Lebel, Catherine A.Geeraert, Bryce Landon2020-01-062020-01-062020-01-03Geeraert, B. L. (2020). Late Childhood Refinements of White Matter Microstructure and Links to Reading (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/111436Late childhood and adolescence is a fascinating period of brain development where many sophisticated cognitive skills such as reading are refined. Complex functions like reading are performed by networks of cortical regions connected by white matter tracts. White matter development and links to reading have been well-studied using diffusion tensor imaging (DTI), but DTI lacks both specificity and accuracy. The tensor model is simultaneously sensitive to many white matter microstructural features, and cannot account for complex fiber architecture. Neurite orientation dispersion and density imaging (NODDI), inhomogeneous magnetization transfer (ihMT), and multicomponent driven equilibrium single-pulse observation of T1 and T2 (mcDESPOT) have increased specificity to individual aspects of white matter microstructure. This study sought to leverage advanced imaging methods to build upon the foundation of DTI-based investigations of white matter development and links to reading. Our first aim was to compare the sensitivity of mcDESPOT and ihMT myelin markers to DTI measures, as no previous studies have evaluated the practicality of these techniques in the human brain. Next, we applied NODDI, ihMT, and mcDESPOT alongside DTI to describe development of white matter microstructure during late childhood and adolescence. Finally, white matter microstructure was linked to reading through a cross-sectional principal component analysis and investigations of longitudinal changes in white matter and reading. In this way we identified key components of white matter microstructure and linked microstructural development to reading acquisition. This study has shed new light on the microstructural nuances of white matter development and cognitive refinements occurring during late childhood and adolescence.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.ReadingNeuroscienceHuman DevelopmentEngineering--Biomedicaldoctoral thesis10.11575/PRISM/37409