Scientists Separate Psilocybin's Brain Rewiring From Hallucinations

UC Santa Cruz researchers found in mice that psilocybin's growth of new dendritic spines and its hallucinogenic effect run through distinct cellular pathways. Serotonin 2A receptor signaling in Layer 5 pyramidal neurons was necessary and sufficient for structural changes but not for the head-twitch response. The study appeared in Nature Neuroscience.

• New dendritic spines surged within 24 hours of psilocybin in mice
• Stressed mice showed a larger spine increase than healthy controls
• Restoring 5-HT2A receptors in Layer 5 neurons grew synapses without head-twitch
• Deleting those receptors blocked synapse growth but kept the hallucinogenic response