Dr. David Anderson

And that in turn reflects communication between the brain and the body and it's bi-directional communication.

And it's mediated by the peripheral nervous system, the sympathetic and the parasympathetic nervous system, which control heart rate, for example, blood vessel, blood pressure.

And those neurons receive input from the hypothalamus and other blood vessels.

brain regions central brain regions that control their activity and when the brain is put in a particular state it activates sympathetic and parasympathetic neurons which have effects on the heart and on blood pressure these in turn feed back onto the brain through the sensory system

And a large part of this bidirectional communication is also mediated through the vagus nerve, which many of your listeners and viewers may have heard about because it's become a topic of intense activity now.

The vagus nerve is a bundle of nerve fibers that comes out basically of your skull, out of the central nervous system, and then sends fibers in to your heart,

your gut, all sorts of visceral organs.

That information is both afferent and efferent.

The vagal fibers sense things that are happening in the body.

So the reason you feel your stomach tied up in knots if you're tense is that those vagal fibers are sensing the contraction of the gut muscles.

They're also afferents, which means that information coming out of the brain,

can influence those peripheral organs as well.

And there's work from a number of labs just in the last six months or so where people are starting to decode the components of the different fibers in the vagus nerve.

And it's amazing how much specificity

There are specific vagal nerves that go to the lung, that control breathing responses, that go to the gut, that go to other organs.

It's almost like a set of color-coded lines, labeled lines for those things.

How those vagal afferents play a role in the playing out of emotion states is a fascinating question that people are just beginning to scrape the surface of.

But I think what's exciting now is that people are gonna be developing tools that will allow us to turn on or turn off specific subsets of fibers within the vagus nerve and ask how that affects particular emotional behaviors.

So you're absolutely right.

This brain-body connection is critical, not just for the gut, but for the heart, for the lungs, for all kinds of other parts of your body.