The mammalian lumbar spinal cord has the capability to generate locomotor activity in the absence of input from the brain. Previously, we reported that transcutaneous electrical stimulation of the spinal cord at vertebral level T11 can activate the locomotor circuitry in noninjured subjects when their legs are placed in a gravity neutral position using horizontal suspension device. In this conditions the mechanical stimulation to the soles of the feet could induce the locomotor like activity as well. The objective of this study was to evaluate the effect of non-invasive activation of the neural networks on the spinal cord via transcutaneous stimulation and/or sensory mechanical stimulation of the foot while normal subjects were suspended in vertical position with 100% body weight support over a treadmill with no contract with the treadmill surface. We observed that multi-site independent spinal cord stimulation at T11, T12, and L1 at 30 Hz can activate the neural locomotor networks to generate alternating movements of the two legs with well coordinated EMG patterns in proximal and distal muscles. Sensory stimulation on the other hand resulted in lower excursions in the various joints with less robust EMG patterns. The overall integrated EMG was lower in all muscles except the ankle extensors during sensory stimulation compared to spinal cord stimulation. The best results were observed in all subjects during simultaneous sensory stimulation and spinal cord stimulation with significantly higher EMG levels, robust excursion of various joints and activation patterns. This synergistic effect suggest the convergence of sensory afferent inputs from foot receptors and transcutaneous spinal cord stimulation on similar neuronal networks. This phenomenon has high impact as a strategy to neuromodulate the spinal circuitry and to regain motor functions after a severe SCI.
Society for Neuroscience Chicago 2015 Nanosymposium Advances in SCI Research and Plasticity
Support: Russian Scientific Fund project № 14-45-00024 NIH U01EB15521, NIH R01EB007615
Authors: *P. GAD1, D. SAYENKO2, Z. MCKINNNEY2, R. GORODNICHEV3, T. MOSHONKINA4, I. KOZLOVSKAYA5, V. EDGERTON2, Y. GERASIMENKO2,4; 1Univ. Of California Los Angeles, Woodland Hills, CA; 2Univ. Of California Los Angeles, Los Angeles, CA; 3Vehlie Lukie Sports Inst., Vehlie Lukie, Russian Federation; 4Pavlov Inst. of Physiol., St. Petersburg, Russian Federation; 5Inst. of Biomed. Problems, Moscow, Russian Federation
Disclosures: P. Gad: None. D. Sayenko: None. Z. McKinnney: None. R. Gorodnichev: None. T. Moshonkina: None. I. Kozlovskaya: None. V. Edgerton: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); Neurorecovery Technologies. Y. Gerasimenko: E. Ownership Interest (stock, stock options, royalty, receipt of intellectual property rights/patent holder, excluding diversified mutual funds); Neurorecovery Technologies.