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 DMN is especially active, research shows, when one engages in introspective activities such as daydreaming, contemplating the past or the future, or thinking about the perspective of another person. Unfettered daydreaming can often lead to creativity. The default mode network is also active when a person is awake. However, in a resting state, when a person is not engaged in any demanding, externally oriented mental task, the mind shifts into “default.”
You know the feeling of walking to the train station for your morning commute, but your mind checks out and your body operates on autopilot. Your body goes through the motions of getting you to work without taxing the brain, all of which sounds beneficial. It is indeed useful, but only up to a point. The problem: You do not remember much about that commute because your default mode network kicked in, you may start with daydreaming, but you start to ruminate over what happened the day before and what will happen in the days to come. You are anxious about past performance, and you are anxious about upcoming performance. The default mode network can hijack the mind to mull over worries.
The default mode network is about self-focus and mental time-travel, and its inactivity appears to be related to varied forms of mental illness. The DMN is involved in episodic memory processing, with introspection and autobiographic memory as important cognitive processes. Researchers have reported dysregulation between the components of the default mode network in patients with Alzheimer’s disease as well as those with Parkinson’s disease, illnesses that affect memory processing.
Connectivity between particular default mode network areas of the brain has been linked to higher levels of rumination in depressed individuals. The depressive among us ruminate about their regrets, failures, shame, and anger. Further links with default mode network dysregulation have been made to autism, schizophrenia, and other conditions.
The DMN is also thought to play a role, in combination with other brain networks, in key qualities such as creativity. As a person idles and her mind drifts, the activity of the DMN may help give rise to ideas that other networks then vet and process further.
Studies show that the default mode network is also active during sleep. An active DMN has been associated with mental imagery and dreaming. In a study that appeared in Frontiers in Human Neuroscience, daydreaming and dreaming may use similar brain mechanisms. The state of dreaming is a more intense version of daydreaming or waking mind wandering. Dreams are longer and more visual, and more strongly engaged in the DMN.
The default mode network, discovered by neurologist Marcus Raichle, spans a number of brain regions, incorporating parts of the prefrontal, parietal, and temporal cortices that show joint activation, or deactivation, in connection with particular mental functions. It is one of a number of such brain networks, which also include the salience network and the executive control network.
This network uses nodes in the insular cortex; it alerts us to what is important, and where we should focus our attention. If you are feeling fearful, the salience network kicks in, searching for threats that may endanger you.
The executive control network monitors what is happening around us, it manages emotional parts of the brain, it directs our attention, and is crucial in decision-making. It also helps process sensory and memory information.
The task-positive network is known as the opposite of the default mode network. The brain’s TPN kicks in when we are focused and engaged in a task. Also known as the dorsal attention network, this network involves part of the brain including the prefrontal regions and the intraparietal sulcus. If a task demands attention, the task-positive network wants to be as alert as possible.
Relaxation techniques, mindfulness, meditation, and even deep breathing can quiet the default mode network. A study that appeared in the journal of Cognitive, Affective, and Behavioral Neuroscience, showed that meditation is associated with reduced activity in the default mode network
In a study of meditators, some were more adept at meditating and others more neophyte. The more experienced meditators had much less activity in the default mode network, they were much better than the neophyte in curtailing mind wandering. In another study that appeared in Biological Psychiatry, researchers also found that meditation quiets the DMN and boosts well-being through decreased inflammation and stress.
Any experience of awe, such as hiking to a mountain top or watching the moon rise or swimming in the ocean, can take you out of your mind. Your focus is not on everyday worries, but more on the big picture. We are insignificant in the grand scheme, and we do not have to stew in our troubles.