Head & Gut connection: https://www.scientificamerican.com/article/gut-feelings-the-second-brain-in-our-gastrointestinal-systems-excerpt/
Head-heart-gut communication via neural networks: https://owlcation.com/stem/your-second-brain-is-in-your-heart
A little easier read: Cephalic, Cardiac & Enteric Brains: https://www.forbes.com/sites/forbescoachescouncil/2019/03/04/change-leadership-why-your-head-heart-and-gut-are-critical-to-listen-to/#d708ec44a965
Mac's Adventure 