DIY Neuroscience
Greg Gage: How you can make a fruit fly eat veggies
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Can the mind be manipulated to love a food we loathe? The evidence from fruit flies is compelling, and perhaps surprising. Our tag team of neuroscientists attempts to change a fly's preference for fruit over vegetables simply by shining a light on their brain.
Greg Gage - Neuroscientist
TED Fellow Greg Gage helps kids investigate the neuroscience in their own backyards. Full bio
TED Fellow Greg Gage helps kids investigate the neuroscience in their own backyards. Full bio
Double-click the English transcript below to play the video.
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Greg Gage: It's an age-old
pursuit of all parents,
pursuit of all parents,
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getting their kids
to eat their vegetables.
to eat their vegetables.
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But getting them to eat
cookies or ice cream
cookies or ice cream
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is relatively easy,
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and that's because our brains
prefer sweetness.
prefer sweetness.
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Now, there's a new technology
called optogenetics
called optogenetics
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which may be able to trick our taste buds,
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for instance preferring
vegetables over sweets.
vegetables over sweets.
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We're going to try this today
using fruit flies.
using fruit flies.
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[DIY Neuroscience]
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The reason why we experiment
with fruit flies
with fruit flies
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is they have a small enough nervous system
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that gives us a fighting chance
to really understand what's going on.
to really understand what's going on.
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And believe it or not, their taste buds
are very similar to ours.
are very similar to ours.
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But before we try to manipulate
their taste preferences,
their taste preferences,
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we need to establish:
What is the baseline of the fruit fly?
What is the baseline of the fruit fly?
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What does it prefer?
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We call this a control experiment.
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Spencer's been hard at work doing this.
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OK, Spencer, let's do
our first experiment.
our first experiment.
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We want to test to see if fruit flies
prefer bananas or broccoli.
prefer bananas or broccoli.
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So what do we need?
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Spencer Brown: So we need the fly pad,
which is basically an iPad for flies.
which is basically an iPad for flies.
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It measures the touch.
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GG: You put a fly in each chamber?
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SB: Yeah. Inside, we'll offer them
banana and broccoli
banana and broccoli
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to see which one they prefer.
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GG: In order to count how many times
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the fruit fly eats a banana
versus the broccoli,
versus the broccoli,
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these chambers have been outfitted
with a small electrode
with a small electrode
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that sends data to a computer.
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And so what were your findings
on banana versus broccoli?
on banana versus broccoli?
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SB: I found that the flies
visited banana the most.
visited banana the most.
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GG: Both were there, but like most kids,
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they choose not to eat the broccoli,
and they go switch to something sweeter.
and they go switch to something sweeter.
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GG: Now a quick background
on how taste works.
on how taste works.
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Taste buds are made up
of specialized neurons
of specialized neurons
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called taste receptors.
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When we eat something
that triggers a particular taste,
that triggers a particular taste,
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those taste neurons will fire
a signal to the brain.
a signal to the brain.
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This allows our brain to know
what's sweet and what's bitter.
what's sweet and what's bitter.
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So when a fruit fly eats a banana,
its sweet taste neurons will fire.
its sweet taste neurons will fire.
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But when it eats broccoli,
those same neurons stay pretty quiet.
those same neurons stay pretty quiet.
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But what if we could force
those sweet-tasting neurons to fire
those sweet-tasting neurons to fire
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every time the fruit fly eats broccoli?
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We may be able to get the fruit fly
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to like broccoli as much as banana.
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Enter optogenetics.
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This is the revolutionary new tool
that's taking neuroscience by storm,
that's taking neuroscience by storm,
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and in this case, "opto" means light
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and "genetic" refers to the fact
that these fruit flies have been modified
that these fruit flies have been modified
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to contain a special gene that makes
only certain neurons respond to light.
only certain neurons respond to light.
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In our case, we've added the special gene
to the sweet taste receptors.
to the sweet taste receptors.
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Now here's the fun part.
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Optogenetics means that we
can control these special neurons
can control these special neurons
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whenever they're exposed
to a bright-colored light,
to a bright-colored light,
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causing them to send
messages to the brain.
messages to the brain.
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In this experiment, we're going to have
these modified fruit flies
these modified fruit flies
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choose between banana and broccoli again,
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only this time, every time
the fruit fly eats the broccoli,
the fruit fly eats the broccoli,
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we're going to trigger
a big bright red light.
a big bright red light.
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And when the channels see that red light,
they're going to open up,
they're going to open up,
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and they're going to cause
that neuron to fire,
that neuron to fire,
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and the sweet taste message
will be sent to the brain.
will be sent to the brain.
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How do you get them out?
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SB: So we're going to be using
a mouth aspirator,
a mouth aspirator,
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so it's just two straws put together.
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GG: So it's a fancy name for a straw.
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SB: Basically.
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GG: So you're going to suck those out.
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Have you ever sucked up a fly before?
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SB: Once or twice.
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GG: There we go. You got all four.
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OK, perfect.
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So you're going to turn on
your OptoStimmers here.
your OptoStimmers here.
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You're going to park the light
right on top of the chambers.
right on top of the chambers.
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So now we sit here and we wait
for them to eat broccoli,
for them to eat broccoli,
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and then when the light fires,
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they're going to think
it's tasting something sweet.
it's tasting something sweet.
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Come on. Oh, he's getting closer.
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Come on. It tastes good now.
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SB: It's about to.
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GG: Oh, he's back. All right!
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All right, so now we see
that some of these flies
that some of these flies
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are switching over from
the banana to the broccoli.
the banana to the broccoli.
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SB: Exactly, yeah.
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GG: Every time this light goes off,
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that means that they think
they're tasting something sweet.
they're tasting something sweet.
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SB: Yeah. So this guy's
really going after it.
really going after it.
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GG: So we saw that we were able
to rescue broccoli
to rescue broccoli
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and make it just as appealing
as banana to our fruit flies.
as banana to our fruit flies.
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And we're able to replicate
these same results
these same results
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in all of our experiments.
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So the question is: Can we
do the same thing in humans?
do the same thing in humans?
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Well, that depends on a number of items.
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First, do optogenetic tools
even work in humans?
even work in humans?
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And that looks like the answer is yes,
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and in fact, clinical trials
are already being planned
are already being planned
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that will treat chronic pain
and blindness using optogenetics.
and blindness using optogenetics.
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And the next question is,
can we easily trigger a light source
can we easily trigger a light source
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so that every time we eat
vegetables, it will go off?
vegetables, it will go off?
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For that, I'm afraid at least
at this time, the answer is still no.
at this time, the answer is still no.
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But today, we got to witness
just a taste of optogenetics
just a taste of optogenetics
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and its amazing potential.
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(Music)
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ABOUT THE SPEAKER
Greg Gage - NeuroscientistTED Fellow Greg Gage helps kids investigate the neuroscience in their own backyards.
Why you should listen
As half of Backyard Brains, neuroscientist and engineer Greg Gage builds the SpikerBox -- a small rig that helps kids understand the electrical impulses that control the nervous system. He's passionate about helping students understand (viscerally) how our brains and our neurons work, because, as he said onstage at TED2012, we still know very little about how the brain works -- and we need to start inspiring kids early to want to know more.
Before becoming a neuroscientist, Gage worked as an electrical engineer making touchscreens. As he told the Huffington Post: "Scientific equipment in general is pretty expensive, but it's silly because before [getting my PhD in neuroscience] I was an electrical engineer, and you could see that you could make it yourself. So we started as a way to have fun, to show off to our colleagues, but we were also going into classrooms around that time and we thought, wouldn't it be cool if you could bring these gadgets with us so the stuff we were doing in advanced Ph.D. programs in neuroscience, you could also do in fifth grade?" His latest pieces of gear: the Roboroach, a cockroach fitted with an electric backpack that makes it turn on command, and BYB SmartScope, a smartphone-powered microscope.
Greg Gage | Speaker | TED.com