Interoception: Understanding the sensing of what’s going on inside us

By Carl Zimmer

The New York Times

Last year, Ardem Patapoutian got a tattoo. An artist drew a tangled ribbon on his right arm, the diagram of a protein called Piezo. Patapoutian, a neuroscientist at Scripps Research in La Jolla, discovered Piezo in 2010, and in 2021 he won a Nobel Prize for the work. Three years later, he decided to memorialize the protein in ink.

Piezo, Patapoutian had found, allows nerve endings in the skin to sense pressure, helping to create the sense of touch. “It was surreal to feel the needle as it was etching the Piezo protein that I was using to feel it,” he recalled.

Patapoutian is no longer studying how Piezo informs us about the outside world. Instead, he has turned inward to examine the flow of signals that travel from within the body to the brain. His research is part of a major new effort to map this sixth, internal sense, which is known as interoception.

Scientists are discovering that interoception supplies the brain with a remarkably rich picture of what is happening throughout the body — a picture that is mostly hidden from our consciousness. This inner sense shapes our emotions, our b...