Epidural spinal cord stimulation improves forelimb reaching and grasping in cervical spinal cord injured rats

Epidural spinal cord stimulation improves forelimb reaching and grasping in cervical spinal cord injured rats

Abstract: Electrically enabling motor control (eEmc) via epidural stimulation of spinal cord is a promising therapeutic technique for the recovery of motor function after spinal cord injury. In the present study, we tested whether electrical stimulation delivered epidurally in the cervical spinal cord would facilitate the recovery of fine forelimb motor function after a dorsal funiculi crush (DFC) injury at C4. Adult Long-Evans rats were trained to reach and grasp sugar pellets. Intramuscular EMG electrodes were implanted in forelimb muscles and epidural stimulation electrodes were implanted at cervical spinal cord segments C6 and C8. Immediately after the spinal cord injury, the rats demonstrated significant deficits in forelimb fine-motor function of reaching and grasping. The rats were tested to reach and grasp sugar pallets with and without eEmc during 10 weeks post-injury. To determine the best stimulation parameters to activate the cervical spinal networks involved in fine forelimb motor function, monopolar and bipolar pulses were delivered at varying frequencies (20, 40, and 60Hz) concomitant with the reaching and grasping task. Video and forelimb EMG were recorded during this behavioral task. The DFC injury resulted in a significant drop in the success rates for reaching and grasping scores. Bipolar stimulation (C6- C8+ and C6+ C8-) resulted in a better success rate compared to monoplar stimulation (C6- Ref+ and C8- Ref+). Lower frequency stimulation (20 Hz) had a better effect in improving forelimb function compared to higher frequencies (40 and 60Hz). Interestingly, the reaching and grasping scores remained elevated after cessation of the stimulation, suggesting that eEmc had a durable effect beyond the stimulation period. Video analyses revealed improved movement trajectories during forelimb reaching and grasping with eEmc compared to without. Combined, these data suggest that eEmc has therapeutic potential for rehabilitation after a cervical SCI.

Society for Neuroscience Chicago Nanosymposium Advances in SCI Research and Plasticity

Disclosures: M. Alam: None. B. Jin: None. G. Garcia-Alias: None. Y. Gerasimenko: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); NeuroRecovery Technologies. H. Zhong: None. R. Roy: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); NeuroRecovery Technologies. D. Lu: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); NeuroRecovery Technologies. R. Edgerton: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); NeuroRecovery Technologies.

Support: NIH Grant U01EB015521

Authors: *M. ALAM1, B. JIN2, G. GARCIA-ALIAS2, Y. GERASIMENKO2, H. ZHONG2, R. ROY2, D. LU1, R. EDGERTON2; 1Dept. of Neurosurg., 2Dept. of Integrative Biol. and Physiol., Univ. of California Los Angeles, Los Angeles, CA

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