Research Advances in Psychedelic Compounds and Brain Activity

New scientific studies are exploring both the development of psychedelic derivatives with reduced hallucinogenic effects and the fundamental ways these compounds alter brain function. One research effort has identified a modified psilocybin compound that demonstrated therapeutic potential with fewer psychedelic-like responses in mice. Concurrently, other studies have mapped how psychedelics shift brain perception from external input to internal memory in mice and identified a common neural signature across multiple psychedelic drugs in human brains, characterized by altered connectivity between brain networks.

Development of Psilocybin Derivatives with Reduced Hallucinogenic Effects

Scientists are investigating psilocybin, a compound found in certain mushrooms, for its potential therapeutic applications in conditions such as depression, anxiety, and substance use disorders. However, its associated hallucinogenic effects may limit its widespread medical use.

Recent research, published in ACS' Journal of Medicinal Chemistry, describes the creation of modified forms of psilocin, the active compound that psilocybin converts into within the body. An early study in mice indicated that these new molecules maintained biological activity while triggering fewer psychedelic-like effects compared to pharmaceutical-grade psilocybin.

Andrea Mattarei, a corresponding author of the study, noted that the findings suggest a potential dissociation between psychedelic effects and serotonergic activity, which could allow for the design of therapeutics that retain beneficial biological activity while reducing hallucinogenic responses.

The research team, including Sara De Martin, Mattarei, and Paolo Manfredi, developed five chemical variants of psilocin. These compounds were engineered to allow for a slower and steadier release of the active molecule into the brain.

Compound 4e emerged as a promising candidate. In laboratory tests, it demonstrated strong stability during absorption, a gradual release of psilocin, and activation of key serotonin receptors at levels comparable to psilocin. When administered orally to mice, 4e efficiently crossed the blood-brain barrier, producing a lower but longer-lasting level of psilocin in the brain than pharmaceutical-grade psilocybin.

Behavioral observations indicated that mice treated with 4e showed significantly fewer head twitches, an indicator of psychedelic-like activity in rodents, despite its strong interaction with serotonin receptors. Researchers attribute this difference to the quantity and rate of psilocin release in the brain.

The authors acknowledged funding from MGGM Therapeutics, LLC, in collaboration with NeuroArbor Therapeutics Inc. Several authors are inventors on patents related to psilocin. Further research is required to fully understand these molecules and their biological impact before evaluating their safety and therapeutic potential in humans.

Psychedelics' Impact on Brain Activity

Concurrently, other studies have focused on understanding how psychedelics affect brain perception and connectivity.

A study conducted on mice suggests that psychedelics increase the brain's tendency to perceive images from memory over external visual input. This research utilized mice genetically engineered for their brain cells to glow when active, allowing researchers to record voltage changes across the brain's surface.

During experiments, mice were exposed to visual stimuli and blank screens. After receiving an injection of a chemical that selectively activates the 5-HT2A serotonin receptor—similar to the action of LSD and psilocybin—researchers observed a shift in brain communication. Prior to the drug, the visual cortex exhibited 5-Hz brain oscillations.

Following psychedelic administration, theta rhythm oscillations, which are linked to attention, memory consolidation, and stimulus familiarity, significantly intensified in power and duration. These low-frequency waves in the visual processing areas synchronized with the retrosplenial cortex, a region involved in encoding, storing, and retrieving memories, with an approximate 18-millisecond delay.

The administered psychedelic appeared to dampen the brain's response to external visual input from the eyes while enhancing connections with memory areas. This mechanism suggests the brain generates visual information from its internal memory stores, rather than relying solely on external input, offering an explanation for visual hallucinations.

The lead researcher, Dirk Jancke, compared this state to a partial dream where internal imagery overrides external reality. Limitations of the study include the possibility of mice being distracted by repetitive images, and the uncertainty of whether these findings can be directly mapped to human hallucinogenic experiences.

A major study, published in Nature Medicine, identified a common neural signature produced by several psychedelic drugs in the human brain. This research combined 11 brain imaging datasets from around the world, analyzing over 500 brain scans from 267 individuals across five countries. It represents the largest study of its kind on psychedelics and the human brain to date.

The study observed this 'neural fingerprint' across individuals who had used LSD, psilocybin, DMT, mescaline, and ayahuasca. Dr. Danilo Bzdok, a senior author from McGill University, stated that these drugs demonstrate common effects on brain function.

Key findings include:

• Weakened Internal Connections: Connections within individual brain systems showed weakening, leading to less rigid network structures.
• Increased Inter-network Communication: Psychedelics enhanced communication between different brain networks, allowing signals to cross typically separate boundaries. This "crosstalk" was observed between higher-level cognitive brain networks and more primitive networks associated with vision and sensation, as well as in deeper subcortical regions involved in habits, learning, movement, perception, motivation, and reward.

The study's findings contrast with some previous theories suggesting that psychedelics cause individual brain networks to disintegrate. Dr. Emmanuel Stamatakis of the University of Cambridge, a senior co-author, emphasized the need for large-scale, coordinated evidence for responsible development in psychedelic research.

Broader Context and Future Directions

Both lines of research contribute to the understanding of psychedelics and their potential therapeutic applications. The development of psilocybin derivatives aims to create compounds that could provide mental health benefits without the intense hallucinogenic experiences that may deter patients.

Simultaneously, insights into how psychedelics alter brain activity and perception can inform the design of new pharmacological treatments. The identification of a common neural signature across multiple psychedelics may also provide a benchmark for future studies and influence the easing of regulations on psychedelic research, potentially aiding their exploration as widespread mental health therapies for conditions like depression, anxiety, schizophrenia, and post-traumatic stress disorder.