Exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD), but many patients do not respond. Brain functions governing treatment outcome are not well characterized. The authors examined brain systems relevant to emotional reactivity and regulation, constructs that are thought to be central to PTSD and exposure therapy effects, to identify the functional traits of individuals most likely to benefit from treatment.

Individuals with PTSD underwent functional MRI (fMRI) while completing three tasks assessing emotional reactivity and regulation. Participants were then randomly assigned to immediate prolonged exposure treatment (N=36) or a waiting list condition (N=30). A random subset of the prolonged exposure group (N=17) underwent single-pulse transcranial magnetic stimulation (TMS) concurrent with fMRI to examine whether predictive activation patterns reflect causal influence within circuits. Linear mixed-effects modeling in line with the intent-to-treat principle was used to examine how baseline brain function moderated the effect of treatment on PTSD symptoms.

At baseline, individuals with larger treatment-related symptom reductions (compared with the waiting list condition) demonstrated 1) greater dorsal prefrontal activation and 2) less left amygdala activation, both during emotion reactivity; 3) better inhibition of the left amygdala induced by single TMS pulses to the right dorsolateral prefrontal cortex; and 4) greater ventromedial prefrontal/ventral striatal activation during emotional conflict regulation. Reappraisal-related activation was not a significant moderator of the treatment effect.

Capacity to benefit from prolonged exposure in PTSD is gated by the degree to which prefrontal resources are spontaneously engaged when superficially processing threat and adaptively mitigating emotional interference, but not when deliberately reducing negative emotionality.

暴露疗法是治疗创伤后应激障碍（PTSD）的有效方法，但许多患者没有反应。控制治疗结果的脑功能尚未很好地表征。作者检查了与情绪反应和调节有关的大脑系统，被认为对PTSD和暴露疗法的影响至关重要的结构，以确定最有可能从治疗中受益的人的功能特征。

患有PTSD的患者在完成三项评估情绪反应和调节的任务时接受了功能性MRI（fMRI）。然后将参与者随机分配到立即延长暴露治疗（N = 36）或等待名单条件（N = 30）。长时间暴露组（N = 17）的随机子集进行单脉冲经颅磁刺激（TMS），同时进行功能磁共振成像，以检查预测性激活模式是否反映电路内的因果关系。使用符合意向性治疗原则的线性混合效应模型来研究基线脑功能如何缓解治疗对PTSD症状的影响。

基线时，在情绪反应期间，与治疗相关的症状减轻程度更大（与等候清单条件相比）的个体表现出1）背侧前额叶激活更多，2）左杏仁核激活更少；3）单个TMS脉冲对右背外侧前额叶皮层更好地抑制了左杏仁核；4）在情绪冲突调节期间更大的腹膜前额叶/腹侧纹状体激活。重新评估相关的激活不是治疗效果的显着调节剂。

当从表面上处理威胁并适应性地减轻情感干扰时，自发地利用前额资源的程度决定了从长期暴露于PTSD中受益的能力，而当故意减少负面情感时则不然。