Signals traveling from the gut through the vagus nerve help form memories

When French writer Marcel Proust famously recalled his childhood from the taste of a Madeline cookie, his stomach may have done some of the work.

We generally associate our memories almost exclusively with the brain, which we imagine both forms and stores them. New research led by Scott Kanoski, professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences, has found that our gut may also play an important role in helping us to remember experiences, especially those revolving around food.

The study, published in Nature Communications, focused on the vagus nerve, a major communication highway that connects the digestive system to the brain. Scientists have long known that the vagus nerve helps regulate digestion, hunger and feelings of fullness. Now, researchers have uncovered evidence that signals traveling from the gut through the vagus nerve can also help to form memories.

The researchers found that when rats consumed nutritious foods, neurons communicating to the hippocampus, a part of the brain critical for learning and memory, released higher levels of a chemical called acetylcholine. This neurotransmitter supports memory formation and helps the brain encode new experiences.