Psilocybin, the active compound in magic mushrooms, had several clear and repeatable immediate effects on mouse behavior, including increased anxiety and avoidance and reduced fear expression. However, its effects one day later were not consistent across five different laboratories, and no reliable changes were seen in depression-like behavior, fear extinction learning, social preference, or social reward learning. Using about 200 mice per experiment across five independent labs, the findings show that psilocybin's lasting behavioral effects in mice are more modest and less reliable than previously claimed. This coordinated multi-lab approach highlights the importance of replication for producing trustworthy results.
A single dose of psychedelics causes lasting changes in alternative splicing in the mouse medial prefrontal cortex, particularly in parvalbumin interneurons, that persist for at least a month. While gene expression is only modestly altered, splicing patterns shift dramatically in a cell type-specific manner. These changes are linked to modifications in the extracellular matrix, synaptic physiology, and intrinsic physiology days to a week after treatment. The findings provide a resource for understanding the molecular and cellular basis of psychedelic-induced plasticity.