fMRI studies of semantic and episodic memory retrieval

描述（由申请人提供）：本研究的主要目的是探索内侧颞叶内结构（包括海马和邻近结构）在记忆检索中的功能作用。该建议建立在研究者最近提出的关于内侧颞叶参与记忆巩固、存储和检索的新观点的基础上，称为多重痕迹理论（MTT）。传统观点认为，内侧颞叶结构在记忆中的作用是有时间限制的，只会持续到新皮层的记忆痕迹巩固完成，之后记忆就可以在没有海马参与的情况下保留和提取。相反，MTT认为海马体在记忆的存储和检索中起着持久的作用，海马体的中心作用反映了它在处理各种类型的空间信息中的重要作用。提出的研究将探讨海马体是否在三种对个人记忆重要的空间信息的检索中起特殊作用：空间背景、空间位置和空间关系。这些研究还将探索各种形式的个人记忆或情景记忆，将个人记忆与世界知识或语义记忆进行比较。健康成人将参与一系列实验，使用功能性磁共振成像（fMRI）。在扫描仪中，他们将被要求回忆个人经历、最近学到的信息和公认的世界知识，以便比较在检索这些不同类型的记忆时，大脑内侧颞叶和新皮层结构的激活情况。有些记忆会包含空间信息或空间关系，而有些则不会。这项研究不仅将直接测试MTT的一些断言，而且还将提供有关人类长期存储和检索的神经机制的重要信息。

DESCRIPTION (provided by applicant): The primary goal of the proposed research is to explore the functional roles in memory retrieval of structures within the medial temporal lobe, including the hippocampus and adjacent structures. The proposal builds on recent work by the investigators positing a new view of medial temporal lobe involvement in memory consolidation, storage, and retrieval, referred to as Multiple Trace Theory (MTT). Tradition holds that the role of medial temporal lobe structures in memory is time-limited, lasting only until consolidation of the memory trace in neocortex is complete, after which memories can be retained and retrieved without hippocampal involvement. MTT, in contrast, argues that the hippocampus plays a lasting role in the storage and retrieval of memory, and that the central role of the hippocampus reflects its essential role in the processing of various types of spatial information. The proposed studies will ask whether the hippocampus plays a special role in the retrieval of three kinds of spatial information important to personal memories: spatial context, spatial location, and spatial relations. The studies will also explore the various forms of personal or episodic memory, comparing personal memory to world knowledge or semantic memory. Healthy adults will participate in a series of experiments, using functional magnetic resonance imaging fMRI). While in the scanner, they will be asked to recollect personal experiences, recently learned information, and well-established world knowledge, in order to compare activation within medial temporal and neocortical brain structures during retrieval of these varied types of memories. Some memories will include spatial information or spatial relations, while others will not. The study will not only directly test some of the assertions from MTT, but it will also provide important information regarding the neural mechanisms underlying long-term storage and retrieval in humans.