Individual Differences in the Development of Spatial Skills: Role of Hippocampal Function and Structure

记住你把钥匙放在哪里，在拥挤的停车场找到你的车，在地图上定位物品，以及在一个不熟悉的社区导航，这些都是需要空间技能的任务，比如空间记忆、导航和重新定位。这些空间技能是对生存至关重要的适应性功能。海马体是一种神经结构，对动物和成人的空间技能都至关重要。相比之下，人们对儿童海马的功能和结构与各种空间技能之间的关系知之甚少。众所周知，与学龄儿童和成人相比，学龄前儿童在空间任务上的表现往往较差，这表明他们的海马体可能还不够成熟，无法处理这些任务的要求。不幸的是，这些研究只主要关注年龄组之间的差异（例如，4岁与6岁），这使得我们对这个发展跨度中存在的表现个体差异的理解存在知识空白，以及可能导致这种差异的潜在神经机制。因此，为了解决我们知识上的这一差距，目前的研究将检查空间技能发展的个体差异，以及这些差异是否可以用海马体功能和结构的发育变化来解释。具体来说，在拟议的为期4年的R01资助中，该项目利用208名4岁、5岁和6岁儿童的经济和民族/种族多样性样本，旨在：(1)通过使用横截面样本采用海马依赖的联想学习任务（即EBC），确定空间任务的个体差异是否可以用海马功能的个体差异来解释；(2)确定空间任务的个体差异是否可以用海马结构的个体差异来解释，包括子场体积、神经突密度、皮质髓磷脂和海马-皮质连通性，这些差异是通过使用横截面样本的结构磁共振成像测量的；(3)通过对一组4岁儿童进行纵向观察，表征导致空间技能获得和发展的海马功能和结构的变化。因此，拟议的拨款提供了一个框架，以确定以前未研究过的发展中人群的海马体功能和结构，并检查海马体在儿童空间能力发展中的作用。除了进一步了解海马体在儿童空间技能发展中的作用外，该研究的结果将为未来研究典型和非典型（如威廉姆斯综合征）发展人群的海马体结构和功能，以及未来研究海马体发展个体差异的级联认知后果（如空间工作记忆、空间焦虑）奠定基础。

PROJECT SUMMARY/ABSTRACT Remembering where you left your keys, finding your car in a crowded parking lot, locating items on a map, and navigating through an unfamiliar neighborhood are all tasks that require spatial skills, such as spatial memory, navigation, and reorientation. These spatial skills are adaptive functions that are critical for survival. The hippocampus has been well established as a neural structure that is essential for spatial skills in both animals and human adults. In contrast, relatively little is known about how hippocampal function and structure relates to various spatial skills in children. It is know that, compared to school-aged children and adults, preschool children tend to perform poorly on spatial tasks, suggesting that their hippocampi may not be mature enough to process the demands of such tasks. Unfortunately, these studies have only primarily focused on differences between age groups (e.g., 4-year-olds vs. 6-year-olds) leaving a knowledge gap in our understanding of the individual differences that exists in performance across this span of development, as well as the underlying neural mechanisms which may contribute to this variability. Therefore to address this gap in our knowledge, the current study will examine individual differences in the development of spatial skills and whether these differences can be explained by developmental changes in hippocampal function and structure. Specifically, in the proposed 4-year R01 grant, the project, utilizing an economically- and ethnically/racially-diverse sample of 208 4-, 5-, and 6-year-olds aims to: (1) determine whether individual differences on spatial tasks can be explained by individual differences in hippocampal function by employing a hippocampal-dependent associative learning task (i.e., EBC) using a cross-sectional sample; (2) determine whether individual differences on spatial tasks can be explained by individual differences in hippocampal structure, including subfield volume, neurite density, cortical myelin, and hippocampal-cortical connectivity, measured via structural magnetic resonance imaging using a cross- sectional sample, and; (3) characterize changes in hippocampal function and structure that result in gains in and development of spatial skills using a cohort of 4-year-olds that will be observed longitudinally at 6 years of age. Thus, the proposed grant provides a framework for identifying hippocampal functioning and structure in a developing population not previously studied and for examining the role of the hippocampus in children’s developing spatial competence. In addition to advancing knowledge about the role of the hippocampus in children’s developing spatial skills, results from the proposed research would lay the foundation for future work addressing hippocampal structure and functioning in both typical and atypical (e.g., Williams Syndrome) developing populations, as well as future work examining the cascading cognitive consequences (i.e., spatial working memory; spatial anxiety) of individual differences in hippocampal development.