Parietal memory representations as a window into hippocampal learning

海马体对于形成持久的情节记忆是必不可少的。然而，海马区的活动模式 与单个事件相关的信息会随着经验和学习而不断变化。后果是什么？ 这些变化对底层内存表示法有何影响？在啮齿动物中，海马区的现象 模式变化被称为“重新映射”，最典型的是在原地单元中报告的。这使得 以使重新映射与环境的空间编码直接相关。然而，在人类身上，这一点就不那么清楚了。 海马区活动模式的重新配置(重新映射样现象)如何转化为特定的 内存表示形式的更改。潜在地，海马体活动模式的变化反映了 当捆绑在一起时构成记忆的特定特征。 这项拟议的研究的目标是深入了解海马体活动模式(和 更广泛地说，记忆)随着学习而改变。我们将通过开发和利用创新技术解决这个问题 以及高灵敏度的基于模式的功能磁共振成像方法，将记忆的特定特征映射到大脑皮质的模式 活动。特别是，我们将使用这些方法从内存中重建图像并读出 记忆的语义成分。这将使我们能够测量记忆的各个特征是如何变化的 通过学习并测试皮质表达的特征变化是否通过类似重映射的方式预测 海马体中的现象。我们将专门针对外侧顶叶皮质的特征表征， 动机是越来越多的证据表明，外侧顶叶皮质活跃地代表了记忆和 在功能上与海马体相连。 这项拟议的研究将在啮齿动物和人类的记忆模型之间架起桥梁，同时引入概念 有可能显著推进这一领域的途径和分析方法。因为 这项研究的特定大脑区域(海马体和外侧顶叶皮质)是 这项研究经常与疾病和中风相关的记忆障碍有关，建议的研究还将 支持有可能指导临床干预的关键基础知识。

The hippocampus is essential for forming long-lasting episodic memories. Yet, patterns of hippocampal activity associated with an individual event continue to change with experience and learning. What consequence do these changes have for the underlying memory representations? In rodents, the phenomenon of hippocampal pattern change has been termed `remapping' and has most typically been reported in place cells. This allows for remapping to be directly related to spatial coding of the environment. In humans, however, it is less clear how reconfiguration of hippocampal activity patterns (remapping-like phenomena) translates to specific changes in memory representations. Potentially, changes in hippocampal activity patterns reflect changes in the specific features that, when bound together, comprise a memory. The goal of the proposed research is to gain insight into how and why hippocampal activity patterns (and memories more generally) change with learning. We will address this by developing and leveraging innovative and highly-sensitive pattern-based fMRI methods that map specific features of a memory to patterns of cortical activity. In particular, we will use these methods to reconstruct images from memory and to read out the semantic components of memories. This will allow us to measure how individual features of a memory change with learning and to test whether cortically-expressed feature changes are predicted by remapping-like phenomena in the hippocampus. We will specifically target feature representations in lateral parietal cortex, motivated by accumulating evidence that lateral parietal cortex actively represents the contents of memory and is functionally coupled with the hippocampus. The proposed research will bridge rodent and human models of memory while introducing conceptual approaches and analysis methods that have the potential to significantly advance the field. Because the specific brain regions that will be targeted in the research (the hippocampus and lateral parietal cortex) are frequently implicated in disease- and stroke-related memory impairments, the proposed research will also support critical foundational knowledge that has the potential to guide clinical interventions.