Connectivity in ALS II (CoALS II): a study of structural and functional connectivity in ALS.

Background: Amyotrophic lateral sclerosis (ALS) is increasingly recognized as a network-level neurodegenerative disease involving distributed disruptions across structural and functional systems. While previous studies have often examined white matter integrity or functional connectivity in isolation, the nature of structure-function coupling and its reorganization in ALS remains poorly understood. Methods: We conducted a multimodal connectomic analysis in ALS patients and matched controls, integrating cortical thickness-based structural covariance networks, diffusion MRI tractography, and resting-state and task-based functional MRI. Graph-theoretical metrics were derived, and cross-modal structure-function correspondence was quantified using ROI-wise correlation analyses. A comprehensive 104-node parcellation scheme based on the Desikan-Killiany atlas was employed. Results: ALS participants showed preserved global network topology ( Conclusions: Structure-function coupling in ALS is not globally diminished but reorganized, with robust white matter-functional relationships coexisting alongside weak cortical covariance-functional associations. These findings refine the traditional disconnection model and highlight the utility of multimodal metrics for understanding disease mechanisms and developing biomarkers for progression and therapeutic response.