Cerebellar Gray Matter Volume Changes Across Development: Posterolateral and Vermal Transient Increases during Adolescence

The cerebellum undergoes substantial maturation with regionally distinct developmental trajectories. This study examined cerebellar gray matter volume (GMV) in healthy children, adolescents, and adults, using voxel-based morphometry, the ACAPULCO algorithm, and the SUIT toolbox for cerebellum-optimized analyses. A total of 104 typically developing children (n=31, 6-9 years), adolescents (n=35, 13-17 years), and adults (n=38, 30-40 years) were included. We hypothesized age group differences in cerebellar GMV, with adolescents showing the greatest volume, specifically in posterolateral regions. Results revealed significant group differences in GMV. We observed region-specific volumetric patterns, with some areas (e.g., Crus II, lobule X) increasing from childhood to adolescence followed by stabilization, whereas other areas (e.g., lobules I-IV and VI, Crus I, vermis VI and VIIb) exhibited peak GMV during adolescence, with lower volumes in both children and adults. These patterns were partly consistent with our hypothesis. Notably, no regions had greater GMV in adults than adolescents, suggesting that cerebellar growth peaks in adolescence before stabilizing. Our findings indicate differential developmental patterns both between and within lobules of the cerebellum, and highlight adolescence as a peak period of cerebellar growth, with potential implications for the development of cerebellar-supported cognitive and emotional functions that undergo significant changes during this period.