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

海马（HC）结构对于情景记忆是至关重要的结构。然而，由于HC形成中的结构异质性，其确切功能尚未得到充分说明，这给人体体内测量带来了技术困难。直到最近，在结构和功能的高分辨率成像的进展，使研究记录不同的海马子字段的计算过程，是重要的记忆，包括模式分离和完成的差异贡献。在这种情况下，模式分离是指将相似的表示（例如从感知或记忆中导出的表示）转换为高度不相似的非重叠表示的计算操作。相比之下，模式完成操作允许从部分可用的信息恢复完整的表示。来自健康老年人的年龄比较研究的初步证据支持海马老化的动物模型，表明与年龄相关的减少的模式分离处理有助于衰老中新信息的获得减少。然而，我们对儿童时期HC结构和功能的变化掌握得很薄弱，更不用说对发展中儿童模式分离和模式完成过程发展的HC子领域的变化了。此外，在多大程度上前额叶控制机制可以改变相对倾向从事模式分离/完成反应在成年期仍然难以捉摸。因此，本申请提出了两组研究，以便a）绘制跨越海马子区的模式分离和模式完成机制的发展，以及B）测试成年期间通过适当的自上而下控制状态对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.