The Gut: The Second Brain
Ninety percent of your serotonin is in your gut. It can't reach your brain.
The enteric nervous system contains up to 600 million neurons, produces over 90% of the body's serotonin, and is wired to the brainstem by a nerve that carries nine times more information upward than downward. But gut serotonin can't cross the blood-brain barrier. This episode traces what the gut actually does to the brain — from millisecond neural signalling to disease climbing from stomach to skull — and asks whether we got the hierarchy backwards.
One story, one sitting.
Mythio is a library of audio documentaries on the ideas, people, and events that shaped the world. Each episode is researched across the best sources, fact-checked, and told in full. Most run twenty to thirty minutes, long enough to go deep, short enough to finish in one sitting.