Motor control physiology below spinal cord injury: residual volitional control of motor units in paretic and paralyzed muscles.

We have described motor control in people with different degrees of SCI by using surface polyelectromyographic recordings during single- and multijoint volitional motor tasks. We have shown that neurobiologic conditions of the injured spinal cord can be expressed in two main categories: "new anatomy" and "reduced anatomy". The evidence for a variety of definite features of motor control elicited by volitional effort for the performance of a present or even clinically absent motor task suggests that we can benefit from animal experimental neurobiologic studies while we are progressing toward the application of this new knowledge for the restoration of impaired spinal cord function in humans. Reports on the successfully enhanced regenerating capabilities of the axons and improved connectivity within neuronal circuits after SCI encourage us to intensify our efforts in parallel with studies on the recovery processes found in experimentally induced lesions in animals, as well as in accidentally induced SCI in humans.