Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Centre, 2333 ZC Leiden, The Netherlands.
Department of Physiology, Anatomy and Genetics, University of Oxford, OX1 3PT Oxford, UK.
Sci Rep. 2017 Mar 3;7:43656. doi: 10.1038/srep43656.
Changes in sleep pattern are typical for the normal aging process. However, aged mice show an increase in the amount of sleep, whereas humans show a decrease when aging. Mice are considered an important model in aging studies, and this divergence warrants further investigation. Recently, insights into the network dynamics of cortical activity during sleep were obtained by investigating characteristics of individual electroencephalogram (EEG) slow waves in young and elderly humans. In this study, we investigated, for the first time, the parameters of EEG slow waves, including their incidence, amplitude, duration and slopes, in young (6 months) and older (18-24 months) C57BL/6J mice during undisturbed 24 h, and after a 6-h sleep deprivation (SD). As expected, older mice slept more but, in contrast to humans, absolute NREM sleep EEG slow-wave activity (SWA, spectral power density between 0.5-4 Hz) was higher in the older mice, as compared to the young controls. Furthermore, slow waves in the older mice were characterized by increased amplitude, steeper slopes and fewer multipeak waves, indicating increased synchronization of cortical neurons in aging, opposite to what was found in humans. Our results suggest that older mice, in contrast to elderly humans, live under a high sleep pressure.
睡眠模式的变化是正常衰老过程的典型特征。然而，老年小鼠的睡眠时间增加，而人类随着年龄的增长睡眠时间减少。小鼠被认为是衰老研究中的重要模型，这种差异值得进一步研究。最近，通过研究年轻和老年人类个体脑电图 (EEG) 慢波的特征，获得了睡眠期间皮质活动网络动力学的新见解。在这项研究中，我们首次研究了年轻（6 个月）和老年（18-24 个月）C57BL/6J 小鼠在未受干扰的 24 小时和 6 小时睡眠剥夺 (SD) 后，EEG 慢波的参数，包括它们的发生率、幅度、持续时间和斜率。正如预期的那样，老年小鼠睡眠时间更长，但与人类相反，与年轻对照组相比，老年小鼠的非快速眼动 (NREM) 睡眠 EEG 慢波活动 (SWA，0.5-4 Hz 之间的频谱功率密度) 更高。此外，老年小鼠的慢波表现出幅度增加、斜率更陡和多峰波减少，表明衰老过程中皮质神经元的同步性增加，与人类的发现相反。我们的研究结果表明，与老年人类相比，老年小鼠生活在高睡眠压力下。
