fMRI studies of semantic and episodic memory retrieval

描述(申请人提供)：拟议研究的主要目标是探索内侧颞叶结构，包括海马体和邻近结构在记忆提取中的功能作用。这项建议建立在研究人员最近的工作基础上，他们提出了内侧颞叶参与记忆巩固、存储和提取的新观点，称为多重痕迹理论(MTT)。传统认为，内侧颞叶结构在记忆中的作用是有时间限制的，只能持续到新皮质内记忆痕迹的巩固完成，之后记忆可以在不涉及海马区的情况下被保留和提取。相比之下，海马体在记忆的存储和检索中发挥着持久的作用，而海马体的中心作用反映了它在处理各种类型的空间信息方面的基本作用。这项拟议中的研究将询问海马体是否在提取三种对个人记忆重要的空间信息方面发挥特殊作用：空间背景、空间位置和空间关系。这些研究还将探索个人记忆或情景记忆的各种形式，将个人记忆与世界知识或语义记忆进行比较。健康的成年人将参与一系列实验，使用功能磁共振成像(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，以便比较在提取这些不同类型的记忆时，内侧颞叶和新皮质大脑结构中的激活情况。一些记忆将包括空间信息或空间关系，而另一些则不会。这项研究不仅将直接测试MTT的一些断言，而且还将提供关于人类长期储存和提取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.