Neuroscience and Behavior Program, University of Massachusetts Amherst, Amherst, MA, USA.
Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, MA, USA.
Eur J Neurosci. 2021 Nov;54(9):7332-7354. doi: 10.1111/ejn.15468. Epub 2021 Oct 5.
Ageing-related changes in grey matter result in changes in the intensity and topography of sleep neural activity. However, it is unclear whether these findings can be explained by ageing-related differences in sleep pressure or circadian influence. The current study used high-density electroencephalography to assess how grey matter volume differences between young and older adults mediate and moderate neuroscillatory activity differences during a midday nap following a motor sequencing task. Delta, theta, and sigma amplitude were reduced in older relative to young adults, especially over frontocentral scalp, leading to increases in relative delta frontality and relative sigma lateral centroposteriority. Delta reductions in older adults were mediated by grey matter loss in frontal medial cortex, primary motor cortex, thalamus, caudate, putamen, and pallidum, and were moderated by putamen grey matter volume. Theta reductions were mediated by grey matter loss in primary motor cortex, thalamus, and caudate, and were moderated by putamen and pallidum grey matter volume. Sigma changes were moderated by putamen and pallidum grey matter volume. Moderation results suggested that across frequencies, young adults with more grey matter had increased activity, whereas older adults with more grey matter had unchanged or decreased activity. These results provide a critical extension of previous findings from overnight sleep in a midday nap, indicating that they are not driven by sleep pressure or circadian confounds. Moreover, these results suggest brain regions associated with motor sequence learning contribute to sleep neural activity following a motor sequencing task.
年龄相关的灰质变化导致睡眠神经活动的强度和拓扑结构发生变化。然而，目前尚不清楚这些发现是否可以用睡眠压力或昼夜节律的影响来解释与年龄相关的差异。本研究使用高密度脑电图来评估年轻人和老年人之间的灰质体积差异如何在完成运动序列任务后的中午小睡期间调节和适度神经振荡活动的差异。与年轻人相比，老年人的 delta、theta 和 sigma 振幅降低，尤其是在前额中央头皮，导致相对 delta 额侧性和相对 sigma 侧后中央性增加。老年人的 delta 减少与额叶内侧皮质、初级运动皮质、丘脑、尾状核、壳核和苍白球的灰质损失有关，并且受到壳核灰质体积的调节。theta 减少与初级运动皮质、丘脑和尾状核的灰质损失有关，并受到壳核和苍白球灰质体积的调节。sigma 变化受壳核和苍白球灰质体积的调节。调节结果表明，在不同频率下，灰质较多的年轻人活动增加，而灰质较多的老年人活动不变或减少。这些结果为以前在中午小睡中进行的整夜睡眠研究中的发现提供了重要的扩展，表明它们不是由睡眠压力或昼夜节律的混淆引起的。此外，这些结果表明与运动序列学习相关的大脑区域有助于运动序列任务后的睡眠神经活动。
