title: The Dissociative Subtype of Posttraumatic Stress Disorder: Unique Resting-State Functional Connectivity of Basolateral and Centromedial Amygdala Complexes.
abstract: Previous studies point towards differential connectivity patterns among basolateral (BLA) and centromedial (CMA) amygdala regions in patients with posttraumatic stress disorder (PTSD) as compared with controls. Here we describe the first study to compare directly connectivity patterns of the BLA and CMA complexes between PTSD patients with and without the dissociative subtype (PTSD+DS and PTSD-DS, respectively). Amygdala connectivity to regulatory prefrontal regions and parietal regions involved in consciousness and proprioception were expected to differ between these two groups based on differential limbic regulation and behavioral symptoms. PTSD patients (n=49) with (n=13) and without (n=36) the dissociative subtype and age-matched healthy controls (n=40) underwent resting-state fMRI. Bilateral BLA and CMA connectivity patterns were compared using a seed-based approach via SPM Anatomy Toolbox. Among patients with PTSD, the PTSD+DS group exhibited greater amygdala functional connectivity to prefrontal regions involved in emotion regulation (bilateral BLA and left CMA to the middle frontal gyrus and bilateral CMA to the medial frontal gyrus) as compared with the PTSD-DS group. In addition, the PTSD+DS group showed greater amygdala connectivity to regions involved in consciousness, awareness, and proprioception-implicated in depersonalization and derealization (left BLA to superior parietal lobe and cerebellar culmen; left CMA to dorsal posterior cingulate and precuneus). Differences in amygdala complex connectivity to specific brain regions parallel the unique symptom profiles of the PTSD subgroups and point towards unique biological markers of the dissociative subtype of PTSD.
authors: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors: Andrew A
authors: AA
authors: Nicholson
authors: Lawson Health Research Institute, London, Ontario, Canada.
authors: Maria
authors: M
authors: Densmore
authors: Lawson Health Research Institute, Western University, London, Ontario, Canada.
authors: Paul A
authors: PA
authors: Frewen
authors: Department of Diagnostic Imaging, St Joseph's Health Care London, Departments of Medical Imaging, Medical Biophysics and Psychiatry, Western University, London, Ontario, Canada.
authors: Jean
authors: J
authors: Théberge
authors: Departments of Psychology and Psychiatry, Neuroscience Program, Western University, London, Ontario, Canada.
authors: Richard Wj
authors: RW
authors: Neufeld
authors: McMaster University, St Joseph's Healthcare Hamilton, Homewood Research Institute, Hamilton, Ontario, Canada.
authors: Margaret C
authors: MC
authors: McKinnon
authors: Lawson Health Research Institute, Western University, London, Ontario, Canada.
authors: Ruth A
authors: RA
authors: Lanius
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D066272:Basolateral Nuclear Complex / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D016022:Case-Control Studies; D066276:Corticomedial Nuclear Complex / Q000098:blood supply / Q000502:physiology*; D004213:Dissociative Disorders / Q000209:etiology / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000098:blood supply / Q000502:physiology*; D012146:Rest; D012189:Retrospective Studies; D013313:Stress Disorders, Post-Traumatic / Q000145:classification* / Q000473:pathology*