Default Mode Network Modulation by Psychedelics: A Systematic Review

Summary & key facts

Researchers reviewed studies that looked at how classic psychedelic drugs — LSD, psilocybin, and ayahuasca — change activity in a brain system called the Default Mode Network, or DMN. The DMN is a set of brain regions that are more active when we rest and do things like daydream, think about ourselves, or remember our past. Across studies, psychedelics tended to disrupt connections inside the DMN and increase connections between different brain networks. This pattern is consistent, but it is still not clear whether these brain changes are the main reason psychedelics might help with mental health. The review calls for more research to figure out how these brain effects relate to real changes in mood and behavior.

Key facts:

• The Default Mode Network, or DMN, is a group of brain areas that usually work together when people are resting and doing self-focused thinking, like remembering the past or daydreaming.
• The review looked at research on three classical psychedelics: LSD, psilocybin, and ayahuasca.
• Across studies, psychedelics consistently caused an acute disruption in connectivity inside the DMN during resting states.
• Psychedelics were also found to increase functional connections between the DMN and other standard resting brain networks.
• Altered DMN connectivity has been linked in other research to conditions such as depression, anxiety, post-traumatic stress disorder, attention-deficit hyperactivity disorder, and obsessive-compulsive disorder.
• Even though the DMN is consistently affected by psychedelics, the review says it is unclear how central DMN changes are to any therapeutic effects of these drugs.
• The authors suggest more focused research is needed to connect the brain-network changes seen with psychedelics to actual psychological and clinical outcomes.

Abstract

Psychedelics are a unique class of drug that commonly produce vivid hallucinations as well as profound psychological and mystical experiences. A grouping of interconnected brain regions characterized by increased temporal coherence at rest have been termed the Default Mode Network (DMN). The DMN has been the focus of numerous studies assessing its role in self-referencing, mind wandering, and autobiographical memories. Altered connectivity in the DMN has been associated with a range of neuropsychiatric conditions such as depression, anxiety, post-traumatic stress disorder, attention deficit hyperactive disorder, schizophrenia, and obsessive-compulsive disorder. To date, several studies have investigated how psychedelics modulate this network, but no comprehensive review, to our knowledge, has critically evaluated how major classical psychedelic agents-lysergic acid diethylamide, psilocybin, and ayahuasca-modulate the DMN. Here we present a systematic review of the knowledge base. Across psychedelics there is consistent acute disruption in resting state connectivity within the DMN and increased functional connectivity between canonical resting-state networks. Various models have been proposed to explain the cognitive mechanisms of psychedelics, and in one model DMN modulation is a central axiom. Although the DMN is consistently implicated in psychedelic studies, it is unclear how central the DMN is to the therapeutic potential of classical psychedelic agents. This article aims to provide the field with a comprehensive overview that can propel future research in such a way as to elucidate the neurocognitive mechanisms of psychedelics.

Topics

Chemical synthesis and alkaloids Nicotinic Acetylcholine Receptors Study Psychedelics and Drug Studies

Categories

Clinical Psychology Psychology Social Sciences

Tags

Acoustics Computer science Default mode network Functional connectivity Modulation (music) Neuroscience Physics Psychology

Substances

Ayahuasca LSD Psilocybin

Conditions & symptoms

ADHD Anxiety Depression Obsessive-Compulsive Disorder PTSD Anxiety or worry Difficulty focusing Feeling disconnected from others Sadness or low mood