When you think about the brain, it's difficult to understand, because if I were to ask you right now, how does the heart work, you would instantly tell me it's a pump. It pumps blood. If I were to ask about your lungs, you would say it exchanges oxygen for carbon dioxide. That's easy. If I were to ask you how the brain works, it's hard to understand because you can't just look at a brain and understand what it is. It's not a mechanical object, not a pump, not an airbag. It's just like, if you held it in your hand when it was dead, it's just a piece of fat. To understand how the brain works, you have to go inside a living brain. Because the brain's not mechanical, the brain is electrical and it's chemical. Your brain is made out of 100 billion cells, called neurons. And these neurons communicate with each other with electricity. And we're going to eavesdrop in on a conversation between two cells, and we're going to listen to something called a spike. But we're not going to record my brain or your brain or your teachers' brains, we're going to use our good friend the cockroach. Not just because I think they're cool, but because they have brains very similar to ours. So if you learn a little bit about how their brains work, we're going to learn a lot about how our brains work. I'm going to put them in some ice water here And then -- Audience: Ew! Greg Gabe: Yeah ... Right now they're becoming anesthetized. Because they're cold blooded, they become the temperature of the water and they can't control it so they just basically "chillax," right? They're not going to feel anything, which may tell you a little about what we're going to do, a scientific experiment to understand the brain. So ... This is the leg of a cockroach. And a cockroach has all these beautiful hairs and pricklies all over it. Underneath each one of those is a cell, and this cell's a neuron that is going to send information about wind or vibration. If you ever try to catch a cockroach, it's hard because they can feel you coming before you're even there, they start running. These cells are zipping up this information up to the brain using those little axons with electronic messages in there. We're going to record by sticking a pin right in there. We need to take off the leg of a cockroach -- don't worry, they'll grow back -- then we're going to put two pins in there. These are metal pins. One will pick up this electronic message, this electric message is going by. So, we're now going to do the surgery, let's see if you guys can see this. Yeah, it's gross ... All right. So there we go. You guys can see his leg right there. Now I'm going to take this leg, I'm going to put it in this invention that we came up with called the Spikerbox -- and this replaces lots of expensive equipment in a research lab, so you guys can do this in your own high schools, or in your own basements if it's me. (Audience: Laughter) So, there. Can you guys see that? Alright, so I'm going to go ahead and turn this on. I'm going to plug it in. (Tuning sound) To me, this is the most beautiful sound in the world. This is what your brain is doing right now. You have 100 billion cells making these raindrop-type noises. Let's take a look at what it looks like, let's pull it up on the iPad screen. I plugged my iPad into here as well. So remember we said the axon looks like a spike. So we're going to take a look at what one of them looks like in just a brief second. We're going to tap here, so we can sort of average this guy. So there we see it. That's an action potential. You've got 100 billion cells in your brain doing this right now, sending all this information back about what you're seeing, hearing. We also said this is a cell that's going to be taking up information about vibrations in the wind. So what if we do an experiment? We can actually blow on this and hear if we see a change. Are you guys going to be ready? If I blow on it you tell me if you hear anything. (Blowing) (Sound changes) Let me just touch this with a little pen here. (Noise) That was the neural firing rate. That actually took a while in neuroscience to understand this. This is called rate coding: the harder you press on something, the more spikes there are, and all that information is coming up to your brain. That's how you perceive things. So that's one way of doing an experiment with electricity. The other way is that your brain is not only taking in electrical impulses, you're also sending out. That's how you move your muscles around. Let's see what happens if I've plugged in something that's electric into the cockroach leg here. I'm going to take two pins, I'm going to plug them onto the cockroach. I'm going to take the other end, I'm going to plug in into my iPod. It's my iPhone actually. Do you guys know how your earbuds work in your ears? You have a battery in your phone, or iPod, right? It's sending electrical current into these magnets in your earbuds which shake back and forth and allow you to hear things. But that current's the same currency that our brain uses, so we can send that to our cockroach leg and hopefully if this works, we can actually see what happens when we play music into the cockroach. Let's take a look. (Music beat) Can we turn it up? There we go. (Audience reacts and gasps) GG: So what's happening? Audience: Wow! (Laughter) So you see what's moving. It's moving on the bass. All those audiophiles out there, if you have awesome, kicking car stereos, you know, the bass speakers are the biggest speakers. The biggest speakers have the longest waves, which have the most current, and the current is what's causing these things to move. So it's not just speakers that are causing electricity. Microphones also cause electricity. (Beat) So I'm going to go ahead and invite another person out on the stage here to help me out with this. So there we go. (Beatboxing) This is the first time this has ever happened in the history of mankind. Human beatbox to a cockroach leg. When you guys go back to your high school, think about neuroscience and how you guys can begin the neuro-revolution. Thank you very much. Bye bye. (Applause)
(音樂) 當你想到大腦 它是個複雜難解的器官 因為如果我問你 心臟是如何運作 你一定能馬上跟我說這是一個泵 它輸送血液 如果我問你肺是如何運作 你一定知道肺的功能是氧氣和二氧化碳的交流 很簡單對吧 但如果我問你大腦如何運作 這就不容易解釋了 因為它的構造複雜難解 它不是一個機械物體 不是泵,也不是一個氣囊 一個大腦就只是一陀脂肪 所以要了解大腦的運作 你需要研究活大腦。因為大腦有電性和化學性 不是一個機械物體 你的大腦是由上百億個神經細胞組成的 這些神經細胞借由電傳導傳達訊息 現在我們要來聽聽神經細胞間的對話 這叫做神經衝動 但我們要用的不是我的、你們的 或你們老師的大腦 我們要借用我們好友小強 (蟑螂)的 這不是因為蟑螂的大腦很酷 是因為牠們的大腦類似我們的 所以我們可以從了解蟑螂的大腦功能 進而認識我們的大腦運作 首先我要將蟑螂放入這冰水中 然後... (觀眾: 厭惡聲)...耶... 這步驟是將牠們麻醉 因為牠們是冷血動物,沒有體內調溫系統 體溫隨外溫變動,所以牠們現在是冷凍了 牠們不會有任何感觸 這提示了一點我們將要做甚麼 我們將要做一個了解大腦的科學實驗 這樣... 這是一條蟑螂腿 蟑螂有好多美麗的毛髮 和刺 這每一個底下都是一個細胞 這一個是神經細胞 能傳達風向或震動的訊息 蟑螂不好抓是因為 牠們能感應到你的動作而開始逃跑 這些神經細胞是利用軸突 和電傳導訊息到大腦 我們要用這根針來記錄這訊息 首先我們要先將一條蟑螂腿拔下 別擔心,這會再長回去 然後把這兩根針插這裡 這其中一根鐵針 能接受到這用電傳導的訊息 現在讓我們來做個小手術,都看得到吧? 的確有點噁心... 好了... 你們可以看到牠的腿 現在我要把這腿放到我們發明的這儀器 叫做神經衝動箱 這可以取代很多昂貴的實驗設備 讓你們在自己的中學實驗室也可以做 或如果是我的話,我家的地下室 好了 (笑聲) 看得到嗎? 要開始了 把這插進去 (神經細胞發射聲) 我覺得這是世上最美妙的聲音 你們的大腦現在也正在這麼做 你們有上百億的神經細胞正在發出這雨滴聲 讓我們來看看這看起來是如何 讓我們用 iPad 看 看這 iPad 的螢幕 還記得我說過的軸突和電傳導 的神經衝動 (spike) 嗎? 這就是我們等會要看的 這裡點一下,平均一下這傢伙 這就是動作電位 (action potential) 你們上百億的神經細胞也正是如此運作 將你們所看和聽到的訊息傳達到大腦 我說過這神經細胞能傳達風向訊息 來試驗一下吧 我可以在這吹一下 聽看看有什麼變動 準備好了嗎? 我要吹了,跟我說你們聽到了什麼 (隨吹氣變動的神經衝動聲) 讓我用鉛筆在這裡按一下 (雜音) 這就是神經射程 這是長期的 神經科學研究成果 這叫速率編碼 當你按的越重 就會有越多的神經衝動 傳達信息到你的大腦 這就是你如何感受周遭事物 這是測試電傳導的實驗之一 大腦在接收訊息的同時也在發出訊息 例如移動你的手腳 現在讓我們來看看把電插到蟑螂腿上 會如何 我將把這兩根針插入這蟑螂 然後把這另一端插入我的 iPod 其實這是我的 iPhone 你們知道耳塞型耳機是如何運作的嗎? 你們都知道手機和 iPod 裡都有電池吧? 這利用電流震動耳機內的磁鐵 讓你聽得到東西 大腦裡的電流跟這類似 讓我用這蟑螂腿來示範 放音樂對這腿有什麼影響 讓我們來看看吧 (音樂) 可以大聲點嗎? (音樂) (觀眾驚嚇的反應) 這是什麼? (音樂) 它在動 隨著低音在動 在座的發燒友 如果你有很棒的車內音響 你們應該都知道低音喇叭最大 最大的喇叭的聲波最長和最多電流 電流能造成東西移動 除了喇叭能傳導電流 麥克風也可以 (音樂節拍) 現在我要請一位幫手出台 看好了 (節奏口技) 這是世上第一的 隨節奏口技起舞的蟑螂腿 我希望這能啟發你們 對神經科學的興趣和創新 謝謝 再見 (掌聲)