Memory consolidation in typical and atypical development

众所周知，睡眠会影响巩固脆弱记忆的过程，使其变得强大。睡眠的组成部分，如“慢振荡”影响这个巩固过程。然而，人们对儿童睡眠如何影响巩固知之甚少。这一点很重要：儿童的睡眠中有更多对巩固记忆至关重要的成分，可能会显示出更大的影响。鉴于儿童以惊人的速度接触新信息，了解哪些因素会影响巩固，以确保学习是最佳的，这一点很重要。此外，睡眠困难在儿童时期很常见，特别是在以语言学习障碍为特征的神经发育障碍中（例如，自闭症谱系障碍; ASD），但在研究这些群体中学习和睡眠困难是否相关方面进展甚微。不同年龄段的比较，以及同一年龄段的典型和非典型群体之间的比较，提供了一个机会来测试巩固理论，看看它们是否可以解释发展过程中和发展过程中的实质性差异。Strand 1专注于典型的发展，使用10-12岁的儿童（当慢振荡活动达到峰值时），以及成人，在某些情况下更年幼的儿童。Strand 2专注于非典型发育，包括首次系统评估非典型睡眠是否与具有不同语言表型的ASD儿童和无ASD的语言障碍（LI）儿童的语言学习困难有关。这使我们能够将与ASD相关的学习机制与语言障碍相关的学习机制分开。我们的实验包括学习新材料，然后是延迟。对于睡眠条件，参与者的大脑活动在家中记录。后来的测试决定了新记忆的强度和性质。例如，一项研究探讨了睡眠是否有助于新记忆的稳定，并研究了学习和睡眠之间的最佳延迟（这可能与儿童特别相关）。另一项研究考察了先前知识对睡眠巩固的影响。成人和儿童在他们带来学习环境的先验知识方面存在差异，这可能会掩盖儿童更强的巩固能力。此外，有语言障碍的儿童词汇量不足，这可能导致“马太效应”（即，富者越富，贫者越贫），我们的研究将直接检验这一假设。许多研究关注睡眠在语言学习中的作用。我们跟踪学习口语单词及其含义的时间进程，以及这些新信息随着时间的推移而加强的程度，与现有知识相结合，并推广到新的范例。这些研究允许彻底检查语言学习困难是否与ASD和LI的睡眠结构差异有关。我们将利用2年内从同一儿童收集的数据来研究睡眠变量是否可以预测更长时间内的词汇结果。最后，在一项跨领域研究中，我们通过检查睡眠对一种相当不同类型的记忆的影响来检查睡眠对典型和非典型发展的任何影响的普遍性，这种记忆仍然依赖于巩固：空间位置。我们的目标是建立一个全面的理论，典型和非典型的巩固和遗忘跨越清醒和睡眠，提出了典型语言习得理论和语言异质性理论。计划中的研究的理论应用有可能提高我们对如何使记忆在儿童和成人中保持的实际理解，并最终改善结果。

Sleep is known to affect the consolidation process that takes fragile memories and makes them robust. Components of sleep such as "slow oscillations" influence this consolidation process. However, little is known about how children's sleep may influence consolidation. This is important: children's sleep has more of the components that are crucial for consolidation of memory, and may show more substantial effects. Given that children encounter new information at a dramatic rate, it is important to understand what factors influence consolidation to ensure that learning is optimal. Furthermore, sleep difficulties are common in childhood, particularly in neurodevelopmental disorders characterised by language learning impairments (e.g., autism spectrum disorder; ASD), but little progress has been made in examining whether learning and sleep difficulties are related in these groups. Comparisons across ages, as well as between typical and atypical groups of the same age, offer an opportunity to test theories of consolidation in terms of whether they can explain the substantial variability across and within development.Our plans provide a comprehensive evaluation of the influence of sleep on consolidation of memory in development. Strand 1 focuses on typical development, using children aged 10-12 (when slow-oscillation activity peaks), as well as adults, and in some cases younger children. Strand 2 focuses on atypical development, comprising the first systematic evaluation of whether atypical sleep relates to language learning difficulties in children with ASD with varying language phenotypes and in children with language impairment (LI) without ASD. This enables us to separate learning mechanisms associated with ASD from those attributable to language impairment. Our experiments involve learning of new materials, followed by a delay. For sleep conditions, participants' brain activity is recorded at home. Later tests determine the strength and nature of the new memory. For example, one study addresses whether sleep facilitates stabilisation of new memories, and looks at the optimal delay between learning and sleep (which may be particularly pertinent for children). Another examines the influence of prior knowledge on consolidation during sleep. Adults and children differ in terms of the prior knowledge that they bring to a learning situation and it is possible that this can mask the stronger consolidation ability of children. Furthermore, children with language impairments have impoverished vocabularies which may lead to a 'Matthew Effect' (i.e., the rich get richer and the poor get poorer) in the consolidation of new words; our studies will test this hypothesis directly. Many studies focus on the role of sleep in language learning. We track the timecourse of learning spoken words and their meanings, and the extent to which this new information is strengthened over time, integrated with existing knowledge, and generalised to new exemplars. Such studies permit a thorough examination of whether language learning difficulties are associated with differences in sleep architecture in ASD and LI. We will exploit data collected from the same children over a 2-year period to examine whether sleep variables predict vocabulary outcomes over a longer period. Finally, in a cross-cutting study we examine the generality of any effects of sleep across both typical and atypical development by examining the influence of sleep in a rather different type of memory that is nonetheless dependent on consolidation: spatial location.We aim to create a comprehensive theory of typical and atypical consolidation and forgetting across wake and sleep, and advance theories of typical language acquisition and language heterogeneity in ASD and LI. The theoretical applications of the planned research have the potential to improve our practical understanding of how to make memories stick in children and adults, and ultimately improve outcomes.