Dr. Matt Walker

And this is where I just almost lose it every time I see it.

The brain now goes back down and its speed of oscillation of going up and down is maybe just one or two times per second.

It's incredibly slow.

And this is whole brain activity or localized activity?

So we'll come on to this.

At first, the way we would measure it is just from these electrodes, which are measuring hundreds of thousands of brain cells underneath them.

So a good analogy would be, let's say you're at a football stadium.

And it's Stanford playing Berkeley in American football.

And what we've got is a single microphone dangling over the middle of the stadium.

And that microphone is picking up the summed voices of the 60, 70,000 people underneath.

It's the same thing with when we place an electrode on your head, you're measuring the summed activity of hundreds of thousands of neurons underneath.

But we've now started to use maybe 100, 200 electrodes on your head, and we can pick these up in local territories of your brain.

But that beautiful, powerful, slow brain waves that we're getting during deep non-REM stages three and four, it's not just slow activity.

You would think, okay, that sounds like the brain is dormant.

No, no, no.

The brain at that point, the size of the waves is almost quadruple, maybe 10X the size of the brain waves when you are awake.

Why is that?

Meaning that the brain waves are going up and down very slowly.

But the size of them, which is what we call the amplitude, that is now huge.

It's epic.