Trying to forget: Characterizing the mechanisms and consequences of intentional forgetting

我们都有过宁可忘记的经历，尽管我们经常能够将这些想法从脑海中抹去，但当我们面临合适的提醒时，它们仍然会偶尔重新出现。我的大部分研究都集中在描述基本的机制，通过这些机制，当面对这样的提醒时，不想要的记忆会被阻止出现在脑海中，或者当它们出现时，会被从思想中推开。无论以哪种方式控制内存，都会降低将来再次出现目标内存的可能性。然而，关于这些机制是如何实施的，仍有很多事情要知道。因此，我的长期目标是开发一个神经认知模型，描述编码和提取过程中控制不想要的记忆的机制。我过去的工作表明，试图在曝光后不久忘记一张图像，会涉及一个或多个活跃的机制，这些机制与将注意力从图像的表示和空间位置以及其他时间上接近的信息上抽离有关。然而，足以调用这些机制的情况、类似的机制是否控制不想要的检索以及在编码或检索时控制存储器是否以类似的方式影响不想要的存储器的表示仍是未知的。本提案将在健康的大学年龄人口中处理这些主题，采用一系列方法，重点是操纵参与者执行任务指令的方式，同时使用行为或心理生理措施来表征所涉及的认知机制的性质。考虑到这一点，本建议的目的是1)隔离在编码时实施记忆控制机制的情况，并将其推广到提取控制；2)使用心理生理学标记来跟踪这些机制的时间属性及其与成功控制的关系；以及3)将对不想要的记忆的编码和提取的主动控制与测试时这些记忆的保真度的变化相关联。通过比较编码和提取时记忆控制的神经认知机制，这项工作将提供一个强大的刺激，使人们从理论上共同理解记忆控制背后的基本认知机制，以及这些机制是如何在各种条件下灵活地实施来控制不想要的经历的。在这样做的过程中，这个研究项目将产生对我们理解人类大脑如何工作的基本知识，并告知我们对其他更高层次的认知能力的理解。

We all have experiences that we would rather forget and although we are often able to push these thoughts from mind, they still re-emerge on occasion when faced with a suitable reminder. Much of my research has focused on characterizing the basic mechanisms through which unwanted memories are prevented from coming to mind when faced with such a reminder or pushed from thought when they do. Controlling memory in either manner reduces the probability of the target memory coming to mind again in the future. However, much remains to be known concerning how these mechanisms are implemented. It is therefore my long-term goal to develop a neurocognitive model characterizing the mechanisms involved in the control of unwanted memories at both encoding and retrieval. My past work has shown that trying to forget an image shortly following exposure engages one or more active mechanisms associated with the withdrawal of attention away from the representation and spatial location of that image as well other temporally proximate information. Yet, the circumstances sufficient to invoke these mechanisms, whether similar mechanisms control unwanted retrieval and whether controlling a memory at encoding or retrieval impacts the representation of an unwanted memory in a similar fashion remains unknown. The present proposal will address these topics in a healthy, university-aged population using a combination of approaches focused on manipulating the manner in which participants enact the task instructions while using behavioural or psychophysiological measures to characterize the nature of the cognitive mechanisms involved. With this in mind, the objectives of this proposal are to 1) isolate the circumstances under which memory control mechanisms are enacted at encoding and generalize them to the control of retrieval; 2) use a psychophysiological marker to track the temporal properties of these mechanisms and their relation to successful control; and, 3) relate active control over the encoding and retrieval of unwanted memories to changes in the fidelity of those memories at test. By drawing parallels between the neurocognitive mechanisms of memory control applied at both encoding and retrieval, this work will provide a powerful stimulus towards a common theoretical understanding of the basic cognitive mechanisms behind memory control and how these mechanisms are implemented flexibly to control unwanted experiences under a variety of conditions. In doing so, this program of research will generate knowledge fundamental to our understanding of how the human mind works and inform our comprehension of other, higher-order cognitive abilities.