A team of researchers at USC has traced a quiet but consequential pathway running from the gut to the brain's memory center — the vagus nerve — revealing that what we eat shapes not only our bodies but our capacity to remember. When nutritious food is consumed, this nerve fires signals that release acetylcholine in the hippocampus, the chemical that allows experience to become memory; when poor diets dominate, that conversation degrades, and with it, cognition. The discovery illuminates a biological mechanism behind the long-observed link between diet, cognitive decline, and Alzheimer's diseas