How to look inside the brain
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0:00 - 0:04This is a thousand-year-old drawing of the brain.
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0:04 - 0:06It's a diagram of the visual system.
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0:06 - 0:08And some things look very familiar today.
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0:08 - 0:12Two eyes at the bottom, optic nerve flowing out from the back.
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0:12 - 0:15There's a very large nose
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0:15 - 0:18that doesn't seem to be connected to anything in particular.
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0:18 - 0:20And if we compare this
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0:20 - 0:21to more recent representations of the visual system,
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0:21 - 0:25you'll see that things have gotten substantially more complicated
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0:25 - 0:27over the intervening thousand years.
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0:27 - 0:29And that's because today we can see what's inside of the brain,
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0:29 - 0:32rather than just looking at its overall shape.
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0:32 - 0:35Imagine you wanted to understand how a computer works
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0:35 - 0:38and all you could see was a keyboard, a mouse, a screen.
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0:38 - 0:42You really would be kind of out of luck.
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0:42 - 0:44You want to be able to open it up, crack it open,
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0:44 - 0:45look at the wiring inside.
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0:45 - 0:48And up until a little more than a century ago,
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0:48 - 0:50nobody was able to do that with the brain.
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0:50 - 0:51Nobody had had a glimpse of the brain's wiring.
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0:51 - 0:54And that's because if you take a brain out of the skull
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0:54 - 0:56and you cut a thin slice of it,
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0:56 - 0:58put it under a very powerful microscope,
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0:58 - 1:00there's nothing there.
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1:00 - 1:01It's gray, formless.
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1:01 - 1:04There's no structure. It won't tell you anything.
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1:04 - 1:06And this all changed in the late 19th century.
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1:06 - 1:10Suddenly, new chemical stains for brain tissue were developed
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1:10 - 1:14and they gave us our first glimpses at brain wiring.
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1:14 - 1:15The computer was cracked open.
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1:15 - 1:17So what really launched modern neuroscience
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1:17 - 1:21was a stain called the Golgi stain.
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1:21 - 1:22And it works in a very particular way.
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1:22 - 1:25Instead of staining all of the cells inside of a tissue,
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1:25 - 1:27it somehow only stains about one percent of them.
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1:27 - 1:31It clears the forest, reveals the trees inside.
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1:31 - 1:34If everything had been labeled, nothing would have been visible.
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1:34 - 1:37So somehow it shows what's there.
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1:37 - 1:39Spanish neuroanatomist Santiago Ramon y Cajal,
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1:39 - 1:41who's widely considered the father of modern neuroscience,
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1:41 - 1:45applied this Golgi stain, which yields data which looks like this,
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1:45 - 1:50and really gave us the modern notion of the nerve cell, the neuron.
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1:50 - 1:52And if you're thinking of the brain as a computer,
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1:52 - 1:55this is the transistor.
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1:55 - 1:55And very quickly Cajal realized
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1:55 - 1:58that neurons don't operate alone,
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1:58 - 2:01but rather make connections with others
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2:01 - 2:03that form circuits just like in a computer.
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2:03 - 2:04Today, a century later, when researchers want to visualize neurons,
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2:04 - 2:09they light them up from the inside rather than darkening them.
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2:09 - 2:10And there's several ways of doing this.
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2:10 - 2:12But one of the most popular ones
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2:12 - 2:14involves green florescent protein.
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2:14 - 2:15Now green florescent protein,
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2:15 - 2:17which oddly enough comes from a bioluminescent jellyfish,
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2:17 - 2:19is very useful.
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2:19 - 2:22Because if you can get the gene for green florescent protein
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2:22 - 2:24and deliver it to a cell,
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2:24 - 2:25that cell will glow green --
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2:25 - 2:30or any of the many variants now of green florescent protein,
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2:30 - 2:32you get a cell to glow many different colors.
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2:32 - 2:33And so coming back to the brain,
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2:33 - 2:37this is from a genetically engineered mouse called Brainbow.
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2:37 - 2:38And it's so called, of course,
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2:38 - 2:42because all of these neurons are glowing different colors.
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2:42 - 2:46Now sometimes neuroscientists need to identify
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2:46 - 2:48individual molecular components of neurons, molecules,
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2:48 - 2:50rather than the entire cell.
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2:50 - 2:51And there's several ways of doing this,
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2:51 - 2:52but one of the most popular ones
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2:52 - 2:56involves using antibodies.
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2:56 - 2:57And you're familiar, of course,
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2:57 - 2:58with antibodies and the henchmen of the immune system.
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2:58 - 3:02But it turns out that they're so useful to the immune system
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3:02 - 3:04because they can recognize specific molecules,
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3:04 - 3:07like, for example, the code protein
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3:07 - 3:10of a virus that's invading the body.
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3:10 - 3:11And researchers have used this fact
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3:11 - 3:15in order to recognize specific molecules inside of the brain,
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3:15 - 3:17recognize specific substructures of the cell
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3:17 - 3:20and identify them individually.
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3:20 - 3:24And a lot of the images I've been showing you here are very beautiful,
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3:24 - 3:25but they're also very powerful.
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3:25 - 3:28They have great explanatory power.
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3:28 - 3:29This, for example, is an antibody staining
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3:29 - 3:33against serotonin transporters in a slice of mouse brain.
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3:33 - 3:34And you've heard of serotonin, of course,
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3:34 - 3:37in the context of diseases like depression and anxiety.
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3:37 - 3:38You've heard of SSRI's,
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3:38 - 3:41which are drugs that are used to treat these diseases.
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3:41 - 3:44And in order to understand how serotonin works,
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3:44 - 3:48it's critical to understand where the serontonin machinery is.
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3:48 - 3:49And antibody staining like this one
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3:49 - 3:52can be used to understand that sort of question.
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3:52 - 3:54I'd like to leave you with the following thought.
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3:54 - 3:58Green florescent protein and antibodies
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3:58 - 3:59are both totally natural products at the get-go.
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3:59 - 4:04They were evolved by nature
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4:04 - 4:06in order to get a jellyfish to glow green for whatever reason,
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4:06 - 4:10or in order to detect the code protein of an invading virus, for example.
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4:10 - 4:13And only much later did scientists come onto the scene
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4:13 - 4:13and say, "Hey, these are tools,
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4:13 - 4:17these are functions that we could use
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4:17 - 4:19in our own research tool pallet."
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4:19 - 4:23And instead of applying feeble human minds
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4:23 - 4:23to designing these tools from scratch,
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4:23 - 4:27there were these ready-made solutions right out there in nature
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4:27 - 4:30developed and refined steadily for millions of years
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4:30 - 4:32by the greatest engineer of all.
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4:32 - 4:34Thank you.
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4:34 - 4:37(Applause)
- Title:
- How to look inside the brain
- Speaker:
- Carl Schoonover
- Description:
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There have been remarkable advances in understanding the brain, but how do you actually study the neurons inside it? Using gorgeous imagery, neuroscientist and TED Fellow Carl Schoonover shows the tools that let us see inside our brains.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 19:17
Cynthia Betubiza edited English subtitles for How to look inside the brain | ||
Jenny Zurawell edited English subtitles for How to look inside the brain | ||
Bruce Liu edited English subtitles for How to look inside the brain | ||
Bruce Liu edited English subtitles for How to look inside the brain | ||
Bruce Liu edited English subtitles for How to look inside the brain | ||
Jenny Zurawell approved English subtitles for How to look inside the brain | ||
Jenny Zurawell edited English subtitles for How to look inside the brain | ||
Morton Bast accepted English subtitles for How to look inside the brain |