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Oh, wait, you're listening.

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You're listening to Radiolab.

Radiolab. From WNYC.

See?

Yeah.

Okay, Lulu.

Yeah.

We're going to start today.

Mm-hmm.

Back in 2010 in a lab in Vienna.

Oh, jumping right in.

Yeah.

Just picture sort of a lab with microscopes, computers, experiments.

And off in one corner.

Hello.

Hi, how's it going?

Wearing glasses and a white lab coat is this scientist named Dr. Madeline Lancaster.

Call me Madeline.

Madeline has just finished her PhD and moved to Austria, just joined the lab to start her postdoc research.

So still sort of making friends.

Still trying to make a good impression.

Getting to know people, you know.

And one of the first things her boss asked her to

do was something called a screen just basically looking for specific genes in mouse neural stem cells.

So that's like baby brain cells of mice?

Yeah.

Now, she hadn't done exactly this kind of gene screen before.

And that's probably why I didn't really, you know, I was kind of naive about it all.

Hmm.

But she got to work.

You put this enzyme on, it just cuts those proteins.

Preparing the baby mouse cells.

The cells all become loose and apart from each other.

That part she'd actually done before, so, you know, easy enough.

Yeah, but.

Then, something she hadn't done before, she needed to get those cells to stick flat to the glass bottom of her dish

so that she could do that screen.

And to do that, she needed to use special organic proteins as a glue.

And I hadn't, they hadn't come in yet.

I'd ordered them, but they hadn't come in yet.

And instead of just, you know, waiting for them to arrive.

I don't know.

I was so anxious to do the experiment.

She decided to improvise.

And so I just kind of like rummaged through the freezer.

Found a random tube of glue-like proteins.

I don't know how old they were.

And anyway, and I used those.

Squirted it on the dishes, pipetted in the cells, popped them in the incubator, and went home for the night.

Next morning.

Came in.

Took a look in her Petri dishes, hoping to see a nice, clean, clear layer of cells.

Like flat on the dish.

But instead, everything in there was...

Really cloudy.

Hmm.

Shouldn't be cloudy.

Cloudy means those cells are floating freely around in there, which means that those tubes of protein glue she used...

You know, we're no good, and the cells hadn't stuck.

And if the cells aren't stuck in the protein, that means they're probably dead.

Yeah, all the cells are dead.

I'll just throw it away.

And I don't know why I did this, but...

Right before she tossed it, she thought...

You know, but I'll check it.

I'll just take a peek.

Why not?

So she slides these cloudy dishes under the microscope, peers into the eyepiece, and in the circle of light, she sees...

These weird.. blobs.

The cells weren't dead.

They were...

Alive and healthy and...

Plumped into three or four blobs.

Huh.

Yeah, can you as vividly as you can describe them?

I mean, they're like a sort of beige color, like an off-white tiny...

About the size of a grain of sand.

Or these floating balls of cells. And she's like, huh.

Weird.

So she zeroes in on one of these blobs, turns the dial on the microscope to zoom in until she's looking basically inside the blob.

And that's when she sees a tube, a tube.

Yeah.

So she's like looking down into like one end of the tube.

So it looks almost like a donut shape.

Had you ever seen anything like that before?

No. No. Huh.

Yeah.

I mean, as far as she knew, if the cells weren't in that protein stuff, stuck, you know, flat to the bottom,

they should sort of die and fall apart and make a big random mess.

But these ones seem to be coming together to make this shape.

So she gets up from the microscope and starts.

Sort of going around the lab a little bit subtly at first, kind of just like, hey,

has anybody ever like seen cells do funny things, you know?

clump up together.

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And everybody was just sort of like, oh, well, if they're supposed to be laying flat, if they're not laying flat, you screwed it up.

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Like, they just weren't that interested.

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No. So I just kind of like put it in formaldehyde, put it away in the fridge for a little while and was like, okay.

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Let's try this gene screen again.

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But this time, no floaty clumps, gonna get those cells to stick flat on the bottle.

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And eventually she decides to try something new.

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This thing that I had read about called Matrigel.

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Basically, cellular crazy glue.

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Like, she's not taking any chances.

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I'm just going to put a whole bunch in my dish.

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So she squirts a lot of it on there.

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Okay.

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She puts her cells on top. And again.

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Pops them in the incubator, crosses her fingers, and goes home for the night.

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She comes back in the morning.

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Yeah, same thing.

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You go to the incubator, you take it out of the incubator, you look at it, and I was like, okay, this is weird.

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Once again.

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There's a bunch of stuff floating in there.

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Huh.

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I was like, okay, well, the Matrigel didn't work like it was supposed to.

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Again, it seemed like the cells had started clumping together.

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And that's when I then took them, put them on the tissue culture microscope, looked down the eyepiece, and again...

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There they were.

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Funny-shaped balls.

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These ones were also beige-ish.

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Off-white kind of color.

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But they were bigger.

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And they sort of have, like, bulges coming off of them.

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And this time, when she looked inside, she saw full-on...

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Architecture.

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There was a tube, but also...

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A little circle, sort of oblong-shaped thing.

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And a fat layer of tightly packed cells...

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All lined up around a space in the middle.

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They were making structures, they were making things.

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Kind of like what cells do as an embryo is developing, which to Madeline didn't make any sense.

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Everybody had always taught me that cells need things coming from other tissues in the body,

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you know, of the embryo that are necessary for building that embryo.

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And here was a situation where nothing was telling them what to do because they'd been completely taken out of the embryo.

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And they were like forming structures with no instructions.

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She's like, oh my God, like this is like there are things developing here. But toward what?

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Well, to Madeline, it kind of looked like...

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They were building a brain.

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So these are neural stem cells, which inside a developing mouse...

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Starts out as a sheet of cells, and then they fold up and close and form a tube.

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And then the neural tube elongates, and that becomes the spinal cord.

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One end of it balloons out, and that becomes the brain.

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And that's what it looked like the cells in Madeline's dish were doing.

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It seemed like these cells on their own were starting to try to make themselves into a mouse brain.

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At the time, yeah, at the time, I was just kind of confused.

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So she showed some other people around the lab what she'd seen.

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I showed some of these structures.

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The tubes, the circles, the lines, but...

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Several people in the lab were just kind of, I think they were just totally bored.

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They were like, I don't know, sometimes things just grow weird.

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You probably just did the gel wrong.

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And the director of the lab, her boss, was like, I thought you were going to do a screen.

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You know, make a flat dish of cells to screen for genes.

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What are you doing?

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And I was like, don't worry, I'm working on it.

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And so over the next few months,

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Madeline focused on getting a nice flat layer of mouse neural stem cells on the bottom of her Petri dishes

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so she could do those screens.

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And so that was like mostly what I was talking about with people in the lab.

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But at the same time...

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Off by herself, in her little corner, no one was paying attention.

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I was always still playing around with Matrigel, growing these weird balls of cells.

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Tweaking the recipe.

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Trying to make sure I could get it to happen reproducibly.

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And then one day, she gets her hands on some human stem cells.

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Cells that come from skin or blood that you can reprogram to an embryonic state.

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Where do you get those from?

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I think these were actually made from discarded human foreskin.

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Wow. So specific.

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Okay.

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What a detail.

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All right.

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Thank you for that.

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Because it's just a bit of tissue that's thrown away.

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Yeah.

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Right. Of course. Of course.

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Literally thrown away.

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All right.

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Okay. So, wow.

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Yeah.

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So anyway, so then...

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So she got these human stem cells.

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She put them in the matrigel, swirled them around in this nutrient-rich fluid so they could kind of eat.

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and she would watch as these formerly foreskin cells started forming into clumpy parts of a human brain.

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Oh my God.

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And then she kept tweaking when and how much of the matrigel she would add

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and she would just watch these blob shapes over time get bigger.

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I mean, they can get as big as like a pencil eraser.

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Side note, at the time she was pregnant.

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Yeah, my oldest, I was pregnant with her.

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So she said she had this extra maternal instinct and she was like just really nurturing these little brain balls.

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Yeah.

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And then one day, a couple months after, she's been tweaking her ball recipe.

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And I looked under the microscope.

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Inside.

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Yeah.

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On this beige lump, she could see a perfect ring of black pigment.

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And that was just, I looked at that.

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I was like, that's a developing eye.

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Shut up.

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And it was growing on a developing human brain.

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You're like, no, what?

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Yeah.

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No, you, what?

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And then, then.

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That was then when she went to her weekly lab meeting.

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I presented this data.

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I showed this picture of this beginning of an eye.

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And I remember hearing audible gasps.

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And then she showed them pictures of the cells forming tubes and lobes and...

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Ventricles, like an actual brain.

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Everybody in the lab started to get it.

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They were like, hey, wait a second.

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It's like you have a version of an early human brain in this dish,

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and you can actually watch the earliest stages of this process of development.

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That we know almost nothing about. Is that true, though?

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Do we not know anything about early human brain development?

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I just think you get all these little...

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Like when you're pregnant, you get a scan here, a scan there.

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Maybe we know something from animal models.

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But this was literally the first time anyone in human history

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had ever watched the early brain develop right from the beginning like this.

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Yeah.

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Which is especially important when something in the brain has gone wrong.

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Now we can actually watch this process instead of just looking at the end when the person is already severely suffering.

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We can try to understand how it got there.

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So Madeline and her boss, Jurgen Knoblik, who's on board with the whole project now,

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in 2013, they team up with a bunch of other researchers and publish a paper in the journal Nature.

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In that paper, they describe how this disorder microcephaly develops in a fetal brain.

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And they were like, oh, and to see all of this, we use these tiny 3D brain balls, which we have decided to call cerebral organoids.

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That's when, like, everything changed.

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If you were studying human brain development, it was like someone just invented the microscope.

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Yes.

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You can see things that were invisible before.

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So this is Carl Zimmer, science journalist, New York Times columnist, book writer.

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Ah, you got Zimmer.

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Yeah, as soon as I heard about this stuff, of course, he's my first phone call.

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And he was all over it.

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Sort of like humanoid, organoid, very sci-fi.

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And the first thing that he pointed out is that there are so many neurological disorders where...

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The key moments are during development.

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It's like the key plot points are happening when we can't watch the movie.

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Right.

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Totally off limits. But 2013...

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Madeline and Juergen published their paper and boom.

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We could watch human progenitor brain cells give rise to parts of the brain.

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What would you do with that?

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Like, what would you see?

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So one example is a, there's a scientist at Stanford, Sergio Pasca, and he studied a very rare disease called Timothy syndrome.

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It's caused by a genetic mutation that causes severe neurodevelopmental problems.

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And he basically created an organoid with that mutation so that he could see how a brain with Timothy syndrome develops, like from the beginning.

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Yeah.

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Now you can actually see what

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Timothy syndrome is about.

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So when, what did he see?

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So there are certain kinds of cells called interneurons, and they make very important connections between different parts of the brain.

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And with kids with Timothy syndrome, they just don't.

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They just fail to get where they need to go.

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And now that he knew what was going wrong...

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He started testing out some drugs to see if he could fix that.

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Yeah.

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And he and his colleagues actually ended up finding a small drug that actually did help these neurons to find their way.

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Ah.

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In an organoid.

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So he cured it in an organoid.

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Right.

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Huh.

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And they are on track to actually start clinical trials with that drug next year.

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Wow.

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And you could imagine that's one disorder.

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That's right.

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A lot of other conditions.

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Epilepsy, schizophrenia.

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Fetal alcohol syndrome.

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Any of these brain conditions that have an issue starting in development

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or where we might even suspect they might start that early but aren't sure yet, now you can see it.

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A lot of people in the field said, whoa, I got to try this.

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This whole field of neural organoids has just totally exploded.

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I think there's thousands of labs actually using these tools now.

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The study of the brain is fundamentally different now.

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That's what we are doing on Radiolab today.

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We are just, Lulu, we're gonna jump into the ball pit of brain balls.

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Okay.

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In which there are tons of new opportunities, but also confounding questions.

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Are there thoughts in there?

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Is there thinking in there?

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How brainy are these balls?

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We are gonna get there after the break.

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All right, here we are.

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I'm in the 72nd

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Street subway station, and I am walking to go see a fridge full of brains.

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Hey, I'm Latif Nasser.

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I'm Lulu Miller.

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This is Radiolab.

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More specifically, a fridge full of brain organoids.

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Just before the break, we learned from Madeline that now thousands of labs around the world are growing these brain organoids.

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And it turns out that one of them happens to be just up the street from our studio in New York City.

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Only when you're recording are you truly conscious of, like, how much you breathe.

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So we sent our producer, Mona McGaulker.

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Laboratory, caution, hazardous materials.

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To check them out.

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Where are we entering?

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So we're entering, so we have special rooms called cell culture rooms where we grow, oops, we grow the organoids.

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This is Dr. Howard Fine.

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I'm a medical and neuro-oncologist.

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And this is his lab at the Weill Cornell Medical Center where he studies brain cancer.

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The type of brain tumor known as a glioblastoma.

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A very bad kind.

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Probably now the most lethal of all human cancers.

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The average survival is about 15 or 16 months.

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And Dr. Fine says around 15 years ago or so, he hit a wall in his research.

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We've probably made the least amount of progress with.

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So he'd been studying glioblastoma, mostly, of course, in mice, right?

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And he admits he actually calls this at the time it was the dirty little secret of oncology

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that for all this research, they were basically getting nowhere.

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Whoa.

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But then, you know, he came across Madeline's work on organoids.

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And it was Lancaster's paper.

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I read in Nature, and it's like, literally, not many times in my 37 career, did I truly have a light bulb moment?

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And I read that paper and said, this is what we're looking for.

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And that's when he pivoted away from mice and started making brain organoids.

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Can we see them?

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We can take a look.

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Okay, so he's opening the incubator and he's pulling out.

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These are the stem cells.

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And they looked just like Madeline described.

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They're kind of like a beige color.

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They look like a kidney bean or like a nerd candy.

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Little beige balls floating in liquid in a dish.

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It feels surrounded by a major child.

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And under the microscope.

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I see like a dark shape and then I see these little bubbles off the side, almost like little popcorn-y shapes.

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You can see structure.

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Dr. Vint, these are from specific patients, like your patients?

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Yes.

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But the difference between these organoids and Madeline's organoids was that these ones had cancer.

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So the idea is we're going to make a mini brain from an individual patient. And then...

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Oh, these are the glioma cells.

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Wow.

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They take cells from that patient's brain tumor.

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Almost just looks like sugar that hasn't dissolved in tea.

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And then we retroengineer the patient's own glioma stem cells into the mini brain.

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Basically, they can put a version of your brain tumor on your...

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A version of your brain on a version of your brain, and they can basically make a bunch of those.

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We can test hundreds or thousands of drugs.

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And then try a bunch of medicines on them.

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To look for the drugs or combination of drugs that might be most effective.

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So you're saying that, like, you can try every chemotherapy that's out there and decide, like, which one?

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Everything, only limited by resources, as you could imagine.

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Oh, my God.

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That is beautiful.

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I mean, that just thinking about a way of like a kind of bespoke medical future exploration.

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Right.

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Way better than just using mice.

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Oh, my gosh.

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Partly

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because it also could help us leapfrog one of the biggest

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reasons on average 90 percent of clinical trials for neurological drugs fail.

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And for brain cancer, by the way, that number is even higher, 95 percent.

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They're failing because they're not predicting whether the drug actually works on the disease.

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And this is something that Madeline told me, too.

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You might have a drug that works really well for treating mouse spinal cord injury.

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Like it's like, OK, great.

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This is not going to kill you.

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Because you've got the animal work to show you that it's safe.

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But it also doesn't make them better after the spinal cord injury.

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But now, sure, they can do a mouse trial for safety.

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But they can also test that drug to see if it works on a spinal cord organoid,

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which is, you know, just a tiny version of an actual human spinal cord.

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Wait, what?

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I thought we were talking brain organoids.

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Are there are there spinal cord organoids?

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Spinal cord organoids?

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Yeah.

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Okay.

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So as Madeline was developing her brain organoids, independently, around the same time,

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other scientists all over the world are growing intestinal organoids, lung organoids, liver organoids, muscle organoids,

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skin organoids, ancreas organoids, stomach organoids, heart organoids, kidney organoids, breast tissue organoids that actually produce milk.

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Ah, they can have a breast tissue organoid that can make milk?

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Yes.

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Weird.

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Has anyone tasted that milk?

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I certainly haven't.

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I've only read about it.

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I don't know.

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I don't know.

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That's a good question.

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Anyway.

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That's science writer

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Carl Zimmer again.

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And he says now you can make an organoid of basically any part of the body.

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And then you can connect them.

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What?

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You can, like, you can...

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Does that work?

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You can do that?

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Oh, yeah.

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They call them assembloids.

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Assembloids.

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Yeah.

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No, like you can Mr. Potato Head assemble.

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Correct.

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But then do they attach to each other?

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They attach to each other, yeah.

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And do they communicate with each other?

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They communicate with each other, yeah.

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Okay, and then what? Do what?

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With your charm bracelet human body?

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So here's an example.

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So Sergio Pasca...

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Neuroscientist at Stanford University and his colleagues thought, can we use an assembloid to study pain?

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The pathway of pain.

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So they started with the finger.

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A finger organoid?

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No, no, no, sorry.

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Just a nerve in the finger.

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Oh, okay.

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The sensory organoid.

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Connect that.

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Like with some other cells in the dish.

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Another organoid, the spinal cord.

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Yeah, it's the little teeny piece of spinal cord.

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Now we're going to connect that.

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To a brain organoid that is specifically the thalamus, which is the central hub in the brain that directs signals in all sorts of different ways.

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And finally, we're going to connect that one to one more brain organoid, a cortex organoid.

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Whoa, this is so weird.

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I mean, it's like Legos.

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It's like Legos.

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With the human body.

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Correct.

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So then they took capsaicin.

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That's the molecule in...

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In like spicy food, is that right?

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In spicy food, in chili peppers, yeah.

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It can be very painful to the skin.

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Okay.

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And they said, okay, let's hit it with capsaicin and see what happens.

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Uh-huh.

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Boom.

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Immediately, that sensory organoid goes...

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Right.

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And starts sending really strong signals.

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And those signals, Carl says, zoom right up through this assembloid.

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To the spinal cord, the thalamus, to the cortex.

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Just like it would in your own body.

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And they can see some kind of registering?

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Correct.

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And when they watch the way the signal travels, which is something that's normally hidden inside a body...

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They discovered all sorts of things about what happens when we feel pain that they didn't know about before.

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Like, for example, signals from different parts of the assembloid began firing together in these synchronized waves of signals.

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Okay.

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And the more you know about how those signals work or move, the better chance you have at stopping them.

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You could, for example, say, okay, can I put a molecule into this assembloid that will stop the pain?

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Oh, wow.

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But, um, So if they're using these things to study pain, is it feeling pain?

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No, probably not.

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These organoids are just little bits of human tissue.

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In order to feel pain the way we feel pain, there are other parts of the brain that come into play.

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The assembloid is just this super basic circuit that you send a signal through.

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So like this pain, it seems to be superficially registering it.

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And like what is it, I think?

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The capsaicin in that case.

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No, no, no. I'm the first it.

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It's like it is this little ball, but is the it a thing?

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Like, what is it?

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Well, they crackle with electricity.

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They form connections called synapses.

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They replicate parts of the human brain with astonishing accuracy.

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But, Carl says...

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They're not brains.

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They're not brains.

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That's right.

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So if there's like a slider and on one end is brains

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and then on the other hand is just like some neurons in a dish, where is this on the slider and how do you?

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Yeah, I would say

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that it's closer still for the time being to the neuron end of the slider simply based on numbers.

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Our brain has something like 80 billion neurons neurons.

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And the biggest human brain organoids contain about 2 million cells.

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That's 0.0025%.

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Well under 1%.

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Yeah.

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And you know, these things don't have blood vessels.

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So that is a very important limiting factor to how big and complex it can get.

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Yeah.

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And they're not in a body.

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So they can't interact with the world in like a meaningful way.

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Okay.

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Well, but when I was talking to Carl about this. So, um...

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He said that a lot of that might no longer be true.

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Some scientists have, you know, taken organoids from human cells and put them into the brains of rats.

496

What?

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So basically what they did is they basically took a rat and they, like, carved out a chunk of its brain.

498

But they left some of it?

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They left most of it.

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And it's almost like, think about it, it's almost like they gave a rat a little human tumor something.

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I mean, it doesn't...

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But the tumor is like just brain, human brain.

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It's human brain.

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It's human brain.

505

And these human organides are pretty happy in there.

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It's sort of wired in.

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They connect up with the rat neurons.

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They get supplied by the rat blood system.

509

So they have made, in a real sense, like a new kind of being.

510

Yeah, yeah, yeah.

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That did not exist before this.

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Correct.

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Okay.

514

It feels like there should have been a bigger press release, but okay, do the rats act any differently?

515

Are they suddenly like into podcasts and coffee?

516

When you do studies on these rats, behavioral tests, memory tests, all sorts of things, they're just rats.

517

There seems to be nothing human-y about them.

518

Okay.

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But one thing they did notice, when you tickle its whiskers...

520

Yeah.

521

You can actually measure signals from the human brain organoid neurons.

522

The human part of the brain lights up.

523

What?

524

Yeah.

525

So it's registering the feeling?

526

They are receiving signals from the rat's senses.

527

I mean, strictly speaking, they are receiving signals from the rat's senses.

528

Are they feeling it?

529

feeling it gets hard because it's kind of the pain question again.

530

But yeah, but now they're in a body.

531

I mean, they're in a being.

532

Yes, but they're not the like driving force of that being.

533

They're like a house guest in the attic.

534

Okay, Latif, would you put, make a brain ball, brain organoid of your brain cell and put in a rat?

535

If I'm being honest, probably not.

536

Probably not.

537

Okay.

538

So I don't know, but I just think you're more on my side

539

that this is a little scary than you in your little with your reporter's wand are letting on to because, yes, there's exciting research,

540

but it just feels like every time you try to comfort me with what we know about these things, you then end up not comforting me.

541

And then the scientists take it one step further anyway.

542

Um, okay.

543

Well, it's as if you have seen the future and what the next chapter holds, because that exact thing is going to happen.

544

It's going to get weirder and creepier and stranger, and that's all after the break.

545

Stick with us.

546

Latif.

547

Lulu, Radiolab.

548

We are back talking about brain balls, you know, bitty brains, boba brains, the brain-ish in a dish.

549

Yes, ha ha, with all your clever wordplay.

550

But you are about to send us into the next existential tailspin about how people are using these things.

551

It is possible.

552

So the final thing I was told to do is push record.

553

Record, yes.

554

That's an important button.

555

Now, tell me who you are.

556

So I'm Brett.

557

This is Brett Kagan.

558

He's a neuroscientist.

559

I'm the chief scientific officer here at Cortical Labs.

560

Cortical Labs.

561

We're a small tech startup here in Melbourne, Australia.

562

Did you start it?

563

Did someone else start it?

564

No, well, it was founded by, there was a few of us, and I was contacted by Dr. Hon Weng Chong and Andy Kitchen,

565

and they were looking for a neuroscientist.

566

Brett had been an academic, obsessed with this particular question.

567

How do you get intelligence out of brain cells that are in a dish?

568

And this company was like, why don't you leave academia and help us find out?

569

The question they had was, can brain cells in a dish do anything at all that we might want them to do?

570

Hmm.

571

Like, do what?

572

What better to pick than Pong?

573

Pong?

574

The, like, 70s computer game?

575

Yeah, the game with the paddles and the little ball.

576

Why that?

577

Everybody knows Pong.

578

It was one of the first computer games.

579

It was the first thing that machine learning, which people now like to call AI, really was trained on as a big breakout success.

580

And he figured the brain runs on electricity.

581

And it's also a shared language as silicon computing.

582

So why wouldn't we be able to get neurons to do something a computer could do? That exactly.

583

Like play a simple video game.

584

We used some hardware that allowed us to record the activity of the cells, process that, and then deliver small electrical pulses back into the cultures.

585

And they did it.

586

Scientists just put pieces of human and mice brain on a plate and wired it to a computer to play pong.

587

They learned to track the ball and control a paddle.

588

Seriously, this is one of the craziest things I've ever covered.

589

So here's what's going on.

590

What?

591

No. Yeah.

592

And this wasn't even an organoid.

593

This was just a flat sheet of neurons in a dish.

594

I mean, how could it possibly be doing that?

595

Like, I mean, can really dumb things do that?

596

Could like a tree do that?

597

Trees don't have neurons.

598

I don't think a tree could do that.

599

Okay, so, but well, what does this mean?

600

Like, are they learning?

601

Well, Brett says yes.

602

I called it learning.

603

And I think learning was an incredibly fair definition

604

because what would an improvement over time in a way that would suit a goal be called other than learning?

605

But other people, including Madeline Lancaster...

606

I actually remain to be convinced anybody has really shown that.

607

Say no. because it's really hard to interpret the signals coming from the neurons.

608

She says when you teach brain cells to play Pong, they're, you know, connected to a computer.

609

So what people do is they use algorithms to sort of decode that message and then send a signal back to neurons.

610

And so you kind of have like two black boxes that you've just hooked up.

611

It's sort of a collaboration between the brain cells and the computer.

612

And you don't really know what either of them are doing.

613

Anyway, whatever is happening here, what Brett and his team took away from this is if neurons can do something a computer does,

614

why don't we use neurons as computers?

615

What?

616

Yeah.

617

Literally a couple months ago, they released their first computer called the CL1.

618

And it is, they don't call it this, but it's effectively a biocomputer.

619

It has neurons in it.

620

Ew.

621

Brain, sticky, real human brain matter in it?

622

Yeah.

623

It's got like little brain organoids in it.

624

It has 800,000 neurons interfaced with a silicon chip you can use it to do computer stuff with.

625

Okay.

626

I mean, I can get behind the brain balls being used for neurological disorder research.

627

Great.

628

You know what?

629

Bespoke cancer treatments?

630

Cool.

631

But why are we hooking up human brain cells to computers to, like, make money?

632

That, to me, feels like not worth the risk.

633

Well, think about the problems we are having right now with all of these data centers chugging all this energy, right?

634

Absolutely wrecking the planet.

635

Right.

636

So our brains are so impressively efficient.

637

Energy wise, we have like a dim light bulb like screwed into our heads.

638

Right.

639

That's the amount of energy that we need to do all the complex things that we do.

640

If AI or if some supercomputer was doing the equivalent, it would need millions of times more power.

641

Like the difference between a single light bulb and a large town. So flattering.

642

The other thing is that, like, think about these AIs.

643

You need to train it on the whole Internet, right?

644

A human brain is much quicker to learn.

645

If you could harness that energy efficiency, if you could harness that kind of like a knowledge efficiency in a computer, you could move mountains.

646

OK, but I guess my authentic question at this point is like, OK, you have shown us all this stuff.

647

At this point, it seems pretty clear that they can definitely register input, right?

648

Like there's the tickle, the pain, the signal they're getting from Pong.

649

Okay.

650

And then this Pong example at least shows us they are then able, based on that input, to produce some kind of output.

651

Yeah.

652

Okay.

653

So let's say it is.

654

Yeah.

655

Okay.

656

So my question is, if they can do those things, wouldn't they have to have some thrumming level of consciousness?

657

No, actually.

658

No, they really don't.

659

Like a bunch of the things you just talked about, AI can do those.

660

Is AI conscious?

661

Even going further than that, like a Roomba can do, like navigate a room.

662

Is a Roomba conscious?

663

That's a signal in and out.

664

Yeah, right.

665

A Roomba's going, oh, there's an edge.

666

Let me go this way.

667

That's a signal in and out.

668

When we talk about human consciousness, we mean self-consciousness.

669

Like you are aware of yourself.

670

You have a past.

671

You have a future that you're concerned about.

672

There's like that continuity of experience.

673

This is Dr. In-Soo Hyun.

674

I'm the director of the Center for Life Sciences at the Museum of Science in Boston.

675

He's a bioethicist, and he's worked on a bunch of teams with scientists who are studying brain organoids.

676

We try to identify what are the emerging scientific and ethical issues.

677

You're like kind of like their conscience?

678

Is that sort of the thing?

679

You know what?

680

Sometimes I feel like a priest in secular clothes.

681

And he says at this point, he is not worried about brain organoids having anything like human consciousness.

682

The brain organoids in the dish don't have that continuity.

683

They don't have all the regions.

684

They don't have the interaction with the outside world.

685

But when he thinks about the future that

686

Brett and others are trying to create,

687

where maybe people start connecting more and more complicated and even more and more structured clumps of human brain cells to computers.

688

Maybe you get, it might not even human consciousness, but some kind of consciousness could emerge.

689

he's hooked up to the world

690

yeah okay so what about this Latif

691

I would if I may I would like to just issue a commandment that all the smart people who are like

692

excited by brain organoids.

693

They all take one year to stop making organoids

694

and use their smarts and their technologies

695

and their labs to like try to understand the consciousness of the organoids that have already been made.

696

You know, like ideally they could all be in a dark room and just have candles and quietly,

697

meditatively watch for any flickers to understand what's going on.

698

And then And then we have a grand assembly where everyone reports back and we all collectively decide what to do.

699

But I know that like some of these scientists have this fire inside them to be like,

700

how many cures am I not going to find in that year?

701

Like how many people am I not going to help in that year?

702

Like the glioblastoma, like those people don't have a year.

703

And those people are telling me to just shut up because this is a piece of discarded foreskin.

704

That's right.

705

If we have a tool that we don't use.

706

Madeline Lancaster again.

707

And there are millions of actually conscious human beings out there that don't have treatments.

708

But we decide, no, we're going to put the value of organoids higher than those people. That would be unethical.

709

It's funny, like at the beginning, like you asked me, like, would you make a brain ball of yourself?

710

And I said no. And then at some point, like my thinking switch where I'm like,

711

oh, no, unless it would save someone's life.

712

Well, that's noble.

713

And now I feel even worse saying I don't know that I would.

714

I just I mean, yeah.

715

OK, if it's my own kid, sure.

716

I don't care if I'm like a little enslaved human consciousness, if it saves my kid.

717

But as you have shown us, the scientists are going to do more.

718

They're going to try new things.

719

They're going to build bigger brains.

720

And like, there is a line and we will cross it and we won't know that we've crossed it, you know?

721

Right.

722

And the thing about these organoids is that they're already crossing all kinds of lines.

723

You disrupt categories that we thought were so neat and tidy and distinguishable.

724

Life, non-life.

725

Human, non-human.

726

Human, computer.

727

We thought those were pretty clean categories.

728

But this research is kind of upsetting the very foundations of what we think separates these categories apart.

729

It does feel like it's like, oh, we've created a new category of thing, like a new category of thing that is maybe alive.

730

It is alive.

731

We have created a new category of thing that is alive.

732

That is weird.

733

Oh, yeah.

734

It's hard.

735

It's hard to actually put it into a category that already exists, I think, because they're not actual brains that we can say absolutely certainly.

736

But they're also not just a few neurons in a dish either.

737

We almost don't really even have the words for it.

738

I think it's kind of a new thing.

739

Latif Nasser.

740

This episode was produced by Annie McKeown, Mona Madgaukar, and Pat Walters.

741

It was edited by Alex Neeson and Pat Walters with fact-checking by Natalie Middleton and Rebecca Rand.

742

Special thank-you shout-outs to Lynn Levy, Jason Yamada-Hanf, David Fagenbaum, Andrew Verstein, Anne Hamilton, Christopher Mason, Madeline Mason-Mariarty,

743

plus Howard Fine and his whole team at Weill Cornell for hosting us.

744

And if you're looking for more musings on the nature of life and what it means to be alive,

745

Carl Zimmer has a terrific book out all about this stuff.

746

It's called Life's Edge, the search for what it means to be alive.

747

Get it at your local bookstore.

748

That's it for us from our brain balls to yours.

749

See you next week.

750

Okay, start now.

751

I almost practiced.

752

No, you don't need to.

753

You don't need to practice anymore.

754

Shh.

755

We're recording now.

756

Hi, I'm Ellie Columns, and I'm from Louisville, Kentucky, and here are the staff credits.

757

And she's Molly's niece.

758

Yeah.

759

Radio Lab is hosted by Lulu Miller and Latif Nasser.

760

Sorin Wheeler is our executive editor.

761

Sarah Sandback is our executive director.

762

Our managing editor is Pat Walters.

763

Dylan Keefe is our director of sound design.

764

Our staff includes Jeremy Bloom, W.

765

Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindhu Nana Sambandan

766

Matt Kilty Mona Madgavkar Annie McEwan Alex Neeson Sarah Kari

767

Anissa Vietes Arian Wack

768

Molly Webster and Jessica Young With help from Rebecca Rand Our fact checkers are Diane Kelly Emily Krieger

769

and Natalie Middleton I love your giggle

770

leadership support for radio lab science programming is provided by the simons foundation

771

and the john templeton foundation foundational support for radio lab was provided by the alfred p sloan foundation

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Recommend Video

552 sentences

Vocabulary and speaking notes for this lesson

The speaker keeps coming back to these words: brain, organoid, cell. This video has 771 sentences and 6651 words to shadow. The speech runs for 41:20. The speaker talks at a natural 161 words per minute, close to everyday conversation. Only 81% of the words are among the 3,000 most common in English, so the vocabulary is demanding.

Key vocabulary in this video

15 words from the video worth learning, with pronunciation and meaning:

Word	Pronunciation	Meaning
dish noun	/dɪʃ/	A vessel such as a plate for holding or serving food, often flat with a depressed region in the middle.
mouse noun	/maʊs/	Any mammal of the many rodent families (especially Muridae) that have a small body and a long tail.
tube noun	/tuːb/	Anything that is hollow and cylindrical in shape.
cord noun	/ˈkoɹd/	A long, thin, flexible length of twisted yarns (strands) of fibre (a rope, for example).
spinal adjective	/spaɪ.nəl/	Of or relating to the spine.
consciousness noun	/ˈkɑnʃəsnəs/	The state of being conscious or aware; awareness.
stem noun	/stɛm/	The stock of a family; a race or generation of progenitors.
microscope noun	/ˈmaɪ.kɹəˌskoʊp/	An optical instrument used for observing small objects.
connect verb	/kəˈnɛkt/	To join (to another object): to attach, or to be intended to attach or capable of attaching, to another object.
lab noun	/læːb/	A Labrador retriever.
tissue noun	/ˈtɪʃ.(j)u/	Thin, woven, gauzelike fabric.
syndrome noun	/ˈsɪndɹoʊm/	A recognizable pattern of signs, symptoms and/or behaviours, especially of a disease or medical or psychological condition.
tumor noun	/tuː.məɹ/	An abnormal growth; differential diagnosis includes abscess, metaplasia, and neoplasia.
neural adjective	/ˈnʊɹəl/	Of, or relating to the nerves, neurons or the nervous system.
gene noun	/d͡ʒiːn/	A theoretical unit of heredity of living organisms which may take several values and (in principle) predetermines a precise trait of an organism's form…

Phrasal verbs you will hear

Word	Pronunciation	Meaning
end up verb		To bring to a conclusion.
hook up verb		To assemble the parts of a mechanism, especially by connecting wires.
shut up	/ʃʌt ʌp/	Stop talking (usually in the form of making annoying, irrelevant, or false comments, during a period of peace and quiet, or when one is not allowed to talk)…
throw away verb		To discard (trash, garbage, or the like), to toss out, to put in the trash.
come across verb		To change sides; to cross over to work for the opposition.
fall apart verb		To disintegrate, to break into pieces.
find out verb		To discover, as by asking or investigating.
fold up verb		To make or become more compact by folding.

Sentences worth repeating

Short, complete lines from the video that you can reuse in everyday conversation:

Had you ever seen anything like that before?
Where do you get those from?
You're like, no, what?
What would you do with that?
You're like kind of like their conscience?

Grammar in this video

The structures the speaker uses most, with the exact words from the video:

Structure	In the video
Conditional sentences if + clause, will/would + verb — a condition and its result	if they can do those things, wouldn't they · if I may I would like
Present perfect have/has + past participle — a past action that still matters now	has just finished · has gone · have decided
Passive voice be + past participle — the focus is on what happens, not who does it	were actually made · was told · was founded
Relative clauses who / which + clause — extra information about a person or thing	there, which means · thalamus, which is · travels, which is

Pronunciation to watch

The speaker uses 131 contractions and reduced forms, such as don't, they're, I'm. Say them the short way, as you hear them.

The “th” sounds: breathe /bɹiːð/, thalamus /ˈθæləməs/
The “sh” and “zh” sounds: dish /dɪʃ/, consciousness /ˈkɑnʃəsnəs/, tissue /ˈtɪʃ.(j)u/, conscious /ˈkɑn.ʃəs/, sheet /ʃit/
Long words — get the stress right: neurological /nɝəˈlɑd͡ʒɪkəl/, electricity /ɪˌlɛkˈtɹɪsɪti/, efficiency /ɪˈfɪʃ.ən.si/, experiment /ɪkˈspɛɹ.ə.mənt/, communicate /kəˈmjuːnɪkeɪt/

How to practise with this video

Listen to the whole video once without speaking and note the words you do not know.
Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
Record yourself and compare with the original, paying attention to words like dish, mouse, tube.

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

Shadowing technique: read the full step-by-step guide →

Shadowing Practice: Brain Balls | Radiolab Podcast - Learn English Speaking with Video

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Vocabulary and speaking notes for this lesson

Key vocabulary in this video

Phrasal verbs you will hear

Sentences worth repeating

Grammar in this video

Pronunciation to watch

How to practise with this video

What is the Shadowing Technique?