This episode is an exploration of glial cells with R Douglas Fields, author of "The Other Brain: The Scientific and Medical Breakthroughs That Will Heal Our Brains and Revolutionize Our Health." Glial Cells outnumber the neurons in our nervous system, but until the last few years they were thought to merely support cells. Dr. Fields takes us through the discovery that they have their own signaling methods and are much more important than we ever imagined.