Key PointsQuestionWhat are the spatial profiles of longitudinal changes in brain volume and their rates in aging individuals with normal cognition, at the population and individual levels?FindingsIn this cohort study, 653 adults with normal cognition were followed up annually for over 10 years, with a total of 7915 visits. The volume of each brain structure exhibited characteristic age-related trajectories, with acceleration of volume reduction over age and cross-individual variability noted in individuals with normal cognition.MeaningThese results provide insight into brain aging at the individual level, which is essential for understanding the process of age-related neurodegenerative diseases.