科学与数学npr.org
大脑在睡眠时自我清除毒素
Brains Sweep Themselves Clean of Toxins During Sleep (2013)
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NPR 2013 年报道一项研究：睡眠时大脑会通过增强的脑脊液流动冲刷代谢废物，包括对脑细胞有害的蛋白质，从而完成自我清理。文章把这一过程与睡眠的功能以及阿尔茨海默病等神经退行性疾病联系起来。标题里的“毒素”更准确地说应是脑内代谢废物。
为什么经久不衰：它用直观的“大脑夜间清洗”解释了睡眠为何不可或缺，并把睡眠与神经退行性疾病联系起来，因此多年后仍被反复讨论。
HN 评论精选
致死性家族失眠症说明长期完全失眠可在约 9 到 18 个月内致命，睡眠对生存至关重要。
有一次公路旅行，我和朋友熬夜争论人不睡多久会死。起初我认为睡眠比吃饭更重要，人会先因缺觉而死。查资料后我们了解到致死性家族失眠症：一种突变蛋白导致永久失眠，无药可治，全球约 100 人患病。患者出现症状后平均寿命约 18 个月；前 9 个月失眠不断加重，出现偏执、惊恐发作和幻觉，安眠药和巴比妥类会加重病情并加速发病；之后患者完全无法入睡，进入痴呆状态，最终变得缄默、无反应，这一永久失眠阶段持续 9 个月。所以最终学到的是：人可以在约 9 个月完全不睡后才死去；不确定何时出现不可逆脑损伤，但这仍是个有趣的发现。
roymurdock查看英文原文
My friends and I were up late on a road trip once. We started to argue about how long it would take someone to die from lack of sleep. Initially, I held the position that sleep was probably more important than eating food, and that you would die from sleep deprivation before you died from starvation. We looked it up, and learned about a disease called fatal familial insomnia. A mutated protein causes the onset of permanent insomnia, and there is no cure. It affects about 100 individuals worldwide. [1] The average life expectancy of a patient is 18 months after the onset of symptoms. The first 9 months is a worsening case of insomnia, where the patient will experience paranoia, panic attacks, and hallucinations. Sleeping pills and barbiturates have been shown to worsen the clinical manifestations and hasten the onset of the disease. The individual then becomes completely unable to sleep, and will enter a state of dementia before becoming completely mute and unresponsive. This second state of permanent insomnia lasts for 9 months. So ultimately, we learned that you can go for 9 months without sleeping before you die. I'm not sure at what point you'll suffer irreversible brain damage, but that was an interesting finding for me nonetheless. [1] https://en.wikipedia.org/wiki/Fatal_familial_insomnia
能否在清醒时人工诱发脑脊液冲刷，从而减少睡眠需求，是一个有实际应用潜力的工程设想。
作为工程师，我忍不住想：这能人工合成吗？如果在清醒时诱发这种“洗碗机式”的脑脊液冲刷，我们能否大幅减少睡眠甚至不睡？我不是说这一定是好主意，但它会有很多实际应用——飞行员、卡车司机等可以健康地保持清醒，而不是靠兴奋剂。我对睡眠科学感兴趣已久，还写过 side project sleepyti.me，流量不错，但神经科学我大多不懂。
david_shaw查看英文原文
The engineer in me has to wonder: is this something we can synthesize? If it were possible to induce this "dishwasher-like" surge of cerebrospinal fluid in the brain during waking hours, would we be able to live off of significantly less (or no) sleep? I'm not saying that it's necessarily a good idea, but it would have a plethora of practical applications -- pilots, truckers, etc. would be able to stay awake in a healthful way, rather than by ingesting stimulants. I've been interested in the science of sleep for a while -- I wrote a side project, http://sleepyti.me, that actually gets quite a bit of traffic -- but neuroscience is mostly lost on me.
脑内代谢废物若清除不及时会损害突触传递和神经元，因此睡眠清理过程很重要。
又一个要好好睡一觉的理由。神经元活动的许多代谢降解产物（不只是 beta-淀粉样蛋白）本应被快速高效地从脑间质中清除，因为神经元对环境高度敏感。已记录的负面影响包括：影响突触传递、降低胞质 Ca2+ 浓度（Ca2+ 是触发神经递质释放到突触、促进信息传递的最终环节之一），以及造成不可逆的神经元损伤。
roflmyeggo查看英文原文
Yet another reason to get a good nights sleep. Many of these metabolic degradation products (not just beta-amyloid) of neuronal cell activities should readily be cleared quickly and efficiently from the interstitial space of the brain due to the highly sensitive nature of neuronal cells to their environment. Some negative effects documented from these byproducts include: negatively effecting synaptic transmission[1], decreasing cytosolic Ca2+ concentrations[2] (Ca2+ is one of the final players in the triggering the release of neurotransmitters into the synapse between neurons to facilitate messages), and irreversible neuronal injury[3]. [1] - K. Parameshwaran, M. Dhanasekaran, V. Suppiramaniam, Amyloid beta peptides and glutamatergic synaptic dysregulation. Exp. Neurol. 210, 7–13 (2008) [2] - K. V. Kuchibhotla, S. T. Goldman, C. R. Lattarulo, H. Y. Wu, B. T. Hyman, B. J. Bacskai, Abeta plaques lead to aberrant regulation of calcium homeostasis in vivo resulting in structural and functional disruption of neuronal networks. Neuron 59, 214–225 (2008) [3] - M. P. Mattson, Calcium and neuronal injury in Alzheimer’s disease. Contributions of beta-amyloid precursor protein mismetabolism, free radicals, and metabolic compromise. Ann. N. Y. Acad. Sci. 747, 50–76 (1994)
报道整体可靠，但“toxins”是外行且易误导的用词；TBI 与长期睡眠紊乱的关联也值得研究。
实际研究相当有趣，睡眠障碍本身也很迷人。有证据表明创伤性脑损伤（TBI）可造成持久的睡眠周期紊乱；睡眠紊乱对 TBI 长期影响的作用，可能比先前认为的大得多。文章评论：这算是相当好的科学报道，确实提供了所引用研究的链接。我的小意见是它使用了“Toxins”一词；这个词会触发我的警惕，让我立刻怀疑报道。关于人体的科学论文很少使用“Toxins”，而更偏好精确术语，如“脑内废物产物”，或直接使用化学名称。“Toxins”是个规范性的外行词，常被用来囊括各种考虑不周的解释和伪科学。
bitexploder查看英文原文
The actual research is quite interesting. Sleep disorders themselves are fascinating. There is evidence that TBI (traumatic brain injury) can cause lasting sleep cycle disruption. Perhaps sleep disruption and TBI is a much bigger factor in the lasting impact of TBI than previously thought. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482689/). Article review: This is pretty good science reporting, actually providing a link to the study being referenced. My one nit is the use of the word "Toxins". That is a trigger word for me that immediately makes me suspicious of the reporting. Scientific papers about the human body very rarely if ever use the word "Toxins" preferring precise terminology such as "brain waste products" or just keeping to the chemical names at hand. "Toxins" is one of those normative layman words that gets used to sweep up all sorts of ill-conceived explanations and pseudo-science.
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