal fasciculus as well as FA reductions in broader areas were all associated with major depression. Seventeen nodes were selected to build the depression-related subnetwork. Decreased local efficiency of the subnetwork was a significant risk factor for poststroke major depression (relative risk 0.84, 95% confidence interval 0.72-0.98, p = 0.027).
  
  
  CONCLUSIONS
  The inability of DTI tractography to process fibre crossings may have resulted in inaccurate construction of white matter networks and affected statistical findings.
  
  
  CONCLUSIONS
  The present study provides, to our knowledge, the first graph theoretical analysis of white matter networks linked to poststroke major depression. These findings provide new insights into the neuroanatomical substrates of depression that develops after stroke.
authors: Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
authors: Songran
authors: S
authors: Yang
authors: Department of Cardiovascular Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors: Ping
authors: P
authors: Hua
authors: Department of Neurology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.
authors: Xinyuan
authors: X
authors: Shang
authors: State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
authors: Zaixu
authors: Z
authors: Cui
authors: State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
authors: Suyu
authors: S
authors: Zhong
authors: State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
authors: Gaolang
authors: G
authors: Gong
authors: Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
authors: Glyn W
authors: GW
authors: Humphreys
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D003866:Depressive Disorder / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009434:Neural Pathways / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications / Q000453:epidemiology / Q000473:pathology*