Neuronal plasticity during motor rehabilitation training after spinal cord injury

Understanding how the injured nervous system adapts to training is key to advancing rehabilitation across neurological disorders. Using spinal cord injury (SCI) as a model of severe motor-sensory disruption, we investigate whether training-induced structural plasticity in the brain is preserved despite ongoing neurodegeneration. Thirty-two healthy controls and 17 chronic SCI patients (SCI > 6 months) undergo training in a bimanual-bipedal computer-controlled motion game for one hour, four times a week, over one month, with longitudinal microstructural MRI at 3 T, including multiparameter mapping and diffusion MRI. All SCI patients exhibit performance improvements over the training period. These improvements are accompanied by spatially and temporally distributed changes in both gray and white matter, encompassing alterations in volumetric and myelin-sensitive MRI markers. SCI patients demonstrate trajectories of training-induced neuroplasticity that are comparable to, and in some cases greater than, those of healthy controls. Our findings highlight a fundamental capacity of the injured nervous system to adapt through rehabilitation, with evidence from SCI patients showing that-despite severe motor and sensory deficits-the brain can undergo learning-related structural changes. These results suggest that the mechanisms of training-induced plasticity observed in SCI may generalize to rehabilitation across a broad spectrum of neurological disorders.