Discussion
neuronal loss, atrophy, MCI, visual memory recall
ATROPHY
This study aimed to provide an understanding of the positive effects of 8 weeks of CCT on global cognition and memory function in MCI patients. Significant differences between the CCT and control groups were found in global cognition and memory function and the DMN, SOM, and VIS networks. Our significant findings were that CCT resulted in increases in SC-FC coupling and global functional topography of the DMN and SOM networks but decreases in coupling of the VIS network. In addition, the CCT participants showed different patterns of changes in the nodal degree and efficiency in the left and right hemispheres. The changes in SC-FC coupling and nodal topography within different functional networks were found to be specific to the participant’s cognitive function gains. More importantly, our findings of SC-FC coupling and topography changes are consistent with the common theoretical models explaining age-related cognitive decline: the posterior–anterior shift in aging (PASA) model and the hemispheric asymmetry reduction in older adults (HAROLD) model.In this study, we revealed that after receiving cognitive training, the participants showed increases in the SC-FC coupling and global clustering coefficients of the DMN and SOM networks, which were correlated with improvements in global cognition and memory function. In contrast, there were decreases in the SC-FC coupling of the VIS network, which were correlated with improvements in visual memory recall function. These distinct neural changes after CCT reflect the posterior-to-anterior dynamic in the neural activities described in the PASA model [The nodal topological results suggest the possibility of CCT-related modifications of right–left lateralization in the participants. This phenomenon is consistent with the HAROLD model proposed by Cabeza et al. [It was evidenced that individuals could maintain good cognitive abilities and successful day-to-day functioning despite significant neuronal loss and atrophy [The CCT-induced changes in SC-FC coupling and nodal topography indicate the neuroplastic characteristics of the MCI participants. The plastic changes covered the functional DMN, SOM, and VIS. Notably, these neural changes were found to correspond to specific improvements in cognitive function. These results further illustrate the scaffolding theory of aging and cognition–revised (STAC-r) proposed by Reuter-Lorenz PA et al. [