June 14, 2005
By Mark Mills
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)
"[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?'
