4 from ritual to theater and back: the efficacy ... - AAAARG.ORG

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rasaesthetics
conducted by Michael D. Gershon (see his The Second Brain 1998) whose
work was summarized in the New York Times by Sandra Blakeslee:
The gut’s brain, known as the enteric nervous system [ENS], is located
in sheaths of tissue lining the esophagus, stomach, small intestine,
and colon. Considered a single entity, it is a network of neurons,
neurotransmitters, and proteins that zap messages between neurons,
support cells like those found in the brain proper and a complex circuitry
that enables it to act independently, learn, remember, and, as
the saying goes, produce gut feelings.
(Blakeslee 1996: CI)
The ENS derives from the “neural crest,” a bunch of related cells that
forms in mammals and birds early in embryo genesis: “One section
turns into the central nervous system. Another piece migrates to
become the enteric nervous system. Only later are the two nervous
systems connected via a cable called the vagus nerve” (Blakeslee
1996: C3). According to Gershon:
The ENS resembles the brain and differs both physiologically and
structurally from any other region of the PNS [peripheral nervous system].
5 . . . Both the avian and mammalian bowel are colonized by
émigrés from the sacral as well as the vigil level of the neural crest.
. . . The PNS contains more neurons than the spinal cord and, in
contrast to other regions of the PNS, the ENS is capable of mediating
reflex activity in the absence of central neural input. In fact, most of the
neurons of the ENS are not directly innervated by a preganglionic
input from the brain or spinal cord. The functional independence of
the ENS is mirrored in its chemistry and structure.
(Gershon et al 1993: 199)
And again, as summarized by Blakeslee:
Until relatively recently, people thought that the gut’s muscles and
sensory nerves were wired directly to the brain and that the brain
controlled the gut through two pathways that increased or decreased
rates of activity [. . .]. The gut was simply a tube with simple reflexes.
Trouble is, no one bothered to count the nerve fibers in the gut. When