Semantic contributions to episodic memory

这份申请描述了一项为期3年的培训计划，这将使我成为一名认知神经科学家，拥有 在记忆巩固和神经成像方法的背景下，对两者的相互作用进行研究 在语义知识和情景记忆之间。由专家Sharon Thompson-Schill博士共同监督 在概念和语义知识的认知和神经组织领域，H. Coslett是一位在脑刺激方面拥有丰富经验的神经学家，我建议研究一下语义 知识塑造新的情节记忆，以及它们的大脑皮层表征如何变化可能决定 情景记忆受语义知识影响的程度。拟议中的实验旨在 解决关于语义知识和情景记忆巩固的文献中的两个空白。第一，记忆 整合研究通常将新的情节记忆视为与其他过去截然不同(正交化)的记忆 经历，而实际上，情节记忆几乎总是由元素的重新组合组成 (例如，位置、地点、物体)，我们已经获得了丰富的语义知识。怎么会这样呢 随着时间的推移，语义元素与记忆中新的情节元素相互作用或产生偏向尚不清楚。第二, 过去研究先验知识在新记忆中的作用的工作通常集中在先验知识如何 促进了新记忆的编码和检索，而不是它们可能被先前的 知识。为了解决以前工作的局限性，我提出了一系列实验，探索语义是如何 知识系统性地偏向情节记忆，以及这种偏向可能如何受到 前颞叶(ATL)中记忆的表征，这是一种对完整语义至关重要的皮质结构 知识。在目标1中，我提出了一个行为实验，该实验利用 语义知识，即范畴典型性和抽象程度，以了解语义如何 知识会影响新的情节记忆。我使用了一种连续的检索手段来解开 由语义知识驱动的偏见来自于因遗忘而产生的错误。在目标2中，我将这个实验改编为 卒中后皮损患者了解类别知识中的具体损害如何影响 取回。虽然我概述了对ATL损伤程度更大的患者的具体预测，但我采用了一种 探索性的方法来确定语义信息和情节信息之间的其他潜在整合地点。 在目标3中，我使用经颅磁刺激来测试情节记忆是否更偏向于 语义知识，因为随着时间的推移，它们在ATL中的表示越来越多。拟议的研究将 有助于我们理解语义知识贡献的神经机制 新的情节记忆，这可能会启发患有记忆障碍的个人的新康复策略 减损。

This application describes a 3-year training plan that will enable me, a cognitive neuroscientist with a background in memory consolidation and neuroimaging methods, to conduct research on the interaction between semantic knowledge and episodic memory. Co-supervised by Dr. Sharon Thompson-Schill, an expert in the field of the cognitive and neural organization of concepts and semantic knowledge, and Dr. H. Branch Coslett, a neurologist with extensive experience in brain stimulation, I propose to examine how semantic knowledge shapes new episodic memories, and how changes their cortical representation may determine the extent to which episodic memories are influenced by semantic knowledge. The proposed experiments aim to address two gaps in the literature on semantic knowledge and episodic memory consolidation. First, memory consolidation research typically treats new episodic memories as distinct (orthogonalized) from other past experiences, when in reality, episodic memories are virtually always made up of re-combinations of elements (e.g. locations, places, objects) for which we already have acquired rich semantic knowledge. How such semantic elements interact with, or bias, new episodic elements in memories over time is unclear. Second, past work investigating the role of prior knowledge on new memories is often focused on how prior knowledge facilitates the encoding and retrieval of new memories, rather than how they may be biased by prior knowledge. To address this limitation of prior work, I propose a series of experiments that probe how semantic knowledge systematically biases episodic memories, and how this bias may be influenced by the representation of the memory in the anterior temporal lobe (ATL), a cortical structure critical for intact semantic knowledge. In Aim 1, I propose a behavioral experiment that leverages the hierarchical organization of semantic knowledge, namely category typicality and levels of abstraction, to understand how semantic knowledge influences new episodic memories. I employ a continuous measure of retrieval to disentangle biases driven by semantic knowledge from errors due to forgetting. In Aim 2, I adapt this experiment for patients with post-stroke lesions to understand how specific impairments in category knowledge influence retrieval. While I outline specific predictions for patients with greater extent of damage in ATL, I adopt an exploratory approach to identify other potential sites of integration between semantic and episodic information. In Aim 3, I employ transcranial magnetic stimulation to test whether episodic memories are more biased by semantic knowledge as they become increasingly represented in ATL over time. The proposed research will contribute to our understanding of the neural mechanisms underlying the contributions of semantic knowledge to new episodic memory, and it may inspire novel rehabilitation strategies for individuals suffering from memory impairments.