Brain functional plasticity at rest and during action in multiple sclerosis patients

We aimed to demonstrate that basal functional connectivity reorganization observed in a specific network at rest using resting state functional MRI (rs-fMRI) could be associated with functional cortical reorganization in such network during action (ta-fMRI) in a population of early multiple sclerosis (MS) patients. Altered basal functional connectivity has been previously reported in patients with MS but relationships with cortical reorganization during action have not been explored. Thirteen patients with early relapsing-remitting MS and 14 matched healthy controls were explored on a 3T MRI scanner at rest and during a motor task (conjugate finger flexion and extension movements of each hand). Hand motor networks were extracted from rs-fMRI data using group spatial independent component analysis. For the non-dominant motor network, patients presented a higher basal functional connectivity at rest and recruited a supplementary prefrontal cortical area during action compared to the controls. The levels of hyperconnectivity at rest and of activation in the recruited area during action were significantly correlated. No differences were demonstrated for the dominant motor network at rest and during action. The present study, combining rs-fMRI and ta-fMRI in non-disabled patients with early MS, revealed for the first time a direct association between functional reorganization depicted at rest and during action within the same system.