Human Body: Pushing the Limits Page #2

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or red or blue at this point."

NARRATOR:
Using these red,

blue, and green signals,

the brain creates an impression

spanning the entire

visual spectrum...

...a range

of over 1 0 million colors.

[ l ndistinct talking on radio ]

Color vision leads Dan

straight to the fire.

FLEM l NG:
To my surprise,

it went out very quickly.

And l started scanning around to

see what else was in that room.

Whenever you can get glimpses,

that's so important'

but l'm taking the whole room in

as l'm scanning.

NARRATOR:

l n a flash,

Dan's brain calculates

what has to be there,

even though he sees

only tiny frag ments.

This is what our brains do

constantly --

fill gaps with data

from our visual memory bank.

l n fact' our brain interprets

most of our vision

out of a lifetime

of stored images.

Then Dan recognizes something.

A white shape --

a cup of coffee.

Black and white squares --

a half-completed crossword.

Are these crucial signs

that someone could still be

in the house?

There, through the smoke,

Dan sees a blurred

and unusual shape.

FLEM l NG:
My initial instinct was

there's something on the couch.

l'm not sure what it was.

Requesting backup!

We have a saying --

When in doubt' check it out'

and that's what l did.

Give me a hand!

l got a victim!

Get the gurney in here, guys.

NARRATOR:
Dan Fleming has used

his brain's visual memory

to transform a blur

into the outline of a body,

saving a man's life.

The power of human sight

comes from millions of years

of evolution.

We can't even understand it.

And technology today can't begin

to match the sophistication

of our incredible eyes.

But for the first time,

science is pushing human vision

to new limits

by connecting directly

with the brain's vision center.

This means that one day,

we might even see

in the invisible worlds

of infrared, have X-ray vision,

or plug video games

straight into the brain.

Cheri Robertson from Missouri

is about to step

into this virtual world.

l was in a car accident

when l was 1 9 years old.

l was a passenger in the car.

And the driver fell asleep at

the wheel, and we hit head-on

with a small truck'

and both of my eyes

were just destroyed.

NARRATOR:

Hoping to regain her sight'

Cheri volunteers

for a pioneering procedure.

lt involves marrying technology

to the huge processing power

of the brain's visual cortex.

lt was a chance for me

to be able to see again

when the doctors had always told

me l would never see anything.

NARRATOR:
Cheri is about to have

an extraordinary experience.

Doctors drill through both sides

of her skull,

exposing her brain.

Then they implant

two triangular plates,

each holding

directly onto Cheri's

visual cortex.

Finally, the surgeons

string cables

from the plates to terminals

sticking out of her skull.

Next' the electrodes run

through a computer

to a camera

on Cheri's eyeglasses.

All of this technology

is designed

to help Cheri regain some sight.

ROBERTSON:
lt was, l guess,

quite a shock for me

when l felt my head

and l felt these terminals

sticking out behind my head.

'Cause l guess

l really wasn't expecting that.

NARRATOR:
But for her to see

what the camera sees,

many things have to happen.

And that requires a step

into the unknown.

Each electrode touches a

different part of Cheri's brain.

When the system triggers

an electrode,

she sees a flash somewhere

in her visual field.

Where, the doctors don't know.

Now.

NARRATOR:
So they trigger

each electrode one by one

to learn where in her visual

field Cheri sees flashes.

MAN:
Now.

ROBERTSON:
Oh, wow.

That was right there.

Okay.

NARRATOR:

When she sees a flash,

Cheri points to top, bottom,

left' or right.

[ Beeping ]

With every electrode mapped,

the doctors connect the camera'

making certain that what it sees

matches the flashes

in Cheri's brain.

ROBERTSON:

Yeah. Right in the same spot.

So it works for us.

NARRATOR:
Finally,

with the camera mounted,

Cheri's mother helps connect the

gear to try the new settings.

WOMAN:
Ready?

l think my computer

gained weight.

[ Laughs ]

NARRATOR:
Has technology helped

bring Cheri's sight back?

Oh!

Wow!

Oh, wow.

[ Laughs ]

Oh, wow.

When l finally saw my first

light' it took my breath away.

l could not believe it.

We knew it worked,

and that was very,

very thrilling for me.

Oh, something's lighting me up.

NARRATOR:

We can't know what Cheri sees.

But we do know

what she describes.

Whoa. l'm seeing

two big dots of light.

And they are white with

a little bit of red in them.

Wow. Those were two really big

flashes, and they moved.

Wow. l saw a big flash

of light there.

NARRATOR:

This early in the project'

doctors have activated

only some of Cheri's electrodes.

Eventually, they hope to connect

many more,

vastly improving the scope

of her vision.

Oh, wow.

Because l can only use 1 0

of my electrodes,

whenever an object goes

in front of my camera'

l will see two flashes of light.

And they're about the size

of a big peanut M&M --

just one on top of the other.

Saw a couple more.

l'm not sure if it's the waves.

And that way, l know

that there is an object there.

Now, l'm not sure what it is.

They're sailboats?

ls that it still here?

That is cool.

When l am able to use

all of my electrodes, however'

l will be able to see

the outlines of things

l'm looking at.

So l'll know if l'm looking

at a tree or a person or a car.

So l'll actually know

what l'm looking at.

NARRATOR:
No one pretends

that Cheri's vision is back.

But the fact she can sense

any of the visual world

makes her

an extraordinary pioneer.

l magine if one day we could feed

complete vision signals

directly to the brain.

What could we see?

We might see a world

that we've been blind to,

as if we were seeing

through night-vision lenses,

infrared cameras,

even X-ray vision.

l magine a sum mer weekend

on a California beach

dense with bodies.

But for one onlooker'

this seemingly calm scene

may be a series of accidents

waiting to happen.

How does a lifeguard know

when a raised arm means,

" l need help "'

not' "Hey, this is fun"?

The guard's skill at spotting

that one desperate person

among thousands is phenomenal,

truly testing his sight

and understanding.

We see the way we do so we can

spot danger to ourselves.

l call!

NARRATOR:
But nothing

is threatening the lifeguard.

l n fact' the eye,

observing a harmless pattern

across its view,

normally relaxes.

Motion-sensing rod cells

switch off

when they detect action

that's consistent and constant.

So the lifeguard

has to trick his eyes.

He does this by scanning,

forcing his eyes to lock

onto small details.

TU RN ER:
Our frontline defense

are the tower guards.

Their job is to scan the water'

so their eyes are moving

across the water

and letting their brain filter

out that information they see,

looking for something wrong,

looking for that odd one out

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