David Eagleman

And so we realized the problem is the visual system needs some way of defending itself against takeover.

And that is what dreams are about.

So every 90 minutes, you've got these very ancient circuits in your midbrain that just blast random activity just into your visual cortex.

That's the only place it's hitting is just primary visual cortex.

And every 90 minutes just blasts random activity in there.

And so dreaming is the brain's way of defending the visual cortex against takeover.

It's essentially a screensaver.

So we published this and we studied 25 different species of primates and looked at how plastic they are.

In other words, humans are extraordinarily adaptable and plastic in their brains.

And that means they're at higher risk of the visual cortex getting taken over.

Whereas other primates,

primates like the gray mouse lemur it's called it happens to be very let's call it pre-programmed where it hits adolescence fast and learns how to walk fast and weans from its mother fast and all this stuff reproduces fast and so we looked at how how much dreaming there is and it turns out humans have lots of dreaming to prevent take over the visual cortex whereas other you know less flexible animals have less dreaming because they just don't need it as much

That's exactly right.

Yeah, it's just random activity.

What happens is the synapses, the connections that are hot during the day are the ones when you blast random activity in there, those tend to be the stories that get activated.

So, you know, if I'm thinking about my boss who said this to me, or I'm thinking about this big thing that I have to do tomorrow, then it's likely that that's going to come up in my dreams.

But we all know dreams are just

They're so weird in their plot lines.

And because the brain is a natural storyteller, we end up imposing narrative.

And by the way, when you wake up and you tell somebody else your dream, you're doing a whole nother layer of imposing narrative on it.