Reciprocal Predictions Between Reading Achievement and Cognitive Flexibility Development in Children and the Mediating Roles of the Left Middle Frontal Gyrus.

The development of reading skills and cognitive flexibility is crucial for success in childhood and adulthood. Although previous studies demonstrate the existing links between the development of cognitive flexibility and the reading acquisition in children, it remains unclear how baseline reading achievement influences later cognitive flexibility, or vice versa, particularly in relation to the underlying brain development. Therefore, in this prospective longitudinal study, we investigated the reciprocal prediction between reading achievement and cognitive flexibility, along with the underlying brain development that potentially mediated this relationship in school-aged children. By employing a self-recruited longitudinal dataset with two time points spaced 12 months apart, we found a significant association between baseline reading achievement and later cognitive flexibility, as well as between baseline cognitive flexibility and later reading achievement. Moreover, the left middle frontal gyrus emerged as a central neural hub supporting the development of both abilities. Increases in its gray matter volume and enhanced its functional connectivity to the salience network significantly mediated the longitudinal associations between reading achievement and cognitive flexibility. Taken together, our findings demonstrate the vital role of the left middle frontal gyrus in integrating language information processing and higher-order cognitive control. This provides evidence for future reading or cognitive interventions.