Background: Studies exploring neuroanatomic correlates of reading have associated white matter tissue properties with reading disability and related componential skills (e.g., phonological and single-word reading skills). Mean diffusivity (MD) and fractional anisotropy (FA) are widely used surrogate measures of tissue microstructure with high sensitivity; however, they lack specificity for individual microstructural features. Here we investigated neurite features with higher specificity in order to explore the underlying microstructural architecture. Methods: Diffusion weighted images (DWI) and a battery of behavioral and neuropsychological assessments were obtained from 412 children (6 – 16 years of age). Neurite indices influenced by orientation and density were attained from 23 major white matter tracts. Partial correlations were calculated between neurite indices and indicators of phonological processing and single-word reading skills using age, sex, and image quality metrics as covariates. In addition, mediation analysis was performed using structural equation modeling (SEM) to evaluate the indirect effect of phonological processing on reading skills. Results: We observed that orientation dispersion index (ODI) and neurite density index (NDI) were negatively correlated with single-word reading and phonological processing skills in several tracts previously shown to have structural correlates with reading efficiency. We also observed a significant and substantial effect in which phonological processing mediated the relationship between neurite indices and reading skills in most tracts. Conclusions: In sum, we established that better reading and phonological processing skills are associated with greater tract coherence (lower ODI) and lower neurite density (lower NDI). We interpret these findings as evidence that reading is associated with neural architecture and its efficiency.

Original languageEnglish
Article number118426
Number of pages11
JournalNeuroImage
Volume241
Early online date22 Jul 2021
DOIs
StatePublished - 1 Nov 2021

    Scopus subject areas

  • Neurology
  • Cognitive Neuroscience

    Research areas

  • Diffusion measures, Neurite density, Neurite orientation, Reading disability, School-aged children, Tractography, Neurites/physiology, Humans, Male, Cell Count/methods, Reading, Brain/cytology, Adolescent, Neuronal Plasticity/physiology, Phonetics, Female, Diffusion Magnetic Resonance Imaging/methods, Child, BRAIN BASIS, NO EVIDENCE, SPINAL-CORD, MICROSTRUCTURE, ORIENTATION DISPERSION, LETTER-SOUND KNOWLEDGE, WHITE-MATTER STRUCTURE, CONNECTIVITY, DYSLEXIA, DIFFUSION

ID: 86662390