This Radiolab podcast delves into the fascinating idea of critical periods in the brain—specific times when learning happens most effectively. Neuroscientist Gül Dölen's research shows that psychedelics like MDMA, LSD, psilocybin, and ketamine can reopen these critical periods in adult mice, enabling them to learn anew, especially in social situations. This finding opens up exciting possibilities for treating brain injuries and mental health issues by tapping into the brain's ability to reorganize itself. It emphasizes the need for context and therapeutic support when using psychedelics. Interestingly, the length of the psychedelic experience seems to influence how long these critical periods stay open, hinting at a unique window for therapeutic opportunities and vulnerabilities.