Differential contributions of the middle frontal gyrus functional connectivity to literacy and numeracy.

Literacy and numeracy equally affect an individual's success in and beyond schools, but these two competencies tend to be separately examined, particularly in neuroimaging studies. The current resting-state fMRI study examined the neural correlates of literacy and numeracy in the same sample of healthy adults. We first used an exploratory "Multivariate Distance Matrix Regression" (MDMR) approach to examine intrinsic functional connectivity (iFC), highlighting the middle frontal gyrus (MFG) for both competencies. Notably, there was a hemispheric asymmetry in the MDMR-based MFG findings, with literacy associated with the left MFG, whereas numeracy associated with the right MFG (R.MFG). Results of post-hoc seed-based correlation analyses further strengthened differential contributions of MFG connections to each competency. One of the most striking and novel findings from the present work was that numeracy was negatively related to R.MFG connections with the default network, which has been largely overlooked in the literature. Our results are largely consistent with prior neuroimaging work showing distinct neural mechanisms underlying literacy and numeracy, and also indicate potentially common iFC profiles to both competencies (e.g., R.MFG with cerebellum). Taken together, our iFC findings have a potential to provide novel insights into neural bases of literacy, numeracy, and impairments in these competencies.