The Second Brain by Michael Gershon is a fascinating book. I came across it in an advertisement for Science News Books in Science News Magazine. Part of the reason I read it was the blurb mentioned Irritable Bowl Syndrome and, at the risk of providing too much information, I was suffering mightily from it at the time. The book is part memoir, part textbook, part science mystery, and all good.
The structure of the book is provided by the argument (I’m sure in scientific circles they have another word for it) over whether there is an independent central nervous system (AKA “brain”) in the gut or the neurons in the gut are part of the peripheral nervous system. Consequently, you are treated to a description of the people (memoir) and evidence (textbook). The book provides a great primer of both the human nervous system and digestive system, their structures, functions, and taxonomy. It also provides a good firsthand account of the personalities and mechanics of scientific inquiry.
The book ultimately concludes that indeed, a second brain is responsible for digestion, and is responsible for the control of internal organs extending from your mouth to your anus, with other organs such as your pancreas along the way. The characteristics include the use of the same neurotransmitters as brain number one, and crosslinking of neurons.
The book explains how digestion is carried out when it works properly, and many of the ways it can go wrong. It’s a fascinating book that despite its heavy dose of science is an engrossing and engaging read.