Functional imaging has incorporated a new field, functional magnetic resonance imaging (fMRI), the mapping of brain activation by magnetic resonance. The signal in cortical areas depends on the content of deoxyhaemoglobin,1 and its variations during the performance of tasks are large enough to be perceived when the comparison is achieved with proper statistical tools. The clinical applications of this method have initially been of interest in the fields of brain tumours, epilepsy and cerebrovascular disease.2,3 In multiple sclerosis (MS) the question of the prognosis of the disease is still open and not well resolved by the morphological approach of imaging. fMRI has the ability to globally test systems, which is a strategy certainly well suited for this disease. It could allow verification of the extent to which brain plasticity participates in the mechanism of the remittence observed in MS. Axonal loss accompanying increased severity of the clinical picture in MS may have definite consequences on the fMRI profile and some prognosis information could be expected.