Microstructure & Connectivity Lab
Publications (Microstructure)
Microstructure & Connectivity Lab
Publications (Microstructure)
Embedded Files
Publications (Microstructure)
White Matter Geometry Confounds Diffusion Tensor Imaging Along Perivascular Space (DTI-ALPS) Measures
White Matter Geometry Confounds Diffusion Tensor Imaging Along Perivascular Space (DTI-ALPS) Measures
Authors: Kurt G. Schilling, Allen Newton, Chantal Tax, Markus Nilsson, Maxime Chamberland, Adam Anderson, Bennett Landman, Maxime Descoteaux
Journal: Human Brain Mapping (2025)
Background: The perivascular space (PVS) is integral to glymphatic function, facilitating fluid exchange and waste clearance in the brain. Here, we take a critical look at a recently proposed noninvasive marker of perivascular diffusion: the Diffusion tensor imaging along the perivascular space (DTI-ALPS) index. The ALPS measure inherently assumes that diffusion perpendicular to white matter pathways is the same in all directions (i.e., radial symmetry, characterized by equal transverse diffusion eigenvalues, λ2 = λ3), and interprets deviations (i.e., radial asymmetry, where λ2 > λ3) as reflecting PVS contributions. However, we test whether anatomical or microstructural features may incluence these measures.
Results: We show that radial asymmetry is widespread across white matter and persists even at high b-values, suggesting a dominant contribution from axonal geometry rather than faster PVS-specific diffusion. Crossing fibers significantly inflate ALPS indices, with greater radial asymmetry observed in regions with a greater prevalence of crossing fibers. Furthermore, anisotropic axonal dispersion and undulations introduce systematic asymmetry independent of perivascular diffusion. Finally, high-resolution vascular imaging reveals substantial heterogeneity in medullary vein orientation, challenging the assumption that PVS consistently aligns with the left–right axis in ALPS regions.
Why this matters: ALPS indices are significantly influenced by white matter microstructure, including fiber crossings, undulations, and dispersion. These findings suggest that ALPS-derived metrics may not provide a direct measure of glymphatic function but rather reflect underlying axonal geometry. Interpretations of ALPS-derived metrics as biomarkers of glymphatic function must consider these anatomical complexities
Microstructural Characterization of Short Association Fibers Related to Long‐Range White Matter Tracts in Normative Development
Microstructural Characterization of Short Association Fibers Related to Long‐Range White Matter Tracts in Normative Development
Authors: Chloe Cho, Maxime Chamberland, Francois Rheault, Daniel Moyer, Bennett Landman, Kurt Schilling
Journal: Human Brain Mapping (2025)
Summary: This study investigates the microstructural development of short association fibers (SAFs) in relation to long-range white matter tracts during normative development. Using DTI and NODDI models in a large cohort of youth aged 5–22 years, we identify shared and distinct developmental trajectories across superficial and deep white matter. Key differences emerged in features like FA, AD, and ODI, suggesting unique maturation profiles between these types of fibers. Significant sex and age-sex interaction effects were also observed. This study provides insights into typical microstructural changes of SAFs and long-range white matter tracts during development, laying a foundation for future research to investigate atypical development and dysfunction in disease pathology.
The relationship of white matter tract orientation to vascular geometry in the human brain
The relationship of white matter tract orientation to vascular geometry in the human brain
Authors: Kurt G. Schilling, Allen Newton, Chantal M. W. Tax, Maxime Chamberland, Samuel W. Remedios, Yurui Gao, Muwei Li, Catie Chang, Francois Rheault, Farshid Sepherband, Adam Anderson, John C. Gore & Bennett Landman
Journal: Scientific Reports (2025)
Link: https://www.nature.com/articles/s41598-025-99724-z
Summary: The white matter of our brain has a complex and organized structure, composed of both nerve fibers and blood vessels. While we know that both these structures have preferred orientations, how they relate to each other is less understood. In this study, we used advanced MRI techniques to compare the alignment of nerve fibers and blood vessels in the white matter. We found that while blood vessels don't always follow the main nerve fiber direction, they do align with some fibers in each location. Interestingly, our results suggest that blood supply isn't specific to individual nerve pathways. These findings provide a deeper understanding of the brain's micro-organization and can help us better interpret brain scans in health and disease.
White matter tract microstructure, macrostructure, and associated cortical gray matter morphology across the lifespan
White matter tract microstructure, macrostructure, and associated cortical gray matter morphology across the lifespan
Authors: Kurt G. Schilling, Jordan A. Chad, Maxime Chamberland, Victor Nozais, Francois Rheault, Derek Archer, Muwei Li, Yurui Gao, Leon Cai, Flavio Del’Acqua, Allen Newton, Daniel Moyer, John C. Gore, Catherine Lebel, Bennett A. Landman
Journal: Imaging Neuroscience (2023)
Summary: This study provides a comprehensive analysis of white matter pathways across the human lifespan, using data from 2,789 imaging sessions spanning ages 0 to 100 years. By examining white matter microstructure, macrostructure, and associated cortical features, we identify unique developmental and aging trajectories that vary across different brain pathways. These findings establish normative benchmarks for studying brain maturation and degeneration, with implications for understanding neurodevelopmental and neurodegenerative disorders.
Why this is a Notable Lab publication: This study maps how white matter in the brain changes from infancy to old age, providing crucial insights into brain development and aging that can help detect early signs of neurological diseases.
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