Charting human subcortical maturation with in vivo 7 T MRI

The human subcortex comprises hundreds of unique structures. Subcortical functioning is crucial for behavior, and disrupted subcortical function is observed in common neurodegenerative diseases. Despite their importance, human subcortical structures continue to be difficult to study in vivo. Here, we zoom in on 17 prominent subcortical structures, by describing their approximate iron and myelin contents and thickness, and by providing detailed accounts of their age-related changes across the normal adult lifespan. The results provide compelling insights into the highly heterogeneous morphometry and intricate age-related variations of these structures. They also show that the locations of these structures shift across the lifespan, which is of direct relevance for the use of standard magnetic resonance imaging atlases. The results further our understanding of subcortical morphometry and neuroimaging properties, and of normal aging processes which ultimately can improve understanding of neurodegeneration.