Content representation in the human medial temporal lobe

描述(由申请人提供)：记忆功能的基本问题是信息在大脑中是如何表示的。目前的模型表明，我们经验的内容可能由解剖上不同的大脑结构来表示，这些表示的性质可能会随着它们从新信息转化为存储的记忆而改变。尽管内侧颞叶(MTL)在情节记忆--对单个事件的记忆--中的核心作用已经确定，但MTL中内容表征的性质仍然不清楚。MTL的解剖学组织表明，个别MTL亚区对基于内容的情节记忆的编码做出了独特的贡献。然而，这些区别的证据一直好坏参半。这项研究提案将结合高分辨率功能磁共振成像(FMRI)和高维分析，以比以前可能的更高精度揭示MTL次区域对内容敏感编码的贡献。实验1将检验这样一种假设，即MTL皮质亚区和海马体对不同形式的内容做出独特的反应，以支持项目水平的编码。一种新的多变量分析技术将使我们能够评估阈值以下活动所携带的信息。它还将揭示内容表示的发展性质，因为它们被成功编码。实验2将检验这样的假设，即特定类别的内容表征被恢复以支持对情节细节的记忆。我们还将考虑海马区的反应，以确定它们在调节编码和恢复过程中的计算作用。实验3将测试内容表征被重新激活以帮助预测未来的假设。多变量 对预期事件之前的时间点期间模式化激活的分析将测试它们是否携带预测这些事件内容的信息。这项研究将有助于识别MTL中内容表征的性质，让我们更清楚地了解我们如何记忆周围的世界。它还将让我们深入了解内容代码在 MTL。通过完成拟议的项目，了解这些悬而未决的问题将有助于我们确定影响MTL功能或结构的疾病的潜在损害性质，包括阿尔茨海默病、创伤后应激障碍和精神分裂症。) 公共卫生相关性：这项拟议的研究调查了内侧颞叶结构如何支持对经历过的事件内容的记忆。它还将揭示我们的记忆是如何被重新激活以理解当前事件或预测未来的。了解这些机制将有助于我们从影响MTL功能或结构的疾病中识别损害的潜在性质，包括阿尔茨海默病、创伤后应激障碍和精神分裂症。)

DESCRIPTION (provided by applicant): The fundamental question underlying memory function is how information is represented in the brain. Current models suggest that the content of our experiences might be represented by anatomically distinct brain structures, and the nature of those representations might change as they are transformed from novel information to stored memories. Although the central role of the medial temporal lobe (MTL) in episodic memory-memory for individual events-is well established, the nature of content representation in the MTL is still unclear. The anatomical organization of the MTL suggests that individual MTL subregions make unique contributions to the encoding of episodic memories based on content. However, evidence for these distinctions has been mixed. This research proposal will combine high-resolution functional magnetic resonance imaging (fMRI) and high-dimensional analyses to reveal the MTL subregional contributions to content-sensitive encoding with greater precision than previously possible. Experiment 1 will test the hypothesis that MTL cortical subregions and hippocampus make unique responses to different forms of content to support item- level encoding. A novel multivariate analytical technique will allow us to assess the information carried by subthreshold activity. It will also reveal the developing nature of content representations as they are successfully encoded. Experiment 2 will test the hypothesis that specific categories of content representation are reinstated to support memory for episodic details. We will also consider the responses of hippocampal subfields to determine their computational role in mediating encoding and reinstatement. Experiment 3 will test the hypothesis that content representations are reactivated to help anticipate the future. Multivariate analysis of patterned activation during timepoints before expected events will test whether they carry information predicting the content of those events. This research will help identify the nature of content representation in the MTL, giving us a clearer picture of how we remember the world around us. It will also give us insight into the possible functional role of content codes in MTL. Understanding these open questions through the completion of the proposed project will help us identify the underlying nature of impairment from conditions that affect MTL function or structure, including Alzheimer's disease, post-traumatic stress disorder, and schizophrenia. ) PUBLIC HEALTH RELEVANCE: The proposed research investigates how medial temporal lobe structures support memory for the content of experienced events. It will also reveal how our memories are reactivated to make sense of current events or predict the future. Understanding these mechanisms will help us identify the underlying nature of impairment from conditions that affect MTL function or structure, including Alzheimer's disease, post-traumatic stress disorder, and schizophrenia.)