The Gut: Our Second Brain (2014)

Original title: Le ventre, notre deuxième cerveau

For years, scientists have known about the existence of another brain within our bodies. Our stomach functions totally independently and does far more than just digestion. It reigns over a spectacular colony of one hundred thousand billion bacteria that have a strong impact on our personalities. Some diseases of the brain, like Parkinson’s, may stem from the degeneration of intestinal neurons.