The Second Brain: A Groundbreaking New Understanding of Nervous Disorders of the Stomach and Intestine [Englisch] [Taschenbuch]

Gershon's book is really two books in one: a memoir or exposition of all that is involved in medical research (including the politics), and a detailed explanation of the neuroscience and neurochemistry of the enteric nervous system (e.g., digestive tract). This is not a simple book to read -- it takes concentration, and I certainly had my highlighter out to draw attention to several terms or ideas I wanted to recall. The narrative can get fairly scientific, but to add to your understanding the author uses commonplace allegories or diagrams -- and just when it starts to get too "heavy", he gives you a break by turning autobiographical, telling stories about his research community that are very interesting. This isn't a textbook, but rather a lengthy exposition on a man's search for scientific truth. I am a scientist myself and often wonder what draws an individual to a focused "obsession" with a single idea, and Gershon in his pursuit of knowledge through experimentation and conceptualization gave me insights into one type of scientific mind. The digestive system, via Gershon's work, is the source of neurotransmitters, so there is a substantial amount of information here for anyone interested in neurology, neuroscience, psychiatry, and of course the behavior of the digestive tract. This is not a book for anyone who has a digestive problem who wants a cure -- it is a book for understanding digestion and/or the nervous system. However, if you are interested in deep science, this is one of the best written and thorough books I've read.

This has been a challenging book to read, but well worth the effort. It is a peculiar mix of memoir and introductory textbook on the enteric (gut) system. I found myself woefully unprepared to consume the text. Gershon has tried to write for the lay reader, but that lay reader had better be comfortable with organic chemistry. Despite the jargon, Gershon's enthusiasm is infectious. This would be a great gift for any pre-med student in need of inspiration.

The title is somewhat misleading. 'The second brain' is a catchy phrase, but only token effort is made to prove the assertion. In simple terms, Gershon argues:
1. At the cellular level, enteric neurology uses the same building blocks as spinal neurology, so there is no evidence enteric neurology couldn't be a second brain.
2. The fundamental process managed by enteric neurology is the peristaltic reflex.
3. The peristaltic reflex requires sophisticated neurological controls for managing
a) motion of food through the gut
b) control of pH, viscosity, appropriate digestive enzyme, etc.
4. Since the gut can function adequately despite cutting the neural connection between spine (brain) and gut, the neural mass in the gut must constitute an independent cognitive center (brain).

The first 100 pages address Gershon's efforts to prove enteric neurology uses the same neurotransmitters as the spinal chord. The second 100 pages offers a tour of the gut, starting at the mouth and walking down the lining to the colon. The final section provides a blow-by-blow description of his lab's trial-and-error experimental approach to enteric developmental neurology, with emphasis on microbiological techniques for examining the neural crest's role. There is little or no text defining the systemic nature of a 'brain', and then asking if the enteric neural system qualifies for the title 2nd brain. In short, Gershon avoids the quagmire of differentiating peristaltic reflex from peristaltic cognition.

Since one cannot address this question without assimilating most of the material Gershon presents (perhaps without the historonics), and the book is so much fun as it is, who am I to complain?

Important subtopics:
The academic battles Gershon fought to make enteric neurology an accepted academic field of study.
How 17th century European poisons help illuminate enteric neurology.
How cholera is perfectly designed to fool enteric defenses (including enteric neural signals).
A detailed review of developmental issues producing aganglionic megacolon (Hirschsprung's Disease)

Scattered about are surprising literary references:

"[the bowel's lining is] very much like the fields of Agincourt after Henry V finished dealing with the French army, a turf littered with the rotting remains of dead soldiers. The soldiers in the bowel, of course, are fallen enteric nerve cells..."

"Functional bowel disease is what Winston Churchill called the Soviet 'Union in 1939: a riddle wrapped in a mystery inside an enigma."

Gershon concludes with a wonderful, and very personal, answer to his recently deceased father's often asked question: 'what practical benefits does your research offer?'

Michael Gershon is a gifted writer and equally gifted scientist. He takes the world of the gut and explains its workings in great detail eliminating historical misunderstandings and common misperceptions along the way.

I thought his development of the history of the branches of the nervous system was fascinating and demonstrated some of the politics and the effects of unexamined assumptions on how scientific discoveries are interpreted.

There is an extensive section on the use of various toxins to discover how the nervous system was organized and this section is developed very logically and includes a lot of interesting scientific history. Sometimes, it included more than I wanted to know, but I must say he was very comprehensive.

This book is also well organized in thorough in every respect. The tour of the GI is well done and includes all the important things one would want to know.

I have a very good background in biology and for me this book was a pleasant read. However, it is not always an easy read and it certainly doesn't read like a dime store novel. It is a book that is intellectually challenging, but fascinating and relatively easy to read considering the scope and depth of the topic.

This is not a quick fix manual for people with gastrointestinal ailments. It is more about how the gut is built and how it works. It would be useful book for someone with gastrointestinal ailments for understanding this part of the body, but the emphasis is not on disease mechanisms and treatments. If that is the only thing you are looking for, then this book may not be for you.

I think we all admit tacitly at some level that the gut has some sort of special relation to the rest of the body in terms of sophisticated neurological processing. I think this is revealed by common sayings such as "I have butterflies in my stomach" or "I had a gut feeling something was wrong." Gershon presents a plausible explanation for the sophistication of the GI tract that sheds some light on why these expressions may have entered our lexicon.

If you are interested in the mind-body connection, this is also a useful book. It reopens many questions about the gut and how it interacts or works independently of the brain. It is great food for thought that reopens a lot of questions about how the body is organized and the relationship of the brain to the internal workings of the body. I'm not saying it's revolutionary, but it certainly challenges the current paradigm in some significant ways.

Some interesting facts that Gershon bring up is that the vast majority of serotonin is made in the gut, not the brain. He also points out that if the vagus nerve is cut, the bowel can still go on functioning without input from the brain. He also talks about the density of neurons in the gut and how no other area of the body except the brain can match it. These facts have interesting implications and lead one to formulate some interesting questions for reflection.