一个永不睡觉的身体单元

According to the National Sleep Foundation, almost every part of the body experiences significant changes during sleep. When we fall asleep, sleep signals are sent throughout the body as thousands of neurons in the brain shift from the waking to sleeping state. Getting restorative sleep reinforces the cardiovascular and immune systems, helps regulate metabolism, consolidates memory, and allows the body to recover in general. Things like our breathing, muscle tone, heart rate, and hormone levels change considerably when sleeping.

根据美国国家睡眠基金会的报道，几乎身体的每一部分在睡眠过程中都经历了显著的变化。当我们进入睡眠状态时，睡眠信号被发送到全身，大脑中成千上万的神经元从清醒状态转移到睡眠状态。获得恢复性睡眠可以增强心血管和免疫系统，帮助调节新陈代谢，巩固记忆，并使身体总体恢复。睡眠时，我们的呼吸、肌肉张力、心率和激素水平都会发生显著变化。

But according to a study in Nature Human Behavior, sleeping is not an isolated activity. Slumberers go into "standby mode," where they can continue tracking relevant signals, maintaining the ability to "rapidly awake when necessary." It's how a new parent can wake instantly to the sound of their crying infant but ignore the din of traffic outside their window. Or how you can wake up to the sound of someone calling your name, but tune out other conversation.

但根据《自然人类行为》的一项研究，睡眠并不是一项孤立的活动。睡眠者进入“待机模式”，他们可以继续跟踪相关信号，保持“必要时快速醒来”的能力。这就是为什么新手爸妈能够在听到婴儿哭闹声时立即醒来，而忽略窗外的交通噪音。或者你可以在听到有人叫你的名字时醒来，而听不到其他的谈话。

Researchers at Vanderbilt University studied the brainwaves of preschool-aged children to look for memory traces for sounds heard during nap time (via Newswise). The researchers tested children individually using a portable electroencephalogram (EEG) machine in a silent room at a university preschool. Once the children were asleep, three "nonsense words" were played to each child for a short span of time. Then, once the children were awake, they were again hooked up to the EEG machine and played the same words, mixed in with other words they had not heard previously. The children showed positive signs for recognizing these test words, indicating that they continued to process auditory information even when sleeping.

范德比尔特大学的研究人员研究了学龄前儿童的脑波，以寻找在午睡时听到的声音的记忆痕迹。研究人员在一所大学幼儿园的一间安静的房间里，使用便携式脑电图仪对儿童进行了单独测试。一旦孩子们睡着了，就开始播放三个“无意义的单词”，时间很短。然后，一旦孩子们醒来，他们再次被连接到脑电图机，播放相同的单词，并混入其他他们之前没有听到的单词。这些孩子在识别这些测试词时表现出积极的迹象，这表明他们即使在睡觉时也在继续处理听觉信息。

Thomas Andrillon, a research fellow at Monash University in Australia who worked on the Nature Human Behavior study, confirmed that people are more likely to wake up to relevant sounds. "It seems therefore that the sleeping brain remains somewhat vigilant," he told Vice. So even though it might seem like our ears turn off while sleeping, science tells us they're always on alert. Next time you think your sleeping partner or child in the room can't register what you're saying, think again.

澳大利亚莫纳什大学(Monash University)研究人员托马斯·安德里隆(Thomas Andrillon)参与了《自然与人类行为》(Nature Human Behavior)的研究，他证实，人们更有可能在相关声音中醒来。“因此，睡眠中的大脑似乎仍保持着一定程度的警觉。”所以，尽管看起来我们的耳朵在睡觉时关掉了，但科学告诉我们，它们一直都在保持警惕。下次当你认为你的伴侣或孩子在房间里不能听到你在说什么时，再想想。