Media release

From: Flinders University

New research led by Flinders University explains the complexities of the enteric nervous system (ENS) in the gastrointestinal tract, showcasing how it behaves similar to other neural networks in the brain and spinal cord. The study again confirms the ENS as the 'first brain' in the evolutionary process.

In a new paper in Communications Biology (Nature), lead researcher Flinders University Professor Nick Spencer says the latest findings are "far more complex than we expected and considerably different from the mechanisms that underlie the propulsion of fluid along other hollow smooth muscle organs that have evolved without an intrinsic nervous system; like in lymphatic vessels, ureters or the portal vein".

"Synchronisation of neuronal activity across large populations of neurons is common in the nervous system of many vertebrate animals," Professor Spencer says.

“The study suggests that the ENS in the gut is the 'first brain' and evolved long before the brain as we know it, in humans."

The research team were able to show how  thousands of neurons in the ENS communicate with each other to cause the muscle layers to contract and propel content. Until now, this system was not clearly understood.

The researchers took advantage of a recent technical advance developed at their Flinders University laboratory which enables them to record the smooth muscle electrical activity along the length of the colon at the same time as correlating electrical activities with dynamic changes in colonic wall diameter, during propulsion.

This new technique helps to finally explain how all the different types of neurons in the ENS come together and coordinate the 'firing' to generate propulsion of content along the colon - which is a very long, and complex organ of the body.

"Interestingly the same neural circuit was activated during both propulsive and non-propulsive contractions," Professor Spencer says.

The article, Long range synchronization within the enteric nervous system underlies propulsion along the large intestine in mice (2021) by Nick J Spencer, Lee Travis, Lukasz Wiklendt, Marcello Costa, Timothy J Hibberd, Simon J Brookes, Phil Dinning, Hongzhen Hu, David A Wattchow and Julian Sorensen, will be published in Communications Biology.

Photo Caption: Flinders University Professor Nick Spencer with an image showing activation of the neural network in the enteric nervous system - or 'first brain' - in a live gut.