The Default Mode Network and how it’s impacted by Psychedelics
The default mode network is an interactive group of brain regions that is found to be most active when a person is in a resting state. This brain activity is associated with focused thinking on self and others, rumination on the past, and thoughts of the future.
The DMN is the “default” setting of the brain that help us function in the world. While there is nothing inherently wrong with this setting of the brain, fMRI studies show that hyperactivity of this network of the brain is linked to mental health conditions including anxiety, depression, Alzheimer’s Disease, OCD, Schizophrenia and even chronic pain.
Essentially, there is a healthy level of remembering past events, thinking toward the future, and recognizing the actions of others and how they impact us, but hyperactivity of this network causes obsessive thinking, rumination over negative experiences and thoughts, and even inaccurate thoughts about ourselves, others, and our experiences in the world.
How does Psilocybin impact the DMN?
Psilocybin is known to profoundly impact activity in the DMN by weakening neural connections within the network. “Ego Death” is a common phrase used when people describe their psychedelic experiences. This term refers to the dissolution of the Ego, meaning thoughts of the individual focus less on the self and borders between the self and the outside world seem to dissolve. The term of “Ego Death” is what is commonly referred to when people Identify their experience as bringing a sense of unity or oneness to their awareness. Although Psilocybin initially decreases activity of the DMN, research suggests that after some time the DMN is reestablished. You can imagine it’s as though you are hitting reset on the DMN, ultimately impacting your default thoughts, patterns and behaviors.
The dissolutions of the DMN also relates to the more chaotic or disordered state of the brain that is shown in individuals who have ingested psychedelics.
While the DMN is an essential part of being able to function in our day-to-day life, research suggests that it is often hyperactive causing unnecessary stress and dissatisfaction. Meditation is a commonly known mediation for deactivating the DMN, however recent psychedelic research studies indicate that psychedelics may have a profound impact on the DMN, especially with the ability to “reset” the DMN and allow the mind a more balanced relationship within this network.
Carhart-Harris RL, Leech R, Hellyer PJ, et al. The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs. Frontiers in Human Neuroscience. 2014;8. doi:10.3389/fnhum.2014.00020
Andrews-Hanna JR. The brain's default network and its adaptive role in internal mentation. Neuroscientist. 2012 Jun;18(3):251-70. doi: 10.1177/1073858411403316. Epub 2011 Jun 15. PMID: 21677128; PMCID: PMC3553600.