A pinboard by Gregory Fonzo
Postdoctoral Fellow, Stanford University School of Medicine
The intrinsic functional connectivity patterns of the resting brain change following PTSD treatment.
Post-traumatic stress disorder (PTSD) is a debilitating psychiatric disorder characterized by abnormalities of brain function across numerous domains, including the processing of emotional stimuli, threat, and memory functions. These abnormalities parallel symptoms observed in the clinical disorder, i.e. emotional dysregulation, hypervigilance to threat, and intrusive traumatic memories. However, PTSD is also characterized by a disruption of intrinsic functional connectivity patterns that characterize the brain at rest. Although not directly engaged in mental functions, participants at rest inside an MRI scanner demonstrate coherent resting state brain networks that parallel functional segregation during task completion. Abnormalities of these resting brain networks have also been detected in PTSD, primarily encompassing abnormal connectivity patterns of limbic and paralimbic structures involved in threat detection and emotion generation, i.e. the amygdala and insula. Exposure-based psychotherapy for PTSD, such as prolonged exposure, is empirically-supported and is the most effective treatment in our current therapeutic armamentarium. However, the way in which such treatments impact brain function during completion of emotional/cognitive processes, much less resting state dynamics, is largely unknown and not well characterized. We employed a randomized clinical trial design to investigate the brain mechanisms underlying therapeutic effects of prolonged exposure therapy in adults with PTSD. Thirty-six individuals were randomized to immediate psychotherapy treatment with 9 to 12 once or bi-weekly sessions of prolonged exposure, and thirty individuals were randomized to a psychotherapy waitlist condition for a comparable period of time. We investigated resting state connectivity patterns of the brain using functional magnetic resonance imaging (fMRI) and how these patterns changed one month following treatment cessation. We observed striking changes in the intrinsic connectivity of limbic and paralimbic structures with widespread and diffuse cortical and subcortical regions, demonstrating that exposure-based psychotherapy for PTSD specifically alters functional brain dynamics in states absent of task demands and devoid of emotional provocation. These findings demonstrate that the effects of psychotherapy on the brain in PTSD are pervasive and generalize to environmental contexts seemingly unrelated to symptoms or treatment targets.
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