Posttraumatic stress disorder (PTSD) is marked by alterations in emotional functioning, physiological reactivity, and attention. Neural reactivity to acoustic startle stimuli can be used to understand brain functions related to these alterations. Investigations of startle reactivity in PTSD have yielded inconsistent findings, which may reflect the heterogeneity of the disorder. Furthermore, little is known of how the common co-occurrence of mild traumatic brain injury (mTBI; i.e., concussion) may influence neural reactivity. We examined the event-related potentials (ERPs) of combat veterans (n = 102) to acoustic startle probes delivered during viewing of pleasant, neutral, unpleasant, and combat-related pictures. Interview-based assessments yielded dimensional characterizations of PTSD and mTBI. The P3 ERP response to startle probes was reduced during all affective relative to neutral pictures but failed to be associated with a PTSD diagnosis. However, two separable domains of PTSD symptomatology were associated with startle ERPs regardless of the picture conditions. Maladaptive avoidance was associated with smaller N1, P2, and P3 amplitudes, while intrusive reexperiencing was associated with larger P2 amplitudes. There were no main effects of mTBI. Findings suggest that level of symptomatology rather than a formal diagnosis of PTSD better explains alterations in neural reactivity after traumatic events, while mild brain injuries have little impact. Avoidance symptoms of PTSD may dampen neural functions that facilitate reorientation to threat while intrusive reexperiencing of traumatic events appears to heighten sensory reactivity. Considering specific aspects of symptomatology provides insight into the neural basis of trauma-related psychopathology and may help guide individualization of clinical interventions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

中文翻译：

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退伍军人的创伤后应激症状维度和大脑对惊人听觉刺激的反应。

创伤后应激障碍 (PTSD) 的特征是情绪功能、生理反应性和注意力的改变。对声惊吓刺激的神经反应可用于了解与这些改变相关的大脑功能。对 PTSD 惊吓反应性的调查得出了不一致的结果，这可能反映了该疾病的异质性。此外，对于轻度创伤性脑损伤 (mTBI；即脑震荡) 的常见共同发生如何影响神经反应性知之甚少。我们检查了退伍军人 (n = 102) 的事件相关电位 (ERP) 在观看愉快、中性、不愉快和与战斗相关的图片时传递的声惊吓探针。基于访谈的评估产生了 PTSD 和 mTBI 的维度特征。相对于中性图片，P3 ERP 对惊吓探针的反应在所有情感过程中都减少了，但未能与 PTSD 诊断相关联。然而，无论图片条件如何，PTSD 症状学的两个可分离领域都与惊吓 ERP 相关。适应不良回避与较小的 N1、P2 和 P3 振幅相关，而侵入性再体验与较大的 P2 振幅相关。mTBI 没有主要影响。研究结果表明，症状学水平而不是 PTSD 的正式诊断更好地解释了创伤事件后神经反应性的改变，而轻度脑损伤几乎没有影响。PTSD 的回避症状可能会抑制有助于重新定位威胁的神经功能，而创伤事件的侵入性重新体验似乎会增强感官反应。考虑症状学的特定方面可以深入了解创伤相关精神病理学的神经基础，并可能有助于指导临床干预的个体化。（PsycInfo 数据库记录 (c) 2021 APA，保留所有权利）。