Hippocampal Subfield Contributions to Episodic Memory Formation: Child-Developmental Trends and Interaction with Top-down Control during Adulthood

海马体（HC）的形成对情景记忆至关重要。然而，由于HC形成中的结构异质性，其确切功能尚未明确，这给人体体内测量带来了技术困难。直到最近，结构和功能高分辨率成像技术的进步才使研究能够记录不同海马子区对记忆计算过程的不同贡献，包括模式分离和完成。在这种情况下，模式分离是指将类似的表示（例如来自感知或记忆的表示）转换为高度不同的、不重叠的表示的计算操作。相反，模式补全操作允许从部分可用信息中恢复完整的表示。来自健康老年人年龄比较研究的初步证据支持海马衰老的动物模型，表明与年龄相关的模式分离处理减少有助于衰老过程中新信息获取的减少。然而，我们对儿童时期HC结构和功能的变化知之甚少，更不用说在发展中儿童模式分离和模式完成过程中HC子领域的变化了。此外，前额叶控制机制在多大程度上可以改变成年期参与模式分离/完成反应的相对倾向，这仍然是难以捉摸的。因此，本申请提出了两组研究，以便a)绘制海马体子区模式分离和模式完成机制的发展，b)通过适当的自上而下控制状态来测试这些机制的可修改性。

The hippocampal (HC) formation is a structure fundamentally important for episodic memory. However its exact functions have been underspecified due to the structural heterogeneity within the HC formation, posing technical difficulties for in vivo measurement in humans. Only recently advances in structural and functional high-resolution imaging have enabled research to document differential contributions of various hippocampal subfields to computational processes that are important for memory, including pattern separation and completion. In this context, pattern separation refers to computational operations that transform similar representations, for example derived from perception or memory, into highly dissimilar, non-overlapping representations. By contrast, pattern completion operations allow restoration of complete representations form partially available information. Initial evidence from age-comparative studies of healthy aged humans supports animal models of hippocampal aging, demonstrating that age-related reduced pattern separation processing contributes to declining acquisition of new information in aging. However, we have a weak grasp of the changes in HC structure and function during childhood, let alone the changes in HC subfields that underlie the development of pattern separation and pattern completion processes in developing children. In addition, it remains elusive in how far prefrontal control mechanisms can alter the relative propensity to engage in pattern separation/completion responses during adulthood. Accordingly, the present application proposes two sets of studies in order a) to chart the development of pattern separation and pattern completion mechanisms across hippocampal subfields, and b) to test the modifiability of those mechanisms by appropriate top-down control states during adulthood.