Gut bacteria hitch a ride to the brain via the vagus nerve, mouse study suggests

Emory researchers in mouse models of leaky gut and disease show very small numbers of live gut bacteria can reach the brain, with evidence that the vagus nerve serves as the main route; blocking the nerve reduced brain bacterial presence, suggesting a gut-to-brain transmission axis influenced by diet and genetics and potentially reversible by restoring gut integrity. The findings, published in PLOS Biology, are not yet known to occur in humans and the bacteria were present in very low amounts, leaving open questions about their role in inflammation or disease and whether future gut-targeted therapies could affect brain conditions.