Psychedelic drugs reopen critical periods for social learning in mice, with each drug extending the open window from two days to four weeks

Psychedelic drugs reopen critical periods for social reward learning in mice, suggesting a shared mechanism for restoring brain plasticity. Researchers at Johns Hopkins Medicine report that after a single dose, the critical period stays open for different durations depending on the psychedelic: ketamine for about 48 hours, psilocybin for about two weeks, and MDMA, LSD, and ibogaine for roughly two, three, and four weeks respectively. The timing in mice appears to track the typical length of each drug's acute effects reported in people. The study also connects the effect to molecular changes in the brain. In particular, LSD and psilocybin appear to use serotonin receptor binding to open the critical period, while MDMA, ibogaine, and ketamine rely on other molecular routes. Gene expression shifts across dozens of genes during and after the critical period was opened, including changes tied to the extracellular matrix in brain regions involved in social learning, pointing to potential therapeutic value beyond current studies (for example, toward conditions like stroke or deafness).