The Cockroach Beatbox
When you think about the brain,
it’s difficult to understand,
because if I were to ask you right now,
how does the heart work,
you would instantly tell me it’s a pump.
It pumps blood.
If I were to ask about your lungs,
you would say it exchanges
oxygen for carbon dioxide.
That’s easy.
If I were to ask you how the brain works,
it’s hard to understand
because you can’t just look
at a brain and understand what it is.
It’s not a mechanical object,
not a pump, not an airbag.
It’s just like, if you held it
in your hand when it was dead,
it’s just a piece of fat.
To understand how the brain works,
you have to go inside a living brain.
Because the brain’s not mechanical,
the brain is electrical and it’s chemical.
Your brain is made out of
100 billion cells, called neurons.
And these neurons communicate
with each other with electricity.
And we’re going to eavesdrop
in on a conversation between two cells,
and we’re going to listen
to something called a spike.
But we’re not going to record my brain
or your brain or your teachers' brains,
we’re going to use our good
friend the cockroach.
Not just because I think they’re cool,
but because they have brains
very similar to ours.
So if you learn a little bit
about how their brains work,
we’re going to learn a lot
about how our brains work.
I’m going to put them
in some ice water here
And then –
Audience: Ew!
Greg Gabe: Yeah …
Right now they’re becoming anesthetized.
Because they’re cold blooded,
they become the temperature of the water
and they can’t control it
so they just basically “chillax,” right?
They’re not going to feel anything,
which may tell you a little
about what we’re going to do,
a scientific experiment
to understand the brain.
So …
This is the leg of a cockroach.
And a cockroach
has all these beautiful hairs
and pricklies all over it.
Underneath each one of those is a cell,
and this cell’s a neuron
that is going to send information
about wind or vibration.
If you ever try to catch a cockroach,
it’s hard because they can feel you coming
before you’re even there,
they start running.
These cells are zipping up
this information up to the brain
using those little axons
with electronic messages in there.
We’re going to record
by sticking a pin right in there.
We need to take off the leg
of a cockroach –
don’t worry, they’ll grow back –
then we’re going to put two pins in there.
These are metal pins.
One will pick up this electronic message,
this electric message is going by.
So, we’re now going to do the surgery,
let’s see if you guys can see this.
Yeah, it’s gross …
All right. So there we go.
You guys can see his leg right there.
Now I’m going to take this leg,
I’m going to put it in this invention
that we came up with
called the Spikerbox –
and this replaces lots of expensive
equipment in a research lab,
so you guys can do this
in your own high schools,
or in your own basements if it’s me.
(Audience: Laughter)
So, there.
Can you guys see that?
Alright, so I’m going to go ahead
and turn this on.
I’m going to plug it in.
(Tuning sound)
To me, this is the most beautiful
sound in the world.
This is what your brain
is doing right now.
You have 100 billion cells
making these raindrop-type noises.
Let’s take a look at what it looks like,
let’s pull it up on the iPad screen.
I plugged my iPad into here as well.
So remember we said
the axon looks like a spike.
So we’re going to take a look
at what one of them
looks like in just a brief second.
We’re going to tap here,
so we can sort of average this guy.
So there we see it.
That’s an action potential.
You’ve got 100 billion cells
in your brain doing this right now,
sending all this information back
about what you’re seeing, hearing.
We also said this is a cell
that’s going to be taking up information
about vibrations in the wind.
So what if we do an experiment?
We can actually blow on this
and hear if we see a change.
Are you guys going to be ready?
If I blow on it you tell me
if you hear anything.
(Blowing)
(Sound changes)
Let me just touch this
with a little pen here.
(Noise)
That was the neural firing rate.
That actually took a while
in neuroscience to understand this.
This is called rate coding:
the harder you press on something,
the more spikes there are,
and all that information
is coming up to your brain.
That’s how you perceive things.
So that’s one way of doing
an experiment with electricity.
The other way is that your brain is not
only taking in electrical impulses,
you’re also sending out.
That’s how you move your muscles around.
Let’s see what happens if I’ve plugged in
something that’s electric
into the cockroach leg here.
I’m going to take two pins,
I’m going to plug them onto the cockroach.
I’m going to take the other end,
I’m going to plug in into my iPod.
It’s my iPhone actually.
Do you guys know how your earbuds
work in your ears?
You have a battery
in your phone, or iPod, right?
It’s sending electrical current
into these magnets in your earbuds
which shake back and forth
and allow you to hear things.
But that current’s the same currency
that our brain uses,
so we can send that to our cockroach leg
and hopefully if this works,
we can actually see what happens
when we play music into the cockroach.
Let’s take a look.
(Music beat)
Can we turn it up? There we go.
(Audience reacts and gasps)
GG: So what’s happening?
Audience: Wow!
(Laughter)
So you see what’s moving.
It’s moving on the bass.
All those audiophiles out there,
if you have awesome, kicking car stereos,
you know, the bass speakers
are the biggest speakers.
The biggest speakers
have the longest waves,
which have the most current,
and the current is what’s causing
these things to move.
So it’s not just speakers
that are causing electricity.
Microphones also cause electricity.
(Beat)
So I’m going to go ahead and invite
another person out on the stage here
to help me out with this.
So there we go.
(Beatboxing)
This is the first time this has ever
happened in the history of mankind.
Human beatbox to a cockroach leg.
When you guys go back to your high school,
think about neuroscience
and how you guys can begin
the neuro-revolution.
Thank you very much. Bye bye.
(Applause)