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 - 0:09And some things look very familiar today.
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0:09 - 0:13Two eyes at the bottom, optic nerve flowing out from the back.
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0:13 - 0:16There's a very large nose
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0:16 - 0:19that doesn't seem to be connected to anything in particular.
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0:19 - 0:21And if we compare this
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0:21 - 0:23to more recent representations of the visual system,
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0:23 - 0:26you'll see that things have gotten substantially more complicated
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0:26 - 0:27over the intervening thousand years.
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0:27 - 0:30And that's because today we can see what's inside of the brain,
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0:30 - 0:33rather than just looking at its overall shape.
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0:33 - 0:37Imagine you wanted to understand how a computer works
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0:37 - 0:40and all you could see was a keyboard, a mouse, a screen.
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0:40 - 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 - 0:46look at the wiring inside.
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0:46 - 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 - 0:52Nobody had had a glimpse of the brain's wiring.
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0:52 - 0:55And that's because if you take a brain out of the skull
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0:55 - 0:56and you cut a thin slice of it,
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0:56 - 0:59put it under even a very powerful microscope,
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0:59 - 1:00there's nothing there.
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1:00 - 1:02It's gray, formless.
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1:02 - 1:04There's no structure. It won't tell you anything.
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1:04 - 1:07And this all changed in the late 19th century.
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1:07 - 1:11Suddenly, new chemical stains for brain tissue were developed
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1:11 - 1:14and they gave us our first glimpses at brain wiring.
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1:14 - 1:16The computer was cracked open.
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1:16 - 1:19So what really launched modern neuroscience
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1:19 - 1:21was a stain called the Golgi stain.
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1:21 - 1:23And it works in a very particular way.
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1:23 - 1:26Instead of staining all of the cells inside of a tissue,
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1:26 - 1:29it somehow only stains about one percent of them.
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1:29 - 1:32It clears the forest, reveals the trees inside.
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1:32 - 1:35If everything had been labeled, nothing would have been visible.
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1:35 - 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 - 1:42who's widely considered the father of modern neuroscience,
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1:42 - 1:46applied this Golgi stain, which yields data which looks like this,
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1:46 - 1:50and really gave us the modern notion of the nerve cell, the neuron.
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1:50 - 1:53And if you're thinking of the brain as a computer,
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1:53 - 1:55this is the transistor.
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1:55 - 1:57And very quickly Cajal realized
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1:57 - 1:59that neurons don't operate alone,
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1:59 - 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 - 2:07Today, a century later, when researchers want to visualize neurons,
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2:07 - 2:09they light them up from the inside rather than darkening them.
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2:09 - 2:11And there's several ways of doing this.
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2:11 - 2:12But one of the most popular ones
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2:12 - 2:14involves green fluorescent protein.
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2:14 - 2:16Now green fluorescent protein,
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2:16 - 2:19which oddly enough comes from a bioluminescent jellyfish,
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2:19 - 2:20is very useful.
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2:20 - 2:23Because if you can get the gene for green fluorescent protein
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2:23 - 2:25and deliver it to a cell,
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2:25 - 2:27that cell will glow green --
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2:27 - 2:30or any of the many variants now of green fluorescent 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 - 2:39And it's so called, of course,
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2:39 - 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 - 2:49individual molecular components of neurons, molecules,
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2:49 - 2:51rather than the entire cell.
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2:51 - 2:52And there's several ways of doing this,
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2:52 - 2:54but one of the most popular ones
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2:54 - 2:56involves using antibodies.
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2:56 - 2:57And you're familiar, of course,
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2:57 - 3:00with antibodies as the henchmen of the immune system.
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3:00 - 3:03But it turns out that they're so useful to the immune system
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3:03 - 3:05because they can recognize specific molecules,
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3:05 - 3:07like, for example, the coat protein
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3:07 - 3:10of a virus that's invading the body.
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3:10 - 3:12And researchers have used this fact
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3:12 - 3:16in order to recognize specific molecules inside of the brain,
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3:16 - 3:19recognize specific substructures of the cell
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3:19 - 3:21and identify them individually.
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3:21 - 3:24And a lot of the images I've been showing you here are very beautiful,
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3:24 - 3:26but they're also very powerful.
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3:26 - 3:28They have great explanatory power.
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3:28 - 3:30This, for example, is an antibody staining
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3:30 - 3:33against serotonin transporters in a slice of mouse brain.
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3:33 - 3:35And you've heard of serotonin, of course,
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3:35 - 3:38in the context of diseases like depression and anxiety.
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3:38 - 3:39You've heard of SSRIs,
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3:39 - 3:42which are drugs that are used to treat these diseases.
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3:42 - 3:45And in order to understand how serotonin works,
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3:45 - 3:48it's critical to understand where the serontonin machinery is.
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3:48 - 3:50And antibody stainings like this one
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3:50 - 3:53can be used to understand that sort of question.
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3:53 - 3:56I'd like to leave you with the following thought:
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3:56 - 3:58Green fluorescent protein and antibodies
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3:58 - 4:01are both totally natural products at the get-go.
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4:01 - 4:04They were evolved by nature
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4:04 - 4:07in order to get a jellyfish to glow green for whatever reason,
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4:07 - 4:11or in order to detect the coat protein of an invading virus, for example.
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4:11 - 4:14And only much later did scientists come onto the scene
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4:14 - 4:16and say, "Hey, these are tools,
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4:16 - 4:18these are functions that we could use
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4:18 - 4:20in our own research tool palette."
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4:20 - 4:24And instead of applying feeble human minds
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4:24 - 4:26to designing these tools from scratch,
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4:26 - 4:29there were these ready-made solutions right out there in nature
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4:29 - 4:32developed and refined steadily for millions of years
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4:32 - 4:34by the greatest engineer of all.
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4:34 - 4:35Thank you.
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4:35 - 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 |