The Abdominal Brain and Enteric Nervous System
David L. McMillin, M.A., Douglas G. Richards, Ph.D.,
Eric A. Mein, M.D., Carl D. Nelson, D.C.
Meridian Institute
{*filter*}ia Beach, VA 23454
[NOTE: This article was published in The Journal of Alternative and
Complementary Medicine, Vol. 5, No. 6, 1999; see below for continuing
education credit for this article.]
Abstract
Conventional medical treatment for neurological disorders such as
epilepsy, migraine, and autism focuses on the brain. Although
standard medical treatment is often helpful, the underlying causes of
these disorders are not well understood. Furthermore, some
individuals respond poorly, or not all to regular medicine. Evidence
is accumulating in the medical literature that the enteric nervous
system (ENS) - that part of the nervous system associated with the
alimentary c{*filter*}- also plays a role in these disorders.
Historically, the concept of an autonomous abdominal nervous system
was advocated by Byron Robinson, Johannis Langley, and Edgar Cayce.
The work of these three prominent historical figures is considered
along with modern viewpoints on the abdominal nervous system.
Complementary therapies that address the nervous system of the abdomen
hold potential as useful adjuncts to conventional treatment for
certain neurological disorders.
Introduction
It is evident both from the historical and modern literature that the
peripheral nervous system, and particularly that portion associated
with the alimentary canal, is a prominent element in certain
neurological disorders associated with the cerebral brain. For
example, abdominal epilepsy and abdominal migraine are well
established diagnostic entities in modern medicine in both children
and {*filter*}s (Babb and Eckman, 1972; Loar, 1979; Mitchell et al., 1983;
Reimann, 1973; Santoro et al., 1990; Symon and Russell, 1986). Some
researchers regard the presence of abdominal features in these
illnesses as important and of possible etiological significance (Amery
and Forget, 1989; Mavromichalis et al., 1995; Peppercorn and Herzog,
1989). Recently, autism has been added to the list of neurological
conditions with abdominal features (Horvath et al., 1998; Murch et
al., 1998; Wakefield et al., 1998;).
A possible explanation of the relationship between abdominal symptoms
and neurological syndromes can be found in the influence that the
enteric nervous system (ENS) has on the CNS. The ENS is an extensive
network of neurons widely dispersed throughout the gut, that
coordinate together to regulate gastrointestinal events such as
peristalsis, {*filter*} flow, secretion, and absorption (Costa and
Brookes, 1994; Goyal and Hirano, 1996; Gershon et al., 1994). The ENS
can influence the CNS both through nerve reflexes and the production
of neuropeptides. It is estimated that 80% of vagal fibers are
visceral afferents (Davenport, 1978). Recent work has also shown a
vast overlap of neuropeptide activity in the gut and the brain (Pert
et al., 1985). The ENS is an active area in physiological research
with over 600 articles on Medline since 1985.
The revival of interest in the ENS has strong historical roots.
Nearly one hundred years ago, American physician Byron Robinson, a
medical doctor, did extensive research and writing culminating in his
impressive work, "The Abdominal and Pelvic Brain" (Robinson, 1907).
The premise of Robinson's book is that the abdominal viscera contain a
vast and complex nervous system, which influences, and to a great
degree regulates, the vegetative process of the abdominal viscera.
Robinson was not alone in his fascination with the nervous system of
the abdomen. At about the same time that Robinson was discovering the
"abdominal brain," British physiologist Johannis Langley of Cambridge
University recognized that "the nervous system of the gut was capable
of integrative functions independent of the central nervous
system" (Gershon et al., 1994, p. 424). It is now known that the
human GI system, deprived of CNS innervation, is capable of
coordinated digestion, mobility, secretion and absorption (Davenport,
1978). Langley labeled the brain in the gut the enteric nervous
system, the term now used for this system.
Edgar Cayce, who has been called the father of modern holistic
medicine (Callan, 1979; Mein, 1989) was another strong advocate for
the abdominal nervous system. Cayce believed that the idiopathic
forms of certain neurological syndromes (such as epilepsy and
migraine) have an abdominal etiology. A wide variety of non-intrusive
therapies were recommended by Cayce for the treatment of these
syndromes.
The remainder of this article will focus on abdominal epilepsy,
abdominal migraine, and autism with colonic features with the aim of
understanding peripheral nervous system involvement in these
disorders. Theoretical and clinical implications of the re-discovery
of the abdominal nervous system will be explored.
Abdominal Epilepsy
The association of abdominal symptoms with epilepsy has been
recognized for many years. For example, "gastric and intestinal
disturbances" were viewed as primary etiological factors by medical
doctors during the late 19th and early twentieth century (Dercum,
1912, p. 917). Osteopaths noted that, ".in cases where the exciting
factor seems to be in the intestine and there is reverse peristalsis
of the intestines, causing a reversion of the nerve current in the
vagi, thorough rapid abdominal treatment will normalize peristalsis
and aid in preventing an impending attack" (Hazzard, 1905, p. 275).
Edgar Cayce insisted that idiopathic epilepsy is produced by lacteal
duct adhesions along the right side of the abdomen that produce nerve
reflexes to the brain. "From every condition that is of true
[idiopathic] epileptic nature there will be found a cold spot or area
between the lacteal duct and the caecum" (Cayce, 1934). The invention
and clinical application of the electroencephalogram (EEG) during the
1920's shifted the focus of medical attention from the abdomen to the
brain where, for the most part, it has remained to this day.
Another example of the abdominal connection in epilepsy is the aura
which is common in certain types of epilepsy. For example, temp{*filter*}
lobe epileptic seizures frequently begin with an aura. In
neurological terms, an aura is actually a mild seizure which precedes
the primary seizure. It can be thought of as a warning that a seizure
is about to happen. Most often, auras manifest as an altered
consciousness or peculiar sensation. "The most common aura is of
vague gastric distress, ascending up into the chest" (Gordon, 1942, p.
610).
Modern medical science has rediscovered the abdominal connection in
epilepsy. A few papers published in the medical journals during the
1960s called attention to the abdominal features in epilepsy
(Berdichevskii, 1965; Takei and Nakajima, 1967; Juillard, 1967).
Over the past twenty-five years, numerous researchers and clinicians
have reported on various aspects of abdominal epilepsy (Agrawal et
al., 1989; Babb and Eckman, 1972; Bondarenko et al., 1986; Douglas and
White, 1971; Hotta and Fujimoto, 1973; Loar, 1979; Matsuo, 1984;
Mitchell et al., 1983; Moore, 1972; O'Donohoe, 1971; Peppercorn et
al., 1978; Peppercorn and Herzog, 1989; Reimann, 1973; Singhi and
Kaur, 1988; Solana de Lope et al., 1994; Yingkun, 1980; Zarling,
1984).
Common clinical features of abdominal epilepsy include abdominal pain,
nausea, bloating, and diarrhea with nervous system manifestations
such as headache, confusion, and syncope (Peppercorn and Herzog,
1989). "Although its abdominal symptoms may be similar to those of
the irritable bowel syndrome, it may be distinguished from the latter
condition by the presence of altered consciousness during some of
the attacks, a tendency toward tiredness after an attack, and
by an abnormal EEG." (Zarling, 1984, p.687). Mitchell et al., (1983)
regard cyclic vomiting as a primary symptom of abdominal epilepsy
manifesting as simple partial seizures. Although abdominal epilepsy
is diagnosed most often in children, the research of Peppercorn and
Herzog (1989) suggests that abdominal epilepsy may be much more common
in {*filter*}s than is generally recognized.
One of the primary problems in understanding abdominal epilepsy is
clearly defining the relationship of the abdominal symptoms to the
seizure activity in the brain. In other words, what is the
pathophysiology of abdominal epilepsy? Is the essential pathology in
certain areas of the brain which happen to be connected to the
abdominal organs? Or, is the primary pathology in the abdomen, which
is conveyed through connecting nerve fibers to the brain, resulting in
epileptic seizures? Peppercorn and Herzog noted both possibilities in
their attempt to understand the cause of abdominal epilepsy:
"The pathophysiology of abdominal epilepsy remains unclear. Temp{*filter*}
lobe seizure activity usually arises in or involves the amygdala. It
is not surprising, therefore, that patients who have seizures
involving the temp{*filter*}lobe have GI symptoms, since discharges arising
in the amygdala can be transmitted to the gut via dense direct
projections to the dorsal motor nucleus of the vagus. In addition,
sympathetic pathways from the amygdala to the GI tract can be
activated via the hypothalamus. On the other hand, it is not clear
that the initial disturbance in abdominal epilepsy arises in the
brain. There are direct sensory pathways from the bowel via the vagus
nerve to the solitary nucleus of the medulla which is heavily
connected to the amygdala. These can be activated during intestinal
contractions" (Peppercorn & Herzog, 1989, p. 1296).
The vagal link in epilepsy has also received attention with regard to
a surgical procedure in which a pacemaker is implanted on the vagus
nerve in the upper chest. Regular stimulation of the vagus has
reduced or eliminated seizure activity in some treatment-resistent
patients (Amar et al.,
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The Abdominal Brain And Enteric Nervous System