Jay Shetty

The default mode network.

This is the most important brain system that no one tells us about.

For most of neuroscience history, researchers studied the brain by giving people tasks to do and watching which regions activated.

Solve a puzzle, this area lights up.

Process language, that area.

Recognize a face, this region.

The operating assumption was that the interesting action happened when the brain was working.

What nobody thought to ask was, what is the brain doing when it's not working?

In the 1990s, neuroscientist Marcus Reichel at Washington University in St.

Louis was doing exactly this kind of task-based brain imaging.

And he kept noticing something strange.

There was a network of regions that consistently deactivated when people were given tasks to focus on.

They went quiet during directed attention.

And when the task ended, when the person was just resting, just letting their mind wander, this network came roaring back online.

Reichel called it the default mode network, the DMN, the brain's default setting.

For years, the DMN was dismissed as background noise, idling like a car engine at a red light, wasted energy, the brain burning glucose for nothing.

Then in one of the great slow burn reveals in science history, researchers started actually studying the DMN and they found that it was not idling at all.

It was doing the most sophisticated, most important, most deeply human cognitive work of your entire mental life.

Here is what the default mode network is responsible for.

I want you to listen to this list carefully.