Krueger James M, Frank Marcos G, Wisor Jonathan P, Roy Sandip
College of Medical Sciences, Washington State University-Spokane, WA, USA.
College of Medical Sciences, Washington State University-Spokane, WA, USA.
Sleep Med Rev. 2016 Aug;28:46-54. doi: 10.1016/j.smrv.2015.08.005. Epub 2015 Aug 28.
Sleep function remains controversial. Individual perspectives frame the issue of sleep function differently. We briefly illustrate how sleep measurement and the evolution, tissue organization levels, molecular mechanisms, and regulation of sleep could influence one's view of sleep function. Then we discuss six viable theories of sleep function. Sleep serves host-defense mechanisms and conserves caloric expenditures, but these functions likely are opportunistic functions evolving later in evolution. That sleep replenishes brain energy stores and that sleep serves a glymphatic function by removing toxic byproducts of waking activity are attractive ideas, but lack extensive supporting experimental evidence. That sleep restores performance is experimentally demonstrated and has obvious evolutionary value. However, this hypothesis lacks experimentally verified mechanisms although ideas relating to this issue are presented. Finally, the ideas surrounding the broad hypothesis that sleep serves a connectivity/plasticity function are many and attractive. There is experimental evidence that connectivity changes with sleep, sleep loss, and with changing afferent input, and that those changes are linked to sleep regulatory mechanisms. In our view, this is the leading contender for the primordial function of sleep. However, much refinement of ideas and innovative experimental approaches are needed to clarify the sleep-connectivity relationship.
睡眠功能仍然存在争议。个人观点对睡眠功能问题的界定各不相同。我们简要阐述睡眠测量以及睡眠的演化、组织层次、分子机制和调节如何影响人们对睡眠功能的看法。然后我们讨论六种关于睡眠功能的可行理论。睡眠具有宿主防御机制并节省热量消耗，但这些功能可能是在进化后期演化出来的机会主义功能。睡眠补充大脑能量储备以及睡眠通过清除清醒活动产生的有毒副产品发挥类淋巴功能，这些观点很有吸引力，但缺乏广泛的实验证据支持。睡眠恢复表现这一点已得到实验证明且具有明显的进化价值。然而，尽管提出了与此问题相关的观点，但该假设缺乏经过实验验证的机制。最后，围绕睡眠具有连接性/可塑性功能这一广泛假设的观点众多且颇具吸引力。有实验证据表明，连接性会随着睡眠、睡眠剥夺以及传入输入的变化而改变，并且这些变化与睡眠调节机制相关。在我们看来，这是睡眠原始功能的主要竞争者。然而，需要对观点进行大量细化并采用创新的实验方法来阐明睡眠与连接性的关系。
