title: White matter microstructure of the uncinate fasciculus is associated with subthreshold posttraumatic stress disorder symptoms and fear potentiated startle during early extinction in recently deployed Service Members.
abstract: Early intervention following combat deployment has the potential to prevent posttraumatic stress disorder (PTSD), but there is a need for greater understanding of the factors that contribute to PTSD symptom progression. This study investigated: (1) fear-potentiated startle during a fear extinction, (2) white matter microstructure, and (3) PTSD symptom severity, in 48 recently deployed service members (SMs) who did not have sufficient PTSD symptoms to meet criteria for a clinical diagnosis. Electromyography startle during a conditional discrimination paradigm, diffusion tensor imaging, and the Clinician Administered PTSD Scale were assessed in a cohort of SMs within 2 months after their return from Iraq or Afghanistan. Significant correlations were found between left uncinate fasciculus (UF) white matter tract integrity and total PTSD symptoms, r=-0.343, p=0.018; the left UF and hyperarousal symptoms, r=-0.29, p=0.047; right UF integrity and total PTSD symptoms r=-0.3371, p=0.01; right UF integrity and hyperarousal symptoms r=-0.332, p=0.023; left UF and startle during early extinction, r=.31, p=0.033. Our results indicate that compromise of UF tract frontal-limbic connections are associated with greater PTSD symptom severity and lower startle response during extinction. In a subthreshold population, such a relationship between brain structure, physiological reactivity, and behavioral expression may reveal vulnerabilities that could have significant implications for PTSD symptom development.
authors.affiliation: Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; The Henry M. Jackson Foundation, Bethesda, MD, USA; Center for Neuroscience and Regenerative Medicine, Bethesda, MD, USA.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Costanzo
authors.affiliation: Emory University School of Medicine, Department of Psychiatry & Behavioral Sciences, Atlanta, GA, USA.
authors.forename: Tanja
authors.initials: T
authors.lastname: Jovanovic
authors.affiliation: Image Processing Core, Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation, 10 Center Drive, Bethesda, MD, USA.
authors.forename: Dzung
authors.initials: D
authors.lastname: Pham
authors.affiliation: Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Leaman
authors.affiliation: Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; The Henry M. Jackson Foundation, Bethesda, MD, USA; Center for Neuroscience and Regenerative Medicine, Bethesda, MD, USA.
authors.forename: Krista B
authors.initials: KB
authors.lastname: Highland
authors.affiliation: Emory University School of Medicine, Department of Psychiatry & Behavioral Sciences, Atlanta, GA, USA; Mental Health Service Line, Atlanta Veterans' Affairs Medical Center, Decatur, GA, USA.
authors.forename: Seth Davin
authors.initials: SD
authors.lastname: Norrholm
authors.affiliation: Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Center for Neuroscience and Regenerative Medicine, Bethesda, MD, USA. Electronic address: michael.roy@usuhs.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Roy
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging; D005108:Extinction, Psychological; D005239:Fear; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013216:Reflex, Startle; D013313:Stress Disorders, Post-Traumatic / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D014463:Ultrasonography; D014728:Veterans; D000067453:War Exposure; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: Combat veterans; Diffusion tensor imaging; Fear-potentiated startle; Subthreshold PTSD