Hospital nurseries routinely place soft bands around the tiny wrists of newborns that hold important identifying information such as name, sex, mother, and birth date. Researchers at Rockefeller University are taking the same approach with newborn brain cells—but these neonates will keep their ID tags for life, so that scientists can track how they grow and mature, as a means for better understanding the brain’s aging process. As described in a September 28, 2023 paper in Cell, the new method developed by Rockefeller geneticist Junyue Cao, PhD, and his colleagues is called TrackerSci (pronounced “sky”). This low-cost, high-throughput approach has already revealed that while newborn cells continue to be produced through life, the kinds of cells being produced vary greatly in different ages. This groundbreaking work, led by co-first authors grad students Ziyu Lu and Melissa Zhang from Cao’s lab, promises to influence not only the study of the brain but also broader aspects of aging and disease across the human body. The open-access Cell article is titled “Tracking Cell-Type-Specific Temporal Dynamics in Human and Mouse Brains.”