Carrying one or two copies of the APOE4 gene variant significantly increases the risk of developing Alzheimer’s, and a new study reveals how APOE4 can change neuron activity – potentially many years before symptoms such as memory loss start showing.

In young mice bred to have the APOE4 gene, researchers found specific neurons were smaller and more hyperactive in parts of the brain’s memory center, the hippocampus.

What’s more, they were able to identify a protein, Nell2, contributing to the disruption – and a potential pathway to reverse the damage in advanced cases.