title: The rich get richer: brain injury elicits hyperconnectivity in core subnetworks.
abstract: There remains much unknown about how large-scale neural networks accommodate neurological disruption, such as moderate and severe traumatic brain injury (TBI). A primary goal in this study was to examine the alterations in network topology occurring during the first year of recovery following TBI. To do so we examined 21 individuals with moderate and severe TBI at 3 and 6 months after resolution of posttraumatic amnesia and 15 age- and education-matched healthy adults using functional MRI and graph theoretical analyses. There were two central hypotheses in this study: 1) physical disruption results in increased functional connectivity, or hyperconnectivity, and 2) hyperconnectivity occurs in regions typically observed to be the most highly connected cortical hubs, or the "rich club". The current findings generally support the hyperconnectivity hypothesis showing that during the first year of recovery after TBI, neural networks show increased connectivity, and this change is disproportionately represented in brain regions belonging to the brain's core subnetworks. The selective increases in connectivity observed here are consistent with the preferential attachment model underlying scale-free network development. This study is the largest of its kind and provides the unique opportunity to examine how neural systems adapt to significant neurological disruption during the first year after injury.
authors.affiliation: The Pennsylvania State University, Department of Psychology, University Park, Pennsylvania, United States of America.
authors.forename: Frank G
authors.initials: FG
authors.lastname: Hillary
authors.affiliation: The Pennsylvania State University, Department of Mathematics, University Park, Pennsylvania, United States of America.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Rajtmajer
authors.affiliation: The Pennsylvania State University, Department of Psychology, University Park, Pennsylvania, United States of America.
authors.forename: Cristina A
authors.initials: CA
authors.lastname: Roman
authors.affiliation: The Pennsylvania State University, Department of Psychology, University Park, Pennsylvania, United States of America.
authors.forename: John D
authors.initials: JD
authors.lastname: Medaglia
authors.affiliation: Hershey Medical Center, Department of Neurology, Hershey, Pennsylvania, United States of America.
authors.forename: Julia E
authors.initials: JE
authors.lastname: Slocomb-Dluzen
authors.affiliation: The Mind Research Network, Albuquerque, New Mexico, United States of America.
authors.forename: Vincent D
authors.initials: VD
authors.lastname: Calhoun
authors.affiliation: Hershey Medical Center, Department of Neurology, Hershey, Pennsylvania, United States of America.
authors.forename: David C
authors.initials: DC
authors.lastname: Good
authors.affiliation: Kessler Foundation Research Center, West Orange, New Jersey, United States of America.
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Wylie
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology / Q000503:physiopathology; D001930:Brain Injuries / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*