Posttraumatic stress symptomatology rather than mild traumatic brain injury is related to atypical early neural processing during cognitive control.

Many veterans with posttraumatic stress disorder (PTSD) or a history of mild traumatic brain injury (mTBI) report disruptions in cognition; however, the neurophysiological underpinnings of these cognitive difficulties are not well understood. It is also unknown whether PTSD symptomatology or past mTBIs uniquely impact functions important to adaptation such as cognitive control. We examined event-related potentials elicited by a flanker task to evaluate brain responses during conflict monitoring in a sample of 192 U.S. military veterans with combat-zone experience and exposure to explosive blasts. Clinical assessments characterized diagnoses as well as the severity of PTSD symptoms and mTBI so that we could parse overlapping syndromes and directly contrast effects of the two conditions. Across groups, participants performed worse on conflict trials (Incongruent distractors), particularly when preceded by a no-conflict (Congruent distractors) trial. We found that greater dysphoric PTSD symptomatology was related to a reduced early perceptual response (P1), while greater avoidance PTSD symptomatology predicted a larger early visual attention response (N1). Although late cognitive processes (N2, P3) were sensitive to cognitive control demands of the flanker task, posttraumatic symptomatology and mTBI severity were unrelated to them. Results provide evidence that the Avoidance and Dysphoria domains of PTSD symptomatology may differentially relate to early neural functions of perception and visual attention rather than later cognitive responses. Rehabilitation and treatment of individuals with PTSD and mTBI may be most productive when focused on perceptual and attentional processing, which could improve cognitive control. (PsycInfo Database Record (c) 2025 APA, all rights reserved).