Click the link in the description to get a 25% off a Fabulous premium subscription.

點擊描述欄的連結可以獲得 Fabulous 高級訂閱的七五折優惠。

Let me ask you a question: What came first, sleep or the brain?

問你一個問題：是先有睡眠還是先有腦袋？

Many would probably answer that question with "brain", obviously.

很明顯地，許多人可能會回答先有「腦袋」。

Except, recent research points out that sleep might not be as connected to the brain as scientists once thought.

但是最近的研究指出睡眠與大腦的關聯可能與當初科學家認為的不同。

Because organisms with super simple neural networks can still sleep, sort of like us humans.

因為就算只有過度簡單神經系統的有機體仍是可以睡眠，就像人類一樣。

So, if these organisms can sleep, then what is "sleep", anyways?  

如果這些有機體能夠睡眠，那「睡著」到底是什麼？

Well, there are lots of creatures that need to sleep, but they don't all approach it in the same fashion.  

有很多生物都需要睡眠，但他們不會都用同樣的方式。

For example, humans usually sleep for several hours in a row, with teenagers being the ones who sleep the most.

例如人類通常一次要睡好幾個小時，青少年要睡最久。

Wild elephants, though, only sleep for a couple hours a day, sometimes going days without entering a deeper, more restful type of sleep.

野生大象一天只需睡眠幾小時，有時會好幾天都沒有進入深層、休息的睡眠。

So, what's the brain doing while these creatures are snoozing?

當這些生物在小睡時，他們的腦袋在做什麼？

Researchers can measure the electromagnetic signals coming from the brain to get an understanding of what's happening in there during sleep.

研究者透過觀測腦袋的電磁信號來了解腦袋在睡眠時發生的事。

Let's take dolphins, for example.

來看看海豚的例子。

Their way of sleeping is known as unihemispheric, slow-wave sleep.

他們睡覺的方式是半腦慢波睡眠。

Which means they sleep with half of their brain.

代表他們只會用半邊的腦睡眠。

When researchers measured the electromagnetic signals coming from dolphin brains, the signals coming from each side of the brain were completely different.

當研究人員觀測海豚腦袋的電磁信號時，兩邊的波動是完全不同的。

Half of the brain was in slow-wave sleep, while the other side of the brain showed signs of wakefulness.

一邊的腦袋是在慢波睡眠，而另一邊的腦袋則呈現清醒的波動。

But we can also easily observe other, more outward signs that dolphins are asleep.

但我們也可以輕易觀察到海豚睡著時其他的外部特徵。

For example, they might close one eye ⏤ the eye opposite the brain hemisphere that's asleep.

例如他們可能會閉上一隻眼，另一隻眼的腦袋就在睡覺。

And they may stick close to the surface of the water so that they're able to easily surface to breathe.

他們也可能會離水平面很近，這樣他們就可以輕易地浮出水面呼吸。

And studies investigating sleep in invertebrates, like fruit flies and cockroaches, found that these creatures also do things that signal that they're asleep.

研究調查發現無脊椎動物像果蠅或蟑螂在睡眠時，也會有他們睡覺的行為。

These include a decrease in their behavior and responsiveness as well as a change their body posture.

這包括降低他們行為能力和反應能力，也會改變身體姿勢。

So, factoring in the different ways creatures sleep, plus the idea that there are these common tell-tale signs that a creature is sleeping, researchers began to look for sleep all over the tree of life.

分析生物不同的睡眠方式，加上生物睡眠時常見的電磁波訊號，研究者們開始觀察所有生命體的睡眠。

And they found evidence in a lot of organisms, including some very simplistic creatures, like hydras and jellyfish.  

他們發現在許多有機體找到證據，包括過度簡單的生物，像是水螅跟水母。

Compared to us humans, their neurons aren't as densely packed together.

跟我們人類相比，他們的神經元沒有那麼緊密地聚在一起一起。

They're more like a light mesh of neurons than brains.

比起大腦，他們更像一個精巧的神經元網。

By studying this mesh, researchers can tell more about what the first sleeping creature was like and what it was using sleep for.

根據這些神經元網，研究者們可以討論出更多第一種會睡眠生物是什麼，跟睡眠的用意。

A potential clue for that first sleeping critter is jellyfish, which can enter that sleep state, leading scientists to believe that sleep evolved more than one billion years ago.

一個可能的線索指出第一個會睡眠的生物是水母，牠可以進入睡眠狀態。讓科學家們認為睡眠是在一百多萬年前演化出來的。

And finding where in the tree of life organisms like jellyfish converge with mammals can help researchers uncover the incredibly ancient common ancestor that we share.

找到像水母等有機體和哺乳動物在生命樹上是有聚集的，讓研究者揭開我們共享相同的祖先。

Now, for creatures with only a sparse mesh of neurons, researchers think that sleep probably plays a role in their metabolism, the amount of energy a creature's body uses to maintain itself.

對於僅有少數神經元網的生物，研究者認為睡眠可能在他們的新陳代謝扮演重要角色，生物身體要用來維持本身的能量。

So for organisms that have a simplistic neural network, their bodies are just changing what they do with the available energy.

對於只有簡單神經系統的有機體，他們的身體只是跟著可用能量轉換他們的行為。

Entering a state of sleep may trigger reactions to occur that can't happen while the creature is awake.

進入睡眠階段可能會觸發生物在清醒時沒發生過的反應。

Or sleep may just provide enough available energy for these reactions to take place.

或睡眠可能只是為這些反應提供足夠的能量。

For example, the nematode C. elegans uses the time it's asleep to grow and repair its tissues.

例如秀麗隱桿線蟲用睡眠時間來發育跟修復他的組織。

​​This creature doesn't sleep at regular intervals each day.

這種生物不會每天都有規律的休息。

Instead, it only sleeps after periods of development.

他反而會在發育期後睡覺。

And researchers have also found that sleep-deprived hydras pause the daily division of their body cells.

研究者也發現被剝奪睡眠的水螅會中斷每日身體細胞的分裂。

Recent research also links metabolism and sleep in organisms with more complex neural networks, like humans.

近期的研究也把代謝和更複雜神經系統的有機體睡眠結合，就像人類。

So, sleep is tightly woven into the human body's hormonal and metabolic processes and is vital in keeping the metabolism functioning properly.

睡眠跟人類身體的賀爾蒙和代謝過程緊密地相連，對代謝功能正常的運作也是很重要的。

Which means if you're sleep-deprived or have a sleep disorder, it may negatively impact the body's metabolism.

就代表如果你睡眠被剝奪或是有睡眠障礙，就可能會對身體的代謝有負面影響。

So, animals from humans to critters with just a mesh of neurons can at least sort of sleep, but what if you don't have any neurons at all?

從動物到人類到只有神經元網的生物至少都可以睡眠，但萬一你沒有神經怎麼辦？

That ancient common ancestor between jellyfish and mammals probably had neurons that would have transmitted a signal to the muscles to cause the organism to move.

水母和哺乳類在古代的共同祖先可能就有神經元，他們可以把指令傳送到肌肉，讓組織移動。

And when it wasn't moving, it would've been considered to be in a sleep state, like how we can measure the outward behavior of sleeping dolphins, elephants, or humans.

當它不動時，就可能被認為是睡眠階段。就像我們如何觀測海豚、大象或人類在睡眠時的外部行為。

But the jury is still out on creatures lacking neurons and muscles altogether, like sponges, for example.

但是對於缺乏神經元和肌肉的生物，像海綿，就還沒有定論。

Measuring something like this has proven to be a challenge because there's no electrical signals to detect, and the sponge doesn't really move in the same way that other animals do.

觀測這種生物被證實是個挑戰，因為沒有辦法偵測到電磁波訊號，海綿也不會像其他動物一樣移動。

So researchers can't look for a change in body posture as an indicator of sleep.

所以研究者沒有辦法透過觀看身體姿勢改變來作為睡著的指示。

Sponges do have a metabolism; they are, after all, a living, breathing creature that has energy demands.

海綿是有新陳代謝系統的，畢竟他們是會消耗能量來活著跟呼吸的生物。

Researchers just haven't yet come up with a way to tell whether these creatures go through a metabolic cycle, pausing some of their activity to use that energy for other things, on a cellular level.

研究者只是還沒想出方法來告訴這些動物在細胞上是否有新陳代謝的循環，中斷他們使用能量做其他事的活動。

A better understanding of whether these kinds of creatures sleep could help answer many questions surrounding sleep.

一個比較好的見解是這種生物可以幫助回答許多睡眠的問題。

And this, in turn, could help researchers better understand human sleep.

這樣一來，研究者就可以更加理解人類的睡眠。

Potentially leading to new ways of treating sleep-related diseases or the development of new drugs that target spots in the body previously thought to be completely separate from the sleep process.

可能出現睡眠相關疾病的新療法或研發出新藥物對付那些身體之前被認為是跟睡眠活動完全分離的目標器官。

So, thanks to some of the more simplistic creatures on this planet, scientists have learned that sleep is anything but a simple, one-size-fits-all process.

多虧地球上有那些過度簡單的生物，科學家能夠得知睡眠是個簡單又通用的過程。

And something else that could help you keep tabs on your sleep is today's sponsor, Fabulous!

另一個可以幫助你持續紀錄睡眠的是今天的贊助商，Fabulous！

They're a self-care and habit-forming app developed at Duke University's Center for Advanced Hindsight, and they have over 20 million users.

他們是一個自我照顧和習慣養成的應用程式，由杜克大學研究中心研發。他們有超過兩千萬名用戶。

The app is customizable to support your personal goals, like crafting your space to be distraction-free or setting a realistic bedtime goal to have a good night's sleep.

這個應用程式可以客製化的去支持你的個人目標，像是創造出不受干擾的空間，或是設定實際的睡眠目標來獲得良好的睡眠。

And with a Fabulous premium subscription, you also unlock coach sessions and journeys to inspire a shift in mindset, like incorporating small, simple habits in your evening routine.

透過 Fabulous 的高級訂閱，你也可以解鎖教練課程和激勵心態轉變的旅程，像是把微小簡單的習慣合併成你晚上的例行公事。

If you wanna check them out, the first 100 people who click on the link in the description will get 25% off a premium Fabulous subscription.

如果你想要去看看，前一百位點擊描述欄連結的觀眾可以享有 Fabulous 高級訂閱的七五折優惠。

That helps us out too, so, thank you.

那也能幫助我們，謝謝。