How the default mode network rules our brains and makes all the decisions around here

Constant creation in the DMN | Photo by Jené Stephaniuk on Unsplash

Whenever your brain is not doing a specific task it is hanging out in the default mode network. You’ll recognise this space as the one you go to when you’re not paying attention to anything in particular.

Sometimes it is a shiny, happy and warm cocoon. You mull over ideas, reminisce over fond memories and dwell on the tiny small things that made you smile yesterday.

At other times, it is a high-octane ride through the most excruciating parts of your previous day, week, or year. You relive all the things you should have said and shouldn’t have done.

This is the place where memories are processed and creative ideas appear. It is also the place you relive traumatic experiences and emotions over and over.

Neurotypical people can dial this network down or shut it out altogether when there is a specific task at hand using the task-positive network (TPN). Brain imaging has shown that these two mental modes — the TPN and DMN — are designed to work in opposition: as a task is set, the task-positive network ramps up its activity and the default mode network quietens down.

This doesn’t happen for people with ADHD.

The constant buzz hum

My brain is never still. Ever. I can’t turn off the constant churning of internal chatter. I wasn’t aware that this was uncommon until fairly recently and it’s only since discovering the default mode network that I can now give it a name.

In the past, this ceaseless cacophony has been an unbearable weight and taken me to some pretty horrible places. It still wakes me up at 3–4 am every night to tell me the most hideous news it can think of.

It does, however, come with some plus sides.

Dual processing

My wife reads me the most interesting news over coffee most mornings. While she’s doing this I am most often playing Wordle, completing a Sudoku or working my way through 2048. She has commented before that this looks like incredibly hard work: how can I do both these things at once?

My response is that the game-playing is my only way to pay attention! Attempting to just sit and listen to her would be futile as a thousand other thoughts pull my thoughts away. If I plan to stay engaged in her stories rather than mine I need to give that other part of my brain something to do.

Random connections

Spending more time than most in rumination mode makes you better than most at seeing patterns and making interesting connections between things. I often feel my brain works at its best when I go on a long run or fast bike ride and let the default mode kick in. Knotty problems at work or in my personal life unravel as the miles go by.

What does the science say?

My initial research indicates that dysfunction in the default mode network may be central to the definition of ADHD:

What about you?

I’ve connected with a wide range of neurodiverse people on Medium and would love to know what you think. How does this daydreaming, ruminating, never ceasing processing mode affect you? How do you experience it? Are there any other articles you would recommend?

Please do let me know in the comments. :)

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Amy Streator Wilson

Amy Streator Wilson

Interested in everything and everyone… yet hiking, travel, mountains, space, sustainability and the power of compromise really float my boat