Bulk RNA-sequencing studies of ageing have revealed disruptions to essential cellular processes such as transcription, translation and growth-factor signalling3, with processes involved in mitochondrial function, neuronal activity and DNA damage being dysregulated in the ageing brain2,4. Cell-type-specific changes during ageing are obscured in bulk analyses and are poorly understood. This represents a major knowledge gap in the human brain, in which molecularly distinct cell types perform specific functions throughout life.
