Our gut's enteric nervous system (ENS), functions in a similar way to other neural networks in the brain, the spinal cord and so it is often called the second brain'. A new study now reveals more about the ENS's workings.Scientists were able to examine the colons of mice using a newly developed technique that combines high-resolution video recordings and an analysis of biological electric activity. This allowed them to see how the gut moves.One of the most important discoveries was how thousands of neurons in the ENS communicate with one another, causing contractions of the gastrointestinal tract to aid digestion. It was not clear until now how these neurons could collaborate to accomplish this.According to Nick Spencer, a neurophysiologist at Flinders University in Australia, "Interestingly the same neural circuit was activated when both propulsive or non-propulsive contracts."The team discovered large numbers of connecting neurons that were firing to propel colon contents further down the gut via both excitatory motor neurons (causing action), and inhibitory motor neurons (blocking action).This discovery indicates that the ENS is composed of a larger network of circuitry. It covers a wider area of the gut and includes a greater number of different types of neurons.This is another important discovery. It is different from propulsion seen in other muscle organs that do not have a built-in nervous systems, such as the portal vein or lymphatic vessels.The researchers write that the mechanism they have identified is much more complicated than anticipated and very different from fluid propulsion along with other hollow smooth muscles organs.According to the team, it supports the hypothesis that ENS is actually the 'first brain' and not the second. This suggests that it could have evolved in animals long before our brains did.This is a possibility that the effects of the ENS activities on the functioning of the gastrointestinal tract of different species could be significant. However, further research will be needed to confirm this.Spencer says that synchronization of neuronal activity over large numbers of neurons is common in many vertebrate species' nervous systems.Communications Biology published the research.
