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) showing higher GMV in adolescents that in children, while other areas (e.g., lobules I-IV and VI, Crus I, vermis VI and VIIb) showed higher GMV in the adolescent group compared with both children and adults. These patterns were partly consistent with our hypothesis. Notably, no regions showed greater GMV in adults than adolescents, suggesting that the adolescent cerebellum shows a pattern consistent with transient highest GMV relative to both children and adults. Our findings indicate differential developmental patterns both between and within lobules of the cerebellum, and highlight adolescence as a period when GMV is higher relative to both childhood and adulthood, with potential implications for the development of cerebellar-supported cognitive and emotional functions that undergo significant changes during this period.