Communication Between Gut and Brain Affects Our Fear Behaviors


Anyone who goes through each day having to manage troublesome anxiety may be interested in what their stomach has to "say" about it.

Research is proving that when we are fearful it is not just the brain that directs our reactions and behavior. The stomach, or our “gut instinct” sends signals to the brain, influencing our responses.

Most of us experience fear and anxiety in the stomach area as butterflies, tension, or nausea. These feelings seem an uncomfortable nuisance at best. However, they take on added significance when you realize your gut is part of the body’s chemical thought process.

The Gut-Brain Communication Highway

Between our brain and our abdomen runs the vagus nerve. It works like a two-lane highway. Messages from the brain to the abdominal organs travel on the efferent vagus pathway. Signals from the stomach to the brain move along the afferent vagus path.

By cutting the afferent (stomach to brain) nerves in rats, researchers could study the gut instinct’s role in fearful situations. Snipping the nerve did not eliminate the rat’s fear, but it did alter their fear behavior.

The rats with their gut-to-brain communication disconnected showed less innate fear - they were generally less wary or vigilant - but they also retained learned fear responses longer. The investigators also found that having the vagus nerve cut changed the rats’ production of certain neurotransmitters (signaling substances).

“We were able to show for the first time that the selective interruption of the signal path from the stomach to the brain changed complex behavioral patterns,” said researcher Urs Meyer. “This has traditionally been attributed to the brain alone.”

Its Not All In Our Head

This research suggests that the intact vagus nerve, especially the gut-to-brain pathway, is involved in relearning, or learning new behavior responses. Stimulating the vagus may help individuals with PTSD neutralize learned fear reactions owed to trauma by making it easier to associate their triggers with a neutral situation.

The findings also mean those who experience problematic anxiety levels can view their stomach discomfort with a bit of curiosity. Researchers do not yet know what the stomach is “telling” the brain, but those butterflies of fear either coincide with, or are the result of, our body conversing with itself.

Source: Science Daily
Photo credit: Karrie Nodalo (@flickr)


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