(单词翻译:单击)
Thanks to Brilliant for supporting this episode of SciShow. Go to Brilliant.org/SciShow to learn more.
感谢Brilliant对本期节目的支持。登入Brilliant.org/SciShow了解更多。
There's been an advancement in neuroscience that could eventually lead to changes in how we think about death.
神经系统科学取得了一项进步可最终改变我们对死亡的看法。
In a study published on April 17 in the journal Nature,
在4月17日发表于《自然》期刊上的一项研究中，
scientists revealed a method that successfully revived certain processes in the brains of dead pigs.
科学家们揭露了一种方法可以成功复活死猪脑中的某些进程。
While they didn't restore consciousness or even recognizable brain activity,
虽然他们无法恢复大脑意识或可辨识的脑活动，
it's a huge step that's bringing up questions about what death really means
但这一个巨大的进步引出了这样的问题：死亡的真正意义是什么
and what's ethical when it comes to reviving dead brains.
以及复活死亡大脑的道德伦理问题。
Up until now, it's been assumed that when the heart stops or the brain ceases activity for a relatively short period of time,
直到现在，人们还认为当心脏停止跳动或大脑短期停止活动时，
there's no going back. Without oxygen, energy, or electrical activity, brain cells will quickly start to die.
人就活不过来了。没有氧气、能量或脑电活动，脑细胞将迅速死亡。
But even before this breakthrough, there have been hints that this assumption might not be true.
但即使是在取得这次突破前，就有迹象表明这种假设可能不是真的。
Studies in cats and monkeys have demonstrated that the brain can fully recover after an entire hour without blood circulation.
对猫和猴子的研究已经表明一个小时内没有血液循环的大脑可以完全恢复。
There are also examples of people whose hearts have stopped or who suffered a stroke,
还有一些心脏停止或中风的病人的例子，
leaving their brains without blood flow for hours at a time.
他们的大脑在某时好几个小时没有血液供应，
But when their doctors restored their circulation, those people made a full recovery.
但是当他们的医生恢复循环后，这些人有完全恢复了。
Even once cells have been removed from a brain, research has found they can be kept alive for weeks in culture.
甚至有一次细胞被移出大脑，研究发现它们仍可以在培育器皿中存活几个星期。
So it's possible that brains are tougher than we give them credit for.
所以大脑可能比我们以为的要更加坚强。
This new study sought to ask just how tough. They used the brains of pigs, which are big and complex like ours,
这项新研究想要弄清大脑究竟有多么坚强。他们使用了猪脑，猪脑和人脑一样大而复杂，
and therefore very sensitive to any interruption in the flow of oxygen and nutrients.
且对氧气流和营养素中的任何干扰都非常敏感。
And these pigs had already been dead for four hours.
这些猪已经死了四个小时了。
To revive the 32 brains, the researchers developed a system they called BrainEx,
为了复活这32只脑子，研究人员开发了一种被他们称为BrainEx的系统，
which kept them sealed in a specially designed chamber.
可以将它们密封在一个特制的室内。
It also pumped a specially formulated blood substitute into their blood vessels.
同时向它们的血管中输送按配方特别制造的血液代用品。
The blood substitute contained oxygen and nutrients to feed the brain cells,
血液代用品中含有供养脑细胞的氧气和营养素，
tiny particles to help it show up on an ultrasound and, importantly, chemicals designed to keep the neurons from firing.
帮助显示超声波的微粒以及最重要的是，用于防止神经元放电的特制化学物质。
That was partly to protect the neurons from damage, and partly for ethical reasons:
这么做一面可以保护神经元免受伤害，一面也是出于道德原因：
the researchers didn't actually want to restart brain activity.
研究人员不想真的重启它们的脑活动。
These brains were detached from their bodies, and no one knows what it would be like for a disembodied brain to regain consciousness
这些大脑与它们的肢体分离，并且没有人知道一个被肢解的大脑重获意识后会是什么样的
but they didn't want to cause any distress, just in case.
但他们在此不想引起任何悲痛。
And if the brains did become active, the researchers actually kept anesthetics on hand to stop them in their tracks.
如果大脑确实变得活跃，那么研究人员随时可以用麻醉剂阻止。
So they pumped the brains with this blood substitute for six hours.
所以他们连续六小时向大脑输送血液代用品。
They could have gone longer - the problem was actually with their control brains,
他们本可以输送更长时间—真正的问题在于他们的对照组大脑，
which deteriorated too much to keep accepting saline instead of the blood substitute.
为了给对照组大脑一直输送盐水而非血液代用品，对照组大脑已经严重恶化了。
But while the cells of the control brains gave out, the cells of the test brains fared much better.
但虽然对照组大脑的细胞已耗尽，但测试组大脑的细胞进展得还不错。
They even performed a lot of their previous functions - like metabolizing nutrients and mounting immune responses.
它们甚至可以进行很多之前的功能，比如营养代谢以及越来越多的免疫反应。
The researchers even found that some neurons still fired when they applied electricity to a sample of the brain tissue.
研究人员甚至发现当他们给脑组织样本通电时，一些神经元仍带电。
Now, here's what they did not do: They didn't restore consciousness to a dead brain.
现在，他们没能做到事情如下：他们没有恢复死亡脑的意识；
They didn't even see anything that could resemble coordinated neurological activity
他们甚至没有看见任何类似协调神经的活动
- EEGs monitoring the brains were completely flat the whole time.
—监控大脑的脑电图一直是平。
It's possible that if they hadn't used the neuron-inhibiting chemical, they might have seen more,
可能，如果他们没有使用神经元抑制化学物的话，或许可以见证更多，
but the researchers have no plans to try again and see if they can trigger real brain activity.
但研究人员没有再次尝试的计划，也无法见证它们是否可以触发真实的脑活动。
And just because it needs to be said, they are nowhere near being able to keep conscious brains in jars like in Futurama,
因为在这里需要说的是，他们远不能像《飞出个未来》一样，把有意识的大脑装在瓶中，
or transplant brains into new bodies like in Frankenstein.
也不能像《弗兰肯斯坦》一样将大脑移植到新的身体上。
Right now, the biggest possibilities are in keeping brain tissue alive during experiments.
现在最大的可能是在实验中保持脑组织的存活。
Brain researchers do what they can with individual cells and tissue samples.
大脑研究人员利用单个细胞和组织样本尽了一切可能。
But studying them in context - in an intact brain - has the potential to be way more informative.
但在此环境中研究它们—在一个完整脑内—有可能提供更多信息。
Even though they didn't restore consciousness, and even though this was only pig brains that had been removed from pig bodies,
虽然他们没有恢复意识，虽然这只是一个被切割的猪脑，
the breakthrough does bring up a whole lot of ethical and regulatory questions.
但此次突破确实提出了许多关于道德和监管的问题。
Right now, regulations on animal research cover living animals and mostly exclude dead ones.
现在对于动物研究的规范仅覆盖到了活体动物且大部分不包括死亡动物。
There are no guidelines for what to do with an animal that was dead but had its brain activity restored.
关于如何处理已死亡但大脑活动已恢复的动物还没有任何指导方针。
What's the best way to test for consciousness? Which animals should be off limits?
测试意识最好的方法是什么？哪些动物应被排除在外？
Should researchers be required to use neuron inhibitors and anesthetics in future studies?
研究人员应被要求在未来研究中使用神经元抑制剂和麻醉剂吗？
And then there are also questions about the meaning of death.
然后还有关于死亡意义的问题。
Right now, physicians stop trying to resuscitate someone when they believe there's no chance they'll come back.
现在当内科医生认为无力回天时，他们会停止抢救他们。
But if the human brain is viable for longer than we thought without blood flow, that changes things.
但如果人脑在没有血液流动的情况存活的时间比我们认为的要更长，那么事情就发生了变化。
It could affect when physicians and first responders actually decide when someone is and is not dead.
这会影响内科医生判断病人是否死亡的决定。
Which, in turn, could affect things like organ donation.
反过来就会影响很多事情，如器官捐献。
This technology is extremely far from being ready to use in a healthcare setting.
这项技术远还没有准备好被应用于医疗保健环境之中。
So we don't have to answer all these questions right now.
所以现在我们不必回答所有这些问题。
But the researchers behind the study, and others, are calling for the discussion to at least begin.
但此研究背后的研究人员和其他人都呼吁至少该开始讨论。
One thing is for sure though: this study changes a lot of what we thought we knew about our brains.
有一件事是确定的：该研究改变了我们之前关于大脑的很多认识。
It's a big deal. Even though we did not make pig zombies.
这是个大事件。虽然我们没有做出猪僵尸。
We know that you don't shy away from complex topics like how we study brains and what that tells us about death.
我们知道大家不避讳这些复杂的话题，比如我们如何研究大脑以及大脑和死亡。
And if you want to learn more about the world around us and how we study it,
如果你想更多的了解周围的世界以及我们如何研究它，
you can try the interactive courses and challenges over at Brilliant.
你可以尝试一下Brilliant上的交互课程和挑战。
Brilliant offers daily challenges to help you sharpen your brain.
Brilliant提供每日挑战帮助提升大脑。
Every day, there are new questions in topics ranging from computer science to statistics,
每天都会有关于各种话题的新问题，比如电脑科学和数据学，
with animations, illustrations, and all the context you need to arrive at a solution.
还有各种解决问题所需的动画图画等等。
The Daily Challenges are absolutely free for everyone, but Premium members get access to the entire archive of past challenges.
每日挑战绝对免费，但高级会员将享受往期挑战的完整档案。
And, big news, Brilliant's iOS app now has an offline mode. So no matter where you are - you'll be able to keep learning.
好消息，Brilliant的iOS app可以离线使用。不论你在哪都能继续学习啦。
And also the first 200 people to go sign up at Brilliant.org/SciShow
前200名注册Brilliant.org/SciShow的观众
will get 20% off an annual Premium subscription, so get ready to learn something new!
将获得年度高级会员八折折扣，准备开始学习新知识吧！
