Super-agers have long puzzled scientists. Despite being in their 70s and 80s, they have the physical ability and cognitive function of people much younger. Now, researchers at Northwestern University in Illinois may have discovered one of the reasons super-agers are able to stay so mentally sharp: the neurons in their entorhinal cortex, the part of the brain responsible for storing memories, are much larger than those of their cognitively average peers. Furthermore, these neurons show no sign of tau tangles, the abnormal accumulations of protein that collect inside neurons and limit the communication between them, which are a telltale sign of Alzheimer’s disease.