Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats
IntroductionEpidural electrical stimulation (EES) has been shown to improve motor dysfunction after spinal cord injury (SCI) by activating residual locomotor neural networks. However, the stimulation current often spreads excessively, leading to activation of non-target muscles and reducing the accu...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2023-11-01
|
| Series: | Frontiers in Neuroscience |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fnins.2023.1282558/full |
| _version_ | 1797629589964455936 |
|---|---|
| author | Xiao-Jun Guo Ziyi Zhao Jia-Qi Chang Le-Wei He Wen-Nan Su Ting Feng Can Zhao Meng Xu Jia-Sheng Rao |
| author_facet | Xiao-Jun Guo Ziyi Zhao Jia-Qi Chang Le-Wei He Wen-Nan Su Ting Feng Can Zhao Meng Xu Jia-Sheng Rao |
| author_sort | Xiao-Jun Guo |
| collection | DOAJ |
| description | IntroductionEpidural electrical stimulation (EES) has been shown to improve motor dysfunction after spinal cord injury (SCI) by activating residual locomotor neural networks. However, the stimulation current often spreads excessively, leading to activation of non-target muscles and reducing the accuracy of stimulation regulation.ObjectivesNear-infrared nerve stimulation (nINS) was combined with EES to explore its regulatory effect on lower limb muscle activity in spinal-cord-transected rats.MethodsIn this study, stimulation electrodes were implanted into the rats’ L3–L6 spinal cord segment with T8 cord transected. Firstly, a series of EES parameters (0.2–0.6 mA and 20–60 Hz) were tested to determine those that specifically regulate the tibialis anterior (TA) and medial gastrocnemius (MG). Subsequently, to determine the effect of combined optical and electrical stimulation, near-infrared laser with a wavelength of 808 nm was used to irradiate the L3–L6 spinal cord segment while EES was performed. The amplitude of electromyography (EMG), the specific activation intensity of the target muscle, and the minimum stimulus current intensity to induce joint movement (motor threshold) under a series of optical stimulation parameters (power: 0.0–2.0 W; pulse width: 0–10 ms) were investigated and analyzed.ResultsEES stimulation with 40 Hz at the L3 and L6 spinal cord segments specifically activated TA and MG, respectively. High stimulation intensity (>2 × motor threshold) activated non-target muscles, while low stimulation frequency (<20 Hz) produced intermittent contraction. Compared to electrical stimulation alone (0.577 ± 0.081 mV), the combined stimulation strategy could induce stronger EMG amplitude of MG (1.426 ± 0.365 mV) after spinal cord injury (p < 0.01). The combined application of nINS effectively decreased the EES-induced motor threshold of MG (from 0.237 ± 0.001 mA to 0.166 ± 0.028 mA, p < 0.001). Additionally, the pulse width (PW) of nINS had a slight impact on the regulation of muscle activity. The EMG amplitude of MG only increased by ~70% (from 3.978 ± 0.240 mV to 6.753 ± 0.263 mV) when the PW increased by 10-fold (from 1 to 10 ms).ConclusionThe study demonstrates the feasibility of epidural combined electrical and optical stimulation for highly specific regulation of muscle activity after SCI, and provides a new strategy for improving motor dysfunction caused by SCI. |
| first_indexed | 2024-03-11T10:55:21Z |
| format | Article |
| id | doaj.art-92c5b89a0e1d447e94047cd90ea1642d |
| institution | Directory Open Access Journal |
| issn | 1662-453X |
| language | English |
| last_indexed | 2024-03-11T10:55:21Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroscience |
| spelling | doaj.art-92c5b89a0e1d447e94047cd90ea1642d2023-11-13T09:56:10ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2023-11-011710.3389/fnins.2023.12825581282558Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured ratsXiao-Jun Guo0Ziyi Zhao1Jia-Qi Chang2Le-Wei He3Wen-Nan Su4Ting Feng5Can Zhao6Meng Xu7Jia-Sheng Rao8Beijing Key Laboratory for Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, ChinaDepartment of Orthopedics, The First Medical Center of PLA General Hospital, Beijing, ChinaSmart Fluid Equipment and Manufacture Lab, School of Automation Science and Electrical Engineering, Beihang Univeristy, Beijing, ChinaBeijing Key Laboratory for Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, ChinaBeijing Key Laboratory for Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, ChinaBeijing Key Laboratory for Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, ChinaInstitute of Rehabilitation Engineering, China Rehabilitation Science Institute, Beijing, ChinaDepartment of Orthopedics, The First Medical Center of PLA General Hospital, Beijing, ChinaBeijing Key Laboratory for Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, ChinaIntroductionEpidural electrical stimulation (EES) has been shown to improve motor dysfunction after spinal cord injury (SCI) by activating residual locomotor neural networks. However, the stimulation current often spreads excessively, leading to activation of non-target muscles and reducing the accuracy of stimulation regulation.ObjectivesNear-infrared nerve stimulation (nINS) was combined with EES to explore its regulatory effect on lower limb muscle activity in spinal-cord-transected rats.MethodsIn this study, stimulation electrodes were implanted into the rats’ L3–L6 spinal cord segment with T8 cord transected. Firstly, a series of EES parameters (0.2–0.6 mA and 20–60 Hz) were tested to determine those that specifically regulate the tibialis anterior (TA) and medial gastrocnemius (MG). Subsequently, to determine the effect of combined optical and electrical stimulation, near-infrared laser with a wavelength of 808 nm was used to irradiate the L3–L6 spinal cord segment while EES was performed. The amplitude of electromyography (EMG), the specific activation intensity of the target muscle, and the minimum stimulus current intensity to induce joint movement (motor threshold) under a series of optical stimulation parameters (power: 0.0–2.0 W; pulse width: 0–10 ms) were investigated and analyzed.ResultsEES stimulation with 40 Hz at the L3 and L6 spinal cord segments specifically activated TA and MG, respectively. High stimulation intensity (>2 × motor threshold) activated non-target muscles, while low stimulation frequency (<20 Hz) produced intermittent contraction. Compared to electrical stimulation alone (0.577 ± 0.081 mV), the combined stimulation strategy could induce stronger EMG amplitude of MG (1.426 ± 0.365 mV) after spinal cord injury (p < 0.01). The combined application of nINS effectively decreased the EES-induced motor threshold of MG (from 0.237 ± 0.001 mA to 0.166 ± 0.028 mA, p < 0.001). Additionally, the pulse width (PW) of nINS had a slight impact on the regulation of muscle activity. The EMG amplitude of MG only increased by ~70% (from 3.978 ± 0.240 mV to 6.753 ± 0.263 mV) when the PW increased by 10-fold (from 1 to 10 ms).ConclusionThe study demonstrates the feasibility of epidural combined electrical and optical stimulation for highly specific regulation of muscle activity after SCI, and provides a new strategy for improving motor dysfunction caused by SCI.https://www.frontiersin.org/articles/10.3389/fnins.2023.1282558/fullspinal cord injuryepidural electrical stimulationnear-infrared nerve stimulationmuscle activityneuromodulationmotor function |
| spellingShingle | Xiao-Jun Guo Ziyi Zhao Jia-Qi Chang Le-Wei He Wen-Nan Su Ting Feng Can Zhao Meng Xu Jia-Sheng Rao Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats Frontiers in Neuroscience spinal cord injury epidural electrical stimulation near-infrared nerve stimulation muscle activity neuromodulation motor function |
| title | Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats |
| title_full | Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats |
| title_fullStr | Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats |
| title_full_unstemmed | Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats |
| title_short | Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats |
| title_sort | epidural combined optical and electrical stimulation induces high specificity activation of target muscles in spinal cord injured rats |
| topic | spinal cord injury epidural electrical stimulation near-infrared nerve stimulation muscle activity neuromodulation motor function |
| url | https://www.frontiersin.org/articles/10.3389/fnins.2023.1282558/full |
| work_keys_str_mv | AT xiaojunguo epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT ziyizhao epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT jiaqichang epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT leweihe epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT wennansu epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT tingfeng epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT canzhao epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT mengxu epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats AT jiashengrao epiduralcombinedopticalandelectricalstimulationinduceshighspecificityactivationoftargetmusclesinspinalcordinjuredrats |