As we grow up, there are certain periods when we can learn very quickly and deeply, known as critical periods. These windows of learning eventually close, locking us into certain behaviors and skills for life. However, recent discoveries suggest that we might be able to reopen these windows. This episode of Radiolab explores these findings and their implications for conditions like PTSD, brain disease, and strokes. The discussion also touches on cuddle puddles and their connection to the feel-good brain chemical oxytocin.