Evaluation of optimal electrode configurations for epidural spinal cord stimulation in cervical spinal cord injured rats

Monzurul Alam, Guillermo Garcia-Alias, Prithvi K. Shah, Yury Gerasimenko, Hui Zhong, Roland R. Roy, V. Reggie Edgerton

Research output: Journal article publicationJournal articleAcademic researchpeer-review

27 Citations (Scopus)


Background: Epidural spinal cord stimulation is a promising technique for modulating the level of excitability and reactivation of dormant spinal neuronal circuits after spinal cord injury (SCI). We examined the ability of chronically implanted epidural stimulation electrodes within the cervical spinal cord to (1) directly elicit spinal motor evoked potentials (sMEPs) in forelimb muscles and (2) determine whether these sMEPs can serve as a biomarker of forelimb motor function after SCI. New method: We implanted EMG electrodes in forelimb muscles and epidural stimulation electrodes at C6 and C8 in adult rats. After recovering from a dorsal funiculi crush (C4), rats were tested with different stimulation configurations and current intensities to elicit sMEPs and determined forelimb grip strength. Results: sMEPs were evoked in all muscles tested and their characteristics were dependent on electrode configurations and current intensities. C6(-) stimulation elicited more robust sMEPs than stimulation at C8(-). Stimulating C6 and C8 simultaneously produced better muscle recruitment and higher grip strengths than stimulation at one site. Comparison with existing method(s): Classical method to select the most optimal stimulation configuration is to empirically test each combination individually for every subject and relate to functional improvements. This approach is impractical, requiring extensively long experimental time to determine the more effective stimulation parameters. Our proposed method is fast and physiologically sound. Conclusions: Results suggest that sMEPs from forelimb muscles can be useful biomarkers for identifying optimal parameters for epidural stimulation of the cervical spinal cord after SCI.

Original languageEnglish
Pages (from-to)50-57
Number of pages8
JournalJournal of Neuroscience Methods
Publication statusPublished - 1 May 2015
Externally publishedYes


  • Cervical spinal cord injury
  • Dorsal funiculi crush
  • Epidural stimulation
  • Motor evoked potentials

ASJC Scopus subject areas

  • General Neuroscience


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