A gutsy move: New study challenges conventional wisdom about nerve cell origins of ‘the second brain’

“Following your gut;” “losing your appetite;” “a gutsy move.” We may think of the gut as a simple digestive organ, but these familiar phrases reflect the central role the gut plays in a much wider range of essential functions. The entire digestive tract is lined by the enteric nervous system (ENS), a vast network of millions of neurons and glial cells—the two primary cell types also found in the central nervous system. While often called the second brain, the ENS produces the same neurotransmitters and originated much before the central nervous system in the brain evolved.