Separate lanes for math and reading in the white matter highways of the human brain

AbstractMath and reading involve distributed brain networks and have both shared (e.g. encoding of visual stimuli) and dissociated (e.g. quantity processing) cognitive components. To date, it is unknown what are shared vs. dissociated gray and white matter substrates of the math and reading networks. Here we address this question using an innovative, multimodal approach applying functional MRI, diffusion MRI, and quantitative MRI to define these networks and evaluate the structural properties of their fascicles. Results reveal that i) there are distinct gray matter regions which are preferentially engaged in either math or reading and ii) the superior longitudinal (SLF) and arcuate (AF) fascicles are shared across math and reading networks. Strikingly, within these fascicles, reading- and math-related tracts are segregated into parallel sub-bundles and show structural differences related to myelination. These novel findings open a new avenue of research that examines the contribution of sub-bundles within fascicles to specific behaviors.