" Scientists are cautiously beginning to question the view that the brain is the sole and absolute ruler over the body. The gut not only possesses an unimaginable number of nerves, those nerves are also unimaginably different from those of the rest of the body. The gut commands an entire fleet of signaling substances, nerve-insulation materials, and ways of connecting. There is only one other organ in the body that can compete with the gut for diversity—the brain. The gut’s network of nerves is called the “gut brain” because it is just as large and chemically complex as the gray matter in our heads. Were the gut solely responsible for transporting food and producing the occasional burp, such a sophisticated nervous system would be an odd waste of energy. Nobody would create such a neural network just to enable us to break wind. There must be more to it than that. "

― Giulia Enders , Gut: The Inside Story of Our Body’s Most Underrated Organ