Step inside the Default Mode Network. Or breathe inside of it? Lose yourself in it? We’re not really sure yet.

We’ve all been there – part way through a lecture, meeting, or workout you find yourself thinking about what to make for dinner, how to remodel your living room, what ever happened to your 4th grade crush, or just staring blankly into space. Daydreaming strikes again.

There aren’t many things that we’re very good at from birth. Walking, communicating, empathising, all come after years of practice and feedback. In fact, of the things you can control, I’d argue there are only 3 things that you are born knowing how to do – breathing, learning, and daydreaming.

Learning is a little more abstract (though arguably most of us learn something everyday – even if we’re not consciously aware of it), so let’s look at breathing.

If you’ve spent any time meditating, doing strenuous exercise, or playing hide-and-go-seek – you’ll be familiar with the concept of noticing your breath and consciously trying to change it in some way. Trying to slow your breath, or breathe more deeply, or hold it all together.

All of this results from the various muscles in our chest cavity – intercostal muscles and the diaphragm both playing important roles. I’m not going to go into the physiology, but basically, these muscles work together to draw air into your lungs and then expel it again. You have some conscious control over some of these muscles that allows you to change the frequency of the breathing, but we’re all pretty familiar with the fact that, in most humans, breathing happens without you thinking about it, and even if you make a conscious effort to change it, when you stop making that effort, it goes back to doing its thing.

Daydreaming or mind wandering is kinda like breathing.

I don’t mean that in the literal sense – the literature is pretty clear that everyone daydreams and that it happens decently frequently, but it’s unclear on its importance. If you don’t breath, you die, I’m pretty sure (not positive though) that if you were prevented from daydreaming your life wouldn’t come to an end. Then again, I couldn’t tell you how one would go about preventing someone from daydreaming… so this is all a little moot.

But here is what we do know. Daydreaming or mind wandering is linked to activity in a neural network called the Default Mode Network, or DMN for short. What is a neural network? A group of brain regions that work together to achieve a certain end goal or brain state.

Just like there are groups of muscles that need to work together for you to do a pull-up or breath (remember those intercostal muscles and diaphragm?), there are groups of brain areas that need to work together for you to do a math problem or, you guessed it, daydream.

There are two key ‘networks’ in the brain involved in focus and attention. One is more active when you are intently focusing on a task or in an ‘alert’ state (think: studying, puzzling out a rubik’s cube, or trying to follow the rhetoric in a political debate) this the Executive Network. This makes a lot of sense – you’re trying to focus, but what’s really cool is that there’s another network that’s active when it seems like you’re doing nothing at all. This ‘resting’ state network – the DMN –  is more active when there is an absence of intent focusing (think: daydreaming, musing about your future, and zoning out because the political rhetoric is overwhelming).

The exact membership of the DMN is still up for some debate, but these are the key players: the medial prefrontal cortex (mPFC), the Anterior cingulate cortex (ACC), and the posterior cingulate cortex (PCC). These areas are involved in a lot of things including memory, executive function, emotion, and decision making to name a few. But they are all active together (as part of the DMN) when you’re thinking about yourself (self-referent, not necessarily selfish) and not focused on completing a task.

Our waking lives are a constant interplay between the Executive Network and the Default Mode Network – focus on sautéing your garlic, get distracted by why vampires seem to hate it so much, then get your attention drawn back to your now burnt garlic by the smoke detector. Constant tug-of-war.


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