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Radomski KL, Zi X, Lischka FW, Noble MD, Galdzicki Z, Armstrong RC. Acute axon damage and demyelination are mitigated by 4-aminopyridine (4-AP) therapy after experimental traumatic brain injury. Acta Neuropathol Commun 2022; 10:67. [PMID: 35501931 PMCID: PMC9059462 DOI: 10.1186/s40478-022-01366-z] [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] [Received: 02/04/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Damage to long axons in white matter tracts is a major pathology in closed head traumatic brain injury (TBI). Acute TBI treatments are needed that protect against axon damage and promote recovery of axon function to prevent long term symptoms and neurodegeneration. Our prior characterization of axon damage and demyelination after TBI led us to examine repurposing of 4-aminopyridine (4-AP), an FDA-approved inhibitor of voltage-gated potassium (Kv) channels. 4-AP is currently indicated to provide symptomatic relief for patients with chronic stage multiple sclerosis, which involves axon damage and demyelination. We tested clinically relevant dosage of 4-AP as an acute treatment for experimental TBI and found multiple benefits in corpus callosum axons. This randomized, controlled pre-clinical study focused on the first week after TBI, when axons are particularly vulnerable. 4-AP treatment initiated one day post-injury dramatically reduced axon damage detected by intra-axonal fluorescence accumulations in Thy1-YFP mice of both sexes. Detailed electron microscopy in C57BL/6 mice showed that 4-AP reduced pathological features of mitochondrial swelling, cytoskeletal disruption, and demyelination at 7 days post-injury. Furthermore, 4-AP improved the molecular organization of axon nodal regions by restoring disrupted paranode domains and reducing Kv1.2 channel dispersion. 4-AP treatment did not resolve deficits in action potential conduction across the corpus callosum, based on ex vivo electrophysiological recordings at 7 days post-TBI. Thus, this first study of 4-AP effects on axon damage in the acute period demonstrates a significant decrease in multiple pathological hallmarks of axon damage after experimental TBI.
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Affiliation(s)
- Kryslaine L. Radomski
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Xiaomei Zi
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Fritz W. Lischka
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Mark D. Noble
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Ave, Box 633, Rochester, NY 14642 USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
| | - Regina C. Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814 USA
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Manto KM, Govindappa PK, Parisi D, Karuman Z, Martinazzi B, Hegarty JP, Talukder MAH, Elfar JC. (4-Aminopyridine)-PLGA-PEG as a Novel Thermosensitive and Locally Injectable Treatment for Acute Peripheral Nerve Injury. ACS APPLIED BIO MATERIALS 2021; 4:4140-4151. [PMID: 34142019 DOI: 10.1021/acsabm.0c01566] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Traumatic peripheral nerve injury (TPNI) represents a major medical problem that results in loss of motor and sensory function, and in severe cases, limb paralysis and amputation. To date, there are no effective treatments beyond surgery in selective cases. In repurposing studies, we found that daily systemic administration of the FDA-approved drug 4-aminopyridine (4-AP) enhanced functional recovery after acute peripheral nerve injury. This study was aimed at constructing a novel local delivery system of 4-AP using thermogelling polymers. We optimized a thermosensitive (4-AP)-poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) block copolymer formulation. (4-AP)-PLGA-PEG exhibited controlled release of 4-AP both in vitro and in vivo for approximately 3 weeks, with clinically relevant safe serum levels in animals. Rheological investigation showed that (4-AP)-PLGA-PEG underwent a solution to gel transition at 32 °C, a physiologically relevant temperature, allowing us to administer it to an injured limb while subsequently forming an in situ gel. A single local administration of (4-AP)-PLGA-PEG remarkably enhanced motor and sensory functional recovery on post-sciatic nerve crush injury days 1, 3, 7, 14, and 21. Moreover, immunohistochemical studies of injured nerves treated with (4-AP)-PLGA-PEG demonstrated an increased expression of neurofilament heavy chain (NF-H) and myelin protein zero (MPZ) proteins, two major markers of nerve regeneration. These findings demonstrate that (4-AP)-PLGA-PEG may be a promising long-acting local therapeutic agent in TPNI, for which no pharmacologic treatment exists.
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Affiliation(s)
- Kristen M Manto
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - Prem Kumar Govindappa
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - Daniele Parisi
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zara Karuman
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - Brandon Martinazzi
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - John P Hegarty
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - M A Hassan Talukder
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
| | - John C Elfar
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedic Research and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, United States
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Gurjar AA, Manto KM, Estrada JA, Kaufman M, Sun D, Talukder MAH, Elfar JC. 4-Aminopyridine: A Single-Dose Diagnostic Agent to Differentiate Axonal Continuity in Nerve Injuries. Mil Med 2021; 186:479-485. [PMID: 33499448 DOI: 10.1093/milmed/usaa310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/23/2020] [Accepted: 09/22/2020] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Traumatic peripheral nerve injuries (TPNIs) are increasingly prevalent in battlefield trauma, and the functional recovery with TPNIs depends on axonal continuity. Although the physical examination is the main tool for clinical diagnosis with diagnostic work up, there is no diagnostic tool available to differentiate nerve injuries based on axonal continuity. Therefore, treatment often relies on "watchful waiting," and this leads to muscle weakness and further reduces the chances of functional recovery. 4-aminopyridine (4-AP) is clinically used in multiple sclerosis patients for walking performance improvement. Preliminary results in conscious mice suggested a diagnostic role of 4-AP in distinguishing axonal continuity. In this study, we thought to evaluate the diagnostic potential of 4-AP on the axonal continuity in unawake/sedated animals. MATERIALS AND METHODS Rat sciatic nerve crush and transection injuries were used in this study. Briefly, rats were anesthetized with isoflurane and mechanically ventilated with oxygen-balanced vaporized isoflurane. Sciatic nerve and triceps surae muscles were exposed by blunt dissection, and a stimulating electrode was placed under a sciatic nerve proximal to the crush injury. A force transducer measured muscle tension response to electrical stimulation of sciatic nerve. Muscle response was measured before crush, after crush, and 30 minutes after systemic 4-AP (150 µg/kg) or local (4-AP)-poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG) treatment. RESULTS We found that both crush and transection injuries in sciatic nerve completely abolished muscle response to electrical stimulation. Single dose of systemic 4-AP and local (4-AP)-PLGA-PEG treatment with crush injury significantly restored muscle responses to electrical stimulation after 30 minutes of administration. However, systemic 4-AP treatment had no effect on muscle response after nerve transection. These results clearly demonstrate that 4-AP can restore nerve conduction and produce muscle response within minutes of administration only when there is a nerve continuity, even in the sedated animal. CONCLUSIONS We conclude that 4-AP could be a promising diagnostic agent in differentiating TPNI based on axonal continuity.
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Affiliation(s)
- Anagha A Gurjar
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedics and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Kristen M Manto
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedics and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Juan A Estrada
- Heart and Vascular Institute, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Marc Kaufman
- Heart and Vascular Institute, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Dongxiao Sun
- Mass Spectrometry Core Facility, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - M A Hassan Talukder
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedics and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - John C Elfar
- Department of Orthopaedics and Rehabilitation, Center for Orthopaedics and Translational Science, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
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Clark AR, Hsu CG, Talukder MAH, Noble M, Elfar JC. Transdermal delivery of 4-aminopyridine accelerates motor functional recovery and improves nerve morphology following sciatic nerve crush injury in mice. Neural Regen Res 2020; 15:136-144. [PMID: 31535662 PMCID: PMC6862422 DOI: 10.4103/1673-5374.264471] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Oral 4-aminopyridine (4-AP) is clinically used for symptomatic relief in multiple sclerosis and we recently demonstrated that systemic 4-AP had previously unknown clinically-relevant effects after traumatic peripheral nerve injury including the promotion of re-myelination, improvement of nerve conductivity, and acceleration of functional recovery. We hypothesized that, instead of oral or injection administration, transdermal 4-AP (TD-4-AP) could also improve functional recovery after traumatic peripheral nerve injury. Mice with surgical traumatic peripheral nerve injury received TD-4AP or vehicle alone and were examined for skin permeability, pharmacokinetics, functional, electrophysiological, and nerve morphological properties. 4-AP showed linear pharmacokinetics and the maximum plasma 4-AP concentrations were proportional to TD-4-AP dose. While a single dose of TD-4-AP administration demonstrated rapid transient improvement in motor function, chronic TD-4-AP treatment significantly improved motor function and nerve conduction and these effects were associated with fewer degenerating axons and thicker myelin sheaths than those from vehicle controls. These findings provide direct evidence for the potential transdermal applicability of 4-AP and demonstrate that 4-AP delivered through the skin can enhance in-vivo functional recovery and nerve conduction while decreasing axonal degeneration. The animal experiments were approved by the University Committee on Animal Research (UCAR) at the University of Rochester (UCAR-2009-019) on March 31, 2017.
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Affiliation(s)
- Andrew R Clark
- Department of Orthopaedics, The University of Rochester Medical Center, Rochester, NY, USA
| | - Chia George Hsu
- Department of Medicine, Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - M A Hassan Talukder
- Center for Orthopaedic Research and Translational Science, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Mark Noble
- Department of Biomedical Genetics, The University of Rochester Medical Center, Rochester, NY, USA
| | - John C Elfar
- Center for Orthopaedic Research and Translational Science, Penn State Hershey College of Medicine, Milton S. Hershey Medical Center, Hershey, PA, USA
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Wen TC, Sindhurakar A, Ramirez VC, Park H, Gupta D, Carmel JB. Targeted Infarction of the Internal Capsule in the Rat Using Microstimulation Guidance. Stroke 2019; 50:2531-2538. [PMID: 31390970 DOI: 10.1161/strokeaha.119.025646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose- Lacunar strokes are subcortical infarcts with small size and high disability rates, largely due to injury of the corticospinal tract in the internal capsule (IC). Current rodent models of lacunar infarcts are created based on stereotactic coordinates. We tested the hypothesis that better understanding of the somatotopy of the IC and guiding the lesion with electrical stimulation would allow a more accurate lesion to the forelimb axons of the IC. Methods- We performed electrophysiological motor mapping and viral tracing to define the somatotopy of the IC of Sprague Dawley rats. For the lesion, we used an optrode, which contains an electrode to localize forelimb responses and an optical fiber to deliver light. The infarct was induced when light activated the photothrombotic agent Rose Bengal, which was administered systemically. Results- We found largely a separate distribution of the forelimb and hindlimb axons in the IC, both by microstimulation mapping and tract tracing. Microstimulation-guided IC lesions ablated the forelimb axons of the IC in rats and caused lasting forelimb impairments while largely preserving the hindlimb axons of the IC and surrounding gray matter. Conclusions- Stimulation guidance enabled selective and reproducible infarcts of the forelimb axons of the IC in rats. Visual Overview- An online visual overview is available for this article.
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Affiliation(s)
- Tong-Chun Wen
- From the Departments of Neurology and Orthopedics, Movement Recovery Laboratory, Carroll Labs, New York, NY (T.-C.W., A.S., H.P., J.B.C.)
| | - Anil Sindhurakar
- From the Departments of Neurology and Orthopedics, Movement Recovery Laboratory, Carroll Labs, New York, NY (T.-C.W., A.S., H.P., J.B.C.)
| | | | - HongGeun Park
- From the Departments of Neurology and Orthopedics, Movement Recovery Laboratory, Carroll Labs, New York, NY (T.-C.W., A.S., H.P., J.B.C.)
| | - Disha Gupta
- Department of Neurology, New York University School of Medicine (D.G.).,Comprehensive Epilepsy Center, Langone Health, New York University (D.G.)
| | - Jason B Carmel
- From the Departments of Neurology and Orthopedics, Movement Recovery Laboratory, Carroll Labs, New York, NY (T.-C.W., A.S., H.P., J.B.C.)
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Ratnadurai Giridharan S, Gupta D, Pal A, Mishra AM, Hill NJ, Carmel JB. Motometrics: A Toolbox for Annotation and Efficient Analysis of Motor Evoked Potentials. Front Neuroinform 2019; 13:8. [PMID: 30971908 PMCID: PMC6444173 DOI: 10.3389/fninf.2019.00008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 02/05/2019] [Indexed: 12/16/2022] Open
Abstract
Stimulating the nervous system and measuring muscle response offers a unique opportunity to interrogate motor system function. Often, this is performed by stimulating motor cortex and recording muscle activity with electromyography; the evoked response is called the motor evoked potential (MEP). To understand system dynamics, MEPs are typically recorded through a range of motor cortex stimulation intensities. The MEPs increase with increasing stimulation intensities, and these typically produce a sigmoidal response curve. Analysis of MEPs is often complex and analysis of response curves is time-consuming. We created an MEP analysis software, called Motometrics, to facilitate analysis of MEPs and response curves. The goal is to combine robust signal processing algorithms with a simple user interface. Motometrics first enables the user to annotate data files acquired from the recording system so that the responses can be extracted and labeled with the correct subject and experimental condition. The software enables quick visual representations of entire datasets, to ensure uniform quality of the signal. It then enables the user to choose a variety of response curve analyses and to perform near real time quantification of the MEPs for quick feedback during experimental procedures. This is a modular open source tool that is compatible with several popular electrophysiological systems. Initial use indicates that Motometrics enables rapid, robust, and intuitive analysis of MEP response curves by neuroscientists without programming or signal processing expertise.
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Affiliation(s)
| | - Disha Gupta
- Department of Neurology, New York University School of Medicine, New York, NY, United States.,Comprehensive Epilepsy Center, NYU Langone Health, New York, NY, United States
| | - Ajay Pal
- Motor Recovery Lab, Burke Neurological Institute, White Plains, NY, United States
| | - Asht M Mishra
- Motor Recovery Lab, Burke Neurological Institute, White Plains, NY, United States
| | - N Jeremy Hill
- Motor Recovery Lab, Burke Neurological Institute, White Plains, NY, United States.,Brain Mind Research Inst., Weill Cornell Medicine Medical College, New York, NY, United States
| | - Jason B Carmel
- Motor Recovery Lab, Burke Neurological Institute, White Plains, NY, United States.,Brain Mind Research Inst., Weill Cornell Medicine Medical College, New York, NY, United States
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A novel simplistic fabrication technique for cranial epidural electrodes for chronic recording and stimulation in rats. J Neurosci Methods 2019; 311:239-242. [PMID: 30389487 DOI: 10.1016/j.jneumeth.2018.10.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/18/2018] [Accepted: 10/29/2018] [Indexed: 01/02/2023]
Abstract
BACKGROUND The demand for neuromodulatory and recording tools has resulted in a surge of publications describing techniques for fabricating devices and accessories in-house suitable for neurological recordings. However, many of these fabrication protocols use equipment which are not common to biological laboratories, thus limiting researchers to the use of commercial alternatives. New method:We have developed a simple yet robust implantable stimulating surface electrode which can be fabricated in all wet-bench laboratories. RESULTS Female Sprague-Dawley rats received epidural implantation of the electrodes over the fore and hind limb areas of their motor cortex. Stimulation of the motor cortex successfully evoked fore- and hind limb motor outputs. The device was also able to record surface potentials of the motor cortex following epidural stimulation of the spinal cord. Comparisons with existing methods:For stimulation of the motor cortex, often stiff stainless or copper wires are roughly tucked underneath the skull, with little accuracy of localization. While, commercially available devices utilize burr holes and screw electrodes. Our new electrode design provides us stereotaxic accuracy that was not previously available. CONCLUSION We developed a chronic implantable electrode capable of being fabricated in all wet-labs, are robust, versatile and electrically sensitive enough for long-term chronic use. The simple and versatile electrode design provides scientific, economical and ethical benefits.
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Mishra AM, Pal A, Gupta D, Carmel JB. Paired motor cortex and cervical epidural electrical stimulation timed to converge in the spinal cord promotes lasting increases in motor responses. J Physiol 2017; 595:6953-6968. [PMID: 28752624 PMCID: PMC5685837 DOI: 10.1113/jp274663] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/13/2017] [Indexed: 12/04/2022] Open
Abstract
Key points Pairing motor cortex stimulation and spinal cord epidural stimulation produced large augmentation in motor cortex evoked potentials if they were timed to converge in the spinal cord. The modulation of cortical evoked potentials by spinal cord stimulation was largest when the spinal electrodes were placed over the dorsal root entry zone. Repeated pairing of motor cortex and spinal cord stimulation caused lasting increases in evoked potentials from both sites, but only if the time between the stimuli was optimal. Both immediate and lasting effects of paired stimulation are likely mediated by convergence of descending motor circuits and large diameter afferents onto common interneurons in the cervical spinal cord.
Abstract Convergent activity in neural circuits can generate changes at their intersection. The rules of paired electrical stimulation are best understood for protocols that stimulate input circuits and their targets. We took a different approach by targeting the interaction of descending motor pathways and large diameter afferents in the spinal cord. We hypothesized that pairing stimulation of motor cortex and cervical spinal cord would strengthen motor responses through their convergence. We placed epidural electrodes over motor cortex and the dorsal cervical spinal cord in rats; motor evoked potentials (MEPs) were measured from biceps. MEPs evoked from motor cortex were robustly augmented with spinal epidural stimulation delivered at an intensity below the threshold for provoking an MEP. Augmentation was critically dependent on the timing and position of spinal stimulation. When the spinal stimulation was timed to coincide with the descending volley from motor cortex stimulation, MEPs were more than doubled. We then tested the effect of repeated pairing of motor cortex and spinal stimulation. Repetitive pairing caused strong augmentation of cortical MEPs and spinal excitability that lasted up to an hour after just 5 min of pairing. Additional physiology experiments support the hypothesis that paired stimulation is mediated by convergence of descending motor circuits and large diameter afferents in the spinal cord. The large effect size of this protocol and the conservation of the circuits being manipulated between rats and humans makes it worth pursuing for recovery of sensorimotor function after injury to the central nervous system. Pairing motor cortex stimulation and spinal cord epidural stimulation produced large augmentation in motor cortex evoked potentials if they were timed to converge in the spinal cord. The modulation of cortical evoked potentials by spinal cord stimulation was largest when the spinal electrodes were placed over the dorsal root entry zone. Repeated pairing of motor cortex and spinal cord stimulation caused lasting increases in evoked potentials from both sites, but only if the time between the stimuli was optimal. Both immediate and lasting effects of paired stimulation are likely mediated by convergence of descending motor circuits and large diameter afferents onto common interneurons in the cervical spinal cord.
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Affiliation(s)
- Asht M Mishra
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Avenue, White Plains, New York, 10605, USA
| | - Ajay Pal
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Avenue, White Plains, New York, 10605, USA
| | - Disha Gupta
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Avenue, White Plains, New York, 10605, USA.,Brain and Mind Research Institute and Departments of Neurology and Pediatrics, Weill Cornell Medical College, New York, NY, 10021, USA
| | - Jason B Carmel
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Avenue, White Plains, New York, 10605, USA.,Brain and Mind Research Institute and Departments of Neurology and Pediatrics, Weill Cornell Medical College, New York, NY, 10021, USA
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Butensky SD, Sloan AP, Meyers E, Carmel JB. Dexterity: A MATLAB-based analysis software suite for processing and visualizing data from tasks that measure arm or forelimb function. J Neurosci Methods 2017; 286:114-124. [PMID: 28583476 DOI: 10.1016/j.jneumeth.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 01/07/2023]
Abstract
BACKGROUND Hand function is critical for independence, and neurological injury often impairs dexterity. To measure hand function in people or forelimb function in animals, sensors are employed to quantify manipulation. These sensors make assessment easier and more quantitative and allow automation of these tasks. While automated tasks improve objectivity and throughput, they also produce large amounts of data that can be burdensome to analyze. We created software called Dexterity that simplifies data analysis of automated reaching tasks. NEW METHOD Dexterity is MATLAB software that enables quick analysis of data from forelimb tasks. Through a graphical user interface, files are loaded and data are identified and analyzed. These data can be annotated or graphed directly. Analysis is saved, and the graph and corresponding data can be exported. For additional analysis, Dexterity provides access to custom scripts created by other users. RESULTS To determine the utility of Dexterity, we performed a study to evaluate the effects of task difficulty on the degree of impairment after injury. Dexterity analyzed two months of data and allowed new users to annotate the experiment, visualize results, and save and export data easily. COMPARISON WITH EXISTING METHOD(S) Previous analysis of tasks was performed with custom data analysis, requiring expertise with analysis software. Dexterity made the tools required to analyze, visualize and annotate data easy to use by investigators without data science experience. CONCLUSIONS Dexterity increases accessibility to automated tasks that measure dexterity by making analysis of large data intuitive, robust, and efficient.
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Affiliation(s)
| | - Andrew P Sloan
- Texas Biomedical Center, The University of Texas at Dallas, Richardson, TX, 75080, USA; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, 75080, USA.
| | - Eric Meyers
- Texas Biomedical Center, The University of Texas at Dallas, Richardson, TX, 75080, USA; Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, 75080, USA.
| | - Jason B Carmel
- Burke Medical Research Institute, White Plains, NY, 10605, USA; Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, 10065, USA; Departments of Neurology and Pediatrics, Weill Cornell Medical College, New York, NY, USA.
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