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Romero-Ortega M. Peripheral Nerves, Anatomy and Physiology of. Encyclopedia of Computational Neuroscience 2022:2715-2719. [DOI: 10.1007/978-1-0716-1006-0_214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Romero-Ortega M. Peripheral Nerve Interface, Regenerative. Encyclopedia of Computational Neuroscience 2022:2694-2697. [DOI: 10.1007/978-1-0716-1006-0_212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Gonzalez-Gonzalez MA, Bendale GS, Wang K, Wallace GG, Romero-Ortega M. Platinized graphene fiber electrodes uncover direct spleen-vagus communication. Commun Biol 2021; 4:1097. [PMID: 34535751 PMCID: PMC8448843 DOI: 10.1038/s42003-021-02628-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 08/30/2021] [Indexed: 11/21/2022] Open
Abstract
Neural interfacing nerve fascicles along the splenic neurovascular plexus (SNVP) is needed to better understand the spleen physiology, and for selective neuromodulation of this major organ. However, their small size and anatomical location have proven to be a significant challenge. Here, we use a reduced liquid crystalline graphene oxide (rGO) fiber coated with platinum (Pt) as a super-flexible suture-like electrode to interface multiple SNVP. The Pt-rGO fibers work as a handover knot electrodes over the small SNVP, allowing sensitive recording from four splenic nerve terminal branches (SN 1–4), to uncover differential activity and axon composition among them. Here, the asymmetric defasciculation of the SN branches is revealed by electron microscopy, and the functional compartmentalization in spleen innervation is evidenced in response to hypoxia and pharmacological modulation of mean arterial pressure. We demonstrate that electrical stimulation of cervical and sub-diaphragmatic vagus nerve (VN), evokes activity in a subset of SN terminal branches, providing evidence for a direct VN control over the spleen. This notion is supported by adenoviral tract-tracing of SN branches, revealing an unconventional direct brain-spleen projection. High-performance Pt-rGO fiber electrodes, may be used for the fine neural modulation of other small neurovascular plexus at the point of entry of major organs as a bioelectronic medical alternative. Gonzalez-Gonzalez et al. use high-performance platinized graphene fiber electrodes to interface individual neurovascular plexus that innervate the spleen. Their approach provides evidence for distinct function of individual spleen terminal branches in organ function.
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Affiliation(s)
- Maria A Gonzalez-Gonzalez
- Biomedical Engineering and Biomedical Sciences, University of Houston, Health 2, 4849 Calhoun Rd., Room 6014, Houston, TX, 77204-6064, USA
| | - Geetanjali S Bendale
- Biomedical Engineering and Biomedical Sciences, University of Houston, Health 2, 4849 Calhoun Rd., Room 6014, Houston, TX, 77204-6064, USA
| | - Kezhong Wang
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Gordon G Wallace
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Mario Romero-Ortega
- Biomedical Engineering and Biomedical Sciences, University of Houston, Health 2, 4849 Calhoun Rd., Room 6014, Houston, TX, 77204-6064, USA.
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Loper H, Leinen M, Bassoff L, Sample J, Romero-Ortega M, Gustafson KJ, Taylor DM, Schiefer MA. Both high fat and high carbohydrate diets impair vagus nerve signaling of satiety. Sci Rep 2021; 11:10394. [PMID: 34001925 PMCID: PMC8128917 DOI: 10.1038/s41598-021-89465-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/26/2021] [Indexed: 11/23/2022] Open
Abstract
Obesity remains prevalent in the US. One potential treatment is vagus nerve stimulation (VNS), which activates the sensory afferents innervating the stomach that convey stomach volume and establish satiety. However, current VNS approaches and stimulus optimization could benefit from additional understanding of the underlying neural response to stomach distension. In this study, obesity-prone Sprague Dawley rats consumed a standard, high-carbohydrate, or high-fat diet for several months, leading to diet-induced obesity in the latter two groups. Under anesthesia, the neural activity in the vagus nerve was recorded with a penetrating microelectrode array while the stomach was distended with an implanted balloon. Vagal tone during distension was compared to baseline tone prior to distension. Responses were strongly correlated with stomach distension, but the sensitivity to distension was significantly lower in animals that had been fed the nonstandard diets. The results indicate that both high fat and high carbohydrate diets impair vagus activity.
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Affiliation(s)
- Hailley Loper
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Monique Leinen
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Logan Bassoff
- Malcom Randall VA Medical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Jack Sample
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,College of Medicine & Life Sciences, University of Toledo, Toledo, OH, USA
| | - Mario Romero-Ortega
- Departments of Biomedical Engineering and Biomedical Sciences, University of Houston, Houston, TX, USA
| | - Kenneth J Gustafson
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Dawn M Taylor
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.,Department of Neurosciences, The Cleveland Clinic, Cleveland, OH, USA
| | - Matthew A Schiefer
- Malcom Randall VA Medical Center, Gainesville, FL, USA. .,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA. .,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
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Meyers EC, Kasliwal N, Solorzano BR, Lai E, Bendale G, Berry A, Ganzer PD, Romero-Ortega M, Rennaker RL, Kilgard MP, Hays SA. Enhancing plasticity in central networks improves motor and sensory recovery after nerve damage. Nat Commun 2019; 10:5782. [PMID: 31857587 PMCID: PMC6923364 DOI: 10.1038/s41467-019-13695-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 11/08/2019] [Indexed: 12/11/2022] Open
Abstract
Nerve damage can cause chronic, debilitating problems including loss of motor control and paresthesia, and generates maladaptive neuroplasticity as central networks attempt to compensate for the loss of peripheral connectivity. However, it remains unclear if this is a critical feature responsible for the expression of symptoms. Here, we use brief bursts of closed-loop vagus nerve stimulation (CL-VNS) delivered during rehabilitation to reverse the aberrant central plasticity resulting from forelimb nerve transection. CL-VNS therapy drives extensive synaptic reorganization in central networks paralleled by improved sensorimotor recovery without any observable changes in the nerve or muscle. Depleting cortical acetylcholine blocks the plasticity-enhancing effects of CL-VNS and consequently eliminates recovery, indicating a critical role for brain circuits in recovery. These findings demonstrate that manipulations to enhance central plasticity can improve sensorimotor recovery and define CL-VNS as a readily translatable therapy to restore function after nerve damage. Peripheral nerve damage generates maladaptive neuroplasticity as central networks attempt to compensate for the loss of peripheral connectivity. Here, the authors reverse the aberrant plasticity via vagus nerve stimulation to elicit synaptic reorganization and to improve sensorimotor recovery.
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Affiliation(s)
- Eric C Meyers
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.
| | - Nimit Kasliwal
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Bleyda R Solorzano
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Elaine Lai
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Geetanjali Bendale
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Abigail Berry
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Patrick D Ganzer
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Mario Romero-Ortega
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Robert L Rennaker
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Michael P Kilgard
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
| | - Seth A Hays
- Texas Biomedical Device Center, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA.,Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX, 75080-3021, USA
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Bucksot JE, Wells AJ, Rahebi KC, Sivaji V, Romero-Ortega M, Kilgard MP, Rennaker RL, Hays SA. Flat electrode contacts for vagus nerve stimulation. PLoS One 2019; 14:e0215191. [PMID: 31738766 PMCID: PMC6862926 DOI: 10.1371/journal.pone.0215191] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 10/30/2019] [Indexed: 02/01/2023] Open
Abstract
The majority of available systems for vagus nerve stimulation use helical stimulation electrodes, which cover the majority of the circumference of the nerve and produce largely uniform current density within the nerve. Flat stimulation electrodes that contact only one side of the nerve may provide advantages, including ease of fabrication. However, it is possible that the flat configuration will yield inefficient fiber recruitment due to a less uniform current distribution within the nerve. Here we tested the hypothesis that flat electrodes will require higher current amplitude to activate all large-diameter fibers throughout the whole cross-section of a nerve than circumferential designs. Computational modeling and in vivo experiments were performed to evaluate fiber recruitment in different nerves and different species using a variety of electrode designs. Initial results demonstrated similar fiber recruitment in the rat vagus and sciatic nerves with a standard circumferential cuff electrode and a cuff electrode modified to approximate a flat configuration. Follow up experiments comparing true flat electrodes to circumferential electrodes on the rabbit sciatic nerve confirmed that fiber recruitment was equivalent between the two designs. These findings demonstrate that flat electrodes represent a viable design for nerve stimulation that may provide advantages over the current circumferential designs for applications in which the goal is uniform activation of all fascicles within the nerve.
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Affiliation(s)
- Jesse E. Bucksot
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
| | - Andrew J. Wells
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
| | - Kimiya C. Rahebi
- Texas Biomedical Device Center, Richardson, Texas, United States of
America
| | - Vishnoukumaar Sivaji
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
| | - Mario Romero-Ortega
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
- Texas Biomedical Device Center, Richardson, Texas, United States of
America
| | - Michael P. Kilgard
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
- Texas Biomedical Device Center, Richardson, Texas, United States of
America
- The University of Texas at Dallas, School of Behavioral Brain Sciences,
Richardson, Texas, United States of America
| | - Robert L. Rennaker
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
- Texas Biomedical Device Center, Richardson, Texas, United States of
America
- The University of Texas at Dallas, School of Behavioral Brain Sciences,
Richardson, Texas, United States of America
| | - Seth A. Hays
- The University of Texas at Dallas, Erik Jonsson School of Engineering and
Computer Science, Richardson, Texas, United States of America
- Texas Biomedical Device Center, Richardson, Texas, United States of
America
- The University of Texas at Dallas, School of Behavioral Brain Sciences,
Richardson, Texas, United States of America
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Stiller AM, González-González MA, Boothby JM, Sherman SE, Benavides J, Romero-Ortega M, Pancrazio JJ, Black BJ. Mechanical considerations for design and implementation of peripheral intraneural devices. J Neural Eng 2019; 16:064001. [DOI: 10.1088/1741-2552/ab4114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Wang K, Frewin CL, Esrafilzadeh D, Yu C, Wang C, Pancrazio JJ, Romero-Ortega M, Jalili R, Wallace G. High-Performance Graphene-Fiber-Based Neural Recording Microelectrodes. Adv Mater 2019; 31:e1805867. [PMID: 30803072 DOI: 10.1002/adma.201805867] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/10/2019] [Indexed: 05/24/2023]
Abstract
Fabrication of flexible and free-standing graphene-fiber- (GF-) based microelectrode arrays with a thin platinum coating, acting as a current collector, results in a structure with low impedance, high surface area, and excellent electrochemical properties. This modification results in a strong synergistic effect between these two constituents leading to a robust and superior hybrid material with better performance than either graphene electrodes or Pt electrodes. The low impedance and porous structure of the GF results in an unrivalled charge injection capacity of 10.34 mC cm-2 with the ability to record and detect neuronal activity. Furthermore, the thin Pt layer transfers the collected signals along the microelectrode efficiently. In vivo studies show that microelectrodes implanted in the rat cerebral cortex can detect neuronal activity with remarkably high signal-to-noise ratio (SNR) of 9.2 dB in an area as small as an individual neuron.
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Affiliation(s)
- Kezhong Wang
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Christopher L Frewin
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Dorna Esrafilzadeh
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2031, Australia
| | - Changchun Yu
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Caiyun Wang
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Mario Romero-Ortega
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Rouhollah Jalili
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2031, Australia
| | - Gordon Wallace
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
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Black BJ, Atmaramani R, Kumaraju R, Plagens S, Romero-Ortega M, Dussor G, Price TJ, Campbell ZT, Pancrazio JJ. Adult mouse sensory neurons on microelectrode arrays exhibit increased spontaneous and stimulus-evoked activity in the presence of interleukin-6. J Neurophysiol 2018; 120:1374-1385. [PMID: 29947589 DOI: 10.1152/jn.00158.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Following inflammation or injury, sensory neurons located in the dorsal root ganglia (DRG) may exhibit increased spontaneous and/or stimulus-evoked activity, contributing to chronic pain. Current treatment options for peripherally mediated chronic pain are highly limited, driving the development of cell- or tissue-based phenotypic (function-based) screening assays for peripheral analgesic and mechanistic lead discovery. Extant assays are often limited by throughput, content, use of tumorigenic cell lines, or tissue sources from immature developmental stages (i.e., embryonic or postnatal). Here, we describe a protocol for culturing adult mouse DRG neurons on substrate-integrated multiwell microelectrode arrays (MEAs). This approach enables multiplexed measurements of spontaneous as well as stimulus-evoked extracellular action potentials from large populations of cells. The DRG cultures exhibit stable spontaneous activity from 9 to 21 days in vitro. Activity is readily evoked by known chemical and physical agonists of sensory neuron activity such as capsaicin, bradykinin, PGE2, heat, and electrical field stimulation. Most importantly, we demonstrate that both spontaneous and stimulus-evoked activity may be potentiated by incubation with the inflammatory cytokine interleukin-6 (IL-6). Acute responsiveness to IL-6 is inhibited by treatment with a MAPK-interacting kinase 1/2 inhibitor, cercosporamide. In total, these findings suggest that adult mouse DRG neurons on multiwell MEAs are applicable to ongoing efforts to discover peripheral analgesic and their mechanisms of action. NEW & NOTEWORTHY This work describes methodologies for culturing spontaneously active adult mouse dorsal root ganglia (DRG) sensory neurons on microelectrode arrays. We characterize spontaneous and stimulus-evoked adult DRG activity over durations consistent with pharmacological interventions. Furthermore, persistent hyperexcitability could be induced by incubation with inflammatory cytokine IL-6 and attenuated with cercosporamide, an inhibitor of the IL-6 sensitization pathway. This constitutes a more physiologically relevant, moderate-throughput in vitro model for peripheral analgesic screening as well as mechanistic lead discovery.
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Affiliation(s)
- Bryan J Black
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rahul Atmaramani
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rajeshwari Kumaraju
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Sarah Plagens
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Mario Romero-Ortega
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Zachary T Campbell
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Richardson, Texas
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
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Romero-Ortega M, Kanneganti A, Bendale G, Seifert J, Bredeson S, Troyk P, Deku F, Cogan S. Chronic and low charge injection wireless intraneural stimulation in vivo. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2015:1013-6. [PMID: 26736436 DOI: 10.1109/embc.2015.7318536] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Functional stability and in-vivo reliability are significant factors determining the longevity of a neural interface. In this ongoing study, we test the performance of a wireless floating microelectrode array (WFMA) over a period of 143 days. The topography of the microelectrodes has allowed for selective stimulation of different fascicles of the rat sciatic nerve. We confirmed that motor evoked thresholds remain stable over time and that the nerve stimulation charges were within tissue safety limits. Importantly, motor evoked responses were elicited at threshold currents in fully awake animals without causing pain or discomfort. These data validate the use of the WFMA system for intraneural interfacing of peripheral nerves for neuroprosthetic and bioelectronics medical applications.
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Bredeson S, Kanneganti A, Deku F, Cogan S, Romero-Ortega M, Troyk P. Chronic in-vivo testing of a 16-channel implantable wireless neural stimulator. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2015:1017-20. [PMID: 26736437 DOI: 10.1109/embc.2015.7318537] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Here, we report on chronic in-vivo testing of a 16-channel wireless floating microelectrode array (WFMA) in a rat sciatic nerve model. Muscle threshold currents, charge injection levels, and charge density were monitored for electrodes of two WFMA devices implanted into animal subjects over a five month period. This type of wireless stimulation device could eliminate problems associated with percutaneous connectors for a variety of neural prostheses and other medical devices.
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Meyers EC, Granja R, Solorzano BR, Romero-Ortega M, Kilgard MP, Rennaker RL, Hays S. Median and ulnar nerve injuries reduce volitional forelimb strength in rats. Muscle Nerve 2017; 56:1149-1154. [PMID: 28120500 DOI: 10.1002/mus.25590] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Peripheral nerve injuries (PNI) are among the leading causes of physical disability in the United States. The majority of injuries occur in the upper extremities, and functional recovery is often limited. Robust animal models are critical first steps for developing effective therapies to restore function after PNI. METHODS We developed an automated behavioral assay that provides quantitative measurements of volitional forelimb strength in rats. Multiple forelimb PNI models involving the median and ulnar nerves were used to assess forelimb function for up to 13 weeks postinjury. RESULTS Despite multiple weeks of task-oriented training following injury, rats exhibit significant reductions in multiple quantitative parameters of forelimb function, including maximal pull force and speed of force generation. DISCUSSION This study demonstrates that the isometric pull task is an effective method of evaluating forelimb function following PNI and may aid in development of therapeutic interventions to restore function. Muscle Nerve 56: 1149-1154, 2017.
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Affiliation(s)
- Eric C Meyers
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, Erik Jonsson School of Engineering and Computer Science, Richardson, Texas, USA
| | - Rafael Granja
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, Erik Jonsson School of Engineering and Computer Science, Richardson, Texas, USA
| | - Bleyda R Solorzano
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA
| | - Mario Romero-Ortega
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, Erik Jonsson School of Engineering and Computer Science, Richardson, Texas, USA
| | - Michael P Kilgard
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, School of Behavioral Brain Sciences, Richardson, Texas, USA
| | - Robert L Rennaker
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, Erik Jonsson School of Engineering and Computer Science, Richardson, Texas, USA.,The University of Texas at Dallas, School of Behavioral Brain Sciences, Richardson, Texas, USA
| | - Seth Hays
- The University of Texas at Dallas, Texas Biomedical Device Center, 800 West Campbell Road, Richardson, Texas, 75080-3021, USA.,The University of Texas at Dallas, Erik Jonsson School of Engineering and Computer Science, Richardson, Texas, USA
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13
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Lozano R, Gilmore KJ, Thompson BC, Stewart EM, Waters AM, Romero-Ortega M, Wallace GG. Electrical stimulation enhances the acetylcholine receptors available for neuromuscular junction formation. Acta Biomater 2016; 45:328-339. [PMID: 27554016 DOI: 10.1016/j.actbio.2016.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/18/2016] [Accepted: 08/05/2016] [Indexed: 01/17/2023]
Abstract
Neuromuscular junctions (NMJ) are specialized synapses that link motor neurons with muscle fibers. These sites are fundamental to human muscle activity, controlling swallowing and breathing amongst many other vital functions. Study of this synapse formation is an essential area in neuroscience; the understanding of how neurons interact and control their targets during development and regeneration are fundamental questions. Existing data reveals that during initial stages of development neurons target and form synapses driven by biophysical and biochemical cues, and during later stages they require electrical activity to develop their functional interactions. The aim of this study was to investigate the effect of exogenous electrical stimulation (ES) electrodes directly in contact with cells, on the number and size of acetylcholine receptor (AChR) clusters available for NMJ formation. We used a novel in vitro model that utilizes a flexible electrical stimulation system and allows the systematic testing of several stimulation parameters simultaneously as well as the use of alternative electrode materials such as conductive polymers to deliver the stimulation. Functionality of NMJs under our co-culture conditions was demonstrated by monitoring changes in the responses of primary myoblasts to chemical stimulants that specifically target neuronal signaling. Our results suggest that biphasic electrical stimulation at 250Hz, 100μs pulse width and current density of 1mA/cm2 for 8h, applied via either gold-coated mylar or the conductive polymer PPy, significantly increased the number and size of AChRs clusters available for NMJ formation. This study supports the beneficial use of direct electrical stimulation as a strategic therapy for neuromuscular disorders. STATEMENT OF SIGNIFICANCE The beneficial effects of electrical stimulation (ES) on human cells in vitro and in vivo have long been known. Although the effects of stimulation are clear and the therapeutic benefits are known, no uniform parameters exist with regard to the duration, frequency and amplitude of the ES. To this end, we are answering several important questions on the parameters for ES of nerve and muscle monocultures and co-cultures by probing the effects on the enhancement of acetylcholine receptors (AChR) clustering available for neuromuscular junction formation using a conductive platform. This work opens the possibility to combine electrical stimulus delivered via conductive polymer substrates, from which biomolecules could also be delivered, providing opportunities to further enhance the therapeutic effect.
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Affiliation(s)
- Rodrigo Lozano
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Kerry J Gilmore
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Brianna C Thompson
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Elise M Stewart
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Aaron M Waters
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Mario Romero-Ortega
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Gordon G Wallace
- Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW 2522, Australia.
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Black B, Granja-Vazquez R, Johnston BR, Jones E, Romero-Ortega M. Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model. PLoS One 2016; 11:e0144268. [PMID: 26760033 PMCID: PMC4712049 DOI: 10.1371/journal.pone.0144268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/16/2015] [Indexed: 11/19/2022] Open
Abstract
Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population.
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Affiliation(s)
- Bryan Black
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, United States of America
| | - Rafael Granja-Vazquez
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, United States of America
| | - Benjamin R. Johnston
- Alpert Medical School, Brown University, 222 Richmond St., Providence, RI, 02903, United States of America
| | - Erick Jones
- Department of Industrial, Manufacturing, and Systems Engineering, University of Texas at Arlington, 500 West 1st St., Arlington, TX, 76019, United States of America
| | - Mario Romero-Ortega
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, United States of America
- * E-mail:
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Gu L, Uhelski ML, Anand S, Romero-Ortega M, Kim YT, Fuchs PN, Mohanty SK. Pain inhibition by optogenetic activation of specific anterior cingulate cortical neurons. PLoS One 2015; 10:e0117746. [PMID: 25714399 PMCID: PMC4340873 DOI: 10.1371/journal.pone.0117746] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 12/31/2014] [Indexed: 01/22/2023] Open
Abstract
Cumulative evidence from both humans and animals suggests that the anterior cingulate cortex (ACC) is important for pain-related perception, and thus a likely target for pain relief therapy. However, use of existing electrode based ACC stimulation has not significantly reduced pain, at least in part due to the lack of specificity and likely co-activation of both excitatory and inhibitory neurons. Herein, we report a dramatic reduction of pain behavior in transgenic mice by optogenetic stimulation of the inhibitory neural circuitry of the ACC expressing channelrhodopsin-2. Electrophysiological measurements confirmed that stimulation of ACC inhibitory neurons is associated with decreased neural activity in the ACC. Further, a distinct optogenetic stimulation intensity and frequency-dependent inhibition of spiking activity in the ACC was observed. Moreover, we confirmed specific electrophysiological responses from different neuronal units in the thalamus, in response to particular types of painful stimuli (i,e., formalin injection, pinch), which we found to be modulated by optogenetic control of the ACC inhibitory neurons. These results underscore the inhibition of the ACC as a clinical alternative in inhibiting chronic pain, and leads to a better understanding of the pain processing circuitry of the cingulate cortex.
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Affiliation(s)
- Ling Gu
- Biophysics and Physiology Group, Department of Physics, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Megan L. Uhelski
- Department of Psychology, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Sanjay Anand
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Mario Romero-Ortega
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Young-tae Kim
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Perry N. Fuchs
- Departments of Psychology and Biology, University of Texas at Arlington, Arlington, TX-76019, United States of America
| | - Samarendra K. Mohanty
- Biophysics and Physiology Group, Department of Physics, University of Texas at Arlington, Arlington, TX-76019, United States of America
- * E-mail:
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Romero-Ortega M. Peripheral Nerves, Anatomy and Physiology of. Encyclopedia of Computational Neuroscience 2015:2320-2323. [DOI: 10.1007/978-1-4614-6675-8_214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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17
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Romero-Ortega M. Peripheral Nerve Interface, Regenerative. Encyclopedia of Computational Neuroscience 2015:2299-2302. [DOI: 10.1007/978-1-4614-6675-8_212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Romero-Ortega M. Peripheral Nerve Interface, Regenerative. Encyclopedia of Computational Neuroscience 2014:1-4. [DOI: 10.1007/978-1-4614-7320-6_212-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 03/06/2014] [Indexed: 09/02/2023]
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Romero-Ortega M. Peripheral Nerves, Anatomy and Physiology of. Encyclopedia of Computational Neuroscience 2014:1-5. [DOI: 10.1007/978-1-4614-7320-6_214-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 03/06/2014] [Indexed: 09/02/2023]
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Abstract
ABSTRACTWe have fabricated micro-probes consisting of gold microelectrode sites (500 μm long and 12 μm wide) modified with conductive polymers and carbon nanotubes to achieve intimate contact with the nervous system. The fabrication process includes photolithography, electroplating and micromachining techniques. In order to obtain a high quality neural contact, we have investigated the preparation and characterization of neural interface materials. Electrochemical polymerization using potentiostatic and galvanostatic methods was used to optimize the surface of the metal electrode sites. Scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to study the surface morphology, electrochemical properties, and stability of electrodeposited polymers. Cytotoxicity tests using fibroblasts and Schwann cells were performed to evaluate the biocompatibility of the micro-probes and neural interface materials. Dorsal root ganglion (DRG) in vitro preparation was used to evaluate neuronal cell cell adhesion to the electrode. Polypyrrole (PPy) and poly(3,4-ethylendioxythiophene) (EDOT) with various thicknesses and dopants were deposited onto microelectrode sites from aqueous solution. Our results demonstrate that we can control the morphology, size and electrical properties of PPy and PEDOT by changing the polymerization conditions and adding dopant structures, such as chloride and carbon nanotubes (CNT). It was observed that the addition of carbon nanotubes favors the formation of nodules and increases the surface roughness. Also, electrochemical impedance spectroscopy revealed that conductive polymer composites lower the impedance of gold microelectrodes by three orders of magnitude. We found that PPy and PEDOT carbon nanotubes composite coated electrodes maintain intimate contact with axons. Using these conductive polymer composites, high quality nerve spike signals can be detected and electrical stimulation of axons can be achieved.
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Romero-Ortega M, Aviles A, Cruz R, Fuentes A, Gómez RM, Plata A. Synthesis of 4-substituted 2-phenylaminothiazoles from amidines. A convenient route to 4-trichloromethylthiazoles. J Org Chem 2000; 65:7244-7. [PMID: 11031062 DOI: 10.1021/jo0009447] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M Romero-Ortega
- Departamento de Química Orgánica, Facultad de Química, Universidad Autónoma del Estado de México, Paseo Colón/Paseo Tollocan s/n Toluca Estado de México, C.P.50000, Mexico
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