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Upper-limb muscle responses to epidural, subdural and intraspinal stimulation of the cervical spinal cord

Lookup NU author(s): Professor Andrew Jackson

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

Objective. Electrical stimulation of the spinal cord has potential applications following spinal cord injury for reanimating paralysed limbs and promoting neuroplastic changes that may facilitate motor rehabilitation. Here we systematically compare the efficacy, selectivity and frequency-dependence of different stimulation methods in the cervical enlargement of anaesthetized monkeys. Approach. Stimulating electrodes were positioned at multiple epidural and subdural sites on both dorsal and ventral surfaces, as well as at different depths within the spinal cord. Motor responses were recorded from arm, forearm and hand muscles. Main results. Stimulation efficacy increased from dorsal to ventral stimulation sites, with the exception of ventral epidural electrodes which had the highest recruitment thresholds. Compared to epidural and intraspinal methods, responses to subdural stimulation were more selective but also more similar between adjacent sites. Trains of stimuli delivered to ventral sites elicited consistent responses at all frequencies whereas from dorsal sites we observed a mixture of short-latency facilitation and long-latency suppression. Finally, paired stimuli delivered to dorsal surface and intraspinal sites exhibited symmetric facilitatory interactions at interstimulus intervals between 2-5 ms whereas on the ventral side interactions tended to be suppressive for near-simultaneous stimuli. Significance. We interpret these results in the context of differential activation of afferent and efferent roots and intraspinal circuit elements. In particular, we propose that distinct direct and indirect actions of spinal cord stimulation on motoneurons may be advantageous for different applications, and this should be taken into consideration when designing neuroprostheses for upper-limb function.


Publication metadata

Author(s): Sharpe AN, Jackson A

Publication type: Article

Publication status: Published

Journal: Journal of Neural Engineering

Year: 2014

Volume: 11

Issue: 1

Pages: 1-16

Print publication date: 01/02/2014

Online publication date: 08/01/2014

Acceptance date: 14/11/2013

Date deposited: 06/07/2015

ISSN (print): 1741-2560

ISSN (electronic): 1741-2552

Publisher: Institute of Physics Publishing Ltd

URL: http://dx.doi.org/10.1088/1741-2560/11/1/016005

DOI: 10.1088/1741-2560/11/1/016005


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Funding

Funder referenceFunder name
086561Wellcome Trust

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