Not many people are aware they have two brains. I personally didn’t know about my second brain until recently. Shame really! Unfortunately, it seems I am not the only uneducated one in this regard. Many people know about the brain in the human skull and its reasoning and intelligence capacity; and the fact that this cerebral brain has two lobes. But not many people know about their second brain. What is this second brain? And to pre-empt the answer, how can your gut feelings affect your decision making process? How do you get ‘butterflies’ in your stomach when you’re emotionally charged?
It’s a scholarly task to try and determine who first touted the idea of a brain in the gut. However, it is known that Dr. Byron Robinson, M.D., a well respected physician and researcher in the 20th century, published an outstanding article in 1907 on the abdomen containing a secondary brain. According to him, ‘In mammals there exist two brains of almost equal importance to the individual and race. One is the cranial brain, the instrument of volitions, of mental progress and physical protection. The other is the abdominal brain, the instrument of vascular and visceral function. It is the automatic, vegetative, the subconscious brain of physical existence. In the cranial brain resides the consciousness of right and wrong. Here is the seat of all progress, mental and moral. However, in the abdomen there exists a brain of wonderful power maintaining eternal, restless vigilance over its viscera. It presides over organic life. It dominates the rhythmical function of viscera. The abdominal brain is a receiver, a reorganizer, an emitter of nerve forces. It has the power of a brain. It is a reflex center in health and disease. The abdominal brain is not a mere agent of the [cerebral] brain and cord; it receives and generates nerve forces itself; it presides over nutrition. It is the center of life itself. In it are repeated all the physiologic and pathologic manifestations of visceral function (rhythm, absorption, secretion, and nutrition). The abdominal brain can live without the cranial brain, which is demonstrated by living children being born without cerebrospinal axis. On the contrary the cranial brain can not live without the abdominal brain.’ (Byron Robinson, 1907, 123 - 126).
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 ganglia of the gut do more than simply relay and distribute information from the cephalic [cerebral] brain. Langley was unable to reconcile conceptually the great disparity between the 2 X 10 (8) neurons in the gut and the few hundred vagus fibers from the big brain, other than to suggest that the nervous system of the gut was capable of integrative functions independent of the central nervous system. He labeled the brain in the gut the enteric nervous system (ENS).
According to Dr. Wood who published his paper in 1994, ‘for several decades Robinson and Langley's work has been ignored. However, modern medical research has finally rediscovered the abdominal brain with its enteric nervous system and now in fact, research on the nerve connections in the abdomen is one of the hot areas of medical research.’ To a considerable extent, the new interest in exploring the ENS has come from the realization that both the ENS and the remainder of the autonomic nervous system are richly endowed with neurotransmitters and neuromodulators. Many substances are found in both the bowel and the brain, a coincidence that strikes most observers as intrinsically interesting, if not immediately explicable. (Gershon, Kirchgessner & Wade, 1994, p. 386).
According to some researchers, the similarity between the structure of the ENS and that of the brain, combined with the ability of the ENS to mediate relatively simple behaviors, suggests that general principles can be derived from studies of the ENS that will eventually be applicable to the CNS. 'Given the unique position of the ENS as the only peripheral system capable of autonomous function, it seems more likely that such principles will emerge from investigations of the ENS than from studies of other aggregates of peripheral ganglia. The parallel between the bowel and the brain also suggests that newly discovered principles of central neural function may find applicability in studies of the ENS, in a sort of reverse form of reductionism whereby the brain serves as a model for the gut.' (Gershon, Kirchgessner & Wade, 1994, p. 414).
In addition to the biochemical and structural similarities between the cerebral brain and the abdominal brain, contemporary researchers are drawing computer analogies and using information processing models to describe the relationship between these two brains of the body. This work suggests that, ‘The cephalic [cerebral] brain communicates with the smaller brain in the gut in a manner analogous to that of interactive communication between networked computers. Primary sensory afferents and extensions of intramural neurons in the gut carry information to the central nervous system. Information is transmitted from the brain to the enteric nervous system over sympathetic and parasympathetic pathways. This, however, represents only one kind of input of an integrative network that also contains microcircuitry for processing information from a variety of sensory receptors along the digestive tract, as well as synaptic circuits that generate programmed patterns of neural outflow to the effector systems. Input to enteric ganglion cells is not exclusively from the central nervous system as once thought, and the old habit of referring to the neurons of the enteric nervous system as postganglionic neurons has become outmoded and abandoned.'
The current concept of the enteric nervous system is that of a minibrain placed in close proximity to the effector systems it controls. Rather than crowding the hundred million neurons required for control of the gut into the cranial cavity as part of the cephalic brain, and transmitting signals over long-unreliable pathways, natural selection placed the integrative microcircuits at the site of the effectors. The circuits at the effector sites have evolved as an organized network of different kinds of neurons interconnected by chemical synapses. (Wood, 1994, p. 424)
Some other medical doctors in their research, Peppercorn and Herzog, allow for the possibility that abdominal epilepsy may be caused by abdominal processes transferred to the brain via the vagus (tenth cranial nerve). Abdominal epilepsy is a form of epilepsy that seems to be not well understood at the moment. The question is, what is it about the abdomen that could possibly produce such an extreme neurological reaction as to cause a seizure in the brain?
To extend Wood's computer analogy of the enteric nervous system to abdominal epilepsy, one might say that the nervous system network "crashes" during a seizure. The linkage between the abdominal brain and cerebral brain is broken. Depending upon the severity of the incoordination, much of the information processing and regulatory functioning of the entire nervous system may temporarily go "offline."
I am no medical doctor, which is why I have opted to quote copiously from medical journals in my write up. If the Medics say we have two brains in our body – the cerebral brain and a second brain in the gut, who am I to disprove them? How well is your second brain functioning? Personally, I am still trying to understand the importance of thinking of the gut as a second brain. But now, hearing of how people have been led astray by their stomach have taken on a new meaning!
Get in touch with us today if you would like further advice on this article or require tips on maintaining a healthy gut.
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