Engineers have discovered that some brain cells age more rapidly than others, and they are disproportionately abundant in individuals afflicted with Alzheimer’s disease. Additionally, researchers observed male-female-specific differences in the aging process of certain brain cells, with the female cortex exhibiting a higher ratio of ‘old’ oligodendrocytes to ‘old’ neurons compared to the male cortex. The discoveries were made possible by a new technique called MUSIC (multinucleic acid interaction mapping in single cells), which allows researchers to peek inside individual brain cells and map out interactions between chromatin–which is the tightly coiled form of DNA — and RNA.