A critical test of the dual-representation account of PTSD

创伤后应激障碍（PTSD）双重表征解释的关键测试

• 批准号: ES/X005240/1
• 负责人: Deborah Talmi
• 金额: $ 80.34万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ES%2FX005240%2F1
• 关键词: critical; test; dual; representation; account

Despite the high prevalence of post-traumatic stress disorder (PTSD) and its debilitating consequences, current psychological treatments are not effective for everyone. There is a clear need to uncover the psychological mechanisms that trigger persistent, intrusive fear memories. Our proposal tackles a rift in research, where a dominant theory of PTSD - the dual representation account - appears to clash with established cognitive-computational models of normal memory, and is challenged by discrepancies in its empirical evidence base. We propose to put the theory to two critical tests. The dual representation account makes two fundamental claims. First, that trauma makes it hard to bind emotional stimuli to their spatiotemporal context, and therefore, the associations between emotional aspects of the trauma and neutral elements of the same episode are weakened. Second, that intrusive memories arise from a separate mechanism than do voluntary memories of the same trauma content - a consequence of the first claim. We challenge the dual representation account by testing these two core claims using laboratory models of trauma, where participants are presented with pictures and film clips that depict aversive content, such as injury and death. Until now, laboratory tests of the first claim involved studies where participants were presented with emotional and neutral stimuli, and then tested for their memory for the association between these stimuli. The interpretation of such tests is complicated because the results depend not only on the critical binding of these stimuli during encoding, but also on subsequent effects of emotion during maintenance and retrieval. We will eliminate these potential confounds by targeting the encoding stage. We adapt a tried-and-true learning task to study the effect of emotion on associative binding without contaminating the measurement by subsequent memory processes. Laboratory evidence for the second claim is a single behavioural dissociation between voluntary and involuntary memory, where only the latter is decreased when participants actively engage in visuospatial manipulations following trauma exposure. Although this dissociation has been demonstrated multiple times, there are differences between the way that previous experiments measured voluntary and involuntary memory that could explain the discrepancy. We offer a more tightly controlled experimental design to confirm this dissociation. We then introduce a manipulation with potential to increase voluntary memory only. If successful, the visuospatial task and our new manipulation will amount to a double dissociation between voluntary and involuntary memory and thus offer stronger support for the dual representation account. To date, the dual-representation account has been mostly been described in words. This makes it difficult to understand the proposed cognitive-computational mechanisms precisely. Mathematical models increase the clarity of theories and make it possible to make, and test, quantitative predictions. As aforementioned, current descriptions of the dual representation account appear to disagree with mainstream theories of memory. We propose a way to adapt existing cognitive-computational models of neutral and emotional memory so that the revised model makes separate predictions for voluntary and involuntary memory. In summary, our proposal builds on the perspective of established models of memory, which appear to disagree with a dominant theory of PTSD. We use this perspective to test the dual-representation account empirically and develop a formal cognitive-computational model of this account. If our proposed model can simulate the empirical data we acquire, including the possible double dissociation we may observe between voluntary and involuntary memory, we will reconcile an important theoretical gap and thereby advance understanding of PTSD.

尽管创伤后应激障碍（PTSD）的患病率很高，而且它会带来令人衰弱的后果，但目前的心理治疗并不是对每个人都有效。显然需要揭示触发持久性、侵入性恐惧记忆的心理机制。我们的提议解决了研究中的一个裂痕，即创伤后应激障碍的主导理论——双重表征理论——似乎与已建立的正常记忆认知计算模型发生冲突，并受到其经验证据基础差异的挑战。我们建议对该理论进行两项关键测试。双重代表账户有两个基本主张。首先，创伤使得很难将情绪刺激与其时空背景联系起来，因此，创伤的情绪方面与同一事件的中性元素之间的关联被削弱。其次，侵入性记忆与相同创伤内容的自愿记忆相比，是由不同的机制产生的——这是第一个主张的结果。我们通过使用创伤实验室模型测试这两个核心主张来挑战双重表征帐户，其中向参与者展示描绘令人厌恶的内容（例如受伤和死亡）的图片和电影剪辑。到目前为止，第一个说法的实验室测试涉及研究，其中向参与者提供情绪和中性刺激，然后测试他们对这些刺激之间关联的记忆。此类测试的解释很复杂，因为结果不仅取决于编码过程中这些刺激的关键结合，还取决于维持和检索过程中情绪的后续影响。我们将通过针对编码阶段来消除这些潜在的混淆。我们采用经过验证的学习任务来研究情绪对联想绑定的影响，而不会影响后续记忆过程的测量。第二个说法的实验室证据是自愿记忆和非自愿记忆之间的单一行为分离，当参与者在遭受创伤后积极进行视觉空间操作时，只有后者会减少。尽管这种分离已经被多次证明，但之前的实验测量自愿和非自愿记忆的方式之间存在差异，这可以解释这种差异。我们提供了更严格控制的实验设计来证实这种解离。然后我们引入一种仅可能增加自愿记忆的操作。如果成功，视觉空间任务和我们的新操纵将相当于自愿记忆和非自愿记忆之间的双重分离，从而为双重表征帐户提供更有力的支持。迄今为止，双重代表账户大多是用文字描述的。这使得准确理解所提出的认知计算机制变得困难。数学模型提高了理论的清晰度，并使做出和测试定量预测成为可能。如上所述，当前对双重表征解释的描述似乎与主流记忆理论不一致。我们提出了一种方法来适应现有的中性记忆和情感记忆的认知计算模型，以便修订后的模型对自愿和非自愿记忆进行单独的预测。总之，我们的建议建立在已建立的记忆模型的视角之上，这似乎与 PTSD 的主流理论不一致。我们使用这个视角来实证测试双重表示帐户，并开发该帐户的正式认知计算模型。如果我们提出的模型能够模拟我们获得的经验数据，包括我们可能观察到的自愿记忆和非自愿记忆之间可能的双重分离，我们将弥合重要的理论差距，从而增进对创伤后应激障碍的理解。