In a new Science Translational Medicine study, Northwestern University scientists have pinpointed when and where toxic proteins accumulate within the brains of Alzheimer’s patients — and discovered a decades-old Food and Drug Administration (FDA)-approved drug that can stop the accumulation process before it even begins. Existing human clinical data also showed the drug slowed the progression of Alzheimer’s pathology.

By studying animal models, human neurons and brain tissue from high-risk patients, the team discovered a particularly toxic protein fragment, called amyloid-beta 42, accumulates inside neurons’ synaptic vesicles — the tiny packets that neurons use to send signals. But, when the scientists administered levetiracetam (an inexpensive, decades‑old anti‑seizure drug) to the animals and human neurons, the drug prevented neurons from forming amyloid-beta 42.