title: Resting-state hippocampal connectivity correlates with symptom severity in post-traumatic stress disorder.
abstract: Post-traumatic stress disorder (PTSD) is a serious mental health injury which can manifest after experiencing a traumatic life event. The disorder is characterized by symptoms of re-experiencing, avoidance, emotional numbing and hyper-arousal. Whilst its aetiology and resultant symptomology are better understood, relatively little is known about the underlying cortical pathophysiology, and in particular whether changes in functional connectivity may be linked to the disorder. Here, we used non-invasive neuroimaging with magnetoencephalography to examine functional connectivity in a resting-state protocol in the combat-related PTSD group (n = 23), and a military control group (n = 21). We identify atypical long-range hyperconnectivity in the high-gamma-band resting-state networks in a combat-related PTSD population compared to soldiers who underwent comparable environmental exposure but did not develop PTSD. Using graph analysis, we demonstrate that apparent network connectivity of relevant brain regions is associated with cognitive-behavioural outcomes. We also show that left hippocampal connectivity in the PTSD group correlates with scores on the well-established PTSD Checklist (PCL). These findings indicate that atypical synchronous neural interactions may underlie the psychological symptoms of PTSD, whilst also having utility as a potential biomarker to aid in the diagnosis and monitoring of the disorder.
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada ; Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.
authors.forename: B T
authors.initials: BT
authors.lastname: Dunkley
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada ; Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada ; Department of Medical Imaging, University of Toronto, Toronto, Canada ; Department of Psychology, University of Toronto, Toronto, Canada.
authors.forename: S M
authors.initials: SM
authors.lastname: Doesburg
authors.affiliation: Directorate of Mental Health, Canadian Forces Health Services, Ottawa, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: Sedge
authors.affiliation: Canadian Forces Environmental Medicine Establishment, Toronto, Canada.
authors.forename: R J
authors.initials: RJ
authors.lastname: Grodecki
authors.affiliation: Defence Research and Development Canada, Toronto, Canada.
authors.forename: P N
authors.initials: PN
authors.lastname: Shek
authors.affiliation: Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada ; Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: E W
authors.initials: EW
authors.lastname: Pang
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada ; Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada ; Department of Medical Imaging, University of Toronto, Toronto, Canada ; Department of Psychology, University of Toronto, Toronto, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Taylor
mesh_terms: D000328:Adult; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009434:Neural Pathways / Q000503:physiopathology*; D012146:Rest; D012815:Signal Processing, Computer-Assisted; D013313:Stress Disorders, Post-Traumatic / Q000503:physiopathology*; D055815:Young Adult
keywords: Functional connectivity; Magnetoencephalography (MEG); Neural network; Post-traumatic stress disorder; Resting-state