Functional network dynamics in progressive multiple sclerosis

Functional reorganization at the progressive stage of multiple sclerosis has received limited attention, despite the fact that functional changes are known to occur. Characterizing large-scale network dynamics at rest has the potential to provide new insights into the complexity of such functional alterations. In this case-control study, we explored the dynamic properties of large-scale functional networks during rest in 25 healthy controls and 32 patients with progressive multiple sclerosis, using the innovation-driven co-activation patterns. Thirty-five subjects also underwent a one-year follow-up examination. Partial least squares correlation analysis was applied to explore the relationship between functional dynamics and clinical disability. We observed a reduced dynamic engagement of the anterior default mode network and its coupling with the executive-control network in patients with progressive multiple sclerosis compared to controls, at baseline and follow-up. The global and motor disabilities were related to functional dynamics of subcortical, sensory-motor and posterior default mode network, while the cognitive disability was associated to the altered dynamics of anterior default mode, visual and temporal networks. These findings reveal that the anterior default mode functional recruitment and its interaction with other networks play a major role in the functional reorganization occurring during the progressive stage of multiple sclerosis. Also, the dynamic properties of large-scale functional networks are steady over one year and unveil the intricate relationship between brain function and clinical disability.