Multi-electrode stimulation of myelinated nerve fibers

Patients with a central nervous system injury resulting in total or partial paralysis of extremities often have an intact peripheral neuromuscular system. Many attempts were made to restore lost functions by artificial electrical stimulation of the peripheral neuromuscular system. In principle, inducing muscle contraction is possible through electrical stimulation of the ventral roots, the peripheral nerves or the muscles themselves. In the latter case the nerve branches in the muscle are stimulated rather than the muscle fibers themselves (Grandjean and Mortimer, 1984; Eichhorn et al., 1984). The stimulation electrodes can be applied on the surface of the skin (transcutaneous stimulation), through the skin (percutaneous stimulation) or by implantation (transcutaneous stimulation

Multielectrode intrafascicular and extraneural stimulation

The relationship between nerve stimulation, pulse amplitude and isometric muscle force was measured to investigate recruitment of motor units. Force addition experiments were performed to obtain insight in the intersection of motor unit groups recruited by different electrodes. Intrafascicular and extraneural multielectrode configurations were used for nerve stimulation. Experiments were performed on rats. The common peroneal nerve was stimulated and the forces of the tibial anterior and extensor digitorum longus muscles were measured isometrically. Recruitment was more stable for intrafascicular electrodes than for extraneural electrodes. Especially for intrafascicular electrodes no strict inverse recruitment was observed. Force addition experiments indicated that small overlap of recruited motor unit groups occurred more often for intrafascicular than for extraneural electrodes