Gut-Brain Axis

The Gut-Brain Highway: How the Vagus Nerve Carries Microbial Signals That Shape Your Mood, Memory, and Motivation Without Your Awareness

Ninety percent of vagal nerve fibres run from the gut to the brain — not the other direction — meaning the enteric nervous system sends far more information upward than the brain sends down, making your gut the primary data source for emotional and cognitive states you experience as originating in your head.