A Data-Driven Method to Map the Functional Organisation of Human Brain White Matter
Authors: Yifei Sun, James M. Shine, Robert D. Sanders, Robin F. H. Cash, Sharon L. Naismith, Fernando Calamante, Jinglei Lv
Organizations: School of Biomedical Engineering, The University of Sydney, Sydney, 2050, Australia. · Brain and Mind Centre, The University of Sydney, Sydney, 2050, Australia. · School of Medical Science, The University of Sydney, Sydney, 2050, Australia. · Sydney Medical School, The University of Sydney, Sydney, 2050, Australia. · Department of Biomedical Engineering, The University of Melbourne, Victoria, 3010, Australia. · Department of Psychiatry, The University of Melbourne, Victoria, 3010, Australia · School of Psychology, The University of Sydney, Sydney, 2050, Australia. · Sydney Imaging, The University of Sydney, Sydney, 2050, Australia.
The white matter of the brain is organised into axonal bundles that support long-range neural communication. Although diffusion MRI (dMRI) enables detailed mapping of these pathways through tractography, how white matter pathways directly facilitate large-scale neural synchronisation remains poorly understood. We developed a data-driven framework that integrates dMRI and functional MRI (fMRI) to model the dynamic coupling supported by white matter tracks. Specifically, we employed track dynamic functional connectivity (Track-DFC) to characterise functional coupling of remote grey matter connected by individual white matter tracks. Using independent component analysis followed by k-medoids clustering, we derived functionally-coherent clusters of white matter tracks from the Human Connectome Project young adult cohort. When applied to the HCP ageing cohort, these clusters exhibited widespread age-related declines in both functional coupling strength and temporal variability. Importantly, specific clusters encompassing pathways linking control, default mode, attention, and visual systems significantly mediated the relationship between age and cognitive performance. Together, these findings depict the functional organisation of white matter tracks and provide a powerful tool to study brain ageing and cognitive decline.
The State Key Lab of Brain-Machine Intelligence, Zhejiang University, Hangzhou 310058, Zhejiang, China · Department of Radiology, Brigham and Women’s Hospital, Mass General Brigham, Boston 02115, Massachusetts, USA · Harvard Medical School, Boston 02115, Massachusetts, USA +4