In the slow erosion of brain tissue caused by reduced blood flow, neurons do not simply fail — they are undone by a precise biochemical cascade involving iron accumulation and lipid damage. Researchers have now traced a countervailing pathway, a molecular chain of events in which a single protein triggers the formation of a circular RNA, which in turn produces an enzyme that unlocks the brain's own defenses against this form of cell death. The discovery, made in mouse models of chronic cerebral ischemia, does not yet promise a cure, but it offers something equally valuable: a map of the machin