The activity of microglia/macrophages, which areknown to rapidly populate post-stroke lesioned tissue,33 could be responsible for the marked anaerobic metabolism, as these cells canproduce lactate even under aerobic circumstances34,35 and prefer aerobic glycolysisduring activation.36 Since the Iba1 staining does not distinguish between brain-resident microgliaand blood-borne macrophages, the observed metabolic changes may also be (partly)caused by infiltrated immune cells. The gene discussed is AIF1; the disease is Stroke.