(intro)
Except for that one weird species of jellyfish that can pop back and forth between larval and adult states,
all living things are built to die.
So as unpleasant as it is,
it's only logical to expect that someday,
you will also
ah, let's put this delicately,
uh, stop being alive.
Now, I'm going to be honest--I personally believe that
a dramatically expanded lifespan would be awesome.
but it's always been a long way off.
And it's probably a longer way off than any of our lives will be,
but there is this vague idea that in the distant future,
humanity might figure out a way to cheat death.
So nobody is getting their hopes up,
but some researchers are trying to close the gap by figuring out how to map the human brain,
and simulate it on a computer.
Essentially in the long term,
they want to figure out how to upload the human mind.
Now, the idea of mind uploading has been floating around science fiction for decades, but it's only recently
that it started to look like actually, maybe, a little bit ...
in the distant future, possible.
In theory all you have to do is program a map of your brain
onto a computer, and once things are all set up you just run
the program and voila:
an uploaded, working brain.
The question, of course, is how to actually do that,
because, like, brains are very complicated.
The average human brain contains
86 billion neurons and each of those neurons can form thousands of
connections with each other,
We're talking, hundreds of trillions of synapses or pathways
that exchange information.
So if you want to build a brain, the first
thing you're gonna need,
is a map.
The goal is to eventually put together a detailed database of
each neuron in the human brain and how they all connect, but first
we're startin' small: millimeter-long round worm small.
C. elegans is a tiny worm that is about a simple as you can get,
which is why it is often used for research.
In 2012, researchers completed it's connectome:
the map of how all of it's neurons interact with one another.
Now it does help that instead of 86 billion neurons,
it has 302.
Other groups are trying to put together
the fruit fly connectome, but that's taking a little longer.
Small it may be, but the fruit fly's brain has
more than 30,000 neurons.
It's taken so long to figure out the round worm
and even small parts of the fruit fly brain, that
it'll be a while, possibly forever, before
we can map out something as complicated as
a human brain.
But even if we did have a perfect map of the human connectome,
that wouldn't really be enough.
Remember, we're talking about hundreds of trillions of connections,
and some of those are transmitting messages at more than 400 km an hour.
No matter how fancy your new gaming laptop is,
even it doesn't have enough processing power to manage all that.
But someday, it might.
Back in 2012, for instance, a team of scientists at IBM
was able to simulate 530 billion neurons
and a 100 trillion synapses using the Blue Gene/Q supercomputer.
Now, those numbers are on the same scale as the human brain,
but it was the simplest model possible,
just a bunch of processors forming a huge network.
They weren't following any prescribed pathways
or processing input the way a human brain would,
Plus, the program was running more than
1500 times slower than a human brain would.
But computers are getting faster all the time, so speed
is an issue that we can solve, even if it takes some decades.
Problem is, we kinda have no idea how to get a network
to act like a brain, even if we know what the connections
are supposed to look like.
Because, even after all these years of developing the field of neuroscience...
we still don't know how brains work
or understand how conciousness happens.
But maybe, it doesn't matter. We have billions of working
human brains at our disposal, all we have to do is
take 'em apart and reverse engineer a computerized version.
Like a paint-by-numbers kit. You don't really need to understand
the complexities of color theory, as long as you have instructions.
We just don't know how detailed those instructions need to be.
For example, a program that models the entire brain at the molecular level
is gonna be much more accurate than one that just simulates the signals between neurons.
But, as the simulation gets more complicated, it becomes even more demanding to program and run.
It's hard enough to model even a single cell right now,
let alone 86 billion of them!
At this point, we don't know how deep we're going to have to go
to get a brain simulation up and running,
especially if we want it to be a conscious brain.
So we have a lot to learn about our minds before we're able to upload one to a computer,
but so far we don't know anything that indicates that it is definitely impossible.
Meanwhile, thank you for using your natural brain (I assume) to watch this episode of SciShow
which was brought to you and inspired by the movie "Self/less"
starring Ben Kingsley and Ryan Reynolds
which explores some of the moral and philosophical questions of this potential future
and also was super-fun to watch! We got to see it here--all the SciShow team.
"Self/less" will be released on July 10th and there's a link to the trailer in the description.