Greg: Santiago was eleven-years-old.
He was in jail.
The trouble had been brewing for a long time.
Santiago fought with his teachers and argued fiercely with his father.
He kept getting kicked out of school, but he didn’t mind—he hated school.
Santiago’s memory was bad.
This made it even harder for him to learn.
Math was something he especially hated.
He wanted to be an artist, but his father thought art was useless.
Santiago was headed for failure.
It’s hard to believe what actually happened.
Santiago won a Nobel Prize—that’s like an Olympic gold medal for science!
He is now called the father of modern neuroscience—that is, the science of how the brain works.
I’m going to tell you about how it happened.
But to understand Santiago’s story, we first need to learn a little more about the brain.
Over to you, Barbara!
Barbara: Your brain has a lot of tiny neurons in it.
But even though they are tiny, neurons are the building blocks of our brain.
To help you understand neurons, let’s think of them as tiny aliens from outer space.
Here’s the eye of the neuron-alien.
Here’s the neuron-alien’s arm.
You can see the neuron-alien’s three legs down below.
Terry, how does this compare with real neurons?
Terry: Well, you can see something more like a “real” neuron right here.
Here are the neuron’s “legs.”
They’re called dendrites.
And here’s the neuron’s “arm.”
It is called an axon.
The “eye” is the main part of the neuron.
(In reality, the eye is called the “nucleus.”)
Real neurons can actually have more than three “legs.”
Many more!
Neurons come in all sorts of shapes and sizes.
Look at those little knobs.
They are called dendritic spines.
You can think of them as being like toes that are scattered all over the space alien’s
legs.
Kind of creepy, but hey, if the neurons didn't have so many toes, they wouldn't be able to
get their jobs done.
Dendritic spines may be small, but they are also important.
The spines help neurons receive signals from other neurons.
Barbara: You can understand this by remembering our space aliens.
When a neuron-alien wants to “talk” to the next alien, its arm gives a tiny shock
to the toe of the next alien.
(Neuron-aliens show friendship by giving tiny shocks to one another.
Just one of those strange things!)
Terry: But it’s surprisingly similar for real neurons.
An axon ripples a signal along its arm.
When the signal gets to the end of the arm, it causes a shock to jump across a special,
narrow gap to the dendritic spine of the next neuron.
The gap, incidentally, is called a synapse.
If the signal travels through a neuron all the way to the end of the axon, it can cause
a spark to go across the synapse gap to the next neuron.
And the next.
It can just keep going.
These flowing signals are your thoughts.
You can also think of them as being like the trails on your mental pinball table.
Incidentally, synapses are the only place where neurons are close enough, and set up
just right, so so that signals can cross from one neuron to the next.
And there are a lot of them in your brain.
A million billion synapses.
If I had a dollar for every synapse in your brain I would a billionaire a million times
over!
Greg: Great!
You now understand how a neuron passes along a signal, and how you think!
Well, maybe it’s more complicated—there’s some chemistry involved.
But you’ve got the basics.
Terry: Yes!
What’s really interesting here is that the more often a neuron shocks the next neuron,
the stronger the synapse connection.
It’s like friends who become better friends because they talk a lot.
Neuroscientists have a saying: "Neurons that fire together, wire together."
"Wiring together" means that a brain-link is being created.
Learning means creating new, or stronger, brain-links.
Barbara: At the beginning, when you’re first beginning to learn something, the brain-link
is weak.
There may only be a few neurons linked together, and the spark between the neurons isn’t
very big.
As you practice a new idea, the synaptic links get stronger.
This means the sparks get bigger.
You can get more neurons, with stronger synapses—the brain-links get bigger and better!
More complicated ideas can make longer brain-links.
People sometimes think of brain-links as if they were mouse paths in a forest.
The more the mouse runs along the path, the wider the path gets.
The easier it is to follow the path!
The fact that paths in your brain change and grow is called neuroplasticity.
This fancy word just means that your neurons can change.
That’s why you can change!
Greg: Now, back to Santiago Ramón y Cajal.
Let’s find out how he was able to change from bad boy to superstar!
Barbara (HB scoots in from side): I’m Barbara Oakley
Greg: I’m Greg Hammons Terry: and I’m Terry Sejnowski
Barbara: we, and Arizona State University, wish you happy learning!