A team of scientists has found that millions of neurons located in the colon perform similarly to how the brain in the head naturally functions.
What's more interesting, though, is that this assembly of neurons can control the intestinal muscle independently from the main brain. It can push down fecal matters by itself without any consultation from the central nervous system contrary to how other bodily systems naturally work.
Enteric Nervous System
Most fascinating of all is that these millions of neurons in the gut, which scientists refer to as the "second brain," may actually have evolved and became functional ahead of the ancient people's actual brain.
This second brain is called the "enteric nervous system" and a team from Australia has, for the first time, observed how it carries out its task during the bowel movement.
Neuronal Firing Of The 'Second Brain' In The Gut
The existence of the second brain has long been known within the scientific community. However, the explanation of how it exactly functions has remained vague until this recent study by scientists from South Australia.
Nick Spencer, a professor from the Visceral Neurophysiology Laboratory at the College of Medicine and Public Health at Flinders University, and his team examined the colons of euthanized mice.
The team employed an imaging technique programmed with electrophysiological records of smooth muscle. The method specifically detects the rhythmic pattern that is taking place inside the colons of the mice.
The researchers stimulated the colons to perform its activities by applying mild electric shocks. When the colon was triggered, the team was then able to observe how the neuronal matrix inside the colon pushed fecal matters down to the large intestine.
"Millions of neurons in the gastrointestinal tract coordinate their activity to generate the muscle contractions that propel waste through the last leg of the digestive system," the team explained.
They called this activity the "neuronal firing." The neuronal firing stimulates portions of intestinal muscles to ensure that the colonic muscles contract and drive feces properly out of the body at a steady pace.
The 'Second Brain' Might As Well Be The 'First Brain'
The team concluded that the neuronal firing being performed by the enteric nervous system may actually be an ancient bodily function selected or preserved when the nervous systems underwent the evolution process. This would mean that neuronal firing from the colon has been the first ever functioning brain in the body.
"It has also been called the "first brain" based on evidence suggesting that the [enteric nervous system] evolved before the [central nervous system]," the team wrote in the study published in JNeurosci.
The Future With The 'Second Brain'
The study performed by Spencer and his team became the first instance that neuronal firing was observed in the enteric nervous system. Now that experts know how the enteric nervous system performs in a healthy body, they can now develop treatments that can address colon diseases.
Previous studies have already established that enteric nervous system produces almost 95 percent of the body's serotonin and 50 percent of the body's dopamine. In fact, a 2010 study found that osteoporosis is linked to the serotonin produced by the gut. Another study, meanwhile, found a link between traumatic brain injury and intestinal damage.