Association among anterior cingulate cortex volume, psychophysiological response, and PTSD diagnosis in a Veteran sample

• Main Authors: Chao, L. (Author), Inslicht, S.S (Author), Metzler, T.J (Author), Neylan, T.C (Author), O'Donovan, A. (Author), Young, D.A (Author)
• Format: Article
• Language: English
• Published: Academic Press Inc. 2018
• Subjects: Acoustic Stimulation; adult; Adult; anterior cingulate; anxiety assessment; Article; auditory stimulation; Biological markers; blinking; Blinking; brain size; cingulate gyrus; Clinician Administered PTSD Scale; conditioned reflex; Conditioning, Classical; Cross-Sectional Studies; cross-sectional study; diagnostic imaging; electric shock; electrodermal response; Electroshock; fear; Fear; female; Female; Galvanic Skin Response; Gulf War; Gyrus Cinguli; Habituation; heart rate; Heart Rate; human; Humans; image processing; Magnetic Resonance Imaging; major clinical study; male; Male; middle aged; Middle Aged; Neuroimaging; nuclear magnetic resonance imaging; pathology; pathophysiology; Persian Gulf syndrome; physiology; posttraumatic stress disorder; psychophysiology; PTSD/Posttraumatic Stress Disorder; Reflex, Startle; Startle; startle reflex; Stress Disorders, Post-Traumatic; Trauma; veteran; Veterans; war
• Online Access: View Fulltext in Publisher

 Posttraumatic stress disorder (PTSD) is associated with fear response system dysregulation. Research has shown that the anterior cingulate cortex (ACC) may modulate the fear response and that individuals with PTSD have abnormalities in ACC structure and functioning. Our objective was to assess whether ACC volume moderates the relationship between PTSD and fear-potentiated psychophysiological response in a sample of Gulf War Veterans. 142 Veteran participants who were associated with a larger study associated with Gulf War Illness were exposed to no threat, ambiguous threat, and high threat conditions in a fear conditioned startle response paradigm and also provided MRI imaging data. PTSD was assessed using the Clinician Administered PTSD Scale (CAPS). Decreased caudal ACC volume predicted greater psychophysiological responses with a slower habituation of psychophysiological magnitudes across trials (p < 0.001). PTSD diagnosis interacted significantly with both caudal and rostral ACC volumes on psychophysiological response magnitudes, where participants with PTSD and smaller rostral and caudal ACC volumes had greater psychophysiological magnitudes across trials (p < 0.05 and p < 0.001, respectively) and threat conditions (p < 0.05 and p < 0.005). Our results suggest that ACC volume may moderate both threat sensitivity and threat response via impaired habituation in individuals who have been exposed to traumatic events. More research is needed to assess whether ACC size and these associated response patterns are due to neurological processes resulting from trauma exposure or if they are indicative of a premorbid risk for PTSD subsequent to trauma exposure. © 2018 Elsevier Inc.