Pro-inflammatory cytokines, such as IL-1β, readily penetrate the blood-brain barrier (BBB) activating microglia and leading to neuroinflammation.[19] In addition, pain is closely related to neuroinflammation.[20] A recent study by Koyama et al[21] described that acute postoperative pain exacerbates neuroinflammation and related delirium-like cognitive dysfunction in rats. The gene discussed is IL1B; the disease is delirium.