title: Combat veterans with comorbid PTSD and mild TBI exhibit a greater inhibitory processing ERP from the dorsal anterior cingulate cortex.
abstract: Posttraumatic stress disorder (PTSD) is common among combat personnel with mild traumatic brain injury (mTBI). While patients with either PTSD or mTBI share abnormal activation of multiple frontal brain areas, anterior cingulate cortex (ACC) activity during inhibitory processing may be particularly affected by PTSD. To further test this hypothesis, we recorded electroencephalography from 32 combat veterans with mTBI-17 of whom were also comorbid for PTSD (mTBI+PTSD) and 15 without PTSD (mTBI-only). Subjects performed the Stop Task, a validated inhibitory control task requiring inhibition of initiated motor responses. We observed a larger inhibitory processing eventrelated potential (ERP) in veterans with mTBI+PTSD, including greater N200 negativity. Furthermore, greater N200 negativity correlated with greater PTSD severity. This correlation was most dependent on contributions from the dorsal ACC. Support vector machine analysis demonstrated that N200 and P300 amplitudes objectively classified veterans into mTBI-only or mTBI+PTSD groups with 79.4% accuracy. Our results support a model where, in combat veterans with mTBI, larger ERPs from cingulate areas are associated with greater PTSD severity and likely related to difficulty controlling ongoing brain processes, including trauma-related thoughts and feelings.
authors.affiliation: VISN-22 Mental Illness, Research, Education and Clinical Center, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States; Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States. Electronic address: ishu@ucsd.edu.
authors.forename: I-Wei
authors.initials: IW
authors.lastname: Shu
authors.affiliation: Naval Health Research Center, 140 Sylvester Road, Department162, San Diego, CA 92106, United States; Institute for Neural Computation, University of California San Diego, 9500 Gilman Drive, #0523, La Jolla, CA 92093, United States.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Onton
authors.affiliation: Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States; Department of Psychiatry, University of California San Diego, 9500 Gilman Drive, #9116A, La Jolla, CA 92037, United States.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: O'Connell
authors.affiliation: Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States; Veterans Affairs San Diego Healthcare System Center of Excellence for Stress and Mental Health, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States.
authors.forename: Alan N
authors.initials: AN
authors.lastname: Simmons
authors.affiliation: VISN-22 Mental Illness, Research, Education and Clinical Center, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States; Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States; Department of Psychiatry, University of California San Diego, 9500 Gilman Drive, #9116A, La Jolla, CA 92037, United States; Veterans Affairs San Diego Healthcare System Center of Excellence for Stress and Mental Health, 3350 La Jolla Village Drive, #116A, San Diego, CA 92161, United States.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Matthews
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D015897:Comorbidity; D004569:Electroencephalography; D004644:Emotions; D005071:Evoked Potentials; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D013850:Thinking; D014481:United States / Q000453:epidemiology; D014728:Veterans / Q000523:psychology / Q000706:statistics & numerical data
keywords: Biomarker; Conflict monitoring; N200; P300; Response inhibition