Electrophysiological Markers of Proactive and Reactive Cognitive Processing in Post-Traumatic Stress Disorder.

Background: Post-Traumatic Stress Disorder (PTSD) is associated with well-documented alterations in reactive brain processing of stimuli or events, whereas little is known about proactive/anticipatory neural dynamics preceding and preparing for task execution. This study aimed to investigate both proactive and reactive brain control of PTSD patients during a cognitive task, using the event-related potential (ERP) method. Methods: Twenty-one PTSD patients were matched to thirty healthy controls. Proactive ERP components, such as the Bereitschaftspotential (BP), prefrontal Negativity (pN), and visual Negativity (vN), were analysed to assess motor, cognitive, and sensory preparation, respectively. Reactive components such as the P1, N1, and P3 were also analysed to evaluate perceptual, attentional, and decisional processes, respectively. Results: Results revealed in PTSD patients a marked reduction in the amplitudes of all anticipatory components, suggesting a generalized impairment of top-down control in task preparation. Analysis of post-stimulus reactive processing revealed no group differences in early components associated with perceptual and attentional processing (P1, N1), but a reduction of the P3 in the PTSD group, indicating impaired higher-order cognitive processing related to decision-making and task closure. Behaviourally, patients exhibited longer and more variable response times, although accuracy remained unaffected, consistent with a speed-accuracy trade-off. Conclusions: To our knowledge, this is the first ERP study to examine anticipatory brain activity in PTSD through the BP, pN, and vN components. These results provide evidence of widespread proactive processing deficits in PTSD, consistent with previous reports of altered functioning within prefrontal, cingulate, and visual association networks. Moreover, anticipatory ERP components may represent promising neurophysiological markers for the assessment of cognitive dysfunction in PTSD.