Dr. Trumble was particularly interested in the ApoE4 gene, often called the Alzheimer’s gene. Americans who carry two copies of the gene are more than 10 times as likely to develop the late-onset form of the disease. Dr. Trumble found something startling when he looked into the Tsimane data: Many of those with a copy of the gene seemed to perform better on the cognitive tests. For the minority who’d managed to elude parasitic infection, however, the opposite was true, and the ApoE4 gene was connected with cognitive decline, just as it is for people in industrialized countries. Changiz Geula, a professor of neuroscience at Northwestern University, has been studying brain tissue collected from people who died at age 90 or older. He found that some people who die with sharp minds have brains that are clogged with the gunk associated with Alzheimer’s pathology. That means it’s possible to have an “Alzheimer’s brain” but no dementia. Dr. Geula believes that in cases like this, some actor in the brain — call it the opposite of Alzheimer’s — is protecting neurons from damage. We still don’t know what it is.
“An ancient cure for Alzheimer’s?” from the New York Times