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 ...

the internal processes that make and remake the brain—the birth of new neurons and death of old ones, the creation and dissipation of neural connections, and more—persist across the lifespan.

Not all brain cells are found in the brain. For example, a team at Caltech has identified two distinct types of neurons in the abdomens of mice that appear to control different aspects of digestion.