Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, Wales, UK.
Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, Wales, UK.
Cortex. 2018 Sep;106:1-11. doi: 10.1016/j.cortex.2018.04.009. Epub 2018 May 9.
Successful retrieval of episodic information is thought to involve the adoption of memory states that ensure that stimulus events are treated as episodic memory cues (retrieval mode) and which can bias retrieval toward specific memory contents (retrieval orientation). The neural correlates of these memory states have been identified in many neuroimaging studies, yet critically there is no direct evidence that they facilitate retrieval success. We cued participants before each test item to prepare to complete an episodic (retrieve the encoding task performed on the item at study) or a non-episodic task. Our design allowed us to separate event-related potentials (ERPs) elicited by the preparatory episodic cue according to the accuracy of the subsequent memory judgment. We predicted that a correlate of retrieval orientation should be larger in magnitude preceding correct source judgments than that preceding source errors. This hypothesis was confirmed. Preparatory ERPs at bilateral frontal sites were significantly more positive-going when preceding correct source judgments than when preceding source errors or correct responses in a non-episodic baseline task. Furthermore this effect was not evident prior to recognized items associated with incorrect source judgments. This pattern of results indicates a direct contribution of retrieval orientation to the recovery of task-relevant information and highlights the value of separating preparatory neural activity at retrieval according to subsequent memory accuracy. Moreover, at a more general level this work demonstrates the important role of pre-stimulus processing in ecphory, which has remained largely neglected to date.
成功检索情景信息被认为涉及到采用记忆状态，以确保刺激事件被视为情景记忆线索（检索模式），并能使检索偏向于特定的记忆内容（检索方向）。这些记忆状态的神经相关物已在许多神经影像学研究中被确定，但至关重要的是，没有直接证据表明它们有助于提高检索的成功率。我们在每个测试项目之前向参与者提示，准备完成情景（检索在研究中对项目执行的编码任务）或非情景任务。我们的设计允许我们根据后续记忆判断的准确性来分离由预备情景线索引起的事件相关电位（ERP）。我们预测，在正确的源判断之前，检索方向的相关物的幅度应该大于在源错误之前的幅度。这个假设得到了证实。在双侧额部位置，预备 ERP 在正确的源判断之前比在源错误或非情景基线任务中的正确反应之前更正向。此外，在与错误源判断相关的被识别项目之前，这种效果并不明显。这种结果模式表明，检索方向直接有助于恢复与任务相关的信息，并突出了根据后续记忆准确性分离检索时预备神经活动的价值。此外，在更一般的层面上，这项工作证明了在情景再现中，刺激前处理起着重要作用，而这一点迄今为止在很大程度上被忽视了。
