T The brain and spinal cord can control most of the body, but some parts treat themselves well without their input, thank you! The enteric nervous system, which operates independently of the brain and spine, controls the vital movements of the digestive system to move food and feces through all these tubes. Some call it the "brain in the rear," but as scientists write in the journal JNeurosci it's a little more complicated than that.
In the paper, released Monday, a team of researchers sub Led by Nick Spencer, Ph.D., Professor of Medicine and Public Health at Flinders University, new insights into the neurons that control the gut are described. The neurons in isolated mouse digestive systems fire in predictable rhythmic patterns. It is believed that these patterns in turn cause the muscle cells in the intestine to depolarize together, causing the muscles to contract at once, driving food from the stomach to the colon. The reference to these well-controlling neurons as the "brain in the rear" is a fun way of describing this phenomenon, but it simplifies a system that has great evolutionary significance.
While the enteric nervous system, referred to by some scientists as a "second brain", is a highly sophisticated system of neurons, this function is independent of the brain, it is not actual a brain (and it is not really in the butt, although it is butt-adjacent). Indeed, the enteric nervous system appears to have first developed in organisms without a central nervous system, which led the researchers to theorize that it could actually predate the brain as we know it. Prior to this study, scientists had already discovered that the enteric nervous system controls blood flow in the digestive tract, regulates the secretion and absorption of substances in the gut and influences the movement of food.
The new paper complements our understanding of the enteric nervous system by revealing "a novel pattern of rhythmically coordinated neural firing in the ENS that has never been identified," the authors of the study write. In other words, they now know which patterns of neuron activation are consistent with the food constraints of the contracting gut. Using high-resolution neuronal imaging, the team captured the activity of individual neurons as well as groups of neurons, while pellets were pushed through the intestine through the normal process of peristalsis. They observed rhythmic patterns of nerve cells that had never been characterized before.
Because these patterns are consistent with the peristaltic movement of the mouse mucous membranes in the form of smooth muscle cell depolarization, the team completes this rhythmic nerve. Burn patterns must be responsible for the muscle contractions that drive food and waste through the gut.
It is not certain that these results will apply to humans, but the specific systems and mechanisms in this study are divided among different mammals. Although there is no immediate medical application to this understanding, these never-before-seen patterns of enteric nervous system coordination contribute to a broader understanding of a fundamental animal process – and confirm that, although there is no "brain" in the butt, the tubes that lead to the piston are indeed quite intelligent.