Sleep and Chronobiology Laboratory, GIGA-CRC in Vivo Imaging, University of Liège, Liège, Belgium.
Psychology and Neuroscience of Cognition Research Unit (PsyNCog), Faculty of Psychology and Educational Sciences, University of Liège, Liège, Belgium.
Sleep. 2023 Sep 8;46(9). doi: 10.1093/sleep/zsad094.
The circadian system orchestrates sleep timing and structure and is altered with increasing age. Sleep propensity, and particularly REM sleep is under strong circadian control and has been suggested to play an important role in brain plasticity. In this exploratory study, we assessed whether surface-based brain morphometry indices are associated with circadian sleep regulation and whether this link changes with age. Twenty-nine healthy older (55-82 years; 16 men) and 28 young participants (20-32 years; 13 men) underwent both structural magnetic resonance imaging and a 40-h multiple nap protocol to extract sleep parameters over day and night time. Cortical thickness and gyrification indices were estimated from T1-weighted images acquired during a classical waking day. We observed that REM sleep was significantly modulated over the 24-h cycle in both age groups, with older adults exhibiting an overall reduction in REM sleep modulation compared to young individuals. Interestingly, when taking into account the observed overall age-related reduction in REM sleep throughout the circadian cycle, higher day-night differences in REM sleep were associated with increased cortical gyrification in the right inferior frontal and paracentral regions in older adults. Our results suggest that a more distinctive allocation of REM sleep over the 24-h cycle is associated with regional cortical gyrification in aging, and thereby point towards a protective role of circadian REM sleep regulation for age-related changes in brain organization.
昼夜节律系统协调睡眠的时间和结构，并随着年龄的增长而改变。睡眠倾向，特别是 REM 睡眠受到强烈的昼夜节律控制，并被认为在大脑可塑性中发挥重要作用。在这项探索性研究中，我们评估了基于表面的脑形态计量学指标是否与昼夜节律睡眠调节有关，以及这种联系是否随年龄而变化。29 名健康的老年人（55-82 岁；16 名男性）和 28 名年轻参与者（20-32 岁；13 名男性）都接受了结构磁共振成像和 40 小时多小睡方案，以在白天和夜间提取睡眠参数。从经典清醒日采集的 T1 加权图像中估计了皮质厚度和脑回指数。我们观察到，在两个年龄组中，REM 睡眠在 24 小时周期中都有明显的调节，与年轻人相比，老年人的 REM 睡眠调节总体减少。有趣的是，当考虑到整个昼夜节律周期中观察到的 REM 睡眠与年龄相关的总体减少时，REM 睡眠的昼夜差异越大，与老年人右额下回和旁中央区域的皮质回纹增加有关。我们的研究结果表明，在 24 小时周期内，REM 睡眠的分配更为独特，与衰老过程中的区域皮质回纹有关，从而表明昼夜节律 REM 睡眠调节对大脑组织与年龄相关的变化具有保护作用。
