(单词翻译:单击)
You know that feeling when you're sick, where you don't want leave the house,
你知道那种生病只想待在家，
you don't want to talk to anyone, and you kinda just want to be left alone to wallow in your own misery and snot?
不想和任何人说话，只想一个人沉浸在自己的痛苦和悲伤中的感觉吗？
Sometimes that's because you're so sick that you literally can't move without risking throwing up or whatever.
有时候是因为你病得很重，要吐了或者怎么样。
But other times, it might have more to do with the way your immune system is connected to your brain—
但其它时候，这可能与你的免疫系统和大脑的连接方式有关——
including how it affects your social behavior.
包括免疫系统如何影响你的社交行为。
A lot of the research on this is really recent, and there's still plenty we don't know about that connection.
这方面的很多研究都是最近才进行的，而且我们对这种联系知之甚少。
But psychologists and doctors are starting to realize that some immune responses can make you more or less social,
但是心理学家和医生开始意识到某些免疫反应可以使你的社交行为增加或减少，
sometimes even without symptoms.
有时甚至没有症状。
At first glance, the brain and immune system can seem pretty separate.
乍一看，大脑和免疫系统似乎无任何关联。
Your brain is in its own little compartment, separated from almost everything else by what's known as the blood-brain barrier.
大脑就在小隔间里，通过所谓的血脑屏障将大脑和其他几乎所有东西隔开。
That's exactly what it sounds like: a literal barrier,
你听到的没错：就是字面上的屏障，
in the form of a membrane that keeps your brain safe from whatever's circulating in your blood.
这种屏障以膜的形式使大脑免受任何血液循环的侵害。
It's really important to have, because it stops almost all germs from infecting your brain.
屏障真的很重要，因为它能阻止大脑免受几乎所有细菌的感染。
Meanwhile, your immune system does its thing in the blood running through the rest of your body, trying to protect you from disease.
与此同时，免疫系统在流经身体其余部分的血液中发挥作用，试图保护你免受疾病侵害。
But your brain needs to know what's going on with your immune system, like if you have a spike in white blood cells to fight off an infection.
但是你的大脑需要知道免疫系统的情况，比如抵抗感染时，白血细胞是否剧增。
So there is at least one major connection between them: the vagus nerve,
所以它们之间至少有一个主要连接：迷走神经，
which connects your brain to the parts of your body where a lot of your immune responses happen, like your gut or lymph nodes.
它将你的大脑连接至身体的某些部位，这些部位会产生很多免疫反应，比如肠道或淋巴结。
The vagus nerve can detect compounds called cytokines, which are released by your immune system when you're fighting an illness.
迷走神经可以检测到一种叫做细胞因子的化合物，当你的身体与疾病作斗争时，免疫系统会释放细胞因子。
And we know that your immune system affects your behavior,
我们知道免疫系统影响你的行为，
and that the vagus nerve is an important part of that connection, because of what happens when you cut it.
由于你切断这种联系所导致的后果，所以迷走神经是该联系的重要组成部分。
Mice and rats with severed vagus nerves don't show that sickness response where you just want to sit at home by yourself.
切断迷走神经的小鼠和老鼠并不显示疾病反应：你只想自己待在家里。
They go hang out and party just as much as healthy mice, and they eat just as much too.
它们和健康的老鼠一样，出去玩，参加聚会，吃的也和它们一样多。
This normal sickness response — hiding at home, not going out to play with your little mouse friends —
这种正常的疾病反应——躲在家里，不出去和小老鼠朋友玩，
is probably an evolutionary adaptation.
可能是一种进化适应。
If you spend a little bit of time being antisocial, you're probably not going to spread whatever germs you're carrying,
如果不社交的话，你可能不会传播自身携带的任何细菌，
which is great for society as a whole. And it helps you on an individual level, too:
这对整个社会大有裨益，从个人层面来说对你也是有好处的：
if you're a little less active, your body can put more resources into fighting the infection.
如果你不那么活跃，你的身体可以投入更多的精力来对抗感染。
But scientists are starting to learn that the situation is probably more complex than that. For example,
但科学家们开始认识到，情况可能比这更复杂。例如，
one 2010 study published in the Annals of Epidemiology found that immune reactions might be related to an increase in social activity.
2010年发表在《流行病学年报》(Annals of Epidemiology)上的一项研究发现，免疫反应可能与社会活动的增加有关。
Researchers tracked 36 people before and after getting a flu vaccine,
研究人员对36名参与者接种流感疫苗前后的情况进行追踪，
and they found the subjects interacted with more people in larger groups right after they got the shot than right before.
发现受试者在注射流感疫苗后与更多人互动。
So, they were spending more time with more people while their bodies were building up an immune response.
因此，他们花更多的时间和更多的人在一起，而他们身体的免疫反应在增强。
Now, it's worth noting that this was just a small first study, and it didn't have a control group of people who, say, got a placebo shot.
值得注意的是，这只是首次小规模研究，没有别的组可以对照，比方说，注射安慰剂。
But the researchers controlled for some obvious problems, like what day they got the shot.
但是研究人员把控了一些显而易见的问题，比如注射时间。
It wasn't like everyone got them Friday morning just before going out to party all weekend.
不是每个人都在周五注射完才去参加周末聚会。
The difference between this study and just looking at what people do when they're actually sick is that in this case,
该研究和观察人们生病时行为的区别在于，
the subjects' immune systems were more active, but they didn't have symptoms.
受试者的免疫系统更活跃，但没有症状。
And the results were the opposite of what people do when they're sick: they were more social when their immune systems were more active.
研究结果与人们生病时的行为相反：当他们的免疫系统更活跃时，社交能力更强。
But based on what we've learned from later research, being more social when your immune system is stronger might actually make sense.
但是根据后来的研究我们了解到，当免疫系统更强的时候，更多的社交可能是有道理的。
In a study of 121 people published in the journal Psychoneuroendocrinology in 2015—
2015年发表在《心理神经内分泌学》(Psychoneuroendocrinology)杂志上的一项研究，对121人进行了测试。
I'm telling you those people named that journal just to mess with us—
告诉你，给那本杂志起名字的那些人只是为了和我们闹着玩
researchers found that people who were more extroverted and social tended to express more of the genes known to increase the immune response.
研究发现，性格外向、社交广泛的人往往出现更多已知的增强免疫反应的基因。
In other words, the more outgoing people seemed to have stronger immune systems, which might be another evolutionary adaptation —
换句话说，越外向的人，他的免疫系统越强，这可能是另一种进化适应。
it could be helpful for them to explore more, take more risks, and meet more people.
这将有助于他们探索更多，承担更多的风险，和更多的人见面。
Again, this research is all really new, and without more studies we can't know for sure that this is what's happening.
此外，该项研究都是新的，没有更多的研究，我们无法确定发生了什么。
But learning more about the connection between the immune system and social behavior could lead to new treatments for clinical conditions that are related to those behaviors.
但是，了解更多免疫系统和社会行为之间的联系，可以为与之相关的临床状况提供新的治疗方法。
For example, we know that some people get more severe symptoms of depression when their cytokines spike in their blood —
例如，我们知道当血液中的细胞因子激增时——就像他们的免疫反应强烈时，
like when they have a strong immune response.
某些人的抑郁症会加重。
And a similar effect has been found in children with autism: increases of some cytokines in the blood can be accompanied by stronger symptoms.
在自闭症儿童身上也发现了类似的效应：血液中某些细胞因子的增加可能伴随着更强烈的症状。
The researchers are starting to investigate ways to use the immune system to affect social behavior on purpose.
研究人员开始研究利用免疫系统故意影响社会行为的方法。
In research published in Nature just last year, neuroscientists studied mice that were raised with impaired immune function.
在去年发表在《自然》杂志上的一项研究中，神经科学家们对免疫功能受损的小鼠进行了研究。
Compared to healthy mice, who are much more interested in hanging out with a new mouse than a new inanimate object,
与健康的老鼠——对新鼠而不是新的无生命体更感兴趣——相比
the impaired mice were kind of equally interested in both.
免疫功能受损的老鼠对两者都很感兴趣。
It was like they saw the other mouse as just another thing.
就好像它们把另一只老鼠当成了另一个东西。
But, when the researchers injected immune cells called lymphocytes from healthy mice into the impaired mice, that difference went away.
但是，当研究人员将健康小鼠的淋巴细胞注射到受损小鼠体内时，这种差异就消失了。
We're still a long way from being able to use the immune system to treat clinical symptoms,
利用免疫系统来治疗临床症状仍然任重而道远，
but with more research, psychologists hope we might someday be able to.
但是随着研究的增多，心理学家希望有一天能够实现。
And maybe all this will give you a little hope too, if you're lying on the couch next to a bucket.
如果你去看心理医师，也许这一切会带给你些许希望。
You'll probably be interested in hanging out with people again soon —
你可能很快就会有兴趣再和别人出去玩了
you just have to wait for your immune system to do its job.
你只需要等待你的免疫系统发挥作用。
In the meantime, while you're sick is a great time to learn weird things about your mind,
与此同时，生病的时候，你可以借机学习大脑的一些奇怪的事情，
you can check out our video about whether you can use electricity to supercharge your brain.
看看我们的视频——是否能用电力给大脑充电。
And if you want to keep getting smarter with us, you can always just go to youtube.com/scishowpsych and subscribe.
如果你想和我们一样更聪明，可以随时访问并订阅youtube.com/scishowpsych。
