How does a short history of spinal cord injury affect movement-related brain potentials?

Brain plasticity following spinal cord injury (SCI) has been studied by a wide range of neurofunctional techniques, which tend to have low temporal resolution or overlook cognitive preparatory processes. This study tried to overcome both limitations by recording the movement-related brain potentials using an experimental task somewhat similar to the contingent negative variation paradigm. The aim was to look for amplitude or topographic distribution changes at an early stage of the SCI. Hence, the brain electrical activity of patients who had a clinical history of less than 6 months of paraplegia was recorded and compared with that of two groups of healthy volunteers. None of the patients was able to move their toes, but they were asked to prepare to carry out this movement and to try to execute it in the same way as one of the control groups. The other control group was instructed to prepare to conduct the same movement but not to execute it. Results did not show significant differences in the readiness potential between patients with paraplegia and both controls. However, the readiness potential topography observed in patients was more similar to that of healthy participants who conducted the movement, whereas a greater similarity was found in the motor potential between patients and healthy participants who did not carry out the movement. These findings suggest that neurofunctional changes that take place in the brain after a SCI may be shown earlier by the motor potential than by the readiness potential.