Aging is the main risk factor for dementia and Parkinson’s disease. As age progresses, toxic protein aggregates pile up in the brain and impair neuronal function. But why does that happen? An international team of scientists coordinated by the Leibniz Institute on Aging – Fritz Lipmann Institute (FLI) (Jena, Germany) and the Scuola Normale Superiore (Pisa, Italy) found answers by studying the brain of the turquoise killifish (Nothobranchius furzeri) brains. They delineate a timeline of molecular events during aging that is triggered by the early reduction of proteasome activity and culminates in aggregates formation. Remarkably, fish that preserve proteasome levels during aging live longer.