People are having a good time with their friends when they have a few too many drinks and suddenly everything is spinning.

大家和朋友享受歡樂時光，不過喝了太多酒後，突然覺得天旋地轉。

They might try to lay down or try to sleep it off, but that just makes it worse.

他們可能想要躺下來或睡覺以消除酒後的不適，但可能會更糟。

Yep, they've got the spins.

沒錯，他們會感覺天旋地轉。

And, strange as it might seem, that's not because the alcohol they drank is messing with their brain.

不過奇怪的是並不是因為他們喝下的酒精擾亂了大腦。

The spins are a form of vertigo, which is the illusion that you or the world around you is moving.

這種感覺是種暈眩感，造成你或你四周的環境在移動的錯覺。

But that illusion doesn't happen because alcohol affects neurons.

但這種錯覺一般不會發生，因為酒精影響神經元。

I mean, don't get me wrong, alcohol does affect neurons.

不要誤解我的意思，酒精確實會影響神經元。

And it messes with your brain in a lot of ways—like, it lowers your inhibitions and impairs your memory.

酒精可以以不同方式來擾亂你的大腦，像是會降低你的抑制能力或是損害你的記憶力。

But the spins happen for a different reason, and to understand that, you first have to understand how your brain knows when you're moving.

不過是另外一個原因導致天旋地轉的感覺。要知道原因，你們必須要先了解當你在移動時，大腦是如何運作的。

Deep within each ear are three semicircular canals—curved tubes which are oriented at different angles and filled with a fluid called endolymph.

每隻耳朵的深處都有三個半規管，三個蜷曲的管子面向不同的角度，裡面充滿稱為內淋巴的液體。

At one end of each tube is a cupula, a jelly-like mound that has a bunch of tiny sensory receptors called hair cells embedded in it.

每一條管的末端連接著頂帽 (cupula)，一種膠狀物質裡佈滿一堆用作感官接收，細小的毛細胞。

As the name implies, these cells have thin, hair-like projections coming out of them.

顧名思義，這些細胞很細小，如毛髮般突起。

And when those quote "hairs" bend, the cells send electrical signals to the brain that say "Hey, something is happening".

當「毛髮」彎曲的的時候，細胞傳送電訊號至大腦，像是在說「嘿，有事正在發生。」

For the hair cells in the cupula, that something is that the head is turning.

對於頂帽裡的毛細胞來說，那件事就是你的頭部在轉動。

When your head turns, the semicircular canals rotate along with it.

當你的頭部在轉動，半規管亦會隨之轉動。

But inertia makes the endolymph inside lag behind a little bit and therefore press up against the cupulas.

不過慣性 (inertia) 會使內淋巴流動的速度變得緩慢，因此會往上擠壓頂帽。

That pressure bends the cupulas and their hair cells.

這壓力擠壓到頂帽並使毛細胞彎曲。

The brain figures out exactly how your head is turning based on which cupulas in which ears are sending it signals that they're being bent.

大腦會根據頂帽受擠壓的那隻耳朵而知道你的頭部往哪個方向轉動。

This is why ballerinas use the technique of spotting when doing a bunch of pirouettes.

這也是女芭蕾舞者在跳出一連串腳尖旋轉 (pirouette) 時會套用定點法。

By keeping their head facing one direction as much as possible, they minimize the amount of time where endolymph is pressing on their cupulas, and essentially "trick" their brains into thinking they're spinning less.

盡可能地把頭部面向一個方向，縮短內淋巴擠壓頂帽的時間，要「欺騙」大腦以為並沒有旋轉很多圈。

But alcohol messes with this whole system for one simple reason: it's not as dense as your endolymph.

但酒精會擾亂這整組系統運作，原因只有一個，酒精的密度比內淋巴低。

There aren't a ton of blood vessels in your inner ear, and most of them are in or near the cupula.

內耳並沒有太多血管，大部分都是在頂帽裡或是四周。

Because of that, alcohol present in your blood diffuses into the cupula faster than it diffuses into the endolymph, making the jelly-like structure less dense than its neighboring fluid.

因此血液裡的酒精會滲透至頂帽的速度會比至內淋巴快，導致膠狀物質的密度比四周的液體低。

The difference in relative densities changes the pressure on the cupula, which causes it to distort.

密度的差異會改變頂帽的壓力，從而使其變形。

And when that distortion happens, the hair cells bend and start signaling to the brain that the head is turning—even though it's staying completely still.

也因為變形的緣故，毛細胞會彎曲並開始向大腦傳送訊息告知頭部在轉動…即使你的頭部沒有在轉動。

And you feel like you're the ballerina doing those pirouettes.

你會產生芭蕾舞者在腳尖旋轉的感覺。

At this point, most people just want to go lie down, close their eyes, and sleep it off—but in the cruelest of ironies, that actually just makes the spins worse.

而在這時刻，大部分的人會想要閉眼躺下，然後睡一覺。但諷刺的是，會加強這天旋地轉的感覺。

See, there's supposed to be a separate system in the inner ear that detects forward-and-back motion and gravity.

內耳原應為一個獨立系統來偵測前後移動和重力。

But if the densities of the cupula and the endolymph aren't exactly equal, the semicircular canal system veers out of its lane.

不過一旦頂帽和內淋巴的密度不一時，半規管系統會偏離軌道。

Instead of the cupula essentially floating in the endolymph, it becomes lighter than it.

與其說頂帽漂浮在內淋巴裡，它反而會變得更輕。

And that means it will distort from any change in head position.

也就是說不管頭部的姿勢如何，它也會受到擠壓。

So it'll sound the rotation alarm in response to linear movements and gravity, too.

看起來這個轉動的警報對平行移動和重力改變產生反應。

You can see evidence of this happening if someone lays down when they're drunk.

當你看到有人喝醉的時候躺下就可以證實到這一點了。

Their eyes will start to drift away from the floor and then they quickly move towards the side they're laying on.

他們的眼睛會開始從地板上移開，然後快速往他們躺下的方向移去。

This is called positional alcohol nystagmus, and it happens because the brain attempts to keep the gaze steady as the head turns—until it realizes the head isn't turning, and snaps the eyes back.

這稱之為「位置性眼球震顫」(positional alcohol nystagmus)，這會發生是因為大腦試圖要在頭部旋轉時讓目光保持穩定，可後來才發現頭部並沒有轉動，然後眼睛快速恢復到原來的位置。

So, to recap: laying down, particularly on your side, makes the spins worse because your brain interprets gravity as rotation.

簡單來說：尤其側躺的話，會加重這種暈眩感，因為你的大腦會把這重力解讀成旋轉。

So, you don't want to lay down.

所以絕對不要躺下。

And you really don't want to close your eyes because they've actually been holding this whole situation in check.

你也絕對不會想要閉上眼睛，因為眼睛會制止這情況。

That's because your ears aren't the only part of you that senses if you're moving.

因為不只有耳朵可以感覺到你在移動。

Your brain likes to use as many sources of information as possible to figure out what's happening around you.

你的大腦會盡可能搜集更多資訊以清楚你四周所發生的事情。

So it combines messages from several different sensory systems.

因此會結合你幾個感官系統所傳送的訊息。

Psychologists call this multisensory integration.

心理學家稱之為「多重感覺統合」。

And during the spins, the inner ear is sending the message of spinning, but the visual system is correctly telling your brain that everything is still.

在天旋地轉之際時，內耳會傳送「在旋轉」的訊息，但你的視覺系統會正確的告訴你的大腦四周依然平靜。

And it just so happens that, as a species, humans rely on our sense of vision more than any other.

碰巧的是，作為人類，比起其他感官我們更是依賴視覺。

So when there's a conflict between sensory systems, your brain tends to default to trusting your eyes.

當感官系統間產生衝突，你的大腦會比較偏向於相信你眼睛所看到的事物。

If you take away that visual input by closing your eyes, the only information your brain gets is your ears' message of spinning.

一旦你閉上眼睛把視覺影像功能拿掉，大腦唯一接收耳朵所發送旋轉的信息。

So it fully commits to that — and your spins feel even worse.

必須要承認，你旋轉的感覺更加糟。

There are a lot of suggestions for how to ease the spins.

有很多不同的建議可以減緩這種旋轉感。

Staying upright and keeping your eyes open can definitely help.

身體挺直並保持眼睛張開。

Some people suggest that if you do lay down, you should keep one foot on the floor so that the brain has some extra information about which direction is down.

有人建議說，如果真的要躺下的話，應該有一隻腳要踩在地板上，以便大腦接收額外的信息以得知哪個方向為下方。

And some people find it's helpful to do something that relies heavily on vision — like watching a movie.

有人表示做一些極度依賴視覺的事情，像是看電影。

But whether such activities help by actively engaging the visual system and overriding the spin signals is unclear.

不過透過視覺活動是否真的有助控制旋轉感仍然是不清楚。

They might just distract you from feeling crummy.

那些行為只是可以分散你的注意力。

If all else fails: wait it out.

如果所有方法都失敗，就等待吧！

After about three hours, alcohol from your blood will have diffused throughout the endolymph.

大概三個小時後，血液裡的酒精會滲透至內淋巴。

So the densities of the cupula and endolymph will have reached and the spinning will stop.

這時候頂帽和內淋巴的密度將會達到平衡，天旋地轉的感覺才會停止。

Then, you just have to worry about a hangover.

接下來，你該擔心的是宿醉的問題。

Thanks for watching this episode of SciShow Psych!

謝謝大家收看我們這支影片！

We hope you enjoyed today's tour of your brain.

希望大家喜歡我們今天講解大腦的部分。

If you want to learn more about how alcohol affects you, you might like our episode on the connection between booze and creativity.

如果想要了解更多酒精對你的影響，你應該會喜歡看酒與創造力之間的關聯的那一支。

So why not watch that one next?

何不現在就去看呢？

And please remember to always drink responsibly!

切記要理智地飲酒！