New Research Reveals How Psychedelics Reshape the Brain

A collection of recent studies has provided new insights into how psychedelic compounds, particularly psilocybin, affect the brain. Research published in multiple journals has identified potential structural brain changes following psilocybin use, a common brain activity signature across several psychedelic drugs, and the development of modified psilocin derivatives with reduced hallucinogenic effects in animal models.

Psilocybin and Brain Structure Changes

Study Design and Methods

A study published in Nature Communications examined the effects of psilocybin on brain structure and psychological well-being in 28 healthy participants in London with no prior psychedelic use or psychiatric diagnoses. The study involved two sessions: participants first received a 1 mg placebo dose of psilocybin (sub-psychedelic) and, one month later, a 25 mg dose, considered standard for therapy.

Researchers recorded brain activity via electroencephalography (EEG) during both sessions. Magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), was conducted before and one month after the 25 mg dose.

Key Findings

• EEG data showed a temporary increase in brain entropy (variability in neural activity) within one hour of the 25 mg dose.
• DTI scans conducted one month after dosing revealed decreased water diffusion along neural tracts between the prefrontal cortex and midbrain regions. Researchers noted multiple possible explanations for this change, including denser nerve tracts, pruning of nerve fibers, or growth of uninsulated nerves.
• Participants who experienced greater brain entropy during the session and reported higher psychological insight the following day showed improved well-being at two-week, four-week, and one-month follow-ups.
• Approximately 70% of participants reported improved well-being two and four weeks post-dose.

"It is remarkable to see potential anatomical brain changes one month after a single dose of any drug."
— Robin Carhart-Harris, University of California, San Francisco

Researcher Statements

Albert Garcia-Romeu (Johns Hopkins Medicine) described the findings as exploratory, noting that some changes resemble those seen in traumatic brain injury. Joshua Siegel (NYU Langone) highlighted the need for larger studies to replicate results and assess therapeutic relevance. Alex Kwan (Cornell University, not involved in the study) cautioned that the study was small and DTI provides an indirect, limited view of brain connections.

Limitations

• Participants could often distinguish the high-dose session from the control, potentially biasing results.
• The authors noted that current assays may not detect all functional brain changes post-psilocybin.
• Some neuroscientists questioned whether brain entropy is a reliable marker of the psychedelic state.

Common Brain Activity Signature Across Psychedelic Drugs

Study Design and Methods

A meta-analysis published in Nature Medicine combined data from 11 brain-imaging datasets from laboratories across five countries. The analysis included over 500 brain scans from 267 individuals who had used LSD, psilocybin, DMT, mescaline, and ayahuasca.

Key Findings

• Researchers identified a common pattern of brain activity across all five psychedelic drugs.
• Psychedelics enhanced communication (described as "cross-talk") between brain networks typically involved in higher-level cognitive processing and networks associated with vision, sensation, and motor control.
• The study found weakened internal connections within individual brain systems under the influence of psychedelics.
• Changes in brain activity were observed between subcortical regions associated with perception, motivation, and reward.
• Contrary to some previous claims, the research found limited reliable evidence that individual brain networks "disintegrate" under the influence of psychedelics.

"These five drugs, analyzed together for the first time, demonstrate common effects on brain function. They dissolve the common order and flatten the hierarchy of brain systems."
— Danilo Bzdok, McGill University

Emmanuel Stamatakis (University of Cambridge), senior co-author, emphasized the need for "large-scale, coordinated evidence" for responsible development in psychedelic research.

Mouse Study on Visual Perception and Memory

Study Design and Methods

A study conducted on mice examined how psychedelic compounds alter visual perception. Scientists used mice genetically engineered to have brain cells that glow when active. During experiments, mice were exposed to visual stimuli (moving black and white bar patterns and blank screens) while researchers recorded voltage changes across the brain's surface. Midway through the experiment, mice received an injection of a chemical that selectively activates the 5-HT2A serotonin receptor, similar to LSD and psilocybin.

Key Findings

• Before the drug, the visual cortex exhibited 5-Hz brain oscillations.
• After psychedelic administration, theta rhythm oscillations (associated with attention, memory consolidation, and stimulus familiarity) significantly intensified in power and duration.
• Low-frequency waves in the visual processing areas synchronized with the retrosplenial cortex, a region involved in memory encoding, storage, and retrieval, with an approximately 18-millisecond delay.
• The administered psychedelic appeared to reduce the brain's response to external visual stimuli while enhancing connections with memory areas.

"The observed state is comparable to partial dreaming, where the brain's internal imagery overrides external reality."
— Dirk Jancke, Lead Researcher

Limitations

• The possibility that mice might have been distracted by repetitive images.
• Uncertainty about whether these findings can be directly mapped to human hallucinogenic experiences.

Development of Modified Psilocin Compounds

Research Focus

New research published in ACS' Journal of Medicinal Chemistry describes the development of modified forms of psilocin, the active compound produced from psilocybin in the body. The goal was to create compounds that maintain biological activity while reducing hallucinogenic-like effects.

Compound Development and Testing

A research team led by Sara De Martin, Andrea Mattarei, and Paolo Manfredi chemically engineered five psilocin derivatives designed for slower and steadier release of the active molecule into the brain. Through tests using human plasma and simulated gastrointestinal absorption, compound 4e was identified as the most promising candidate.

Mouse Study Results

• In mice, oral administration of compound 4e resulted in effective blood-brain barrier penetration and a lower, but more sustained, presence of psilocin in the brain compared to pharmaceutical-grade psilocybin.
• Mice treated with compound 4e exhibited significantly fewer head twitches (an indicator of psychedelic-like activity in rodents) than mice given psilocybin, despite strong serotonin receptor activity.
• Researchers attributed this difference to the quantity and rate of psilocin release in the brain.

"These findings suggest a potential dissociation between psychedelic effects and serotonergic activity, which may enable the design of new therapeutics that retain beneficial biological activity while reducing hallucinogenic responses."
— Andrea Mattarei, Corresponding Author

Future Outlook

The study indicates the feasibility of developing stable, brain-penetrating psilocin derivatives that maintain serotonin receptor activity while reducing acute mind-altering effects. Further research is necessary to clarify their mechanism of action, fully characterize their biological effects, and assess their therapeutic potential and safety in humans. The authors acknowledged funding from MGGM Therapeutics, LLC, in collaboration with NeuroArbor Therapeutics Inc. Several authors are inventors on patents related to psilocin.

Context and Implications

Psilocybin and other psychedelic compounds are under investigation for potential therapeutic applications in conditions including depression, anxiety, substance use disorders, and certain neurodegenerative diseases.

The studies described above contribute to understanding the mechanisms by which these substances affect brain function and structure. Researchers have noted that the subjective experience during psychedelic sessions, including psychological insight, may be a component of therapeutic effects, though debate continues about whether the hallucinogenic experience is essential for therapeutic benefits or whether neuroplasticity (the brain's ability to rewire and form new connections) is the primary mechanism.