title: Increased gamma connectivity during working memory retention following traumatic brain injury.
abstract: Alterations to functional connectivity following a traumatic brain injury (TBI) may lead to impaired cognitive performance and major depressive disorder (MDD). In particular, functional gamma band connectivity is thought to reflect information binding important for working memory. The objective of this study was to determine whether altered functional gamma connectivity may be a factor in MDD following TBI (TBI-MDD).
  
  
  
  This study assessed individuals with TBI-MDD, as well as individuals with TBI alone and MDD alone using electroencephalographic recordings while participants performed a working memory task to assess differences in functional connectivity between these groups.
  
  
  
  Functional connectivity was compared using the debiased weighted phase lag index (wPLI). wPLI was measured from a group of healthy controls (n = 31), participants with MDD (n = 17), participants with TBI (n = 20) and participants with TBI-MDD (n = 15).
  
  
  
  Contrary to the predictions, this study found both the groups with TBI and TBI-MDD showed higher gamma connectivity from posterior regions during WM retention.
  
  
  
  This may reflect dysfunctional functional connectivity in these groups, as a result of maladaptive neuroplastic reorganization.
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Neil W
authors.initials: NW
authors.lastname: Bailey
authors.affiliation: b Monash Clinical and Imaging Neuroscience, School of Psychological Science and Monash Biomedical Imaging , Monash University , Melbourne , Australia.
authors.forename: Nigel C
authors.initials: NC
authors.lastname: Rogasch
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Hoy
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Jerome J
authors.initials: JJ
authors.lastname: Maller
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Segrave
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Caley M
authors.initials: CM
authors.lastname: Sullivan
authors.affiliation: a Monash Alfred Psychiatry Research Centre , Alfred Hospital and Central Clinical School, Monash University , Melbourne , VIC , Australia.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
mesh_terms: D000328:Adult; D000070642:Brain Injuries, Traumatic / Q000150:complications* / Q000503:physiopathology*; D001931:Brain Mapping; D003865:Major Depressive Disorder / Q000150:complications / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology* / Q000503:physiopathology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
keywords: EEG connectivity; Gamma; major depression; traumatic brain injury