Post-traumatic stress disorder (PTSD) is a psychiatric disorder often characterized by the unwanted re-experiencing of a traumatic event through nightmares, flashbacks, and/or intrusive memories. This paper presents a neurocomputational model using the ACT-R cognitive architecture that simulates intrusive memory retrieval following a potentially traumatic event (PTE) and predicts hippocampal volume changes observed in PTSD. Memory intrusions were captured in the ACT-R rational analysis framework by weighting the posterior probability of re-encoding traumatic events into memory with an emotional intensity term I to capture the degree to which an event was perceived as dangerous or traumatic. It is hypothesized that (1) increasing the intensity I of a PTE will increase the odds of memory intrusions, and (2) increased frequency of intrusions will result in a concurrent decrease in hippocampal size. A series of simulations were run and it was found that I had a significant effect on the probability of experiencing traumatic memory intrusions following a PTE. The model also found that I was a significant predictor of hippocampal volume reduction, where the mean and range of simulated volume loss match results of existing meta-analyses. The authors believe that this is the first model to both describe traumatic memory retrieval and provide a mechanistic account of changes in hippocampal volume, capturing one plausible link between PTSD and hippocampal volume.

中文翻译：

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当恐惧使大脑萎缩时：创伤后压力对海马体积影响的计算模型

创伤后应激障碍 (PTSD) 是一种精神疾病，其特征通常是通过噩梦、闪回和/或侵入性记忆重新体验创伤事件。本文提出了一种使用 ACT-R 认知架构的神经计算模型，该模型模拟潜在创伤性事件 (PTE) 后的侵入性记忆检索，并预测在 PTSD 中观察到的海马体积变化。在 ACT-R 理性分析框架中，通过用情绪强度项I加权将创伤性事件重新编码到记忆中的后验概率来捕捉记忆​​入侵，以捕获事件被认为是危险或创伤性的程度。假设 (1) 增加强度IPTE 会增加记忆入侵的几率，(2) 增加入侵频率会导致海马体大小同时减少。运行了一系列模拟，发现我对 PTE 后经历创伤性记忆入侵的可能性有显着影响。该模型还发现I是海马体积减少的重要预测因子，其中模拟体积减少的平均值和范围与现有荟萃分析的结果相匹配。作者认为，这是第一个既描述创伤性记忆提取又提供海马体积变化的机械解释的模型，捕捉了 PTSD 和海马体积之间的一个似是而非的联系。