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On TV or in novels, patients in comas are usually described the same way: like they're sleeping.
在電視或小說中，描述昏迷病人的方式通常都相同：就像他們在睡覺一樣。
On the outside, that makes sense.
從表面來看，這能說得通。
After all, they'll have the same closed eyes and maybe even slower breathing or a peaceful expression.
畢竟，他們都閉著眼睛，甚至呼吸緩慢或表情平靜。
But while a sleeping person and a coma patient might look the same on the outside,
但即使睡著的人和昏迷的病人表面看起來一樣，
on the inside, especially inside their heads, they're very different.
他們的內在，尤其是大腦內部是非常不同的。
For the brain, being in a coma is almost nothing like being asleep.
大腦的昏迷狀態與睡覺狀態幾乎沒有相同點。
It's actually more like being under general anesthesia.
它實際更像是全身麻醉的狀態。
But what's happening in there is pretty fascinating.
但大腦的活動很精彩。
Comas are what clinicians call disorders of consciousness.
昏迷是臨床醫生所說的意識障礙。
There are a few of them, including comas and vegetative states,
意識障礙有幾種類型，包括昏迷和植物人狀態，
and they're caused by some sort of damage to the brain.
它們是由大腦受到的某種創傷導致的。
This could come from something like a stroke, oxygen deprivation,
這種創傷可能來自于中風、缺氧、
or a major hit to the head, like in a car accident.
或者是頭部遭受的重擊，比如車禍中的撞頭等。
The specific mechanism that causes these disorders is still up for debate,
造成這些障礙的具體機制仍有待討論，
but regardless, some damage triggers a deep unconsciousness that can last for days or months.
但不管怎樣，一些傷害可能會引發一種持續數天或數月的深度無意識狀態。
On a philosophical level, what it means to be conscious is debatable.
在哲學層面上，意識的含義是有爭議的。
But medically speaking, a conscious person is generally two things: awake and aware.
但從醫學角度來說，清醒的人通常具備兩個條件：清醒和有意識。
Being awake is pretty simple: It's having the reflexes to do things like open your eyes.
清醒很簡單：你有條件反射，比如睜開你的眼睛。
Being aware means that you can respond to something happening around you,
有意識意味著你可以對周圍發生的事做出反應，
like by squeezing someone's hand if they ask, or holding up a certain number of fingers.
比如，在要求下擠壓某人的手或者舉起特定數量的手指。
When someone has a disorder of consciousness, one or both of these things is disrupted.
當某人有一種意識障礙時，其中一種或兩種條件被破壞了。
And with comas, it's both.
在昏迷狀態下，兩者都被破壞了。
A coma patient will have some basic, automatic responses that show their brain is somewhat functional,
昏迷病人會有一些基本的自動反應，表明他們的大腦有一定的功能，
like pupil dilation, but they won't open their eyes if someone pokes them, even painfully.
比如瞳孔擴張，但如果有人捅他們，即使很痛，他們也不能睜開眼睛。
And they can't respond to what's going on around them.
而且他們不能回應周圍發生的事情。
Now, even though that might sound like you after your last all-night study session,
即使這聽起來可能像你昨晚通宵學習后的狀態，
comas are nothing like being in a heavy sleep.
但昏迷與熟睡完全不同。
For one, the brain is using a lot less energy during a coma,
首先，大腦在昏迷期間消耗的能量要少得多，
about 10 to 20% less than even the deepest part of sleep, and 50 to 60% less than when you're awake.
它比深度睡眠時少10%到20%，比清醒時少50%到60%。
This is a sign of significantly lowered activity all across the brain, and it plays out in a few ways.
這是一個大腦活動明顯降低的信號，它在幾個方面表現出來。
One is that the comatose brain doesn't go through the regular cycles of sleep.
一是昏迷狀態的大腦不會經歷正常的睡眠周期。
Normally, during sleep, your brain goes through periods of rapid eye movement, or REM sleep.
正常情況下，你的大腦在睡眠期間會經歷快速眼動（REM）。
During these times, your brain is actually generating electrical activity at a similar level that it does when it's awake.
此時，大腦產生的電活動和醒著的時候水平相近。
But the comatose brain doesn't produce those high levels of activity,
但昏迷狀態的大腦不能產生這種高水平的活動，
so as far as we can tell from brain scans, it doesn't go through REM cycles.
就腦部掃描的結果來看，它并不會經歷快速眼動周期。
Since REM is the phase of sleep associated with vivid dreams,
因為REM是與生動的夢境相關的睡眠階段，
this also means that coma patients probably don't dream, either,
這也意味著昏迷病人可能不做夢，
although many have reported them on their way out of a coma.
盡管很多人報告說他們正在脫離昏迷狀態。
Probably the biggest difference between comas and other conditions, though,
也許昏迷與其他狀態最大的區別是，
is the activity in the brain's cerebral cortex, or what we tend to think of as the main part of the brain.
發生在大腦皮層或者我們通常認為的大腦主要部位的活動。
During a coma, there's activation in some basic, sensory areas, but they're not being processed normally.
昏迷期間，一些基本的感覺區處于激活狀態，但它們不能正常運轉。
So the brain can't actually make sense of what those sensory signals mean.
所以大腦不能真正理解這些感覺信號的含義。
For example, a study done in the journal Brain in 2000 showed that
例如，2000年發表在《大腦》雜志上的一項研究表明，
five patients in vegetative states and comas had some activity in their auditory cortex in response to sound.
五名植物人和昏迷病人的聽覺皮層有一些活動，后者對聲音有反應。
But those signals weren't sent on to a place in the brain where they could be understood.
但是這些信號并沒有被送到可以理解它們的大腦區域。
So, you might've heard that someone in a coma can understand you, even if they can't respond, but that's not totally true.
所以，你可能聽說過昏迷的人即使不能回應也能理解你，但這不是真的。
They can technically hear you, but according to most research, they won't be able to process anything you say.
理論上他們可以聽到你說的話，但大多數研究表明，他們不能處理它。
It's different than what happens when you say, fall asleep during lecture.
這和上課打瞌睡不同。
According to studies, the sleeping brain can process what it hears, even if you don't realize or remember it.
研究表明，睡眠時大腦可以處理它聽到的內容，即使你沒有意識或記住它。
This lack of processing happens because, during a coma, two major networks in the cortex are disrupted:
昏迷期間大腦不能運轉的原因是大腦皮層的兩個主要網絡被破壞了：
one that covers internal awareness, and one that does external awareness.
這兩個網絡一個覆蓋內在意識，一個覆蓋外部意識。
Internal awareness deals with things like talking inside your head and wandering thoughts.
內在意識處理腦海中的聲音以及散亂的念頭等。
External awareness is more about how you process external stimuli, like what my face looks like.
外部意識更多的與你如何處理外部刺激有關，比如我的臉是什么樣的。
These networks can get interrupted in other disorders, too,
其他障礙也會打斷這些網絡，
like locked-in syndrome, where someone is conscious but can't move normally.
比如閉鎖綜合征，表現為人們有意識但不能正常移動。
But in that case, only one network is disrupted.
但在那種情況下，只有一個網絡被打斷了。
With comas, it's both, so there's not a ton of higher-level processing happening.
而昏迷時兩個網絡都被破壞了，所以不會有高水平的大腦活動。
In general, the comatose brain is a lot more disconnected from the things happening around it
總的來說，與其他狀態或清醒時相比，
than in some other conditions or when you're asleep.
昏迷狀態的大腦與周圍發生的事聯系更少。
If anything, it's actually most similar to being under general anesthesia.
如果有某種狀態可比的話，全身麻醉最相似。
Some physicians even call anesthesia a "reversible coma",
一些醫生甚至稱麻醉為“可逆昏迷”，
and it can be used to study real comas without putting someone in serious danger.
它可以用來研究真正的昏迷，且不會讓人陷入嚴重的危險。
Ultimately, depending on the severity of the damage,
最終，昏迷患者根據損傷程度
a coma patient might heal and slowly come back to regular consciousness, becoming both awake and aware.
可能會痊愈并緩慢恢復到正常意識水平，變得清醒而有意識。
Once they do, they probably won't have any memory of the experience,
他們一旦痊愈，可能就不會有任何這種經歷的記憶了，
even if they do remember the process of waking up.
即使他們確實記得醒來的過程。
Which probably isn't such a bad thing.
這也許不是件壞事。
Although doctors work to get patients out of comas as safely and quickly as possible,
盡管醫生的工作是讓病人盡可能安全快速地離開醫院，
studying them and how they work are really important.
但研究昏迷以及它們的運作方式非常重要。
After all, comas are key ways for us to understand the root of consciousness in our brains.
畢竟，昏迷是我們理解人腦意識根源的關鍵方法。
By untangling the things that are happening inside our heads when we lose connection with the world,
通過了解我們失去與世界聯系時的大腦活動，
we're able to get a better idea of the biology that links us to reality in the first place.
我們能夠更好地理解將我們與現實聯系在一起的生物學。
And that's definitely worth understanding.
這絕對值得了解。
Thanks for watching this episode of SciShow Psych!
感謝您收看本期的心理科學秀！
If you'd like to keep exploring the human mind with us,
如果你想和我們一起探索人類的大腦，
you can go to youtube.com/scishowpsych and subscribe.
可以登錄youtube.com/scishowpsych點擊訂閱。
