 A new study shows how a psychedelic drug can alter the connections in a person's brain. NPR's John Hamilton reports on a new study in the journal Nature. Researchers at Washington University in St. Louis scanned the brains of seven people who took either a stimulant or psilocybin, the active substance in magic mushrooms. Dr. Joshua Siegel says the drug caused dramatic changes in networks of brain cells that usually fire at the same time. What's going on during psilocybin is that