School of Psychology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Sleep Unit, The Royal's Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Learn Mem. 2022 Dec 23;30(1):12-24. doi: 10.1101/lm.053649.122. Print 2023 Jan.
As we age, the added benefit of sleep for memory consolidation is lost. One of the hallmark age-related changes in sleep is the reduction of sleep spindles and slow waves. Gray matter neurodegeneration is related to both age-related changes in sleep and age-related changes in memory, including memory for problem-solving skills. Here, we investigated whether spindles and slow waves might serve as biological markers for neurodegeneration of gray matter and for the related memory consolidation deficits in older adults. Forty healthy young adults (20-35 yr) and 30 healthy older adults (60-85 yr) were assigned to either nap or wake conditions. Participants were trained on the Tower of Hanoi in the morning, followed by either a 90-min nap opportunity or period of wakefulness, and were retested afterward. We found that age-related changes in sleep spindles and slow waves were differentially related to gray matter intensity in young and older adults in brain regions that support sleep-dependent memory consolidation for problem-solving skills. Specifically, we found that spindles were related to gray matter in neocortical areas (e.g., somatosensory and parietal cortex), and slow waves were related to gray matter in the anterior cingulate, hippocampus, and caudate, all areas known to support problem-solving skills. These results suggest that both sleep spindles and slow waves may serve as biological markers of age-related neurodegeneration of gray matter and the associated reduced benefit of sleep for memory consolidation in older adults.
随着年龄的增长，睡眠对记忆巩固的额外益处会消失。与睡眠相关的一个标志性的年龄相关变化是睡眠纺锤波和慢波的减少。灰质神经退行性变与睡眠的年龄相关变化和与年龄相关的记忆变化有关，包括解决问题的技能的记忆。在这里，我们研究了纺锤波和慢波是否可以作为灰质神经退行性变和老年人相关记忆巩固缺陷的生物标志物。40 名健康的年轻成年人（20-35 岁）和 30 名健康的老年人（60-85 岁）被分配到小睡或清醒条件。参与者在早上接受汉诺塔训练，然后是 90 分钟的小睡机会或清醒时间，之后进行重新测试。我们发现，睡眠纺锤波和慢波的年龄相关变化与年轻和老年人大脑中支持解决问题技能的睡眠依赖性记忆巩固的灰质强度存在差异。具体来说，我们发现纺锤波与新皮层区域（例如躯体感觉和顶叶皮层）的灰质有关，而慢波与前扣带、海马体和尾状核的灰质有关，所有这些区域都支持解决问题的技能。这些结果表明，睡眠纺锤波和慢波都可能是与年龄相关的灰质神经退行性变和老年人睡眠对记忆巩固的益处降低的生物标志物。
