White matter tract microstructure, macrostructure, and associated cortical gray matter morphology across the lifespan

Abstract

Characterizing how, when and where the human brain changes across the lifespan is fundamental to our understanding of developmental processes of childhood and adolescence, degenerative processes of aging, and divergence from normal patterns in disease and disorders. We aimed to provide detailed descriptions of white matter pathways across the lifespan by thoroughly characterizing white mattermicrostructure, white mattermacrostructure, and morphology of thecortexassociated with white matter pathways. We analyzed 4 large, high-quality, publicly-available datasets comprising 2789 total imaging sessions, and participants ranging from 0 to 100 years old, using advanced tractography and diffusion modeling. We first find that all microstructural, macrostructural, and cortical features of white matter bundles show unique lifespan trajectories, with rates and timing of development and degradation that vary across pathways – describing differences between types of pathways and locations in the brain, and developmental milestones of maturation of each feature. Second, we show cross-sectional relationships between different features that may help elucidate biological changes occurring during different stages of the lifespan. Third, we show unique trajectories of age-associations across features. Finally, we find that age associations during development are strongly related to those during aging. Overall, this study reports normative data for several features of white matter pathways of the human brain that will be useful for studying normal and abnormal white matter development and degeneration.

Greater white matter degeneration and lower structural connectivity in non-amnestic vs. amnestic Alzheimer’s disease

“…(Qualitative comparisons of GM and WM degeneration or correlations of GM atrophy with voxelwise WM microstructure metrics are more common). However, one recent study based on connectomic imaging from 2,789 datasets (Schilling et al, 2023) reported correlations of similar magnitude between FA and cortical thickness in older adults, in line with the current findings. The relatively modest association between GM and WM degeneration may indicate that both GM atrophy and WM degeneration are driven not only by some common processes but also tissue-specific factors.…”

Deep Normative Tractometry for Identifying Joint White Matter Macro- and Micro-structural Abnormalities in Alzheimer’s Disease

“…[11] found heterogeneous patterns of age-related macrostructural changes in the brain WM compared to the more homogeneous patterns of microstructural changes. In another study, the same authors reported synchronous micro- and macro-structural changes across the human lifespan [12]. Combining DTI, connectivity and tract shape measures (length, diameter and elongation) derived with a fusion prediction network, Liu et al .…”