Half of the cells in the brain are neurons, the other half are glial cells.When scientists first discovered glia over a century ago, they thought that they simply held the neurons together. Their name derives from a Greek word that means glue.In the past decade, researchers have come to understand that glial cells do so much more: They communicate with neurons and work closely with the immune system and might be critical in how we experience pain. They even play an important role in regulating the digestive tract.Ira is joined by Yasemin Saplakoglu, a staff writer at Quanta Magazine who has reported on these lesser-known cells.Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.