TNF and delirium: Our study found that intraperitoneal administration of Ex‐4, a GLP‐1R agonist, ameliorated delirium‐like behavior in aged mice after cardiac surgery while i.c.v. injection of inflammatory mediators such as IL‐1α, TNF‐α, and C1q‐induced A1 astrocyte activation led to delirium‐like behavior in young mice.