Executive functioning in adolescence: Developmental trajectories and longitudinal links to sleep and neural indicators

在青春期的过程中，认知能力发生了巨大的变化，特别是与执行功能(EF)相关的神经认知过程。EF由一套更高层次的认知技能组成，当个体面临认知挑战的情况时，这些技能被招募，并集中参与注意力调节、信息处理和更新以及问题解决。EF被认为是青春期神经认知的中心指标，在很大程度上依赖于涉及前额叶皮质的神经网络，它在整个童年和青春期都经历了显著的发育。这些神经发育包括轴突的髓鞘形成和突触修剪，从而提高了包含EF的神经回路的效率。因此，在整个青春期，与年龄相关的神经认知改善是可望实现的。事实上，EF的年龄差异经常被观察到，在各种执行任务上，年龄较大的青少年表现优于年轻的同龄人。 这些年龄组之间的平均水平差异通常被解释为反映了发展的进步，然而，横断面研究不能说明认知发展本身。横断面研究依赖于不同年龄段青少年群体的比较，因此无法将年龄效应与可能区分年龄组的任何其他特征(队列效应)分开。相反，至少有三个时间点的纵向设计有助于分解年龄和队列效应，以及在两个层面上描述认知发展：每个人内部的变化模式和个人之间在这种人内变化中的差异。因此，三个时间点或更多的纵向设计对于回答有关神经认知发展的关键问题是必不可少的，例如，与青春期EF改善的速度和形状(例如，线性或二次)有关，以及这些模式中的个体差异。 尽管神经认知能力的发展从定义上讲是在人内层面上进行的，但迄今为止所有针对青少年的EF研究都涉及严格的人与人之间的数据分析，或者只依赖于两个评估点。因此，目前对青春期执行力提升的节奏和形式的了解是有限的。这反过来又限制了对与EF发育过程有关的所有其他问题的了解状态，例如这一过程与被认为具有关键重要性的神经生物学基础之间联系的性质，如睡眠模式或大脑解剖和连接。为了解决这些差距，这项纵向研究计划包括四项研究，试图描述青春期EF与年龄相关的改善的节奏和形态，并检查这些改善轨迹与青少年的大脑结构、功能和睡眠模式之间的关系。

Cognitive abilities change dramatically over the course of adolescence, especially the neurocognitive processes related to executive functioning (EF). EF consists of a set of higher-order cognitive skills that are recruited when individuals face cognitively challenging situations, and is centrally involved in attention regulation, information processing and updating, and problem solving. EF is considered to be a central indicator of neurocognition in adolescence and depends heavily on neural networks involving notably the prefrontal cortex, which undergoes significant developments throughout childhood and adolescence. These neurodevelopments include myelination of axons and synaptic pruning, resulting in increased efficiency in the neural circuits that subsume EF. As a result, age-related improvements in neurocognition throughout adolescence are expected. Indeed, age differences in EF are often observed, with older adolescents outperforming their younger counterparts on a variety of executive tasks. These mean-level differences between age groups are generally interpreted as reflecting developmental improvements yet, cross-sectional studies cannot speak to cognitive development per se. Cross-sectional studies rely on comparisons of groups of adolescents of different ages, and thus cannot disentangle age effects from any other characteristic that may distinguish the age groups (cohort effects). In contrast, longitudinal designs with at least three time points facilitate the disaggregation of age and cohort effects, as well as the characterization of cognitive development on two levels: the pattern of change within each individual and differences between individuals in this within-person change. Thus, longitudinal designs with three time points or more are essential for answering key questions about neurocognitive development, pertaining for instance to the rate and shape (e.g., linear or quadratic) of EF improvements throughout adolescence and individual differences in these patterns. Although progression in neurocognitive capacity happens at the within-person level by definition, all EF research with adolescents to date has involved the analysis of strictly between-person data, or has relied on only two assessment points. As a result, current knowledge on the rhythm and shape of executive improvement in adolescence is limited. This, in turn, constrains the state of knowledge on all other questions pertaining to the process of EF development, such as the nature of the links between this process and neurobiological underpinnings presumed to be of key importance, such as sleep patterns or brain anatomy and connectivity. Aiming to address these gaps, this program of longitudinal research consists of four studies seeking to characterize the rhythm and shape of age-related improvements in EF in adolescence, and examine the associations between these improvement trajectories and adolescents' brain structure, function, and their sleep patterns.