Sleep serves disparate functions, most notably neural repair, metabolite clearance and circuit reorganization. Yet the relative importance remains hotly debated. Here, we create a novel mechanistic framework for understanding and predicting how sleep changes during ontogeny and across phylogeny. We use this theory to quantitatively distinguish between sleep used for neural reorganization versus repair. Our findings reveal an abrupt transition, between 2 and 3 years of age in humans. Specifically, our results show that differences in sleep across phylogeny and during late ontogeny (after 2 or 3 years in humans) are primarily due to sleep functioning for repair or clearance, while changes in sleep during early ontogeny (before 2 or 3 years) primarily support neural reorganization and learning. Moreover, our analysis shows that neuroplastic reorganization occurs primarily in REM sleep but not in NREM. This developmental transition suggests a complex interplay between developmental and evolutionary constraints on sleep.

睡眠具有不同的功能，最显着的是神经修复、代谢物清除和电路重组。然而，相对重要性仍然存在激烈的争论。在这里，我们创建了一个新的机制框架，用于理解和预测睡眠在个体发育和整个系统发育过程中的变化。我们使用这个理论来定量区分用于神经重组和修复的睡眠。我们的研究结果揭示了人类在 2 到 3 岁之间的突然转变。具体来说，我们的研究结果表明，系统发育和个体发育晚期（人类 2 或 3 年后）睡眠的差异主要是由于睡眠功能修复或清除，而个体发育早期（2 或 3 年前）睡眠的变化主要支持神经重组和学习。而且，我们的分析表明，神经可塑性重组主要发生在快速眼动睡眠中，而不是在非快速眼动睡眠中。这种发育转变表明睡眠的发育和进化限制之间存在复杂的相互作用。