Sleep spindles are a physiological marker of off-line memory consolidation. In young adults, sleep spindles are preferentially responsive to encoded information that is tagged as having future relevance. Older adults, on the other hand, show reduced capacity for future simulation and alterations in sleep physiology. Healthy young adults (n = 38) and older adults (n = 28) completed an adaptation night, followed by two in-laboratory polysomnography nights, in which they mentally simulated future events or remembered past events, recorded via written descriptions. We quantified the degree of future/past thinking using linguistic analysis of time orientation. In young adults, greater future thinking was linked to greater spindle density, even when controlling for gender, age, and word count (rp = .370, p = .028). The opposite was true for older adults, such that greater future thinking was associated with reduced spindle density (rp = -.431, p = .031). These patterns were selective to future thinking (not observed for past thinking). The collective findings implicate an impaired interaction between future relevance tagging and sleep physiology as a mechanism by which aging compromises sleep-dependent cognitive processing.

中文翻译：

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预期的睡眠大脑：情景未来思维和额叶睡眠纺锤体的年龄相关差异。

睡眠纺锤波是离线记忆巩固的生理标志。在年轻人中，睡眠纺锤波优先响应标记为具有未来相关性的编码信息。另一方面，老年人表现出未来模拟和睡眠生理改变的能力下降。健康的年轻人 (n = 38) 和老年人 (n = 28) 完成了一个适应之夜，然后是两个实验室多导睡眠图之夜，他们在心理上模拟了未来的事件或记住了过去的事件，并通过书面描述记录下来。我们使用时间取向的语言分析量化了未来/过去思考的程度。在年轻人中，更大的未来思维与更大的纺锤体密度有关，即使在控制性别、年龄和字数的情况下也是如此 (rp = .370, p = .028)。老年人的情况正好相反，因此，更大的未来思维与纺锤体密度的降低有关（rp = -.431，p = .031）。这些模式对未来的思考是有选择性的（过去的思考没有观察到）。集体研究结果表明，未来相关性标签和睡眠生理学之间的相互作用受损，这是衰老损害睡眠依赖认知处理的一种机制。