The enteric nervous system (ENS), aka your ‘second brain‘, is a mesh network of millions of neurons that live inside and help control your gastrointestinal tract, and new research in mice shows how these ‘brain cells’ fire to make your colon do its thing.
“These findings identify a previously unknown pattern of neuronal activity in the peripheral nervous system,” explains neurophysiology Nick Spencer from Flinders University in Australia.
The enteric nervous system is ‘peripheral’ in that it’s separate from the central nervous system (CNS) we normally hear about, which is made up of the brain and the spinal cord.
Together, they help control and regulate the majority of our bodily activity, but the second brain is no slouch itself, with its own neural circuits that not only communicate with the CNS but also help the ENS control the digestive tract autonomously.
How that happens in us mammals just got clearer, thanks to Spencer’s new study examining the colons of euthanised mice.
Using high resolution neuronal imaging and electrodes to record electrical impulses from the animals’ smooth muscle tissue, the researchers detected a rhythmic pattern of neuronal firing involving millions of cells that promote muscle contraction in the intestine, propelling waste through the body.
“This represents a major pattern of neuronal activity in the mammalian peripheral nervous system that has not previously been identified,” the authors write.
“The synchronised ENS activity involved simultaneous activation of large populations of excitatory and inhibitory neurons, as well as putative intrinsic sensory neurons.”
While rhythmic, synchronised neuron firing like this has been observed before in the CNS, the detection of these repetitive bursts in the ENS is new, and it adds to our understanding of how our second brain gets its ‘thinking’ done – even if it might seem like a somewhat unglamorous area of research.
The findings are reported in JNeurosci.