That sensory input gets relayed to the hypothalamus, which stimulates the medulla oblongata, which then taps the parasympathetic fibers in the vagus nerve.
The researchers suspected that such effects were controlled by signals from the gut that are being transmitted by the vagus nerve, which connects gut and brain.
The vagus nerve is one of the largest nerve centers in your body, and handles lots of basics, like digestion, breathing, heart rate and blood pressure.
First, the vagus nerve, which runs through the body into the brain, quickly transmits the information to the brain stem, passing near an important area of pain processing.
The brain uses the vagus nerve to connect and communicate with many parts of the body, including the vocal cords, heart, lungs and most of the digestive tract.