Insulin, it turns out, may be as important for the mind as it is for the body. Research in the last few years has raised the possibility that Alzheimer’s memory loss could be due to a novel third form of diabetes.

Now scientists at Northwestern University have discovered why brain insulin signaling — crucial for memory formation — would stop working in Alzheimer’s disease. They have shown that a toxic protein found in the brains of individuals with Alzheimer’s removes insulin receptors from nerve cells, rendering those neurons insulin resistant.