A single dose of the psychedelic compound psilocybin may suffice to alter the connections within specific brain networks.

Psychedelic substances like psilocybin, sourced from various magical mushrooms, impact individuals’ perceptions of time, space, and self. Furthermore, they exhibit potential in addressing mental health issues such as depression and anxiety, largely due to their capability to enhance brain plasticity—though the mechanisms remain unclear.

Currently, Alex Kwan, from Cornell University in Ithaca, NY, and his team conducted experiments where mice received injections of either psilocybin or saline. The following day, they injected a genetically modified rabies virus, known for crossing synaptic gaps and indicating neuron connections.

Scans and dissections helped visualize the virus’s effects throughout the brain, revealing new neuronal connections. This research demonstrated that mice treated with psilocybin fortified the links between the brain’s resfluniur cortex—which integrates imagination, memory, and sensory data—and areas of the prefrontal cortex tied to planning and social behavior, in comparison to those receiving saline solutions.

Moreover, psilocybin seems to reduce connections involved in the cortical recurrent loops, which, while valuable for holding onto important memories, can, in some mental health conditions, perpetuate negative thoughts and behaviors. It is theorized that disrupting these loops is vital in addressing various mental health conditions.

“I believe this is the next phase we need to clarify,” stated Michael Wheeler from Brigham and Women’s Hospital in Boston. “Understanding these circuits that connect associative regions could be pivotal to unlocking mechanisms.”

“The modifications brought about by psilocybin treatment play a significant role in its effects on mood disorders,” said Eero Castén from the University of Helsinki, Finland. He added, however, that psilocybin merely offers a chance for remodeling; the actual circuits that strengthen or weaken may depend on the animal’s actions.

This line of research suggests that in the future, one might be able to select which brain connections to alter based on the mental health condition being treated. “Our findings present an exciting pathway for future work that combines neuroregulation with psychedelics to precisely target specific neuroplastic circuits,” the researchers noted in their publication.

Psilocybin use illustrates the “set and setting” phenomenon linked with psychedelic substances, exploring how various activities and environments influence brain alterations. The user’s mindset and surroundings can significantly impact drug effectiveness, resulting in “good” or “bad” trips.

Although this study was conducted on mice, it remains uncertain if the same connectivity changes occur in humans after consuming psilocybin. Nevertheless, Wheeler suggests the mechanisms might be comparable. This mouse study parallels findings in human brain scan research from 2024, which indicates that psilocybin may enhance connectivity in specific brain areas.