title: Biological vulnerability to depression: linked structural and functional brain network findings.
abstract: BACKGROUND
  Patients in recovery following episodes of major depressive disorder (MDD) remain highly vulnerable to future recurrence. Although psychological determinants of this risk are well established, little is known about associated biological mechanisms. Recent work has implicated the default mode network (DMN) in this vulnerability but specific hypotheses remain untested within the high risk, recovered state of MDD.
  
  
  OBJECTIVE
  To test the hypothesis that there is excessive DMN functional connectivity during task performance within recovered-state MDD and to test for connected DMN cortical gyrification abnormalities.
  
  
  METHODS
  A multimodal structural and functional magnetic resonance imaging (fMRI) study, including task-based functional connectivity and cortical folding analysis, comparing 20 recovered-state patients with MDD with 20 matched healthy controls.
  
  
  RESULTS
  The MDD group showed significant task-based DMN hyperconnectivity, associated with hypogyrification of key DMN regions (bilateral precuneus).
  
  
  CONCLUSIONS
  This is the first evidence of connected structural and functional DMN abnormalities in recovered-state MDD, supporting recent hypotheses on biological-level vulnerability.
authors.affiliation: N. L. Nixon, MBBS, MRCPsych, MMedSci, P. F. Liddle, BMBCh, MRCPsych, PhD, E. Nixon, PhD, G. Worwood, MBBCh, MRCPsych, MMedSci, Division of Psychiatry and Applied Psychology, Institute of Mental Health, University of Nottingham, Nottingham, UK; M. Liotti, MD, PhD, Department of Psychology, Simon Fraser University, Burnaby, Canada; L. Palaniyappan, MBBS, MRCPsych, PhD, Centre for Translational Neuroimaging, Division of Psychiatry and Applied Psychology, Institute of Mental Health, University of Nottingham, Nottingham, UK.
authors.forename: N L
authors.initials: NL
authors.lastname: Nixon
authors.forename: P F
authors.initials: PF
authors.lastname: Liddle
authors.forename: E
authors.initials: E
authors.lastname: Nixon
authors.forename: G
authors.initials: G
authors.lastname: Worwood
authors.forename: M
authors.initials: M
authors.lastname: Liotti
authors.forename: L
authors.initials: L
authors.lastname: Palaniyappan
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D003865:Major Depressive Disorder / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology*; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D059906:Neuroimaging; D055815:Young Adult