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MasakoTamaki_AsymmetricalSleep_2020E-_你能睡觉的同时保持清醒吗?_-
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Many animals need sleep. |
大多动物都需要睡觉, |
Even brainless jellyfish enter sleep-like states where they pulse less and respond more slowly to food and movement. |
甚至没有大脑结构的水母 都会进入类似睡眠的状态, 即脉冲减少,它们会减缓 对食物和周围活动的反应。 |
But all of the threats and demands animals face don’t just go away when it’s time to doze . |
但是动物所面临的威胁和需求, 并不会因为睡眠而自动消失。 |
That’s why a range of birds and mammals experience some degree of asymmetrical sleep where parts of their brain are asleep and other areas are more active. |
这就是为何许多鸟类和哺乳类动物 会经历某种程度的 “半睡眠” 现象, 即大脑的一部分处于休眠状态, 而另一部分则处于清醒状态。 |
brainless:adj.无头脑的,愚蠢的; jellyfish:n.水母;[无脊椎]海蜇;软弱无能的人; pulse:n.脉冲;脉搏;脉率;强劲的音乐节拍;v.搏动;跳动;震动;洋溢着; respond:vi.回答;作出反应;承担责任;n.应答;唱和; doze:vi.打瞌睡;假寐;vt.打瞌睡度过;n.瞌睡; mammals:n.哺乳动物;(mammal的复数) asymmetrical:adj.[数]非对称的(等于asymmetric);不均匀的;不匀称的;
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This is even true for humans. |
甚至人类也会这样。 |
So how does it work? |
那这究竟是怎样做到的呢? |
All vertebrate brains consist of two hemispheres : the right and left. |
所有脊椎动物的大脑 都由两个半球组成:左脑和右脑。 |
Brain activity is usually similar across both during sleep. |
通常,左右脑 在睡眠状态中有相似活动。 |
But during asymmetrical sleep, one brain hemisphere can be in deep sleep while the other is in lighter sleep. |
但在 “半睡眠” 状态下, 大脑的其中一个半球会进入深度睡眠, 而另一个半球则会进入浅度睡眠。 |
vertebrate:adj.脊椎动物的;有脊椎的;n.脊椎动物; consist:v.(与…)一致;并存;共存;由…组成; hemispheres:n.[天]半球(hemisphere的复数形式);
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And in an extreme version called “unihemispheric sleep,” one hemisphere may appear completely awake while the other is in deep sleep. |
在一种叫 “单半球睡眠” 的 极端情况下, 其中一个脑半球会处于完全清醒的状态, 而另一个则处在深度睡眠中。 |
Take bottlenose dolphins. |
以宽吻海豚为例, |
Their breathing is consciously controlled, and they must surface for air every few minutes or they’ll drown . |
它们需要时刻控制呼吸, 每几分钟就需要浮上水面呼吸, 不然就会有溺水的危险。 |
When they have a newborn calf , they must actually swim nonstop for weeks in order to keep it safe. |
当海豚有了新生的幼崽, 它们会不停地游上好几周 以便守在幼崽的身边保证它的安全。 |
extreme:adj.极端的;极度的;偏激的;尽头的;n.极端;末端;最大程度;极端的事物; bottlenose:n.宽吻海豚; consciously:adv.自觉地;有意识地; drown:v.淹没;溺死;浸透;浸泡; newborn:adj.新生的;再生的;n.婴儿; calf:n.小牛;牛犊;腓肠;小腿肚; nonstop:adj.直达的;不休息的;不着陆的;n.直达车;adv.不休息地;
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So dolphins sleep unihemispherically, with just one hemisphere at a time. |
所以海豚是单半球睡眠生物, 每次只用一边大脑睡觉。 |
This allows them to continue swimming and breathing while snoozing . |
这使得它们在打盹的同时, 也能继续游泳和呼吸。 |
Other marine mammals also need asymmetrical sleep. |
还有其他海洋哺乳动物 需要单半球睡眠, |
Fur seals might spend weeks on end migrating at sea. |
像是毛皮海豹, 迁徙时会在海里游上数周, |
They slip into unihemispheric sleep while floating horizontally , holding their nostrils above the surface, closing their upward-facing eye, and keeping their downward-facing eye open. |
其间会横向漂浮在水面 进入单半球睡眠, 将鼻孔伸出水面, 闭上露出水面的那只眼睛, 同时睁开水面以下的那只眼睛。 |
snoozing:n.小睡;打盹儿;vi.小睡;打盹;vt.懒散地打发日子;打盹消磨; marine:adj.海的;海产的;海生的;海船的;n.(尤指美国或英国皇家)海军陆战队士兵; migrating:v.迁移;迁徙;移居(migrate的现在分词); slip:v.溜;下降;滑落;n.纸条;衬裙; horizontally:adv.水平地;地平地; nostrils:n.[解剖]鼻孔(nostril的复数);
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This may help them stay alert to threats from the depths. |
这可以使它们 对海底深处的威胁保持警觉。 |
Similar pressures keep birds partially awake. |
类似的生存压力 也让鸟类保持 “半睡半醒” 的习惯。 |
Mallard ducks sleep in groups, but some must inevitably be on the peripheries . |
绿头鸭喜欢抱团睡觉, 但总有一些会不可避免落单在边上, |
Those ducks spend more time in unihemispheric sleep, with their outward-facing eyes open and their corresponding brain hemispheres more active. |
那些在边上的鸭子 多数时间都处于单半球睡眠。 它们会睁开朝外的那只眼睛, 与此同时,相对应的大脑半球 也会比较清醒。 |
alert:n.警报; adj.警觉的; v.向…报警; partially:adv.部分地;偏袒地; Mallard:n.野鸭;野鸭肉; inevitably:adv.不可避免地;必然地; peripheries:n.外围,边缘;圆周;圆柱体表面; outward-facing:面向外部; corresponding:adj.符合的; v.相一致; (correspond的现在分词)
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Other birds have been shown to catch z’s in midair migration . |
研究证明其他一些鸟 能在半空迁徙时睡觉。 |
While undertaking non-stop transoceanic flights of up to 10 days, frigatebirds either sleep with one or both hemispheres at a time. |
当进行长达 10 天 不眠不休的越洋迁徙时, 军舰鸟可以只有一边大脑在休息, 或是同时两侧大脑都在休息。 |
They do so in seconds-long bursts , usually while riding air currents. |
它们会在快速猛冲时以这种方式入睡, 尤其是穿过气流的时候, |
midair:n.半空中; migration:n.迁移;迁徙;转移;移居; undertaking:n.事业;企业;保证;殡仪业;v.同意;担任;许诺;(undertake的现在分词) non-stop:adj.直达的;中途不停的;adv.不停地; transoceanic:adj.大洋那边的;横渡大洋的; frigatebirds:n.军舰鸟(热带大海鸟)(frigatebird的复数) bursts:[天]爆发;破裂(burst的第三人称单数);
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But the frigatebirds still sleep less than 8% of what they would on land, suggesting a great tolerance for sleep deprivation . |
但军舰鸟在空中的睡眠时间 仍比在陆地上少 8%, 可见它们对睡眠不足 有很强的耐受力。 |
It’s currently unclear whether asymmetrical sleep packs the same benefits as sleep in both hemispheres and how this varies across species . |
目前我们仍不清楚, “半睡眠” 是否与 “完全睡眠” 有一样的好处, 并且这一现象是如何因物种而异的。 |
In one experiment, fur seals relied on asymmetrical sleep while being constantly stimulated . |
在一项实验中,面对不断的刺激, 毛皮海豹倾向于依赖 “半睡眠”。 |
tolerance:n.公差;耐量;宽容;容忍; deprivation:n.剥夺;损失;免职;匮乏;贫困; currently:adv.当前;一般地; unclear:adj.不清楚的;不易了解的; varies:n.多重复合;v.使不同;改变;违背(vary的三单形式); species:n.[生物]物种;种类; relied:v.依赖;依靠;信赖;信任;(rely的过去分词和过去式) constantly:adv.不断地;时常地; stimulated:adj.受激的;v.刺激(stimulate的过去式和过去分词);
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But in recovery , they showed a strong preference for sleep across both hemispheres, suggesting that it was more restorative for them. |
但在补充体力时,它们表现出了 大脑两侧同时睡觉的强烈倾向, 说明这种方式 更有利于它们体力的恢复。 |
Dolphins, on the other hand , have been observed to maintain high levels of alertness for at least five days. |
另一方面, 海豚在至少五天时间内 都保持着高度警惕。 |
By switching which hemisphere is awake, they get several hours of deep sleep in each hemisphere throughout a 24-hour period. |
通过对两侧大脑的交替使用, 它们的每一侧大脑 在二十四小时内都得到了 几小时的深度睡眠时间, |
recovery:n.恢复,复原;痊愈;重获; preference:n.偏爱;爱好;喜爱;偏爱的事物; restorative:n.[药]恢复药,滋补剂;adj.滋补的,有助于复元的;恢复健康的; on the other hand:另一方面; observed:adj.观察的;观测的;v.观察;遵守;注意到(observe的过去分词形式); maintain:v.维持;保持;维修;保养;坚持(意见); alertness:n.警戒;机敏; throughout:adv.自始至终,到处;全部;prep.贯穿,遍及;
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This may be why unihemispheric sleep alone meets their needs. |
这也许是为什么“半睡眠” 足以满足它们的需求。 |
So, what about humans? |
那么,人类又是怎样的呢? |
Have you ever woken up groggy after your first night in a new place? |
当你在新环境过夜后, 醒来是否会觉得大脑昏昏沉沉? |
Part of your brain might’ve spent the night only somewhat asleep. |
那是因为你的部分大脑 没有得到完全的休息。 |
For decades, scientists have recognized that participants sleep poorly their first night in the lab. |
几十年来,科学家们已经意识到 实验对象在实验室过夜的第一天, 睡得并不好, |
groggy:adj.酒醉的,无力的;东歪西倒的; somewhat:n.几分;某物;adv.有点;多少;几分;稍微; recognized:v.认识;认出;辨别出;承认;意识到;(recognize的过去分词和过去式) participants:n.参与者(participant的复数形式);
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It’s actually customary to toss out that night’s data. |
所以,通常他们会 放弃当晚的实验数据。 |
In 2016, scientists discovered that this “first night effect” is a very subtle version of asymmetrical sleep in humans. |
2016 年,科学家们发现这种“初夜效应”, 是一种非常不明显的 人类 “半睡眠” 的例子。 |
They saw that, during the first night, participants experience deeper sleep in their right hemisphere and lighter sleep in their left. |
他们发现,在第一晚 实验对象的右脑会经历更深度的睡眠, 而左脑则是较浅的睡眠。 |
customary:adj.习惯的;通常的;n.习惯法汇编; toss:v.扔,抛,掷;甩(使)摇摆,挥动,颠簸;摇匀;n.掷硬币决定;向上甩头;投掷 subtle:adj.微妙的;精细的;敏感的;狡猾的;稀薄的;
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When exposed to infrequent sounds, that lighter sleeping left hemisphere showed greater bumps in activity. |
当出现低频率声音时, 较浅睡眠的左脑在活动中 显示出了更大的波动, |
Participants also woke up and responded to infrequent sounds faster during the first night than when experiencing deep sleep in both hemispheres during nights following. |
在第一晚实验对象也会醒来 并对低频声音 做出更快的反应, 而第二晚大脑两侧 则都处于深度睡眠。 |
exposed:adj.无遮蔽的; v.暴露; (expose的过去分词和过去式) infrequent:adj.罕见的;稀少的;珍贵的;不频发的; bumps:碰撞(bump的第三人称单数);碰撞(bump的复数); responded:v.回答,回应;作出反应;响应;反应灵敏;(respond的过去式和过去分词)
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This suggests that, like other animals, humans use asymmetrical sleep for vigilance , specifically in unfamiliar environments. |
这一研究结果表明, 像其他动物一样, 人类的 “半睡眠” 是警惕的表现, 特别是当他们处于不熟悉的环境中。 |
So, while your hotel room is obviously not trying to eat you and you’re not going to die if you don’t continue moving, your brain is still keeping you alert. |
显然,你的宾馆房间不会吃了你, 即使你一动不动,你也不会死, 这只是你的大脑表现警惕的方式, |
Just in case . |
以防万一。 |
vigilance:n.警戒,警觉;警醒症; specifically:adv.特别地;明确地; unfamiliar:adj.不熟悉的;不常见的;没有经验的; Just in case:以防万一;作为准备;
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