Take a step into neurobiology. According to recent studies, there is a brain in the belly, literally. The basic research in this area has been conducted by Michael D. Gershon (see his The Second Brain) whose work was summarized in the New York Times by Sandra Blakeslee:

“The gut’s brain, known as the enteric nervous system [ENS], is located in sheaths of tissue lining the esophagus, stomach, small intestine, and colon. Considered a single entity, it is a network of neurons, neurotransmitters, and proteins that zap messages between neurons, support cells like those found in the brain proper and a complex circuitry that enables it to act independently, learn, remember, and, as the saying goes, produce gut feelings.”
︎︎︎from The Enteric Nervous System by Richard Schechner