Recent research has shifted from the brain to the gut and studies have found that the microbiome influences the brain through a neural network via vagus nerve. Metabolites made by gut microbes, including psychoactive metabolites, can transit from the gut across the blood-brain barrier and into the brain, where they can potentially impact mood and behavior and regulate immune cells in the brain. Alpha-synuclein, is a protein that scientists believe to be one of the key mediators of the death of dopamine that is associated with Parkinson’s Disease (PD). When this protein is misfolded groups of these proteins travel through the vagal nerve up to the brain.  - This is nerd speak for, abnormal molecules from gut microbes impact the brain’s response to regulate the immune system and dopamine system.