Multifaceted Characterization of Early Human Brain Development

Multifaceted Characterization of Early Human Brain Development Abstract In the first few years of life, the human brain develops dynamically in both structure and function. Many neuro- developmental disorders are associated with aberrations from normative growth during this critical period of brain development. The longitudinal high-resolution MRI data of children from birth to 5 years of age, made available through the Baby Connectome Project (BCP), affords unprecedented opportunities for precise charting of early brain developmental trajectories in order to understand normative and aberrant growth. Dedicated computational tools have been developed at the University of North Carolina at Chapel Hill for accurate processing and anal- ysis of baby MR images, which typically exhibit dynamic heterogeneous changes across time. The goal of this secondary analysis project is to apply these tools to the data acquired via the BCP to investigate structural and functional connectomes, tissue macrostructure and microstructure, and their interplay during early brain devel- opment. In Aim 1, we will investigate the hierarchical organization of the cerebral cortex by analyzing areal differences in neuroanatomical characteristics involving cortical morphology and microstructure. We will utilize our infant-centric pipeline to delineate cortical geometry by constructing white matter and pial surfaces, based on which macroscopic features of cortical morphology, such as thickness and curvature, and microscopic features of myeloarchitecture and cytoarchitecture, such as neurite and soma densities, will be extracted and analyzed. For completeness, tissue macroscopic and microscopic measurements of subcortical structures will also be included for investigation. In Aim 2, we will study brain development in terms of dense vertex-wise cortical connectivity. We will use our infant-centric diffusion model and tractography algorithm to significantly improve the delineation of white matter pathways, particularly in superficial white matter with characteristically low diffusion anisotropy, and to reduce gyral bias in establishing dense connectivity of cortical surface vertices. Vertex-wise stationary and dynamic functional connectivity will also be analyzed. In Aim 3, we will investigate the interplay of multiple developmental traits during the first years of postnatal brain development. We will study brain subnetworks in association with motor, language, and visual development. We will assess the associations of these networks with psychological assessments such as the Mullen Scales of Early Learning (MSEL) with subdomains including gross/fine motor, receptive/expressive language, and visual reception. This project will involve the utilization of multimodal MRI, including structural, diffusion, and functional MRI, to provide a more complete picture of human brain development. Successful completion of this project will empower the neuroscience community with improved understanding of the development of structure and function of the human brain during its infancy.