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Sagalajev B, Zhang T, Abdollahi N, Yousefpour N, Medlock L, Al-Basha D, Ribeiro-da-Silva A, Esteller R, Ratté S, Prescott SA. Absence of paresthesia during high-rate spinal cord stimulation reveals importance of synchrony for sensations evoked by electrical stimulation. Neuron 2024; 112:404-420.e6. [PMID: 37972595 DOI: 10.1016/j.neuron.2023.10.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/24/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Electrically activating mechanoreceptive afferents inhibits pain. However, paresthesia evoked by spinal cord stimulation (SCS) at 40-60 Hz becomes uncomfortable at high pulse amplitudes, limiting SCS "dosage." Kilohertz-frequency SCS produces analgesia without paresthesia and is thought, therefore, not to activate afferent axons. We show that paresthesia is absent not because axons do not spike but because they spike asynchronously. In a pain patient, selectively increasing SCS frequency abolished paresthesia and epidurally recorded evoked compound action potentials (ECAPs). Dependence of ECAP amplitude on SCS frequency was reproduced in pigs, rats, and computer simulations and is explained by overdrive desynchronization: spikes desychronize when axons are stimulated faster than their refractory period. Unlike synchronous spikes, asynchronous spikes fail to produce paresthesia because their transmission to somatosensory cortex is blocked by feedforward inhibition. Our results demonstrate how stimulation frequency impacts synchrony based on axon properties and how synchrony impacts sensation based on circuit properties.
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Affiliation(s)
- Boriss Sagalajev
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Tianhe Zhang
- Boston Scientific Neuromodulation, Valencia, CA 25155, USA
| | - Nooshin Abdollahi
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Noosha Yousefpour
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Laura Medlock
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Dhekra Al-Basha
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | | | - Stéphanie Ratté
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Steven A Prescott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Medvediev VV, Oleksenko NP, Pichkur LD, Verbovska SA, Savosko SI, Draguntsova NG, Lontkovskiy YA, Vaslovych VV, Tsymbalyuk VI. Effect of Implantation of a Fibrin Matrix Associated with Neonatal Brain Cells on the Course of an Experimental Spinal Cord Injury. CYTOL GENET+ 2022. [DOI: 10.3103/s0095452722020086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Borrell JA, Krizsan-Agbas D, Nudo RJ, Frost SB. Activity dependent stimulation increases synaptic efficacy in spared pathways in an anesthetized rat model of spinal cord contusion injury. Restor Neurol Neurosci 2022; 40:17-33. [PMID: 35213336 PMCID: PMC9108576 DOI: 10.3233/rnn-211214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Closed-loop neuromodulation systems have received increased attention in recent years as potential therapeutic approaches for treating neurological injury and disease. OBJECTIVE The purpose of this study was to assess the ability of intraspinal microstimulation (ISMS), triggered by action potentials (spikes) recorded in motor cortex, to alter synaptic efficacy in descending motor pathways in an anesthetized rat model of spinal cord injury (SCI). METHODS Experiments were carried out in adult, male, Sprague Dawley rats with a moderate contusion injury at T8. For activity-dependent stimulation (ADS) sessions, a recording microelectrode was used to detect neuronal spikes in motor cortex that triggered ISMS in the spinal cord grey matter. SCI rats were randomly assigned to one of four experimental groups differing by: a) cortical spike-ISMS stimulus delay (10 or 25 ms) and b) number of ISMS pulses (1 or 3). Four weeks after SCI, ADS sessions were conducted in three consecutive 1-hour conditioning bouts for a total of 3 hours. At the end of each conditioning bout, changes in synaptic efficacy were assessed using intracortical microstimulation (ICMS) to examine the number of spikes evoked in spinal cord neurons during 5-minute test bouts. A multichannel microelectrode recording array was used to record cortically-evoked spike activity from multiple layers of the spinal cord. RESULTS The results showed that ADS resulted in an increase in cortically-evoked spikes in spinal cord neurons at specific combinations of spike-ISMS delays and numbers of pulses. Efficacy in descending motor pathways was increased throughout all dorsoventral depths of the hindlimb spinal cord. CONCLUSIONS These results show that after an SCI, ADS can increase synaptic efficacy in spared pathways between motor cortex and spinal cord. This study provides further support for the potential of ADS therapy as an effective method for enhancing descending motor control after SCI.
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Affiliation(s)
- Jordan A. Borrell
- Bioengineering Program, University of Kansas, Lawrence, KS, USA
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
| | - Dora Krizsan-Agbas
- Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Randolph J. Nudo
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Shawn B. Frost
- Landon Center on Aging, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City, KS, USA
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Wang D, Chen F, Fang B, Zhang Z, Dong Y, Tong X, Ma H. MiR-128-3p Alleviates Spinal Cord Ischemia/Reperfusion Injury Associated Neuroinflammation and Cellular Apoptosis via SP1 Suppression in Rat. Front Neurosci 2020; 14:609613. [PMID: 33424542 PMCID: PMC7785963 DOI: 10.3389/fnins.2020.609613] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/04/2020] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Neuroinflammation and cellular apoptosis caused by spinal cord ischemia/reperfusion (I/R) injury result in neurological dysfunction. MicroRNAs (miRs) have crucial functions in spinal cord I/R injury pathogenesis according to previous evidences. Herein, whether miR-128-3p contributes to spinal cord I/R injury by regulating specificity protein 1 (SP1) was assessed. METHODS A rat model of spinal cord I/R injury was established by occluding the aortic arch for 14 min. Then, miR-128-3p's interaction with SP1 was detected by dual-luciferase reporter assays. Next, miR-128-3p mimic and inhibitor, as well as adenovirus-delivered shRNA specific for SP1 were injected intrathecally for assessing the effects of miR-128-3p and SP1 on rats with spinal cord I/R injury. SP1, Bax and Bcl-2 expression levels in I/R injured spinal cord tissues were evaluated by Western blotting, while IL-1β, TNF-α, and IL-6 were quantitated by ELISA. Tarlov scores were obtained to detect hind-limb motor function. Evans blue (EB) dye extravasation was utilized to examine blood-spinal cord barrier (BSCB) permeability. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) staining was performed for neuronal apoptosis assessment. RESULTS MiR-128-3p expression was decreased, while SP1 amounts were increased in rat spinal cord tissue specimens following I/R. SP1 was identified as a miR-128-3p target and downregulated by miR-128-3p. MiR-128-3p overexpression or SP1 silencing alleviated I/R-induced neuroinflammation and cell apoptosis, and improved Tarlov scores, whereas pretreatment with miR-128-3p inhibitor aggravated the above injuries. CONCLUSION Overexpression of miR-128-3p protects neurons from neuroinflammation and apoptosis during spinal cord I/R injury partially by downregulating SP1.
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Affiliation(s)
| | | | | | | | | | | | - Hong Ma
- Department of Anesthesiology, The First Hospital of China Medical University, Shenyang, China
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Shkorbatova PY, Lyakhovetskii VA, Merkulyeva NS, Veshchitskii AA, Bazhenova EY, Laurens J, Pavlova NV, Musienko PE. Prediction Algorithm of the Cat Spinal Segments Lengths and Positions in Relation to the Vertebrae. Anat Rec (Hoboken) 2019; 302:1628-1637. [PMID: 30548810 DOI: 10.1002/ar.24054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 09/11/2018] [Accepted: 09/26/2018] [Indexed: 01/25/2023]
Abstract
Detailed knowledge of the topographic organization and precise access to the spinal cord segments is crucial for the neurosurgical manipulations as well as in vivo neurophysiological investigations of the spinal networks involved in sensorimotor and visceral functions. Because of high individual variability, accurate identification of particular portion of the lumbosacral enlargement is normally possible only during postmortem dissection. Yet, it is often necessary to determine the precise location of spinal segments prior to in vivo investigation, targeting spinal cord manipulations, neurointerface implantations, and neuronal activity recordings. To solve this problem, we have developed an algorithm to predict spinal segments locations based on their relation to vertebral reference points. The lengths and relative positions of the spinal cord segments (T13-S3) and the vertebrae (VT13-VL7) were measured in 17 adult cats. On the basis of these measurements, we elaborated the estimation procedure: the cubic regression of the ratio of the segment's length to the lengths of the VL2 vertebra was used for the determination of segment's length; and the quadratic regression of the ratio of their positions in relation to the VL2 rostral part was used to determine the position of the segments. The coefficients of these regressions were calculated at the training sample (nine cats) and were then confirmed at the testing sample (eight cats). Although the quality of the prediction is decreased in the caudal direction, we found high correlations between the regressions and real data. The proposed algorithm can be further translated to other species including human. Anat Rec, 302:1628-1637, 2019. © 2018 American Association for Anatomy.
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Affiliation(s)
- Polina Y Shkorbatova
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia
| | - Vsevolod A Lyakhovetskii
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia.,Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, Russia
| | - Natalia S Merkulyeva
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia.,Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, Russia.,Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia
| | | | - Elena Y Bazhenova
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia
| | - Jean Laurens
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas
| | - Natalia V Pavlova
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia
| | - Pavel E Musienko
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint-Petersburg, Russia.,Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Children's Surgery and Orthopedic Clinic, Department of Nonpulmonary Tuberculosis, Institute of Phthysiopulmonology, Saint-Petersburg, Russia
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Bamford JA, Todd KG, Mushahwar VK. The effects of intraspinal microstimulation on spinal cord tissue in the rat. Biomaterials 2010; 31:5552-63. [PMID: 20430436 DOI: 10.1016/j.biomaterials.2010.03.051] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 03/19/2010] [Indexed: 10/19/2022]
Abstract
Intraspinal microstimulation (ISMS) involves the implantation of microwires into the spinal cord below the level of an injury to excite neural networks involved in the control of locomotion in the lower limbs. The goal of this study was to examine the potential spinal cord damage that might occur with chronic ISMS. We employed functional measures of force recruitment and immunohistochemical processing of serial spinal cord sections to evaluate any damage induced by spinal transection, implantation of ISMS arrays, and electrical stimulation of 4h/day for 30 days. Functional measurements showed no change in force recruitment following transection and chronic ISMS, indicating no changes to underlying neural networks. The implantation of sham intraspinal microwires produced a spatially-limited increase in the density of microglia/macrophages and GFAP+ astrocytes adjacent to the microwire tracks, indicating a persistent immune response. Most importantly, these results were not different from those around microwires that were chronically pulsed with charge levels up to 48nC/phase. Likewise, measurements of neuronal density indicated no decrease in neuronal cell bodies in the ventral grey matter surrounding ISMS microwires (243.6/mm2+/-35.3/mm2) compared to tissue surrounding sham microwires (207.8/mm2+/-38.8/mm2). We conclude that the implantation of intraspinal microwires and chronic application of ISMS are well tolerated by spinal cord tissue.
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Affiliation(s)
- Jeremy A Bamford
- Centre for Neuroscience, Faculty of Medicine and Dentistry, 5005 Katz Group-Rexall Centre for Pharmacy and Health Research, University of Alberta, Edmonton, Alberta, Canada
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