title: Graph theory analysis of cortical-subcortical networks in late-life depression.
abstract: OBJECTIVE
  Late-life major depression (LLD) is characterized by distinct epidemiologic and psychosocial factors, as well as medical comorbidities that are associated with specific neuroanatomical differences. The purpose of this study was to use interregional correlations of cortical and subcortical volumes to examine cortical-subcortical structural network properties in subjects with LLD compared with healthy comparison subjects.
  
  
  METHODS
  This was a cross-sectional neuroimaging study conducted in the general community. We recruited 73 healthy elderly comparison subjects and 53 subjects with LLD who volunteered in response to advertisements. Brain network connectivity measures were generated by correlating regional volumes after controlling for age, gender, and intracranial volume by using the Brain Connectivity Toolbox.
  
  
  RESULTS
  Results for overall network strength revealed that LLD networks showed a greater magnitude of associations for both positive and negative correlation weights compared with healthy elderly networks. LLD networks also demonstrated alterations in brain network structure compared with healthy comparison subjects. LLD networks were also more vulnerable to targeted attacks compared with healthy elderly comparison subjects, and this vulnerability was attenuated when controlling for white matter alterations.
  
  
  CONCLUSIONS
  Overall, this study demonstrates that cortical-subcortical network properties are altered in LLD and may reflect the underlying neuroanatomical vulnerabilities of the disorder.
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL. Electronic address: oajilore@psych.uic.edu.
authors.forename: Olusola
authors.initials: O
authors.lastname: Ajilore
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Melissa
authors.initials: M
authors.lastname: Lamar
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Alex
authors.initials: A
authors.lastname: Leow
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Aifeng
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL; Department of Radiology, University of Illinois at Chicago, Chicago, IL.
authors.forename: Shaolin
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology*; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009434:Neural Pathways / Q000473:pathology; D059906:Neuroimaging
keywords: Connectivity; depression; geriatric; network analysis; neuroimaging