Sleep is known to be crucial for learning and memory formation. What's more, scientists have even managed to pick out specific memories and consolidate them during sleep. However, the exact mechanisms behind this were unknown — until now.
睡眠对于学习和记忆形成至关重要（crucial for），科学家们甚至试图挑选出特定的记忆，并在睡眠中加以巩固。然而，睡眠有利于学习和记忆的确切机制至今不明。
* the mechanism behind/underlying/for this都可以。
Those among us who grew up with the popular cartoon "Dexter's Laboratory" might remember the famous episode wherein Dexter's trying to learn French overnight.
He creates a device that helps him to learn in his sleep by playing French phrases to him.
Of course, since the show is a comedy, Dexter's record gets stuck on the phrase "Omelette du fromage" and the next day he's incapable of saying anything else.
This is, of course, a problem that puts him through a series of hilarious situations.
大家可能还记得动画片“德克斯特的实验室”中的那个著名的情节：
德克斯特把第二天要考试的内容弄到了一个机器里，准备在睡觉的时候听，可是机器故障，一晚上只播放了1个单词。
结果，第二天起床之后这个可怜的孩子只会说Omelette du fromage这一个单词了。
The idea that we can learn in our sleep has captivated the minds of artists and scientists alike; the possibility that one day we could all drastically improve our productivity by learning in our sleep is very appealing. But could such a scenario ever become a reality?
在睡眠中学习的想法吸引（captivate）了众多艺术家和科学家，也许有一天我们都可以通过在睡眠中学习来极大的提高效率，这非常吸引人。不过这样的情景真的能够实现（become a reality）吗？
New research seems to suggest so, and scientists in general are moving closer to understanding precisely what goes on in the brain when we sleep and how therestful state affects learning and memory formation.
新的研究似乎支持这一点，对于睡眠时大脑里在发生什么，以及这种静息状态如何影响学习和记忆形成，科学家们有了越来越清晰的认识（moving closer to understanding precisely）。
For instance, previous studies have shown that non-rapid eye movement (non-REM) sleep — or dreamless sleep — is crucial for consolidating memories.
比如，以往的研究已经表明，非快速动眼睡眠期（无梦期）对于巩固记忆至关重要。
* 两个破折号（em dash）相当于两个逗号。 更多标点符号使用请参考：中国留学生英文论文写作常见标点符号错误及案例解析
It has also been shown that sleep spindles, or sudden spikes in oscillatory brain activity that can be seen on an electroencephalogram (EEG) during the second stage of non-REM sleep, are key for this memory consolidation.
尤其是非快速动眼期的第二阶段出现在脑电图上的睡眠纺锤波对于巩固记忆非常关键。
Scientists were also able to specifically target certain memories and reactivate, or strengthen, them by using auditory cues.
科学家们也能用听觉提示来再次激活（强化）特定的记忆。
However, the mechanism behind such achievements remained mysterious until now. Researchers were also unaware if such mechanisms would help with memorizing new information.
然而，这些成果背后的机制仍然不明确，研究者们也不确定这些机制是否可以帮助记忆新的信息。
* help with sth/doing sth或者help (to) do sth.
Therefore, a team of researchers set out to investigate. Scott Cairney, from the University of York in the United Kingdom, co-led the research with Bernhard Staresina, who works at the University of Birmingham, also in the U.K.
Their findings were published in the journal Current Biology.
因此，两位英国科学家Scott Cairney和Bernhard Staresina共同主持了一项研究来探讨在睡眠中巩固记忆的机制，研究成果发表在了Current Biology上。
Sleep spindles key for memory consolidation
Cairney explains the motivation for the research, saying, "We are quite certain that memories are reactivated in the brain during sleep, but we don't know the neural processes that underpin this phenomenon."
Cairney说：“我们非常肯定记忆在睡眠中会被再次激活，但我们不知道这一现象背后的神经机制（neural processes）。”
* 这里的processes相当于mechanisms；underpin相当于underlie、behind，也可以表达成the neural processes/mechanisms underpinning/underlying/behind this phenomenon.
"Sleep spindles," he continues, "have been linked to the benefits of sleep for memory in previous research, so we wanted to investigate whether these brain waves mediate reactivation."
“以往的研究已经表明，睡眠有益于记忆与纺锤波有关，所以我们想要探究睡眠纺锤波是否介导记忆的再次激活。”
"If they support memory reactivation, we further reasoned that it could be possible to decipher memory signals at the time that these spindles took place."
“如果是这样的话，我们有理由认为，当这些纺锤波出现的时候，我们或许可以破译记忆信号。”
* these brain waves mediate reactivation和they support memory reactivation是一回事，英文里不喜欢重复，同样的事情换着法的说。
To test their hypotheses, Cairney and his colleagues asked 46 participants "to learn associations between words and pictures of objects or scenes before a nap."
为了检验这一假设， Cairney的研究团队让46名试验对象在睡前学习单词以及相关联的物体或情景的图像。
Afterward, some of the participants took a 90-minute nap, whereas others stayed awake. To those who napped, "Half of the words were [...] replayed during the nap to trigger the reactivation of the newly learned picture memories," explains Cairney.
之后，部分试验对象小睡90分钟，而其他试验对象不睡觉。前者在睡眠时，对之前单词中的一半进行重新播放，从而再次激活之前的图像记忆。
"When the participants woke after a good period of sleep," he says, "we presented them again with the words and asked them to recall the object and scene pictures."
试验者醒来后，再次把单词给他们看（present them with sth/present sth to sb），并让他们回忆物体和情景的图片。
"We found that their memory was better for the pictures that were connected to the words that were presented in sleep, compared to those words that weren't," Cairney reports.
试验者对睡眠时重放过的单词的相关图片的记忆要好于那些没有重放过的单词。
* 如果说...their memory of the pictures that were connected to the words that were presented in sleep was better ....，主语就太长了，所以可以把冗长的结构甩到后面，使用... was better for ....这样的句型。
Using an EEG machine, the researchers were also able to see that playing the associated words to reactivate memories triggered sleep spindles in the participants' brains.
脑电图显示，播放相关单词再次激活记忆时，试验者大脑中出现了睡眠纺锤波。
More specifically, the EEG sleep spindle patterns "told" the researchers whether the participants were processing memories related to objects or memories related to scenes.
而且，从睡眠纺锤波的波型可以判断试验者是在处理与物体相关的记忆还是与情景相关的记忆。
How to boost memory while we sleep
"Our data suggest that spindles facilitate processing of relevant memory features during sleep and that this process boosts memory consolidation," says Staresina.
纺锤波促进睡眠时对相关记忆特征的处理，从而促进了记忆的巩固。
"While it has been shown previously," he continues, "that targeted memory reactivation (delivery of auditory cues) can boost memory consolidation during sleep, we now show that sleep spindles might represent the key underlying mechanism."
之前的研究已经表明，睡眠时的靶向记忆再激活（播放相关内容的声音）可以促进记忆的巩固，而这项研究表明睡眠纺锤波可能是这背后的关键机制。
Cairney adds, "When you are awake you learn new things, but when you are asleep you refine them, making it easier to retrieve them and apply them correctly when you need them the most. This is important for how we learn but also for how we might help retain healthy brain functions."
我们在清醒时学习新东西，在睡眠时对其进行完善，使得我们在最需要的时候可以更加容易的在大脑中找到它们并准确应用。这对于我们掌握正确的学习方法以及保持大脑健康很重要。
Staresina suggests that this newly gained knowledge could lead to effective strategies for boosting memory while sleeping.
根据这个新发现，我们可以找到在睡眠中巩固记忆的有效方法，那就是：
Direct induction of sleep spindles — for example, by stimulating the brain with electrodes — perhaps combined with targeted memory reactivation, may enable us to further improve memory performance while we sleep."
- Bernhard Staresina
直接诱导睡眠纺锤波，比如用电极刺激大脑，或许同时还可以播放相关内容的声音，想不想试试。
当然，这种方法不是人人都可以做到的，建议同学们还是按照自己的方法去学习，有需要课程辅导的小伙伴，可以关注留学府在线教育，24小时在线顾问微信：yuff996，尽全力去帮助留学生度过学习难关。