The key feature of cerebral ischemia is that microglia in the brain evolve from a quiescent, branching morphology to an activated, unbranched, amoeboid morphology, which releases a large number of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), inter-leukin-1 beta (IL-1β), inducible nitric oxide synthase (iNOS), and other inflammatory mediators. The gene discussed is NOS2; the disease is brain ischemia.