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Your brain works together with the rest of your body in lots of different ways.
你的大腦和身體的其他部位有很多不同的協(xié)作方式。
If things go wrong with some organs, like if your heart stops pumping,
如果某些器官出了問題，比如心臟停止跳動，
your brain's obviously going to have a bad time.
顯然，你的大腦也不會好過。
But sometimes the connection is a little less straightforward.
但有時這種聯(lián)系不那么直接。
Take the liver, for example: you need it for things
以肝臟為例，你需要它做的工作是
like filtering blood, storing vitamins, and lots of other processes that keep you alive.
過濾血液、儲存維生素以及許多其它維持生存的過程等。
So, basically, what happens in the liver doesn't stay in the liver.
所以，基本上，肝臟的毛病不會只停留在肝臟處。
And an issue there can cause a chain reaction across your body that seriously affects your brain.
一個身體問題會引起它的連鎖反應(yīng)并嚴(yán)重影響大腦。
Patients with many kinds of liver damage or disease
病人的多種肝臟損傷或疾病
can develop a condition called hepatic encephalopathy or HE.
可以發(fā)展成一種叫做肝性腦病（HE）的疾病。
Hepatic refers to the liver, and encephalopathy means brain disease, damage or malfunction.
“Hepatic”是指肝臟，“encephalopathy”是指腦部疾病、腦損傷或腦故障。
Physicians think of HE as a spectrum of symptoms
醫(yī)生認(rèn)為肝性腦病有一系列的癥狀，
that can affect personality, movement, cognition, and even levels of consciousness.
可以影響性格、運(yùn)動、認(rèn)知甚至意識水平。
They can range from mild, like mood swings, to severe, like a coma.
它們的范圍可以從情緒波動等輕微癥狀到昏迷等嚴(yán)重癥狀。
And HE is mainly caused by substances that build up when the liver stops working as well as it should.
肝性腦病主要是由肝臟停止正常工作時積累的物質(zhì)引起的。
In a healthy liver, chemicals from the rest of the body are filtered out of the blood
在健康的肝臟中，身體其余部位的化學(xué)物質(zhì)會從血液中過濾出來，
and broken down by specialized cells and enzymes.
并被特殊的細(xì)胞和酶分解。
If the liver becomes damaged, like from certain drugs, a bad diet,
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or some other kind of injury or disease, the tissue changes structure and gets all scarred.
或者其他傷害或疾病等引起肝臟受損，肝組織就會改變結(jié)構(gòu)并受到創(chuàng)傷。
This scar tissue isn't able to function like normal liver cells.
這種疤痕組織不能像正常肝細(xì)胞那樣運(yùn)轉(zhuǎn)。
Plus, all those structural changes make it harder for blood to get in for detoxification.
此外，所有這些結(jié)構(gòu)上的變化使血液更難進(jìn)入其中排毒。
And in really severe cases, a lot of blood may bypass the liver entirely.
在肝臟受損非常嚴(yán)重的情況下，大量血液可能直接繞過肝臟。
One important toxin your liver deals with is ammonia,
肝臟處理的一種重要毒素是氨。
which mostly comes from the digestion of proteins in your gut.
它主要來自于腸道內(nèi)蛋白質(zhì)的消化。
Ammonia gets turned into urea, which is excreted in pee.
氨轉(zhuǎn)變成尿素，后者從尿中排泄出去。
So a damaged liver can lead to a buildup of ammonia in the bloodstream, which is bad news for the brain.
因此，肝臟受損會導(dǎo)致血液中的氨堆積，這對大腦來說是個壞消息。
Ammonia can cross the blood-brain barrier,
氨可以穿過血腦屏障，
which is a membrane that blocks a lot of molecules in your bloodstream from circulating around your brain,
后者是一種膜，可以阻止血流中大量的分子在大腦周圍循環(huán)，
to protect it from potential damage.
保護(hù)它免受潛在傷害。
Once ammonia slips past, it's mostly taken up by astrocytes,
一旦氨滑過血腦屏障，就會被星形膠質(zhì)細(xì)胞占用，
which are brain cells that help out neurons in a lot of different ways.
星形膠質(zhì)細(xì)胞是一種腦細(xì)胞，可以通過不同的方式幫助神經(jīng)元。
And astrocytes have enzymes that convert ammonia into the amino acid glutamine to help protect the neurons.
它擁有把氨轉(zhuǎn)化成氨基酸的酶來幫助保護(hù)神經(jīng)元。
If they do this too much, though, studies have found that their structure gets messed up.
但是，研究發(fā)現(xiàn)，如果它們的工作量過大，就會導(dǎo)致結(jié)構(gòu)混亂。
Cell-damaging molecules called free radicals get produced,
被稱為自由基的細(xì)胞破壞分子由此產(chǎn)生，
and their mitochondria stop working as efficiently, which means they can't make as much energy.
而且它們的線粒體會停止高效工作，這意味著它們不能產(chǎn)生盡可能多的能量。
As the astrocytes lose function, they stop getting rid of ammonia,
當(dāng)它們失去功能時，就會停止去除氨，
and everything gets even more messed up.
一切變得更加混亂。
Too much ammonia can affect the storage, production, and use of neurotransmitters across the whole brain.
過多的氨會影響整個大腦中神經(jīng)遞質(zhì)的儲存、生產(chǎn)以及使用。
In other words, your neurons can't really communicate,
換句話說，你的神經(jīng)元無法真正交流，
which can cause a whole range of problems with mood, movement ... pretty much anything.
這可能會導(dǎo)致情緒、運(yùn)動等一系列問題，幾乎是所有問題。
Even though ammonia is a significant part of HE, other toxins might be involved too.
即使氨是HE的重要組成部分，但其他的毒素也可能參與其中。
And researchers are still figuring out exactly what they are and how they might make HE worse.
研究人員仍在研究它們到底是什么，以及它們?nèi)绾巫尭涡阅X病變得更糟。
Besides waste products like ammonia,
除了氨這樣的廢物，
your liver also has a huge impact on how long lots of drugs, from aspirin to LSD,
肝臟也會對從阿斯匹林到麥角酸二乙基酰胺（LSD）等很多藥物的時效產(chǎn)生巨大影響，
stay in your system before they're flushed out.
它們在被排出前都會待在你體內(nèi)。
A healthy liver takes drug molecules from your bloodstream and converts them into different chemicals.
健康的肝臟從血液中提取藥物分子，并將其轉(zhuǎn)化為不同的化學(xué)物質(zhì)。
Sometimes they're the active form of a drug,
這些化學(xué)物質(zhì)有時是藥物的活性形式，
but eventually they become more water-soluble compounds that can be peed out.
但最終它們大多會變成可以被排出體外的水溶性化合物。
To do this, it mostly uses a system of enzymes known as the cytochrome p450 family,
為了做到這一點(diǎn)，肝臟主要使用一種酶系統(tǒng)，即細(xì)胞色素p450家族，
which may be responsible for up to 75% of drug metabolism.
它們可能負(fù)責(zé)多達(dá)75%的藥物代謝。
So if a disease damages liver cells or directly interferes with these enzymes, things can go sour.
所以，如果一種疾病損害了肝細(xì)胞或者直接干擾了這些酶，事情就會變糟。
Even just as we age naturally, the activity of cytochrome p450 enzymes seems to dip.
我們自然衰老的時候，細(xì)胞色素p450的酶活性似乎也在下降。
Slower drug metabolism can mean a normally fine painkiller,
緩慢的藥物代謝意味著正常的止痛藥，
like acetaminophen, may build up until it hits toxic levels.
如撲熱息痛，可以累積到有毒水平。
This can lead to more damage, and eventually we're right back to hepatic encephalopathy.
這會導(dǎo)致更多的損傷，最終會導(dǎo)致肝性腦病。
Now some brain diseases are linked to toxic substances that some people intentionally put in their bodies,
現(xiàn)在一些腦部疾病與人們故意注入體內(nèi)的有毒物質(zhì)有關(guān)，
which their livers have to process, like ethanol from alcoholic drinks.
因此他們的肝臟需要處理它們，如酒精飲料中的乙醇等。
Basically, in the process of breaking down ethanol,
基本上，在乙醇分解的過程中，
the byproducts can cause tissue damage and trigger inflammation.
它的副產(chǎn)物可以引起組織損傷并引發(fā)炎癥。
And if your liver keeps getting damaged, it won't be able to handle ethanol as well.
如果你的肝臟繼續(xù)受損，就不能處理乙醇了。
It's a vicious cycle.
這是一個惡性循環(huán)。
It turns out that too much ethanol can affect your cells' ability to take up,
事實(shí)證明，過量乙醇會影響細(xì)胞從飲食中吸收、
store and use thiamine, also known as vitamin B1, from your diet.
存儲以及使用硫胺素（維生素B1）的能力。
Some enzymes that depend on thiamine are a key part of glycolysis,
一些依賴硫胺素的酶是糖酵解的關(guān)鍵，
a process your body uses to break down glucose molecules and make energy.
糖酵解是指你的身體分解葡萄糖分子和制造能量的過程。
So a lack of thiamine can limit the amount of energy your body can get from food.
因此，缺乏硫胺素可能限制你的身體從食物中獲得能量。
And since the brain is basically an energy-hungry monster, that is a recipe for disaster.
因?yàn)榇竽X基本上是一個能量饑渴的怪物，是災(zāi)難之源。
And it can lead to Korsakoff syndrome, one of the lesser-known diseases that affects memory.
它還會導(dǎo)致柯薩可夫綜合癥，一種不太為人所知的影響記憶的疾病。
Patients find themselves basically frozen in time, with retrograde and anterograde amnesia.
患者會感到時間凍結(jié)，有逆行性和順行性遺忘。
So they can't recall large chunks of their past, or form new memories going forward.
所以他們不能回憶起大部分過去，也不能形成新的記憶。
Specifically, in patients' MRIs, we've seen shrinking in the medial thalamus,
具體來說，在病人的核磁共振成像中，我們看到他們的內(nèi)側(cè)丘腦、
mammillary bodies and nearby areas, which are all linked with memory.
乳頭體及附近區(qū)域萎縮了，這些部位都與記憶有關(guān)。
With treatments aimed at getting thiamine and other nutrient levels back to normal,
利用讓硫胺素和其他營養(yǎng)水平恢復(fù)正常的治療，
many Korsakoff's patients can at least partly recover.
許多科薩科夫患者至少可以部分恢復(fù)。
But, basically, if you want to keep your brain in tip-top condition,
但是從根本上說，如果你想讓自己的大腦保持最佳狀態(tài)，
remember to take good care of the rest of you as well.
記住要好好照顧身體的其他部位。
And take special care of your liver, just a good ol'...wherever it is.
還要特別照顧你的肝臟，它是一個好的ol……無論是哪兒都要照顧好。
Thanks for watching this episode of SciShow Psych!
感謝您收看本期的心理科學(xué)秀！
If you want to keep learning about the human brain with us,
如果你想和我們繼續(xù)學(xué)習(xí)人類大腦，
from questions about behavior to more deep dives into disease,
了解更多從行為問題到更深入疾病的內(nèi)容，
you can go to youtube.com/scishowpsych to subscribe!
可以登錄youtube.com/scishowpsych點(diǎn)擊訂閱！
