Motor control in the human spinal cord.

Features of the human spinal cord motor control are described using two spinal cord injury models: (i) the spinal cord completely separated from brain motor structures by accidental injury; (ii) the spinal cord receiving reduced and altered supraspinal input due to an incomplete lesion. Systematic studies using surface electrode polyelectromyography were carried out to assess skeletal muscle reflex responses to single and repetitve stimulation in a large number of subjects. In complete spinal cord injured subjects the functional integrity of three different neuronal circuits below the lesion level is demonstrated: first, simple mono- and oligosynaptic reflex arcs and polysynaptic pathways; second, propriospinal interneuron system with their cell in the gray matter and the axons in the white matter of the spinal cord conducting activity between different spinal cord segments; and third, internuncial gray matter neurons with short axons and dense neuron contact within the spinal gray matter. All of these three systems participate continuously in the generation of spinal cord reflex output activating muscles. The integration of these systems and their relative degree of excitation and set-up produces characteristic functions of motor control. In incomplete spinal cord injured patients, the implementation of brain motor control depends on the profile of residual brain descending input and its integration with the functional neuronal circuits below the lesion. Locomotor patterns result from the establishment of a new structural relationship between brain and spinal cord. The functions of this new structural relationship are expressed as an alternative, but characteristic and consistent neurocontrol. The more we know about how the brain governs spinal cord networks, the better we can describe human motor control. On the other hand such knowledge is essential for the restoration of residual functions and for the construction of new cord circuitry to expand the functions of the injured spinal cord.

Clinical elements for the neuromuscular stimulation and functional electrical stimulation protocols in the practice of neurorehabilitation.

The physicians and their multidisciplinary teams involved in the clinical practice of neurological rehabilitation have more and more opportunities to apply neuromuscular stimulation (NMS) and functional electrical stimulation (FES) of peripheral nerves as a part of their daily practice. In this article, we outline clinical protocols of NMS and FES in the following clinical conditions of upper motor neuron dysfunction: to prevent consequences of disuse of the neuromuscular system of the upper motor neuron, to facilitate recovery processes of impaired upper motor neuron functions due to acute and/or subacute neurological conditions, to maintain or enhance the trophic state of the muscle, to modify altered control of muscle tone, to modify altered patterns of automatic and volitional functional movements, to enhance functional movement of the single joint muscle group within intact functional multijoint movement, and to modify altered neurocontrol of posture, locomotion, and skillful movements. We emphasize the importance of understanding the motor control alteration while developing clinical protocols and defining the goals. It is very important to be aware that similar clinical findings and due to the same cause can have different features of residual motor control, and therefore potentials for recovery or modification can be very different.