Unique neuronal firing patterns in our "second brain" observed for the first time
Using a newly developed imaging technique, a team of researchers in Australia has directly observed a unique neural motor firing pattern outside of the brain or central nervous system. The pattern of neuronal firing, in the intestine, showed exactly how our enteric nervous system coordinates contractions in our gastrointestinal tract.
The enteric nervous system (ENS) is a massive mesh of neurons located in our gastrointestinal tract. It's the largest collection of neurons found in the body outside of the brain, and because of its ability to operate entirely independently it has often been referred to as our "second brain."
It is only recently that science has begun to seriously look at how this so-called second brain actually functions. While we have countless studies correlating neuronal firing in the brain with assorted physical actions, there has been little examination into how neuronal firing in the ENS results in intestinal muscle activity.
The new research outlines the development of a new, high resolution neuronal imaging method designed to expressly examine neuronal firing in the ENS. Using mice models, the researchers were able to watch the rhythmic firing of neurons and see the subsequent contractions in intestinal muscles. This is the first time this kind of repetitive rhythmic neuronal firing pattern has been directly observed in the ENS and the researchers suggest it could be an ancient neuronal pattern that evolved in humans a long time ago.
For years, our second brain has been largely disregarded as simply something that manages the messy complexities of our digestive system, but a growing body of research is beginning to indicate it may have much more broader and holistic effects.
A new field of science, neurogastroenterology, has arisen to study this complicated mass of neurons. Exactly what wider effects this second brain has on our broader well being is yet to be understood, but the ENS does produce, and utilize, a large volume of neurotransmitters, including around 95 percent of the body's serotonin and 50 percent of the body's dopamine.
One study from 2010 found that serotonin released by the gut may be the fundamental cause of the bone-destroying disease osteoporosis. Tests with a drug that inhibits that specific gut-driven release of serotonin in rodents was seen to virtually cure the animals of the disease.
Other more recent work revealed strange connections between traumatic brain injury and intestinal damage. The study suggested a two-way relationship between the brain and gut, with damage in one seemingly being reflected by changes in the other.
This new work examining ENS neuronal firing is a valuable addition to a fascinating growing body of research helping us further understand the workings of this second brain. Maybe that good old "gut feeling" is a consequence of more neuronal activity than we ever previously suspected?
The research was published in the journal JNeurosci.