Vagal Neurons: New findings in the gut-brain connection

Read Tom Myers’ commentary on the findings in this announcement: Your gut is directly connected to your brain, by a newly discovered neuron circuit 

Image credit: Nicole R. Miller / Science Source

From Science Magazine:

The human gut is lined with more than 100 million nerve cells—it’s practically a brain unto itself. And indeed, the gut actually talks to the brain, releasing hormones into the bloodstream that, over the course of about 10 minutes, tell us how hungry it is, or that we shouldn’t have eaten an entire pizza. But a new study reveals the gut has a much more direct connection to the brain through a neural circuit that allows it to transmit signals in mere seconds. The findings could lead to new treatments for obesity, eating disorders, and even depression and autism—all of which have been linked to a malfunctioning gut.

The study reveals “a new set of pathways that use gut cells to rapidly communicate with … the brain stem,” says Daniel Drucker, a clinician-scientist who studies gut disorders at the Lunenfeld-Tanenbaum Research Institute in Toronto, Canada, who was not involved with the work. Although many questions remain before the clinical implications become clear, he says, “This is a cool new piece of the puzzle.”

Click to continue reading the original article. 

Tom says: 

This is a small, one-piece-of-the-puzzle discovery of a humbling but exciting trend in science that the public at large has yet to absorb:

Our gut made us, and continues to run us. We think we ‘have’ a stomach, but our stomach – actually the whole gut – has us to contend with. Our gut was here first. It ‘invented’ our neuromyofascial body: Hundreds of millions of years ago, the first vertebrates strapped a wiggling tail like a polliwog or a sperm onto the back of their gut to help move it around, away from competitors. The idea was to use the increased movement the neuromyofascial system gave them to get better food and better sex.

Hey, brain, how’re you doing with the job your gut gave you? A lot of us are giving our Mother Gut questionable food, and are sitting around too much and making love too little to keep the circulation moving briskly through those organs.

Seriously, in our neuro-centric view of the world, we view the vagus nerve as spreading down through our body from the cranium through the neck past the heart to the gut organs, the primary carrier of parasympathetic signals from the federal brain to the democratic gut. Recently, though, we’re finding out much more about the gut management of the brain it invented: The combined circuitry and chemical signals coming from the gut to the brain.

From the point of view of the gut, it’s still the boss and tells the brain what to do. But the brain is a problem child, always getting into fixes of its own making. The gut withholds serotonin, and only gives it up as a reward when our brains treat it right. And anyone who’s had nausea or explosive gas knows how much our guts can punish us.

Now, the 100 millisecond jumps to the spinal cord described here are much faster than the hormonal drip from the gut into the bloodstream, as important as that is. And the whole cascade of neuropeptides that Candace Pert told us about is part of that ‘body democracy’ too.

It was almost predictable that there would be a way for the gut to tell its ‘brain’child what was up in a hurry – a combination hormone synapse that likely predates our current neural synapses – a shock of chemistry shown from one cell at another: Behave!

But generally if we could reverse our point of view and see the vagus reaching up from the gut brain to tickle the neuromotor plexus in our heads to get it to act right. The guts made us, and they’re doing the best they can, but it’s a long-distance relationship.