Differential effects of cognitive training and aerobic exercise on regional gray matter volume and inter-regional covariance in community-dwelling older adults

Previous studies have shown that both cognitive training and aerobic exercise benefit cognition and brain structure in healthy older adults, yet direct comparisons are limited. This study aimed to compare the effects of three months of cognitive training and aerobic exercise on regional gray matter volume and inter‑regional covariance in community‑dwelling older adults. Structural magnetic resonance imaging (MRI) was conducted at baseline and 12-month follow-up. Repeated-measures analysis of covariance (ANCOVA) revealed nominally significant time-by-group interactions in the left posterior orbital gyrus (POrG), left posterior insula (PIns), left subcallosal area (SCA), and left transverse temporal gyrus (TTG), with only the left POrG remaining significant after false discovery rate (FDR) correction. At the 12-month follow-up, left POrG volume increased only in the aerobic exercise group, whereas the control group showed decreases in the left POrG, left PIns, and left SCA. Inter-regional covariance analyses revealed weaker covariance between volume changes in the left SCA and left TTG in the aerobic exercise group compared with controls, although this effect did not survive FDR correction, suggesting a lower degree of coordinated structural change between these regions. Overall, these findings suggest that both cognitive training and aerobic exercise are associated with attenuated age-related gray matter volume reduction, though they differ in the extent and coordination patterns of these volume changes.