You're probably hearing a lot more about the "human microbiome" these days. It's the collection of bacteria, fungi, and viruses that lives alongside us, inside and out. Some of these organisms are beneficial, and some are harmful. There is growing evidence that bad actors in our digestive tract may produce toxins that travel along the vagus nerve to the brain, where they clump and cause Parkinson's disease. Listen to this PNI Minute to understand this unexpected connection between gut health and the brain.