Functional magnetic resonance imaging in multiple sclerosis

Multiple sclerosis (Ms) commonly features cognitive and motor impairments, both of which remain poorly understood. Functional magnetic resonance imaging (fMRI) is a noninvasive, powerful technique enabling to evaluate the activity of brain regions and how these regions interact within brain networks. Both task-based and resting-state fMRI have been widely applied in Ms, greatly improving our understanding of mechanisms underlying clinical preservation and impairments in Ms. This chapter outlines functional brain changes in Ms and their clinical relevance. In summary, Ms features a complex combination of beneficial functional reorganization, presumably in the form of regional hyperactivation during tasks, and maladaptive hyperconnectivity, centered around the default-mode network. The combination of these changes over time led to the hypothesized “network collapse” as patients clinically progress. Eventually, brain function might find a place in monitoring individual patients, aimed at stimulating beneficial reorganization and preventing the development of the network collapse.