Corticospinal and Neuromuscular Plasticity Induced by Real and Imaginary Contractions.

Physical activity is considered a therapeutic strategy in its own right in a vast majority of disabling chronic disorders. It leads to an increase in physical and probably cognitive capacity, thanks to its effects on both metabolism (muscle hypertrophy, improvement in oxidative metabolism) and the nervous system (neuroplasticity). Nonetheless, even though there is a consensus on the positive effects of physical exercise (PE) on cerebral plasticity, the physiological mechanisms by which PE affects neuroplasticity, in particular depending on the mode of muscle contraction, are still hypothetical. Moreover, several recent studies have shown that mental learning (ML) by motor imagery improves motor performance, thus making it of interest in a context of rehabilitation, in particular in situations where PE is transient of definitively impossible. Yet, the mechanisms and brain structures involved in motor learning by ML have not been established so far. Finally, on the basis of clinical observations concerning the key role of sensory input in motor function, the hypothesis that increased demand on this input by electrical stimulation (ES) as a means to improve motor function has been proposed. However, the mechanisms by which this type of stimulation could induce neuroplasticity is still to be elucidated.