Numerous studies in rodents confirmed these observations, demonstrating impairments in hippocampus-dependent contextual tasks following intraperitoneal (i.p.)[150] or intrahippocampal injection of IL-1β [151] and elevations in endogenous IL-1β evoked by infections [150–152] or psychological and physical stressors [153, 154]. The gene discussed is IL1B; the disease is infection.