title: Default-mode network disruption in mild traumatic brain injury.
abstract: OBJECTIVE
  To investigate the integrity of the default-mode network (DMN) by using independent component analysis (ICA) methods in patients shortly after mild traumatic brain injury (MTBI) and healthy control subjects, and to correlate DMN connectivity changes with neurocognitive tests and clinical symptoms.
  
  
  METHODS
  This study was approved by the institutional review board and complied with HIPAA regulations. Twenty-three patients with MTBI who had posttraumatic symptoms shortly after injury (<2 months) and 18 age-matched healthy control subjects were included in this study. Resting-state functional magnetic resonance imaging was performed at 3 T to characterize the DMN by using ICA methods, including a single-participant ICA on the basis of a comprehensive template from core seeds in the posterior cingulate cortex (PCC) and medial prefrontal cortex (MPFC) nodes. ICA z images of DMN components were compared between the two groups and correlated with neurocognitive tests and clinical performance in patients by using Pearson and Spearman rank correlation.
  
  
  RESULTS
  When compared with the control subjects, there was significantly reduced connectivity in the PCC and parietal regions and increased frontal connectivity around the MPFC in patients with MTBI (P < .01). These frontoposterior opposing changes within the DMN were significantly correlated (r = -0.44, P = .03). The reduced posterior connectivity correlated positively with neurocognitive dysfunction (eg, cognitive flexibility), while the increased frontal connectivity correlated negatively with posttraumatic symptoms (ie, depression, anxiety, fatigue, and postconcussion syndrome).
  
  
  CONCLUSIONS
  These results showed abnormal DMN connectivity patterns in patients with MTBI, which may provide insight into how neuronal communication and information integration are disrupted among DMN key structures after mild head injury.
authors.affiliation: Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, 660 First Ave, 4th Floor, New York, NY 10016, USA.
authors.forename: Yongxia
authors.initials: Y
authors.lastname: Zhou
authors.forename: Michael P
authors.initials: MP
authors.lastname: Milham
authors.forename: Yvonne W
authors.initials: YW
authors.lastname: Lui
authors.forename: Laura
authors.initials: L
authors.lastname: Miles
authors.forename: Joseph
authors.initials: J
authors.lastname: Reaume
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
authors.forename: Robert I
authors.initials: RI
authors.lastname: Grossman
authors.forename: Yulin
authors.initials: Y
authors.lastname: Ge
mesh_terms: D000328:Adult; D016477:Artifacts; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006179:Gyrus Cinguli / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D016018:Least-Squares Analysis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009434:Neural Pathways / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests