When your mind is wandering, your brain’s “default mode” network is active. Its discovery 20 years ago inspired a raft of research into networks of brain regions and how they interact with each other.

What Is the Default Mode Network? The default mode network (DMN) is a system of connected brain areas that show increased activity when a person is not focused on what is happening around them. The ...

When I first heard the term "default mode network," I wondered if it had something to do with telephones or the internet. It doesn't. What it does have to do with is much more intriguing. The default ...

The original version of this story appeared in Quanta Magazine. Whenever you’re actively performing a task—say, lifting weights at the gym or taking a hard exam—the parts of your brain required to ...