Default Mode Network: Wandering

I’ve been mulling over the Default Mode Network (DMN) lately. What got me interested in the DMN was Dr. George Dawson’s Real Psychiatry blog post “Coffee Shop Neuroscience” published on October 22, 2016.

The other major influence on my mind wandering back and forth between the everyday world and the mystery of the DMN is the National Neuroscience Curriculum Initiative (NNCI) website module on the topic, “Default Mode Network: The Basics for Psychiatrists.” One of the authors, Daniel S. Barron, MD, PhD, was a medical student at the time it was produced. It looks like he’s now a resident in Psychiatry at Yale. According to them, the DMN is responsible for what’s often called the wandering mind. Why does it happen? They say:

The simplified answer is the default mode network (DMN). The DMN is a brain system responsible for your self-referential inner monologue or wandering mind. The DMN is thought to recruit memories, associations, and recent events to help you plan for the future. Melding these together allows you to rehearse information and plan by detaching you from what’s going on around you at that moment. While the DMN is active, your brain literally ignores external stimuli, leading to what some call being “spaced out”. While it may be annoying to friends and family when you’re not responding to them, it’s not harmful and is actually a healthy, normal process. During these times, your brain’s attention has merely re-directed its focus on your internal dialogue instead of the outside world [Weissman et al., 2006]. Left with no other required tasks, your brain will gravitate towards the DMN. Indeed, the DMN is so-called because it’s the brain’s default pattern. –Barron and Yarnell, NNCI,  “Default Mode Network: The Basics for Psychiatrists.”

It’s easy to see how this mode could get overactive, say in obsessional rumination. But it could be responsible for other mental disorders as well. An overactive DMN can get in your own way.

The descriptions of the DMN are basically identical between George and Daniel. However, Daniel and his co-author, Dr. Stephanie Yarnell, MD, PhD, also mentioned how Mindfulness meditation might moderate DMN activity.  They linked to an interesting YouTube video about it.

I’ve been practicing mindfulness meditation for a little over a couple of years now, really just a beginner. I now have a definite name for why it’s a tough skill to develop–the DMN. My mind really tends to wander. Our teacher told us that would be the main challenge. Continuing practice is sometimes called “teaching the puppy to stay.” I’d be interested in hearing your thoughts about this.

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