I'm a neuroscientist, and I'm the co-founder of Backyard Brains, and our mission is to train the next generation of neuroscientists by taking graduate-level neuroscience research equipment and making it available for kids in middle schools and high schools.
我是神經科學家, 我是 Backyard Brains (後院頭腦)的共同創辦人, 我們的使命是要訓練 下一代的神經科學家, 做法是把研究所等級的 神經科學研究設備 開放給國中和高中的孩子使用。
And so when we go into the classroom, one way to get them thinking about the brain, which is very complex, is to ask them a very simple question about neuroscience, and that is, "What has a brain?" When we ask that, students will instantly tell you that their cat or dog has a brain, and most will say that a mouse or even a small insect has a brain, but almost nobody says that a plant or a tree or a shrub has a brain. And so when you push -- because this could actually help describe a little bit how the brain actually functions -- so you push and say, "Well, what is it that makes living things have brains versus not?" And often they'll come back with the classification that things that move tend to have brains. And that's absolutely correct. Our nervous system evolved because it is electrical. It's fast, so we can quickly respond to stimuli in the world and move if we need to. But you can go back and push back on a student, and say, "Well, you know, you say that plants don't have brains, but plants do move." Anyone who has grown a plant has noticed that the plant will move and face the sun. But they'll say, "But that's a slow movement. You know, that doesn't count. That could be a chemical process." But what about fast-moving plants?
我們進到教室, 使學生思考複雜頭腦的方式之一 是問他們一個非常 簡單的神經科學問題, 那就是:「什麼有頭腦?」 當我們問這個問題, 學生會馬上告訴你, 他們的貓或狗有頭腦, 大部份人會說,老鼠、 甚至小昆蟲也有頭腦, 但幾乎沒有人會說植物、樹木 或灌木有頭腦。 當你再進一步── 因為這其實可以稍微協助描述 頭腦實際上如何運作── 所以當我們再進一步問說: 「生物有沒有頭腦的差別在哪?」 通常,他們回答的分類是 會動的生物通常有頭腦。 那完全正確。 我們的神經系統是用電的, 所以會進化。 它很快,所以我們能對世界上的 刺激物做出快速反應, 有需要我們也會移動。 但你可以回頭去再問學生: 「你說植物沒有頭腦, 但植物確實會動。」 只要你曾經種過植物, 就會注意到植物會動, 它會面向太陽。 但他們會說: 「但那是很緩慢的移動,不算數。 那可能是種化學過程。」 那動得很快的植物呢?
Now, in 1760, Arthur Dobbs, the Royal Governor of North Carolina, made a pretty fascinating discovery. In the swamps behind his house, he found a plant that would spring shut every time a bug would fall in between it. He called this plant the flytrap, and within a decade, it made its way over to Europe, where eventually the great Charles Darwin got to study this plant, and this plant absolutely blew him away. He called it the most wonderful plant in the world. This is a plant that was an evolutionary wonder. This is a plant that moves quickly, which is rare, and it's carnivorous, which is also rare. And this is in the same plant. But I'm here today to tell you that's not even the coolest thing about this plant. The coolest thing is that the plant can count.
1760 年,北卡羅來納的 皇家總督阿圖杜伯斯 有個非常棒的發現。 在他家後面的沼澤中, 他發現一種植物, 每次只要有一隻蟲落入它中間, 它就會飛快闔上。 他把這植物稱為捕蠅草, 十年內,它就散播到了歐洲, 最終偉大的達爾文 得以研究這種植物, 這植物完全讓他驚呆了。 他稱之為世界上最美妙的植物。 這種植物是演化上的奇蹟。 這種植物動的速度很快, 這點很稀有, 且它是肉食性的,這點也很稀有。 同一種植物有兩種稀有特性。 但今天,我要告訴各位, 這還不是這植物最酷的事。 最酷的事是植物能計數。
So in order to show that, we have to get some vocabulary out of the way. So I'm going to do what we do in the classroom with students. We're going to do an experiment on electrophysiology, which is the recording of the body's electrical signal, either coming from neurons or from muscles. And I'm putting some electrodes here on my wrists. As I hook them up, we're going to be able to see a signal on the screen here. And this signal may be familiar to you. It's called the EKG, or the electrocardiogram. And this is coming from neurons in my heart that are firing what's called action potentials, potential meaning voltage and action meaning it moves quickly up and down, which causes my heart to fire, which then causes the signal that you see here. And so I want you to remember the shape of what we'll be looking at right here, because this is going to be important. This is a way that the brain encodes information in the form of an action potential.
要展現這一點, 我們得要先解決一些字彙的意思。 我打算用我們在教室裡 教學生的方式。 我們要做一個電流生理學實驗, 也就是記錄身體的電訊號, 可能來自神經元或肌肉。 我要在我的手腕貼上電極。 等我把它們弄好, 我們就會看到訊號 出現在螢幕上。 你可能覺得這訊號很熟悉。 它叫 EKG,或心電圖。 這來自我心臟的神經元, 這些神經元會發射所謂的動作電位, 電位就是電壓, 動作就表示它快速上下動。 造成我的心臟反應, 產生出你們在這裡看到的訊號。 請各位記住我們在這裡看到的形狀, 這點之後會很重要。 這是頭腦把資訊編碼成 動作電位的一種形式。
So now let's turn to some plants. So I'm going to first introduce you to the mimosa, not the drink, but the Mimosa pudica, and this is a plant that's found in Central America and South America, and it has behaviors. And the first behavior I'm going to show you is if I touch the leaves here, you get to see that the leaves tend to curl up. And then the second behavior is, if I tap the leaf, the entire branch seems to fall down. So why does it do that? It's not really known to science. One of the reasons why could be that it scares away insects or it looks less appealing to herbivores. But how does it do that? Now, that's interesting. We can do an experiment to find out.
現在,我們來看一些植物。 我要先向各位介紹含羞草, 不是含羞草調酒,是含羞草植物, 在中美和南美可以找到這種植物, 它是有行為的。 我要展示的第一個行為是, 當我觸碰葉子, 你們可以看到葉子會縮起來。 第二個行為是, 如果我輕敲葉子, 整個分枝都會向下倒。 它為什麼要這樣做? 科學還沒有答案。 原因之一可能是它想把昆蟲嚇跑, 或比較不會吸引到食草動物。 但它怎麼做到的?這就很有趣了。 我們可以做個實驗來找出答案。
So what we're going to do now, just like I recorded the electrical potential from my body, we're going to record the electrical potential from this plant, this mimosa. And so what we're going to do is I've got a wire wrapped around the stem, and I've got the ground electrode where? In the ground. It's an electrical engineering joke. Alright.
我們現在要做的, 就像是我記錄我身體的電位一樣, 我們要記錄這含羞草的電位。 我們要做的是, 用電線包住莖的部份, 把接地電極接到哪裡呢? 地上。這是個電子工程師笑話。
(Laughter)
(笑聲)
Alright. So I'm going to go ahead and tap the leaf here, and I want you to look at the electrical recording that we're going to see inside the plant. Whoa. It is so big, I've got to scale it down. Alright. So what is that? That is an action potential that is happening inside the plant. Why was it happening? Because it wanted to move. Right? And so when I hit the touch receptors, it sent a voltage all the way down to the end of the stem, which caused it to move. And now, in our arms, we would move our muscles, but the plant doesn't have muscles. What it has is water inside the cells and when the voltage hits it, it opens up, releases the water, changes the shape of the cells, and the leaf falls.
好。我要輕敲這裡的葉子, 請各位注意看等下會出現 來自植物的電訊號記錄。 哇。好大,我得要縮一下比例。 好了。那是什麼? 那是行動電位, 且是在植物內部發生的。 它為什麼會發生? 因為它想要動,對嗎? 所以當我去觸碰接收器, 它會發送電壓, 一路向下送到莖的底端, 使莖動了。 在我們的手臂中,我們會動肌肉, 但植物沒有肌肉。 它的細胞中有水份, 當電壓接觸到它時, 它會打開,放出水份, 改變細胞的形狀,葉子就會倒下。
OK. So here we see an action potential encoding information to move. Alright? But can it do more? So let's go to find out. We're going to go to our good friend, the Venus flytrap here, and we're going to take a look at what happens inside the leaf when a fly lands on here. So I'm going to pretend to be a fly right now. And now here's my Venus flytrap, and inside the leaf, you're going to notice that there are three little hairs here, and those are trigger hairs. And so when a fly lands -- I'm going to touch one of the hairs right now. Ready? One, two, three. What do we get? We get a beautiful action potential. However, the flytrap doesn't close. And to understand why that is, we need to know a little bit more about the behavior of the flytrap. Number one is that it takes a long time to open the traps back up -- you know, about 24 to 48 hours if there's no fly inside of it. And so it takes a lot of energy. And two, it doesn't need to eat that many flies throughout the year. Only a handful. It gets most of its energy from the sun. It's just trying to replace some nutrients in the ground with flies. And the third thing is, it only opens then closes the traps a handful of times until that trap dies. So therefore, it wants to make really darn sure that there's a meal inside of it before the flytrap snaps shut. So how does it do that? It counts the number of seconds between successive touching of those hairs. And so the idea is that there's a high probability, if there's a fly inside of there, they're going to be quick together, and so when it gets the first action potential, it starts counting, one, two, and if it gets to 20 and it doesn't fire again, then it's not going to close, but if it does it within there, then the flytrap will close.
所以,在這裡我們看到了行動電位 能夠將資訊編碼來造成移動。對吧? 但它能做更多嗎? 我們來找出答案。 我們要來找我們這裡的 好朋友捕蠅草, 我們要來看一下, 當一隻蒼蠅降落在這裡時, 葉子裡會發生什麼事。 現在,我要假裝是一隻蒼蠅。 我的捕蠅草在這裡, 看一下葉子內部, 有三根毛在這裡,它們是感覺毛。 所以當蒼蠅降落── 我現在要來觸碰其中一根毛。 準備好了嗎?一、二、三。 我們得到了什麼? 很漂亮的行動電位。 然而,捕蠅草沒有闔上。 要了解為什麼會這樣, 我們需要多了解一點捕蠅草的行為。 第一,把陷阱重新打開 要花的時間很長── 如果沒有蒼蠅在裡面的話, 大約要 24 到 48 小時。 那要花很多的能量。 第二,一整年間, 它並不需要吃那麼多蒼蠅。 少量即可。 它大部份的能量來自太陽。 它只是試著以蒼蠅 取代一些地面的營養物。 第三, 它只能將陷阱開闔少數幾次, 然後陷阱就會死亡。 因此,它要非常確定 有餐點在陷阱裡面的時候, 它才會快速闔上。 它怎麼做到的? 它會計算秒數, 連續觸碰那些毛之間的時間間隔。 概念是,如果裡面有蒼蠅, 它就非常可能會闔上, 所以當它接到第一個行動電位時, 它就開始計算,一、二, 如果數到二十都不再有電位發出, 它就不會闔上, 但如果有的話,捕蠅草就會闔上。
So we're going to go back now. I'm going to touch the Venus flytrap again. I've been talking for more than 20 seconds. So we can see what happens when I touch the hair a second time. So what do we get? We get a second action potential, but again, the leaf doesn't close. So now if I go back in there and if I'm a fly moving around, I'm going to be touching the leaf a few times. I'm going to go and brush it a few times. And immediately, the flytrap closes. So here we are seeing the flytrap actually doing a computation. It's determining if there's a fly inside the trap, and then it closes.
我們要再回來。 我要再次觸碰捕蠅草。 我已經講話超過二十秒了。 來看看當我二度觸碰 這根毛時會發生什麼事。 我們得到什麼?第二個行動電位, 但同樣的,葉子沒有闔上。 如果我再回來, 如果我是一隻到處跑的蒼蠅, 就會再觸碰葉子幾次。 我要再輕輕拂過它幾次。 馬上, 捕蠅草闔上了。 我們看到捕蠅草真的在計算。 它判斷是否真的有蒼蠅在陷阱中, 然後才闔上。
So let's go back to our original question. Do plants have brains? Well, the answer is no. There's no brains in here. There's no axons, no neurons. It doesn't get depressed. It doesn't want to know what the Tigers' score is. It doesn't have self-actualization problems. But what it does have is something that's very similar to us, which is the ability to communicate using electricity. It just uses slightly different ions than we do, but it's actually doing the same thing. So just to show you the ubiquitous nature of these action potentials, we saw it in the Venus flytrap, we've seen an action potential in the mimosa. We've even seen an action potential in a human.
所以,我們回到原先的問題。 植物有頭腦嗎? 答案是沒有。 這裡面沒有頭腦。 沒有軸突、沒有神經元。 它不會沮喪。 它不會想知道 底特律老虎隊目前得幾分。 它沒有自我實現的問題。 但它有和我們很相似之處, 就是用電來溝通的能力。 只是它用的離子和我們有些微不同, 但做的事是一樣的。 只是要讓大家看看 這些行動電位無所不在的特性, 我們在捕蠅草身上看到了, 我們在含羞草身上看到了。 我們在人類身上看到了。
Now, this is the euro of the brain. It's the way that all information is passed. And so what we can do is we can use those action potentials to pass information between species of plants. And so this is our interspecies plant-to-plant communicator, and what we've done is we've created a brand new experiment where we're going to record the action potential from a Venus flytrap, and we're going to send it into the sensitive mimosa.
這就是頭腦的歐元, 是讓所有資訊得以傳遞的方式。 我們能利用那些行動電位 在不同種的植物之間 傳遞資訊。 這是我們的跨物種 植物對植物的溝通器, 我們創造了一個全新的實驗, 從捕蠅草這裡記錄行動電位, 接著把它傳送給敏感的含羞草。
So I want you to recall what happens when we touch the leaves of the mimosa. It has touch receptors that are sending that information back down in the form of an action potential. And so what would happen if we took the action potential from the Venus flytrap and sent it into all the stems of the mimosa? We should be able to create the behavior of the mimosas without actually touching it ourselves.
請各位回想一下, 當我們觸碰含羞草葉面時 會發生什麼事。 它的觸碰接收器會向下傳送 行動電位形式的資訊。 所以,若我們把捕蠅草的行動電位 傳送到含羞草的莖內 會發生什麼事? 我們應該會在不用自己 觸碰含羞草的情況下 就引發含羞草的行為。
And so if you'll allow me, I'm going to go ahead and trigger this mimosa right now by touching on the hairs of the Venus flytrap. So we're going to send information about touch from one plant to another.
所以,如果可以的話, 我現在就要來觸碰捕蠅草的毛, 來觸發含羞草的行為。 我們將會把觸碰一棵植物的資訊 傳送到另一棵植物。
So there you see it. So --
看到了嗎。 所以,
(Applause)
(掌聲)
So I hope you learned a little bit, something about plants today, and not only that. You learned that plants could be used to help teach neuroscience and bring along the neurorevolution.
我希望各位今天學到了 一點關於植物的知識, 且不只如此。 你們學到了植物能被用來 協助教導神經科學, 並能帶來神經革命。
Thank you.
謝謝。
(Applause)
(掌聲)