Sleep benefits motor memory consolidation in young adults, but this benefit is reduced in older adults. Here we sought to understand whether differences in the neural bases of encoding between young and older adults contribute to aging-related differences in sleep-dependent consolidation of an explicit variant of the serial reaction time task (SRTT). Seventeen young and 18 older adults completed two sessions (nap, wake) one week apart. In the MRI, participants learned the SRTT. Following an afternoon interval either awake or with a nap (recorded with high-density polysomnography), performance on the SRTT was reassessed in the MRI. Imaging and behavioral results from SRTT performance showed clear sleep-dependent consolidation of motor sequence learning in older adults after a daytime nap, compared to an equal interval awake. Young adults, however, showed brain activity and behavior during encoding consistent with high SRTT performance prior to the sleep interval, and did not show further sleep-dependent performance improvements. Young adults did show reduced cortical activity following sleep, suggesting potential systems-level consolidation related to automatization. Sleep physiology data showed that sigma activity topography was affected by hippocampal and cortical activation prior to the nap in both age groups, and suggested a role of theta activity in sleep-dependent automatization in young adults. These results suggest that previously observed aging-related sleep-dependent consolidation deficits may be driven by aging-related deficiencies in fast learning processes. Here we demonstrate that when sufficient encoding strength is reached with additional training, older adults demonstrate intact sleep-dependent consolidation of motor sequence learning.

睡眠有益于年轻人的运动记忆巩固，但这种益处在老年人中减少。在这里，我们试图了解年轻人和老年人之间编码神经基础的差异是否会导致串行反应时间任务 (SRTT) 的显式变体的睡眠依赖性巩固中与衰老相关的差异。17 名年轻人和 18 名老年人完成了两个疗程（午睡、起床），相隔一周。在 MRI 中，参与者学习了 SRTT。在清醒或午睡（用高密度多导睡眠图记录）的下午间隔后，在 MRI 中重新评估了 SRTT 的表现。SRTT 表现的成像和行为结果显示，与等间隔清醒相比，老年人在白天小睡后运动序列学习明显依赖睡眠巩固。然而，年轻的成年人，显示编码期间的大脑活动和行为与睡眠间隔前的高 SRTT 性能一致，并且没有显示出进一步的睡眠相关性能改善。年轻人确实表现出睡眠后皮质活动减少，这表明与自动化相关的潜在系统级整合。睡眠生理学数据显示，在两个年龄组中，sigma 活动地形都受到午睡前海马和皮质激活的影响，并表明 theta 活动在年轻人的睡眠依赖自动化中的作用。这些结果表明，先前观察到的与衰老相关的睡眠依赖性巩固缺陷可能是由快速学习过程中与衰老相关的缺陷驱动的。在这里，我们证明当通过额外的训练达到足够的编码强度时，