The objective of this research is to explore the safety and effectiveness of microstimulation of the spinal cord. If successful, such a technique could be part of a prosthesis to restore genito- urinary, bowel, and other motor functions to victims of spinal cord injury. Information from spinal cord microstimulation studies is especially needed by designers of neural prostheses for paraplegic individuals who have sustained injuries to their spinal cords above the lumbosacral region. In particular, evidence from current studies indicate that is possible to selectively excite neurons innervating the bladder detrusor muscle while simultaneously stimulating interneurons which have inhibitory synaptic connections with neurons innervating the external urethral sphincter. Likewise, discrete control of penile erection, ejaculation, bowel evacuation, and control of the somatic musculature of the limbs may be possible by selective spinal cord microstimulation below the level of spinal cord injury. Current contract research has provided information about the locations of afferent and efferent neurons as well as interneurons controlling urinary function in the cat spinal cord using both normal and spinalized animals. Limited mapping has also been performed on the neurons that control erection in the male cat. The current contract research is also studying the possibility of controlling, by spinal cord microstimulation, the somatic musculature of individuals paralyzed as the result of spinal cord injuries. As an initial feasibility study, the locations of the neurons controlling the flexors and extensors of the knee are being mapped. Microstimulation of these mapped areas has demonstrated activation of both knee flexors and extensors. The present research will provide more detailed maps, and will determine quantitatively, the degree of motor control of paralyzed muscles that can be produced by microstimulation of the lumbosacral spinal cord.

Project Start
1998-09-30
Project End
2001-09-29
Budget Start
1998-09-30
Budget End
1999-09-29
Support Year
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Lemay, Michel A; Grasse, Dane; Grill, Warren M (2009) Hindlimb endpoint forces predict movement direction evoked by intraspinal microstimulation in cats. IEEE Trans Neural Syst Rehabil Eng 17:379-89
Lemay, Michel A; Bhowmik-Stoker, Manoshi; McConnell, George C et al. (2007) Role of biomechanics and muscle activation strategy in the production of endpoint force patterns in the cat hindlimb. J Biomech 40:3679-87
Gustafson, K J; Moffitt, M A; Wang, X et al. (2006) Topography of spinal neurons active during hindlimb withdrawal reflexes in the decerebrate cat. Neuroscience 141:1983-94
Moffitt, Michael A; Grill, Warren M (2004) Electrical localization of neural activity in the dorsal horn of the spinal cord: a modeling study. Ann Biomed Eng 32:1694-709
Grill, W M; Kirsch, R F (2000) Neuroprosthetic applications of electrical stimulation. Assist Technol 12:20-Jun
Barbeau, H; McCrea, D A; O'Donovan, M J et al. (1999) Tapping into spinal circuits to restore motor function. Brain Res Brain Res Rev 30:27-51
Grill, W M; Bhadra, N; Wang, B (1999) Bladder and urethral pressures evoked by microstimulation of the sacral spinal cord in cats. Brain Res 836:19-30