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Thanks to CuriosityStream for supporting this episode! Go to CuriosityStream.com/SciShow to learn more.
感谢CuriosityStream对本期节目的支持！前往CuriosityStream.com/SciShow了解更多。
The planarian is a saltwater and freshwater flatworm known primarily for its regenerative abilities.
真涡虫是一种咸水和淡水扁虫，主要以其再生能力而闻名。
Cut off their tail, and they'll grow it back; cut them in half and they'll become two whole flatworms,
切掉它们的尾巴，尾巴还能再长出来；把它们对半切，它们会变成两只完整的扁虫，
even though they have a distinctive head region with a brain in it.
尽管它们有一个独特的头部区域，里面有大脑。
What's really amazing is that even after losing its brain, a planarian can remember things from before it was beheaded.
真正令人惊奇的是，即使没了脑袋，真涡虫还能记得被砍头前的事情。
Planarians are pretty simple animals, but they do have brains that control things like sensory reception.
虽然真涡虫是相当简单的动物，但它们确实有一个控制感官接收之类的大脑。
And this brain is considered a true brain, not just a bundle of neurons,
并且它们的大脑被认为是一个真的大脑，不仅仅是一束神经元而已，
it has two lobes, it controls nervous function throughout the body, and it has specialized regions.
它有两个脑叶，控制着全身神经功能，并且还有专门的区域。
This means their brains probably look a lot how ours once did.
这意味着它们的大脑可能和我们的一样。
And this makes them a great analog for studying brain evolution, as well as asking fundamental questions about things like memory.
这使它们成为了一个很好的研究大脑进化以及提问关于记忆等基本问题的模型。
It's hard to know what memories a planarian has, of course.
当然很难知道一只真涡虫记得什么。
But you can train them to perform new, unnatural behaviors, and then see if they retain that memory under different conditions.
但你可以训练它们做出新的、非自然的行为，然后观察它们在不同情况下是否保留有这一记忆。
Planarians have simple needs: they like raw meat, and they dislike light and change. Which ... I get it.
真涡虫的需求很简单：它们喜欢生肉，不喜欢光线和变化。这个...我懂的。
They're willing to get over their light aversion for a tasty meal, but if other things change at the same time, they just kind of freak out.
它们愿意为了美食克服对光线的厌恶，但如果其他的事情同时发生变化，它们就会变得很疯狂。
Like, if you take them out of petri dishes with smooth glass and put them into textured petri dishes,
比如，如果你把它们从有光滑玻璃的培养皿里拿出来并将它们放进凹凸不平的培养皿种，
they are too weirded out at first to go for a piece of liver in the middle with a bright light shining on it.
它们一开始就会感觉很奇怪，不愿吃中间有强光照射的一片肝脏。
But, if you put the flatworms in textured dishes for a while beforehand, you can passively train them to be familiar with that environment.
但如果你事先把扁虫放在有纹理的盘子里一段时间，你可以被动地训练它们熟悉那个环境。
Then, when you add the spotlight and liver, they go for it quickly—providing researchers with enough evidence of successful training.
然后当你加入灯光和肝脏，它们很快就会去吃—这为研究人员提供了足够的证据证明训练成功了。
And when scientists have done this training regimen, they've found the planarians can retain such memories for at least 14 days.
当科学家们完成了这个训练，他们发现真涡虫可以将这个记忆保留至少14天。
That raises the question, of course: what happens when you cut off their heads?
当然问题就来了：如果切掉它们的脑袋会发生什么？
We know that within a week, the flatworms grow new, usable heads they can eat with and everything
我们知道在一个星期内，扁虫会长出新的有用的脑袋，它们可以用脑子吃任何东西
and they can make it that long without eating, so they're fine.
并且它们不吃东西也能做到这一点，所以它们会没事。
But, presumably, if you have a brain, that's where your memories are
但假设你有一个大脑，这个大脑就是你的记忆所在
so since the 1950s, scientists have been trying to figure out what happens when the flatworms lose and then regrow their brains.
所以自20世纪50年代，科学家们一只试图弄清楚当扁虫失去并重新长出它们的大脑时会发生什么。
And most strangely, they seem to remember previous training.
最奇怪的是，它们似乎还记得以前的训练。
In a 2013 study, for example, the trained flatworms approached the food faster, even though their training happened with their former heads.
例如，在2013年的一项研究中，受过训练的扁虫接近食物的速度更快，虽然它们是在之前砍脑袋前受到的训练。
The difference between the trained and untrained planarians was not as big as it was pre-decapitation,
受训和未受训真涡虫的区别不如被切脑袋前那么大，
so the researchers concluded that this memory retention isn't quite one hundred percent.
所以研究人员得出结论，记忆并不是100%的被保留了。
But still, it's bizarre that they could remember the training at all.
但奇怪的是它们还记得那次训练。
As for how they retain those memories, well… we don't really know.
至于它们如何保留那些记忆，我们真的不知道。
One intriguing idea is that memories of certain habitual behaviors are partially transferred to neural tissue outside of the brain.
一个有趣的想法是，某些习惯性行为的记忆被部分转移到大脑外的神经组织。
So, somehow there are memories stored in other neurons in the body.
所以这些记忆不知怎么的就被储存在了身体的其他神经元中。
Which is just so completely against everything we thought we understood about memories.
这完全违背了我们对记忆的理解。
I mean, we talk about "muscle memory", but even that is thought to occur in the parts of the brain
我指的是“肌肉记忆”，但即便是肌肉记忆也被认为只发生在控制四肢移动的
that control how you move your extremities, not in those extremities themselves.
部分大脑区域，而不是四肢本身。
A lot more research is needed to fully understand this phenomenon, and to figure out if it's unique to planarians or true of all brainy creatures.
需要进行更多研究才能完全理解这种现象并弄清楚这是否是真涡虫独有还是所有有大脑的生物都这样。
Because if human memories also exist outside of our brains in some way,
因为如果人类记忆也以某种方式存在于我们的大脑之外，
understanding how could lead to better treatments for certain brain injuries, memory loss, or dementias.
理解这一现象可以让我们更好地治疗某种脑损伤、失忆或痴呆。
And that would be some pretty awesome stuff to learn from a headless flatworm.
我们能从无脑扁虫中了解到的将是一些非常了不起的东西。
Speaking of learning awesome stuff, if you liked hearing about these amazing flatworms,
说到学习很棒的东西，如果你喜欢关于这些神奇扁虫的事情的话，
I have a feeling you'll like the videos you can watch with CuriosityStream.
我想你也会喜欢CuriosityStream的视频。
CuriosityStream is a subscription streaming service that offers over 2,400 documentaries
CuriosityStream是一个订阅流媒体服务，上边有2400多个纪录片
and nonfiction titles from some of the world's best filmmakers, including exclusive originals.
和来自世界最好制片人的非虚构作品，包括独家原版。
And they have all sorts of videos that give you a deeper dive into this planet's quirkiest inhabitants.
他们有各种视频，可以让你更深入这个星球最离奇的栖息地。
You might check out The Year of the Hedgehog, for example—it follows these adorable weirdos over the course of a year
例如，你可以看看《The Year of the Hedgehog》—它讲述了一年来这些可爱又古怪故事
while explaining what makes them and the other animals they encounter so wonderfully unique.
同时还解释了是什么让它们和它们遇到的其他动物如此独特。
You can watch it and all of the other videos CuriosityStream offers for as little as $2.99 a month.
每月仅需2.99美元即可观看所有CuriosityStream视频。
And for our audience, the first 31 days are completely free if you sign up at curiositystream.com/scishow
对我们的观众，如果你注册curiositystream.com/scishow并在注册时使用我们的促销码scishow
and use the promo code 'scishow' during the sign-up process.
即可享受前31天免费观看福利 。
