Learning theories of posttraumatic stress disorder (PTSD) purport that fear-learning processes, such as those that support fear acquisition and extinction, are impaired. Computational models designed to capture specific processes involved in fear learning have primarily assessed model-free, or trial-and-error, reinforcement learning (RL). Although previous studies indicated that aspects of model-free RL are disrupted among individuals with PTSD, research has yet to identify whether model-based RL, which is inferential and contextually driven, is impaired. Given empirical evidence of aberrant contextual modulation of fear in PTSD, the present study sought to identify whether model-based RL processes are altered during fear conditioning among women with interpersonal violence (IPV)-related PTSD (n = 85) using computational modeling. Model-free, hybrid, and model-based RL models were applied to skin conductance responses (SCR) collected during fear acquisition and extinction, and the model-based RL model was found to provide the best fit to the SCR data. Parameters from the model-based RL model were carried forward to neuroimaging analyses (voxel-wise and independent component analysis). Results revealed that reduced activity within visual processing regions during model-based updating uniquely predicted higher PTSD symptoms. Additionally, after controlling for model-based updating, greater value estimation encoding within the left frontoparietal network during fear acquisition and reduced value estimation encoding within the dorsomedial prefrontal cortex during fear extinction predicted greater PTSD symptoms. Results provide evidence of disrupted RL processes in women with assault-related PTSD, which may contribute to impaired fear and safety learning, and, furthermore, may relate to treatment response (e.g., poorer response to exposure therapy).

创伤后应激障碍 (PTSD) 的学习理论声称，恐惧学习过程（例如支持恐惧获得和消退的过程）受到损害。旨在捕获恐惧学习中涉及的特定过程的计算模型主要评估了无模型或反复试验的强化学习 (RL)。尽管之前的研究表明，在患有 PTSD 的个体中，无模型强化学习的某些方面受到了干扰，但研究尚未确定基于模型的强化学习（推理和情境驱动）是否受损。鉴于 PTSD 中恐惧的异常情境调节的经验证据，本研究试图使用计算模型来确定基于模型的 RL 过程是否在患有人际暴力 (IPV) 相关 PTSD 的女性 (n = 85) 的恐惧调节过程中发生了改变。无模型，混合和基于模型的 RL 模型应用于恐惧获取和消退期间收集的皮肤电导反应 (SCR)，并且发现基于模型的 RL 模型最适合 SCR 数据。来自基于模型的 RL 模型的参数被用于神经影像学分析（体素分析和独立成分分析）。结果显示，在基于模型的更新过程中，视觉处理区域内的活动减少可以独特地预测更高的 PTSD 症状。此外，在控制基于模型的更新后，恐惧获取期间左额顶叶网络内更大的价值估计编码和恐惧消退期间背内侧前额叶皮层内减少的价值估计编码预测更严重的 PTSD 症状。