Gut–brain interoception drives age-related cognitive decline

Researchers show that aging gut microbiota produce higher levels of medium-chain fatty acids, triggering peripheral inflammation via GPR84 and weakening vagal gut–brain signaling. This interoceptive dysfunction impairs hippocampal memory in aged mice, with promising interventions—phage targeting of Parabacteroides, GPR84 inhibitors, or boosting vagal activity—able to restore memory.