How to Turn off Default Mode Network: Exercise, Meditation, Psychedelics

The brain is the center of all human ingenuity. 

From our greatest scientific and technological achievements to our most profound works of art, our deepest understanding of ourselves to our developing knowledge of the universe – everything flows from this 1.4 kg opaque mass of blood vessels and nerve cells. But how does the brain do all that it does? 

Up until the 1899 publication of neurologist Sigmund Freud’s seminal work The Interpretation of Dreams, most research on brain function was focussed on its waking activities. The majority of scientific and clinical curiosity on the subject was centered on task-related activities of the brain – the way it interacts with the external world, handles challenges, and solves problems. Freud’s insights into the dream workings of our brain opened the doorway to a deeper level of understanding of this complex organ.

German psychiatrist Hans Berger was the first to observe in the 1920s that the brain’s electrical activity did not cease with periods of rest or sleep. Over the next several decades, this and later discoveries culminated in the identification of several resting state networks (RSNs) – organized patterns of brain function that continue across sleep and waking states and even under general anesthesia. The most widely studied of these RSNs is the default mode network or DMN. 

What is Default Mode Network (DMN)?

The default mode network (sometimes referred to as default mode) is a system composed of interconnected brain regions that activate spontaneously when an individual is no longer focused on the external world. In other words, the DMN is a range of stimulus-independent brain activity in people who are conscious and awake but not concentrated on any targeted or purpose-driven task. It fires up whenever we engage in passive activities like introspection and daydreaming, but also during periods of directed mental activity like self-referencing, contemplation of the past, and fantasizing about the future.   

Opinion about the function and purpose of the DMN is divided among researchers. Some say it is involved with the processing of social stimuli, including the way we understand relationships and social hierarchies. Others think it is fundamental to activities like mental time travel and perspective shifting. Yet another explanation is that it enables internal mental simulations – the kind we use to recollect the location of a misplaced wallet or a parked car.  

While there is a diversity of views as to the exact workings of the default mode network, there is no doubt about its significance in our overall mental dynamics. The most important point of this unanimity is that the DMN represents a higher state of mental activity compared to apes and other animals. To put it another way, the human brain’s most sophisticated level of functioning is activated when any immediate or survival-related activity does not encumber it.       

The DMN impact on mental health 

DMN activity in the brain can be measured both through traditional techniques like an electroencephalogram (EEG) and advanced neuroimaging techniques like magnetic resonance imaging (MRI) and functional MRI (fMRI). As a result, the mental health implications of DMN have been the subject of major research and continued clinical interest over the last few decades. DMN integrity is now widely accepted as critical for mental health stability, and several mental health issues have been conclusively shown to display a strong correlation to this critical brain system.

This has led to neurologists and psychiatrists relying on the DMN for two critical mental health-related processes: 

• Diagnosis: Abnormal DMN functioning has been used as a diagnostic tool for mental health disorders such as major depressive disorder (MDD), anxiety, schizophrenia, attention deficit and hyperactivity disorder (ADHD), substance abuse, and Alzheimer’s disease, among others. 
• Treatment response assessment: The same logic through which irregular DMN functioning is used for diagnosis can be applied to evaluate how effective a particular line of treatment has been in treating a particular mental health condition and as a metric for measuring recovery.    

How DMN affects mental health

What has still not been established is whether abnormal DMN functioning has a causal effect behind certain mental health disorders or is merely a symptom of these conditions. For instance, studies have shown a correlation between patients with MDD and increased DMN activity in their brains. Irregularities in the DMN have similarly been linked to a host of other mental health disorders, including Alzheimer’s and Parkinson’s disease, epilepsy, ADHD, and mood disorders. However, the exact nature of the connection between abnormal DMN and these disorders remains to be fully understood.  

Negative effects of DMN

What is known for sure is that DMN is largely manifested as the internal dialogue of a wandering mind. It primarily constitutes the involuntary ruminations that all healthy minds indulge in throughout their lives. That is normal as long as there is a balance between the default mode network and other brain systems. An overly active DMN, on the other hand, can lead to several behavioral abnormalities. For instance, DMN hyperactivity has been linked to ADHD, poor decision-making, decreased concentration and attention spans, and obsessive-compulsive disorder (OCD). A 2011 fMRI study found that increased DMN activity in non-rest states was linked to a higher predisposition towards impulsive behavior in juvenile offenders. 

Positive effects of DMN

The default mode network is closely related to metacognition – self-awareness or understanding of one’s cognitive process, or more simply, the ability to think about one’s own thoughts. While we do not fully understand the functional significance of DMN in this regard, it is believed to be critical in building and updating internal models of the world based on autobiographical memory and the perspectives of others. 

How the DMN supports memory formation and recall

The study of age-related decline in cognitive processes, especially in patients with Alzheimer’s disease, has opened up our understanding of another mental process that is dependent on DMN – memory.  

Studies have shown that DMN supports the formation of episodic memory in healthy individuals. Episodic memory is the long-term memory of a past event or experience that includes contextual markers like the place, time, and emotion. Beyond memory formation, DMN is also believed to be associated with memory retrieval or recall, a process that suffers in conditions of irregular DMN activity. 

How to turn DMN off

The fact that a healthy mind needs a fine-tuned balance between the DMN and other brain systems has already been laid out. Part of that balance depends on the brain’s ability to disengage the default mode network in order to focus on external, goal-oriented tasks. Insufficient suppression of the DMN has been linked to several mental health conditions, especially major depressive disorder and suicidality. A hyperactive or out-of-control DMN can swamp an individual with endless streams of thoughts, running their mental health and producing debilitating physical symptoms.   

If you compare the DMN state to watching a TV show without the sound on, disengaging the DMN would be equivalent to staring at a blank screen. For someone battling depression or contemplating suicide, a deactivated DMN could mean much-needed relief from the constant onslaught of troubling thoughts. That is why spiritual seekers refer to this state as the dissolution of the ego or transcendence. 

But before going any deeper into the subject, let’s first try and understand what it means experientially to switch off the DMN. In clinical terms, a deactivated DMN signifies impaired consciousness. In non-clinical terms, the same has been described as being able to look at the world without the intermediate filter of the mind. Another approach calls it the non-judgemental awareness of one’s thoughts and feelings. Although both of these are non-scientific explanations, they are significant because they define an experience that verges on the metaphysical, and are at the limits of what the conscious mind can perceive or what language can describe.

So is there a way to turn off the DMN? There are actually more ways than one! Let’s find out more about what they are. 

Psychedelics    

Psychedelics are a class of naturally occurring as well as synthetic drugs that are commonly referred to as hallucinogens. Examples of natural psychedelics include psilocybin (from magic mushrooms), mescaline (from peyote cactus), and ayahuasca. Ketamine, LSD, MDMA, and DMT are some of the more common synthetic varieties. They are called hallucinogens because of the mystical and transcendental experiences they induce in users. 

Researchers believe that these experiences are manifested because psychedelics modulate the DMN. Specifically, they reduce the functional connectivity between areas of the brain that govern the DMN. This effect is understood to be behind the feelings of timelessness, spacelessness, and disintegration of the self associated with the use of psychedelics. In other words, suppression of the DMN through psychedelic therapy can lead to improved mental health and well-being.  

Many psychedelic drugs, including psilocybin, LSD, and ayahuasca are known to produce effects consistent with a suppressed DMN. However, even though psychedelics are considered safe when administered under medical supervision, it is not advisable to either experiment with them or use them for mental health treatment outside clinical environments.   

Mediation

Studies have shown that certain types of meditation decrease DMN activity in the brain while simultaneously relaxing the body and mind. Mindfulness meditation, which involves focusing on being aware of the present moment without interpretation or judgment, is one such type.

Often practiced with breathing exercises and guided imagery, mindfulness meditation can help stabilize the mind and keep it from wandering off into stressful territories, like past regrets and future fears. Neuroimaging studies of brain activity also show that meditative practices result in structural and functional changes in the brain, especially in areas associated with self-awareness and self-regulation. Both these attributes are consistent with a deactivated DMN. 

Exercise

Another activity shown to calm down the default mode is exercise, especially aerobics, which is a category of exercise designed to improve cardiovascular health. 

One study that followed 12 participants over six months concluded that exercise is associated with decreased DMN activity. Interestingly, the study also found a correlation between a suppressed DMN and loss of body fat, together with a reduced perception of hunger. 

This just shows that a switched-off DMN is not good for your mental health alone but for your physical and overall health as well.