Why some very old people still have a sharp mind and others don’t

One eighty-year-old becomes demented, while the other remains super sharp. One possible reason: the size of neurons in the brain.

Very elderly people with a sharp mind have much larger neurons in part of their brains than people who are many years younger. This is according to research from the American Northwestern University.

That part of the brain is the second layer of the entorhinal cortex. The entorhinal cortex consists of six layers and plays an important role in our memory. In the second layer, information is collected from other memory areas. And it is precisely in this layer that people over 80 with a sharp mind have remarkably large and healthy neurons.

They are nearly a quarter larger than those of people with early stage Alzheimer’s and 15 percent larger than their peers. The neurons are even 6 percent larger than those of people who are much younger. The so-called superagers were probably born with such large neurons.

Moreover, the neurons do not have the so-called Alzheimer’s nodes, which consist of entangled tau proteins, a hallmark of the disease. The large neurons are thus better able to maintain their structure and remain healthy.