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On TV or in novels, patients in comas are usually described the same way: like they're sleeping.
在电视或小说中，描述昏迷病人的方式通常都相同：就像他们在睡觉一样。
On the outside, that makes sense.
从表面来看，这能说得通。
After all, they'll have the same closed eyes and maybe even slower breathing or a peaceful expression.
毕竟，他们都闭着眼睛，甚至呼吸缓慢或表情平静。
But while a sleeping person and a coma patient might look the same on the outside,
但即使睡着的人和昏迷的病人表面看起来一样，
on the inside, especially inside their heads, they're very different.
他们的内在，尤其是大脑内部是非常不同的。
For the brain, being in a coma is almost nothing like being asleep.
大脑的昏迷状态与睡觉状态几乎没有相同点。
It's actually more like being under general anesthesia.
它实际更像是全身麻醉的状态。
But what's happening in there is pretty fascinating.
但大脑的活动很精彩。
Comas are what clinicians call disorders of consciousness.
昏迷是临床医生所说的意识障碍。
There are a few of them, including comas and vegetative states,
意识障碍有几种类型，包括昏迷和植物人状态，
and they're caused by some sort of damage to the brain.
它们是由大脑受到的某种创伤导致的。
This could come from something like a stroke, oxygen deprivation,
这种创伤可能来自于中风、缺氧、
or a major hit to the head, like in a car accident.
或者是头部遭受的重击，比如车祸中的撞头等。
The specific mechanism that causes these disorders is still up for debate,
造成这些障碍的具体机制仍有待讨论，
but regardless, some damage triggers a deep unconsciousness that can last for days or months.
但不管怎样，一些伤害可能会引发一种持续数天或数月的深度无意识状态。
On a philosophical level, what it means to be conscious is debatable.
在哲学层面上，意识的含义是有争议的。
But medically speaking, a conscious person is generally two things: awake and aware.
但从医学角度来说，清醒的人通常具备两个条件：清醒和有意识。
Being awake is pretty simple: It's having the reflexes to do things like open your eyes.
清醒很简单：你有条件反射，比如睁开你的眼睛。
Being aware means that you can respond to something happening around you,
有意识意味着你可以对周围发生的事做出反应，
like by squeezing someone's hand if they ask, or holding up a certain number of fingers.
比如，在要求下挤压某人的手或者举起特定数量的手指。
When someone has a disorder of consciousness, one or both of these things is disrupted.
当某人有一种意识障碍时，其中一种或两种条件被破坏了。
And with comas, it's both.
在昏迷状态下，两者都被破坏了。
A coma patient will have some basic, automatic responses that show their brain is somewhat functional,
昏迷病人会有一些基本的自动反应，表明他们的大脑有一定的功能，
like pupil dilation, but they won't open their eyes if someone pokes them, even painfully.
比如瞳孔扩张，但如果有人捅他们，即使很痛，他们也不能睁开眼睛。
And they can't respond to what's going on around them.
而且他们不能回应周围发生的事情。
Now, even though that might sound like you after your last all-night study session,
即使这听起来可能像你昨晚通宵学习后的状态，
comas are nothing like being in a heavy sleep.
但昏迷与熟睡完全不同。
For one, the brain is using a lot less energy during a coma,
首先，大脑在昏迷期间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.
它比深度睡眠时少10%到20%，比清醒时少50%到60%。
This is a sign of significantly lowered activity all across the brain, and it plays out in a few ways.
这是一个大脑活动明显降低的信号，它在几个方面表现出来。
One is that the comatose brain doesn't go through the regular cycles of sleep.
一是昏迷状态的大脑不会经历正常的睡眠周期。
Normally, during sleep, your brain goes through periods of rapid eye movement, or REM sleep.
正常情况下，你的大脑在睡眠期间会经历快速眼动（REM）。
During these times, your brain is actually generating electrical activity at a similar level that it does when it's awake.
此时，大脑产生的电活动和醒着的时候水平相近。
But the comatose brain doesn't produce those high levels of activity,
但昏迷状态的大脑不能产生这种高水平的活动，
so as far as we can tell from brain scans, it doesn't go through REM cycles.
就脑部扫描的结果来看，它并不会经历快速眼动周期。
Since REM is the phase of sleep associated with vivid dreams,
因为REM是与生动的梦境相关的睡眠阶段，
this also means that coma patients probably don't dream, either,
这也意味着昏迷病人可能不做梦，
although many have reported them on their way out of a coma.
尽管很多人报告说他们正在脱离昏迷状态。
Probably the biggest difference between comas and other conditions, though,
也许昏迷与其他状态最大的区别是，
is the activity in the brain's cerebral cortex, or what we tend to think of as the main part of the brain.
发生在大脑皮层或者我们通常认为的大脑主要部位的活动。
During a coma, there's activation in some basic, sensory areas, but they're not being processed normally.
昏迷期间，一些基本的感觉区处于激活状态，但它们不能正常运转。
So the brain can't actually make sense of what those sensory signals mean.
所以大脑不能真正理解这些感觉信号的含义。
For example, a study done in the journal Brain in 2000 showed that
例如，2000年发表在《大脑》杂志上的一项研究表明，
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听觉皮层有一些活动，后者对声音有反应。
But those signals weren't sent on to a place in the brain where they could be understood.
但是这些信号并没有被送到可以理解它们的大脑区域。
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，你可能听说过昏迷的人即使不能回应也能理解你，但这不是真的。
They can technically hear you, but according to most research, they won't be able to process anything you say.
理论上他们可以听到你说的话，但大多数研究表明，他们不能处理它。
It's different than what happens when you say, fall asleep during lecture.
这和上课打瞌睡不同。
According to studies, the sleeping brain can process what it hears, even if you don't realize or remember it.
研究表明，睡眠时大脑可以处理它听到的内容，即使你没有意识或记住它。
This lack of processing happens because, during a coma, two major networks in the cortex are disrupted:
昏迷期间大脑不能运转的原因是大脑皮层的两个主要网络被破坏了：
one that covers internal awareness, and one that does external awareness.
这两个网络一个覆盖内在意识，一个覆盖外部意识。
Internal awareness deals with things like talking inside your head and wandering thoughts.
内在意识处理脑海中的声音以及散乱的念头等。
External awareness is more about how you process external stimuli, like what my face looks like.
外部意识更多的与你如何处理外部刺激有关，比如我的脸是什么样的。
These networks can get interrupted in other disorders, too,
其他障碍也会打断这些网络，
like locked-in syndrome, where someone is conscious but can't move normally.
比如闭锁综合征，表现为人们有意识但不能正常移动。
But in that case, only one network is disrupted.
但在那种情况下，只有一个网络被打断了。
With comas, it's both, so there's not a ton of higher-level processing happening.
而昏迷时两个网络都被破坏了，所以不会有高水平的大脑活动。
In general, the comatose brain is a lot more disconnected from the things happening around it
总的来说，与其他状态或清醒时相比，
than in some other conditions or when you're asleep.
昏迷状态的大脑与周围发生的事联系更少。
If anything, it's actually most similar to being under general anesthesia.
如果有某种状态可比的话，全身麻醉最相似。
Some physicians even call anesthesia a "reversible coma",
一些医生甚至称麻醉为“可逆昏迷”，
and it can be used to study real comas without putting someone in serious danger.
它可以用来研究真正的昏迷，且不会让人陷入严重的危险。
Ultimately, depending on the severity of the damage,
最终，昏迷患者根据损伤程度
a coma patient might heal and slowly come back to regular consciousness, becoming both awake and aware.
可能会痊愈并缓慢恢复到正常意识水平，变得清醒而有意识。
Once they do, they probably won't have any memory of the experience,
他们一旦痊愈，可能就不会有任何这种经历的记忆了，
even if they do remember the process of waking up.
即使他们确实记得醒来的过程。
Which probably isn't such a bad thing.
这也许不是件坏事。
Although doctors work to get patients out of comas as safely and quickly as possible,
尽管医生的工作是让病人尽可能安全快速地离开医院，
studying them and how they work are really important.
但研究昏迷以及它们的运作方式非常重要。
After all, comas are key ways for us to understand the root of consciousness in our brains.
毕竟，昏迷是我们理解人脑意识根源的关键方法。
By untangling the things that are happening inside our heads when we lose connection with the world,
通过了解我们失去与世界联系时的大脑活动，
we're able to get a better idea of the biology that links us to reality in the first place.
我们能够更好地理解将我们与现实联系在一起的生物学。
And that's definitely worth understanding.
这绝对值得了解。
Thanks for watching this episode of SciShow Psych!
感谢您收看本期的心理科学秀！
If you'd like to keep exploring the human mind with us,
如果你想和我们一起探索人类的大脑，
you can go to youtube.com/scishowpsych and subscribe.
可以登录youtube.com/scishowpsych点击订阅。
