One of the main characteristics of multiple sclerosis (MS) is the existence of a "clinico-radiological paradox". The discrepancies observed between the clinical and radiological findings might be partly attributable to lack of specificity of the imaging measures, but also to functional reorganization mechanisms occurring at both the brain and spinal cord levels. These neuroplastic processes might provide a means of delaying the clinical expression of some functional symptoms. Functional MRI (fMRI) methods provide a useful means of determining whether functional reorganization mechanisms of this kind are at work. It has been established, for example, that these neuroplastic mechanisms occur right from the start of the disease and may contribute to reducing the expression of the symptoms resulting from pathological tissue damage. This functional reorganization may therefore constitute an important adaptive mechanism during the early stages of the disease. One potential practical application of the findings made on these neuroplastic processes is likely to be the development of specific rehabilitation methods, which can be used to enhance these reactive mechanisms in order to maintain MS patients functional abilities, and other specifically targeted approaches will also predictably be developed.