It is the 3rd most common cause of death in Western countries.
Damage is greater in the depth of the sulci than over the crests.
Within the hippocampus, CAT, CA3 and CA4 are the most vulnerable, whilst CA2 is the resistant zone. The fascia dentata is the least vulnerable zone in the hippocampus. Small cells more vulnerable than large. Centromedian n commonly involved. In preterm baby brain, periventricular leukomalacia is common and is due to failure of perfusion along the boundary between centripetal and centrifugal arteries.