Year: 2011
Type: article
Abstract: Functional electrical stimulation is an important therapeutic tool for improving the quality of life of patients following spinal cord injury. Investigators have developed neural interfaces of varying invasiveness and implant location to stimulate neurons and evoke motor responses. Here we present an alternative interface with the ventral roots (VR) or dorsal root ganglia (DRG). We designed preliminary electrophysiology experiments to evaluate the performance of these interfaces, wherein we stimulated lumbar VR or DRG through a penetrating single-wire microelectrode while recording fixed endpoint force and bipolar electromyograms of hindlimb muscles. Data from rat experiments provided evidence for selectivity for target muscles, graded force recruitment, and nontrivial force magnitudes of up to 1 N. Electrophysiology experiments in cats produced similar results to those in rats. In addition, we developed a computational model to estimate the size and quantity of fibers recruited as a function of stimulus amplitude. This model confirmed electrophysiology results showing differences in the thresholds to detect activity in response to VR versus DRG stimulation. The model also provided insights into the mechanisms by which DRG stimulation is more likely to recruit smaller fibers than larger fibers. Finally, we discuss further work to develop and evaluate these potential interfaces.
Author: Dennis Bourbeau
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W111238453