I call the default mode network (DMN) “the demon of ADHD.” The DMN is one of the most fascinating and significant discoveries to come out of neuroscience in the past 20 years, but most people haven’t heard of it.
The DMN seems to be more active in those of us who have ADHD, and it may explain our tendency to make “careless” mistakes. In fact, when using a functional MRI, you can predict a mistake 20 seconds before it is made by watching for activity in the DMN.
What is this powerful network no one has heard of? In 2001 scientist Marcus Raichle, M.D., noticed that distinct areas of the brain lit up, showing elevated metabolic activities, when the brain was not engaged in a task, conversation, or other activity that required focus. He discovered that when the brain was “at rest,” it was more active than when it was focused on a task.
He called these regions of the brain “the default mode network.” They include the medial prefrontal cortex; the posterior cingulate cortex; the hippocampus; and the amygdala, as well as parts of the inferior parietal lobe.
There is another network called the “task positive network,” or the TPN. Unlike the DMN, this network lights up when the brain is engaged in a task that requires conscious attention.
In people who do not have ADHD, these networks are reciprocal: As one increases in activity, the other declines. In ADHD, however, the DMN remains active while the TPN is active. This competition provides a neurological explanation for what those of us who have ADHD feel so often — a persistent, magnetic pull away from the task at hand into distraction.
The Seat of Angst
When we are under the influence of the DMN, we ruminate. We recall a funny look a colleague gave us, and we wonder what he meant by that look. Was it really a funny look, or was it nothing at all? If it was a funny look, what did we do to prompt it? The hippocampus, the seat of memory, is an active part of the DMN, sending up memories of embarrassing situations we’ve caused or been part of, humiliating moments we can’t forget. The medial prefrontal cortex, another part of the DMN, projects the repetition of these horrible moments into the future, while the amygdala kicks in with more negative feelings.
Researchers at MIT have shown that the 40 percent or so of children with ADHD who significantly improve by the time they reach adulthood, even without treatment, show a restoration of the reciprocal relationship between the two networks. In the adults who remain symptomatic, the DMN continues to ramp up, even when the TPN is trying to keep a person’s focus on a given task.
This is the hell the DMN creates. It can ensnare a person, especially someone with an active imagination and a keen intellect, and reduce that person to misery.
Tame the Demon
The way to manage this demon is to name it. Don’t confuse what the DMN leads you to conjure up — ugly and painful representations of life and of yourself — with the truth. Don’t get sucked into analyzing or parsing it. Once you name it, you can tame it.
Then, you need reliable ways to switch back into the TPN. One easy way I have found is to focus on your breathing. For example, you might pick a pattern, so you have a task to focus on. You may pick 6-3-8-3 — inhale for six beats, hold for three beats, exhale for eight beats, hold for three beats; repeat. Do this for a few cycles and you will have broken out of the DMN. And life will seem brighter and a little more hopeful.