title: Resting-state functional magnetic resonance imaging activity and connectivity and cognitive outcome in traumatic brain injury.
abstract: OBJECTIVE
  The study of brain activity and connectivity at rest provides a unique opportunity for the investigation of the brain substrates of cognitive outcome after traumatic axonal injury. This knowledge may contribute to improve clinical management and rehabilitation programs.
  
  
  OBJECTIVE
  To study functional magnetic resonance imaging abnormalities in signal amplitude and brain connectivity at rest and their relationship to cognitive outcome in patients with chronic and severe traumatic axonal injury.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  University of Barcelona and Hospital Clinic de Barcelona, Barcelona, and Institut Guttmann-Neurorehabilitation Hospital, Badalona, Spain.
  
  
  METHODS
  Twenty patients with traumatic brain injury (TBI) were studied, along with 17 matched healthy volunteers.
  
  
  METHODS
  Resting-state functional magnetic resonance imaging and diffusion tensor imaging data were acquired. After exploring group differences in amplitude of low-frequency fluctuations (ALFF), we studied functional connectivity within the default mode network (DMN) by means of independent component analysis, followed by a dual regression approach and seed-based connectivity analyses. Finally, we performed probabilistic tractography between the frontal and posterior nodes of the DMN.
  
  
  METHODS
  Signal amplitude and functional connectivity during the resting state, tractography related to DMN, and the association between signal amplitudes and cognitive outcome.
  
  
  RESULTS
  Patients had greater ALFF in frontal regions, which was correlated with cognitive performance. Within the DMN, patients showed increased connectivity in the frontal lobes. Seed-based connectivity analyses revealed augmented connectivity within surrounding areas of the frontal and left parietal nodes of the DMN. Fractional anisotropy of the cingulate tract was correlated with increased connectivity of the frontal node of the DMN in patients with TBI.
  
  
  CONCLUSIONS
  Increased ALFF is related to better cognitive performance in chronic TBI. The loss of structural connectivity produced by damage to the cingulum tract explained the compensatory increases in functional connectivity within the frontal node of the DMN.
authors.affiliation: August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Palacios
authors.forename: Roser
authors.initials: R
authors.lastname: Sala-Llonch
authors.forename: Carme
authors.initials: C
authors.lastname: Junque
authors.forename: Teresa
authors.initials: T
authors.lastname: Roig
authors.forename: Jose M
authors.initials: JM
authors.lastname: Tormos
authors.forename: Nuria
authors.initials: N
authors.lastname: Bargallo
authors.forename: Pere
authors.initials: P
authors.lastname: Vendrell
mesh_terms: D000328:Adult; D016880:Anisotropy; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology; D020833:Diffuse Axonal Injury / Q000473:pathology / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006179:Gyrus Cinguli / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009415:Nerve Net / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000473:pathology / Q000503:physiopathology; D055815:Young Adult