To treat diseases associated with vagal nerve control of peripheral organs, it is necessary to selectively activate efferent and afferent fibers in the vagus. As a result of the nerve’s complex anatomy, fiber-specific activation proves challenging. Spatially selective neuromodulation using micromagnetic stimulation(
- NSF-PAR ID:
- 10417527
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Neural Engineering
- Volume:
- 20
- Issue:
- 3
- ISSN:
- 1741-2560
- Page Range / eLocation ID:
- Article No. 036022
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract μ MS) is showing incredible promise. This neuromodulation technique uses microcoils(μ coils) to generate magnetic fields by powering them with a time-varying current. Following the principles of Faraday’s law of induction, a highly directional electric field is induced in the nerve from the magnetic field. In this study on rodent cervical vagus, a solenoidalμ coil was oriented at an angle to left and right branches of the nerve. The aim of this study was to measure changes in the mean arterial pressure (MAP) and heart rate (HR) followingμ MS of the vagus. Theμ coils were powered by a single-cycle sinusoidal current varying in pulse widths(PW = 100, 500, and 1000μ sec) at a frequency of 20 Hz. Under the influence of isoflurane,μ MS of the left vagus at 1000μ sec PW led to an average drop in MAP of 16.75 mmHg(n = 7). In contrast,μ MS of the right vagus under isoflurane resulted in an average drop of 11.93 mmHg in the MAP(n = 7). Surprisingly, there were no changes in HR to either right or left vagalμ MS suggesting the drop in MAP associated with vagusμ MS was the result of stimulation of afferent, but not efferent fibers. In urethane anesthetized rats, no changes in either MAP or HR were observed uponμ MS of the right or left vagus(n = 3). These findings suggest the choice of anesthesia plays a key role in determining the efficacy ofμ MS on the vagal nerve. Absence of HR modulation uponμ MS could offer alternative treatment options using VNS with fewer heart-related side-effects. -
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Abstract Background The purpose of this study was to evaluate if kilohertz frequency alternating current (KHFAC) stimulation of peripheral nerve could serve as a treatment for lumbar radiculopathy. Prior work shows that KHFAC stimulation can treat sciatica resulting from chronic sciatic nerve constriction. Here, we evaluate if KHFAC stimulation is also beneficial in a more physiologic model of low back pain which mimics nucleus pulposus (NP) impingement of a lumbar dorsal root ganglion (DRG).
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p < 0.05), with tactile allodynia reversed during KHFAC stimulation (p < 0.01). Midfoot flexion during locomotion was decreased after injury but improved with KHFAC stimulation (p < 0.05). Animals also placed more weight on their injured limb when KHFAC stimulation was applied (p < 0.05). Electrophysiology measurements at end point showed decreased, but not blocked, compound nerve action potentials with KHFAC stimulation (p < 0.05).Conclusions KHFAC stimulation decreases hypersensitivity but does not cause additional gait compensations. This supports the idea that KHFAC stimulation applied to a peripheral nerve may be able to treat chronic pain resulting from sciatic nerve root inflammation.
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