title: Is Traumatic Brain Injury Associated with Reduced Inter-Hemispheric Functional Connectivity? A Study of Large-Scale Resting State Networks following Traumatic Brain Injury.
abstract: Traumatic brain injury (TBI) often has long-term debilitating sequelae in cognitive and behavioral domains. Understanding how TBI impacts functional integrity of brain networks that underlie these domains is key to guiding future approaches to TBI rehabilitation. In the current study, we investigated the differences in inter-hemispheric functional connectivity (FC) of resting state networks (RSNs) between chronic mild-to-severe TBI patients and normal comparisons (NC), focusing on two externally oriented networks (i.e., the fronto-parietal network [FPN] and the executive control network [ECN]), one internally oriented network (i.e., the default mode network [DMN]), and one somato-motor network (SMN). Seed voxel correlation analysis revealed that TBI patients displayed significantly less FC between lateralized seeds and both homologous and non-homologous regions in the opposite hemisphere for externally oriented networks but not for DMN or SMN; conversely, TBI patients showed increased FC within regions of the DMN, especially precuneus and parahippocampal gyrus. Region of interest correlation analyses confirmed the presence of significantly higher inter-hemispheric FC in NC for the FPN (p < 0.01), and ECN (p < 0.05), but not for the DMN (p > 0.05) or SMN (p > 0.05). Further analysis revealed that performance on a neuropsychological test measuring organizational skills and visuo-spatial abilities administered to the TBI group, the Rey-Osterrieth Complex Figure Test, positively correlated with FC between the right FPN and homologous regions. Our findings suggest that distinct RSNs display specific patterns of aberrant FC following TBI; this represents a step forward in the search for biomarkers useful for early diagnosis and treatment of TBI-related cognitive impairment.
authors.affiliation: 1 Neuroscience Graduate Program, University of Iowa , Iowa City, Iowa.
authors.forename: Arianna
authors.initials: A
authors.lastname: Rigon
authors.affiliation: 1 Neuroscience Graduate Program, University of Iowa , Iowa City, Iowa.|2 Department of Communication Sciences and Disorders, University of Iowa , Iowa City, Iowa.|3 Department of Neurology, University of Iowa , Iowa City, Iowa.
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Duff
authors.affiliation: 5 The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Illinois.|6 Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign , Illinois.
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
authors.affiliation: 5 The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Illinois.
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
authors.affiliation: 1 Neuroscience Graduate Program, University of Iowa , Iowa City, Iowa.|4 Department of Psychological and Brain Sciences, University of Iowa , Iowa City, Iowa.
authors.forename: Michelle W
authors.initials: MW
authors.lastname: Voss
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000070642:Brain Injuries, Traumatic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D063132:Connectome; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: externally oriented networks; inter-hemispheric functional connectivity; internally oriented networks; resting state fMRI; traumatic brain injury