Fiber pathways supporting early literacy development in 5–8-year-old children

•This study explores white matter development in a very young group of emerging readers (5–8-years).•First evidence that the vertical occipital fasciculus is associated with literacy development.•Reinforces the notion that the inferior longitudinal fasciculus is associated with the development of phonological awareness.•Provides evidence of bilateral brain involvement in literacy development. The development of fluent reading is an extended process that requires the recruitment of a comprehensive system of perisylvian brain regions connected by an extensive network of fiber pathways. In the present cross-sectional study, we focused on fiber pathways—the arcuate fasciculus (AF), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF), and vertical occipital fasciculus (VOF)—proposed to support early literacy in typical 5–8-year-old children. We related quantitative metrics of fiber pathway microstructure in these pathways to early literacy measures of phonological awareness and decoding. We found that diffusion properties of the AF, ILF, and VOF not only show age-related differences, but also are predictive of early literacy skills after controlling for the effects of age, general white matter development, sex, IQ, and phonological skill. Perhaps most novel, we provide evidence supporting the involvement of the recently re-identified VOF in early literacy, and further, we provide evidence that a bilateral network of fiber pathways supports early literacy development.