Vagus Nerve Boosts Memory Formation in Rats, Study Shows

Researchers led by Scott Kanoski at the University of Southern California published a study in Nature Communications on July 27 showing that nutrient signals from the gut travel via the vagus nerve to the brain and enhance memory in rats. When rats ate nutritionally rich food, neurons projecting to the hippocampus released more acetylcholine, a neurotransmitter that supports memory formation. Cutting the vagus nerve eliminated the acetylcholine increase and the rats performed worse on tests that required them to remember where the food was located. The effect was specific to real nutrients; sweet‑tasting liquids without calories did not trigger the response. The authors also reported that early exposure to high‑fat, high‑sugar diets impaired vagal‑to‑hippocampal communication in the animals. The work was conducted in rats and has not been tested in humans.