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Ciotti F, John R, Katic Secerovic N, Gozzi N, Cimolato A, Jayaprakash N, Song W, Toth V, Zanos T, Zanos S, Raspopovic S. Towards enhanced functionality of vagus neuroprostheses through in silico optimized stimulation. Nat Commun 2024; 15:6119. [PMID: 39033186 PMCID: PMC11271449 DOI: 10.1038/s41467-024-50523-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
Bioelectronic therapies modulating the vagus nerve are promising for cardiovascular, inflammatory, and mental disorders. Clinical applications are however limited by side-effects such as breathing obstruction and headache caused by non-specific stimulation. To design selective and functional stimulation, we engineered VaStim, a realistic and efficient in-silico model. We developed a protocol to personalize VaStim in-vivo using simple muscle responses, successfully reproducing experimental observations, by combining models with trials conducted on five pigs. Through optimized algorithms, VaStim simulated the complete fiber population in minutes, including often omitted unmyelinated fibers which constitute 80% of the nerve. The model suggested that all Aα-fibers across the nerve affect laryngeal muscle, while heart rate changes were caused by B-efferents in specific fascicles. It predicted that tripolar paradigms could reduce laryngeal activity by 70% compared to typically used protocols. VaStim may serve as a model for developing neuromodulation therapies by maximizing efficacy and specificity, reducing animal experimentation.
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Affiliation(s)
- Federico Ciotti
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Robert John
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Natalija Katic Secerovic
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
- The Mihajlo Pupin Institute, University of Belgrade, Belgrade, Serbia
| | - Noemi Gozzi
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Andrea Cimolato
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland
| | - Naveen Jayaprakash
- Northwell Health, New Hyde Park, NY, USA
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Weiguo Song
- Northwell Health, New Hyde Park, NY, USA
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Viktor Toth
- Northwell Health, New Hyde Park, NY, USA
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Theodoros Zanos
- Northwell Health, New Hyde Park, NY, USA
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
- Elmezzi Graduate School of Molecular Medicine, Manhasset, NY, USA
| | - Stavros Zanos
- Northwell Health, New Hyde Park, NY, USA
- Feinstein Institutes for Medical Research, Manhasset, NY, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
- Elmezzi Graduate School of Molecular Medicine, Manhasset, NY, USA
| | - Stanisa Raspopovic
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zürich, Switzerland.
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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Couppey T, Regnacq L, Giraud R, Romain O, Bornat Y, Kolbl F. NRV: An open framework for in silico evaluation of peripheral nerve electrical stimulation strategies. PLoS Comput Biol 2024; 20:e1011826. [PMID: 38995970 PMCID: PMC11268605 DOI: 10.1371/journal.pcbi.1011826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 07/24/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
Electrical stimulation of peripheral nerves has been used in various pathological contexts for rehabilitation purposes or to alleviate the symptoms of neuropathologies, thus improving the overall quality of life of patients. However, the development of novel therapeutic strategies is still a challenging issue requiring extensive in vivo experimental campaigns and technical development. To facilitate the design of new stimulation strategies, we provide a fully open source and self-contained software framework for the in silico evaluation of peripheral nerve electrical stimulation. Our modeling approach, developed in the popular and well-established Python language, uses an object-oriented paradigm to map the physiological and electrical context. The framework is designed to facilitate multi-scale analysis, from single fiber stimulation to whole multifascicular nerves. It also allows the simulation of complex strategies such as multiple electrode combinations and waveforms ranging from conventional biphasic pulses to more complex modulated kHz stimuli. In addition, we provide automated support for stimulation strategy optimization and handle the computational backend transparently to the user. Our framework has been extensively tested and validated with several existing results in the literature.
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Affiliation(s)
- Thomas Couppey
- Laboratoire ETIS, Cergy Paris Université, ENSEA, CNRS UMR 8051, Cergy, France
| | - Louis Regnacq
- Laboratoire ETIS, Cergy Paris Université, ENSEA, CNRS UMR 8051, Cergy, France
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Roland Giraud
- Laboratoire ETIS, Cergy Paris Université, ENSEA, CNRS UMR 8051, Cergy, France
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Olivier Romain
- Laboratoire ETIS, Cergy Paris Université, ENSEA, CNRS UMR 8051, Cergy, France
| | - Yannick Bornat
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Florian Kolbl
- Laboratoire ETIS, Cergy Paris Université, ENSEA, CNRS UMR 8051, Cergy, France
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
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Zafeiropoulos S, Ahmed U, Bikou A, Mughrabi IT, Stavrakis S, Zanos S. Vagus nerve stimulation for cardiovascular diseases: Is there light at the end of the tunnel? Trends Cardiovasc Med 2024; 34:327-337. [PMID: 37506989 DOI: 10.1016/j.tcm.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/12/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023]
Abstract
Autonomic dysfunction and chronic inflammation contribute to the pathogenesis and progression of several cardiovascular diseases (CVD), such as heart failure with preserved ejection fraction, atherosclerotic CVD, pulmonary arterial hypertension, and atrial fibrillation. The vagus nerve provides parasympathetic innervation to the heart, vessels, and lungs, and is also implicated in the neural control of inflammation through a neuroimmune pathway involving the spleen. Stimulation of the vagus nerve (VNS) can in principle restore autonomic balance and suppress inflammation, with potential therapeutic benefits in these diseases. Although VNS ameliorated CVD in several animal models, early human studies have demonstrated variable efficacy. The purpose of this review is to discuss the rationale behind the use of VNS in the treatment of CVD, to critically review animal and human studies of VNS in CVD, and to propose possible means to overcome the challenges in the clinical translation of VNS in CVD.
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Affiliation(s)
- Stefanos Zafeiropoulos
- Elmezzi Graduate School of Molecular Medicine at Northwell Health, Manhasset, NY, USA; Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Alexia Bikou
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Ibrahim T Mughrabi
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Stavros Stavrakis
- Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Stavros Zanos
- Elmezzi Graduate School of Molecular Medicine at Northwell Health, Manhasset, NY, USA; Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA.
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Berthon A, Wernisch L, Stoukidi M, Thornton M, Tessier-Lariviere O, Fortier-Poisson P, Mamen J, Pinkney M, Lee S, Sarkans E, Annecchino L, Appleton B, Garsed P, Patterson B, Gonshaw S, Jakopec M, Shunmugam S, Edwards T, Tukiainen A, Jennings J, Lajoie G, Hewage E, Armitage O. Using neural biomarkers to personalize dosing of vagus nerve stimulation. Bioelectron Med 2024; 10:15. [PMID: 38880906 PMCID: PMC11181600 DOI: 10.1186/s42234-024-00147-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND Vagus nerve stimulation (VNS) is an established therapy for treating a variety of chronic diseases, such as epilepsy, depression, obesity, and for stroke rehabilitation. However, lack of precision and side-effects have hindered its efficacy and extension to new conditions. Achieving a better understanding of the relationship between VNS parameters and neural and physiological responses is therefore necessary to enable the design of personalized dosing procedures and improve precision and efficacy of VNS therapies. METHODS We used biomarkers from recorded evoked fiber activity and short-term physiological responses (throat muscle, cardiac and respiratory activity) to understand the response to a wide range of VNS parameters in anaesthetised pigs. Using signal processing, Gaussian processes (GP) and parametric regression models we analyse the relationship between VNS parameters and neural and physiological responses. RESULTS Firstly, we illustrate how considering multiple stimulation parameters in VNS dosing can improve the efficacy and precision of VNS therapies. Secondly, we describe the relationship between different VNS parameters and the evoked fiber activity and show how spatially selective electrodes can be used to improve fiber recruitment. Thirdly, we provide a detailed exploration of the relationship between the activations of neural fiber types and different physiological effects. Finally, based on these results, we discuss how recordings of evoked fiber activity can help design VNS dosing procedures that optimize short-term physiological effects safely and efficiently. CONCLUSION Understanding of evoked fiber activity during VNS provide powerful biomarkers that could improve the precision, safety and efficacy of VNS therapies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Guillaume Lajoie
- Université de Montréal and Mila-Quebec AI Institute, Montréal, Canada
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Wang X, Zhang Y, Guo T, Wu S, Zhong J, Cheng C, Sui X. Selective intrafascicular stimulation of myelinated and unmyelinated nerve fibers through a longitudinal electrode: A computational study. Comput Biol Med 2024; 176:108556. [PMID: 38733726 DOI: 10.1016/j.compbiomed.2024.108556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 05/05/2024] [Indexed: 05/13/2024]
Abstract
Carbon nanotube (CNT) fiber electrodes have demonstrated exceptional spatial selectivity and sustained reliability in the context of intrafascicular electrical stimulation, as evidenced through rigorous animal experimentation. A significant presence of unmyelinated C fibers, known to induce uncomfortable somatosensory experiences, exists within peripheral nerves. This presence poses a considerable challenge to the excitation of myelinated Aβ fibers, which are crucial for tactile sensation. To achieve nuanced tactile sensory feedback utilizing CNT fiber electrodes, the selective stimulation of Aβ sensory afferents emerges as a critical factor. In confronting this challenge, the present investigation sought to refine and apply a rat sciatic-nerve model leveraging the capabilities of the COMSOL-NEURON framework. This approach enables a systematic evaluation of the influence exerted by stimulation parameters and electrode geometry on the activation dynamics of both myelinated Aβ and unmyelinated C fibers. The findings advocate for the utilization of current pulses featuring a pulse width of 600 μs, alongside the deployment of CNT fibers characterized by a diminutive diameter of 10 μm, with an exclusively exposed cross-sectional area, to facilitate reduced activation current thresholds. Comparative analysis under monopolar and bipolar electrical stimulation conditions revealed proximate activation thresholds, albeit with bipolar stimulation exhibiting superior fiber selectivity relative to its monopolar counterpart. Concerning pulse waveform characteristics, the adoption of an anodic-first biphasic stimulation modality is favored, taking into account the dual criteria of activation threshold and fiber selectivity optimization. Consequently, this investigation furnishes an efficacious stimulation paradigm for the selective activation of touch-related nerve fibers, alongside provisioning a comprehensive theoretical foundation for the realization of natural tactile feedback within the domain of prosthetic hand applications.
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Affiliation(s)
- Xintong Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yapeng Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tianruo Guo
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Shuhui Wu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Junwen Zhong
- Department of Electromechanical Engineering, University of Macau, Macau SAR, 999078, China
| | - Chengkung Cheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Med-X Research Institute, Shanghai Jiao Tong University, Engineering Research Center of Digital Medicine, Ministry of Education, Shanghai, China
| | - Xiaohong Sui
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Haberbusch M, Kronsteiner B, Aigner P, Kiss A, Podesser BK, Moscato F. Importance of cardiac-synchronized vagus nerve stimulation parameters on the provoked chronotropic response for different levels of cardiac innervation. Front Physiol 2024; 15:1379936. [PMID: 38835728 PMCID: PMC11148559 DOI: 10.3389/fphys.2024.1379936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/02/2024] [Indexed: 06/06/2024] Open
Abstract
Introduction The influence of vagus nerve stimulation (VNS) parameters on provoked cardiac effects in different levels of cardiac innervation is not well understood yet. This study examines the effects of VNS on heart rate (HR) modulation across a spectrum of cardiac innervation states, providing data for the potential optimization of VNS in cardiac therapies. Materials and Methods Utilizing previously published data from VNS experiments on six sheep with intact innervation, and data of additional experiments in five rabbits post bilateral rostral vagotomy, and four isolated rabbit hearts with additionally removed sympathetic influences, the study explored the impact of diverse VNS parameters on HR. Results Significant differences in physiological threshold charges were identified across groups: 0.09 ± 0.06 μC for intact, 0.20 ± 0.04 μC for vagotomized, and 9.00 ± 0.75 μC for isolated hearts. Charge was a key determinant of HR reduction across all innervation states, with diminishing correlations from intact (r = 0.7) to isolated hearts (r = 0.44). An inverse relationship was observed for the number of pulses, with its influence growing in conditions of reduced innervation (intact r = 0.11, isolated r = 0.37). Frequency and stimulation delay showed minimal correlations (r < 0.17) in all conditions. Conclusion Our study highlights for the first time that VNS parameters, including stimulation intensity, pulse width, and pulse number, crucially modulate heart rate across different cardiac innervation states. Intensity and pulse width significantly influence heart rate in innervated states, while pulse number is key in denervated states. Frequency and delay have less impact impact across all innervation states. These findings suggest the importance of customizing VNS therapy based on innervation status, offering insights for optimizing cardiac neuromodulation.
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Affiliation(s)
- Max Haberbusch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Bettina Kronsteiner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Vienna, Austria
| | - Philipp Aigner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Attila Kiss
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Vienna, Austria
| | - Bruno Karl Podesser
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Vienna, Austria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
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Kronsteiner B, Carrero-Rojas G, Reissig LF, Moghaddam AS, Schwendt KM, Gerges S, Maierhofer U, Aszmann OC, Pastor AM, Kiss A, Podesser BK, Birkfellner W, Moscato F, Blumer R, Weninger WJ. Characterization, number, and spatial organization of nerve fibers in the human cervical vagus nerve and its superior cardiac branch. Brain Stimul 2024; 17:510-524. [PMID: 38677543 DOI: 10.1016/j.brs.2024.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 04/29/2024] Open
Abstract
BACKGROUND Electrical stimulation of the vagus nerve (VN) is a therapy for epilepsy, obesity, depression, and heart diseases. However, whole nerve stimulation leads to side effects. We examined the neuroanatomy of the mid-cervical segment of the human VN and its superior cardiac branch to gain insight into the side effects of VN stimulation and aid in developing targeted stimulation strategies. METHODS Nerve specimens were harvested from eight human body donors, then subjected to immunofluorescence and semiautomated quantification to determine the signature, quantity, and spatial distribution of different axonal categories. RESULTS The right and left cervical VN (cVN) contained a total of 25,489 ± 2781 and 23,286 ± 3164 fibers, respectively. Two-thirds of the fibers were unmyelinated and one-third were myelinated. About three-quarters of the fibers in the right and left cVN were sensory (73.9 ± 7.5 % versus 72.4 ± 5.6 %), while 13.2 ± 1.8 % versus 13.3 ± 3.0 % were special visceromotor and parasympathetic, and 13 ± 5.9 % versus 14.3 ± 4.0 % were sympathetic. Special visceromotor and parasympathetic fibers formed clusters. The superior cardiac branches comprised parasympathetic, vagal sensory, and sympathetic fibers with the left cardiac branch containing more sympathetic fibers than the right (62.7 ± 5.4 % versus 19.8 ± 13.3 %), and 50 % of the left branch contained sensory and sympathetic fibers only. CONCLUSION The study indicates that selective stimulation of vagal sensory and motor fibers is possible. However, it also highlights the potential risk of activating sympathetic fibers in the superior cardiac branch, especially on the left side.
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Affiliation(s)
- Bettina Kronsteiner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Genova Carrero-Rojas
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Lukas F Reissig
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Atieh Seyedian Moghaddam
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Karoline M Schwendt
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Sylvia Gerges
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Udo Maierhofer
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Oskar C Aszmann
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria; Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Angel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012, Sevilla, Spain
| | - Attila Kiss
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Austria
| | - Bruno K Podesser
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Center for Biomedical Research and Translational Surgery, Medical University of Vienna, Austria
| | - Wolfgang Birkfellner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Roland Blumer
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.
| | - Wolfgang J Weninger
- Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
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Bhowmick S, Graham RD, Verma N, Trevathan JK, Franke M, Nieuwoudt S, Fisher LE, Shoffstall AJ, Weber DJ, Ludwig KA, Lempka SF. Computational modeling of dorsal root ganglion stimulation using an Injectrode. J Neural Eng 2024; 21:026039. [PMID: 38502956 PMCID: PMC11007586 DOI: 10.1088/1741-2552/ad357f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/23/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Objective.Minimally invasive neuromodulation therapies like the Injectrode, which is composed of a tightly wound polymer-coated Platinum/Iridium microcoil, offer a low-risk approach for administering electrical stimulation to the dorsal root ganglion (DRG). This flexible electrode is aimed to conform to the DRG. The stimulation occurs through a transcutaneous electrical stimulation (TES) patch, which subsequently transmits the stimulation to the Injectrode via a subcutaneous metal collector. However, it is important to note that the effectiveness of stimulation through TES relies on the specific geometrical configurations of the Injectrode-collector-patch system. Hence, there is a need to investigate which design parameters influence the activation of targeted neural structures.Approach.We employed a hybrid computational modeling approach to analyze the impact of Injectrode system design parameters on charge delivery and neural response to stimulation. We constructed multiple finite element method models of DRG stimulation, followed by the implementation of multi-compartment models of DRG neurons. By calculating potential distribution during monopolar stimulation, we simulated neural responses using various parameters based on prior acute experiments. Additionally, we developed a canonical monopolar stimulation and full-scale model of bipolar bilateral L5 DRG stimulation, allowing us to investigate how design parameters like Injectrode size and orientation influenced neural activation thresholds.Main results.Our findings were in accordance with acute experimental measurements and indicate that the minimally invasive Injectrode system predominantly engages large-diameter afferents (Aβ-fibers). These activation thresholds were contingent upon the surface area of the Injectrode. As the charge density decreased due to increasing surface area, there was a corresponding expansion in the stimulation amplitude range before triggering any pain-related mechanoreceptor (Aδ-fibers) activity.Significance.The Injectrode demonstrates potential as a viable technology for minimally invasive stimulation of the DRG. Our findings indicate that utilizing a larger surface area Injectrode enhances the therapeutic margin, effectively distinguishing the desired Aβactivation from the undesired Aδ-fiber activation.
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Affiliation(s)
- Sauradeep Bhowmick
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Robert D Graham
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
| | | | | | - Lee E Fisher
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Andrew J Shoffstall
- Neuronoff Inc., Cleveland, OH, United States of America
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin–Madison, Madison, WI, United States of America
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States of America
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Thompson N, Ravagli E, Mastitskaya S, Challita R, Hadaya J, Iacoviello F, Shah Idil A, Shearing PR, Ajijola OA, Ardell JL, Shivkumar K, Holder D, Aristovich K. Anatomical and functional organization of cardiac fibers in the porcine cervical vagus nerve allows spatially selective efferent neuromodulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574861. [PMID: 38260584 PMCID: PMC10802425 DOI: 10.1101/2024.01.09.574861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cardiac disease progression reflects the dynamic interaction between adversely remodeled neurohumoral control systems and an abnormal cardiac substrate. Vagal nerve stimulation (VNS) is an attractive neuromodulatory option to dampen this dynamic interaction; however, it is limited by off-target effects. Spatially-selective VNS (sVNS) offers a promising solution to induce cardioprotection while mitigating off-target effects by specifically targeting pre-ganglionic parasympathetic efferent cardiac fibers. This approach also has the potential to enhance therapeutic outcomes by eliminating time-consuming titration required for optimal VNS. Recent studies have demonstrated the independent modulation of breathing rate, heart rate, and laryngeal contraction through sVNS. However, the spatial organization of afferent and efferent cardiac-related fibers within the vagus nerve remains unexplored. By using trial-and-error sVNS in vivo in combination with ex vivo micro-computed tomography fascicle tracing, we show the significant spatial separation of cardiac afferent and efferent fibers (179±55° SD microCT, p<0.05 and 200±137° SD, p<0.05 sVNS - degrees of separation across a cross-section of nerve) at the mid-cervical level. We also show that cardiac afferent fibers are located in proximity to pulmonary fibers consistent with recent findings of cardiopulmonary convergent neurons and circuits. We demonstrate the ability of sVNS to selectively elicit desired scalable heart rate decrease without stimulating afferent-related reflexes. By elucidating the spatial organization of cardiac-related fibers within the vagus nerve, our findings pave the way for more targeted neuromodulation, thereby reducing off-target effects and eliminating the need for titration. This, in turn, will enhance the precision and efficacy of VNS therapy in treating cardiac pathology, allowing for improved therapeutic efficacy.
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Affiliation(s)
- Nicole Thompson
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Enrico Ravagli
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Svetlana Mastitskaya
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Ronald Challita
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Joseph Hadaya
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Francesco Iacoviello
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | - Ahmad Shah Idil
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Paul R. Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, United Kingdom
| | - Olujimi A. Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jeffrey L. Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David Holder
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Kirill Aristovich
- EIT and Neurophysiology Research Group, Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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10
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Nicolai EN, Larco JA, Madhani SI, Asirvatham SJ, Chang SY, Ludwig KA, Savastano LE, Worrell GA. Vagus nerve stimulation using an endovascular electrode array. J Neural Eng 2023; 20:10.1088/1741-2552/acdb9b. [PMID: 37276858 PMCID: PMC11123606 DOI: 10.1088/1741-2552/acdb9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 06/05/2023] [Indexed: 06/07/2023]
Abstract
Objective. Vagus nerve stimulation (VNS), which involves a surgical procedure to place electrodes directly on the vagus nerve (VN), is approved clinically for the treatment of epilepsy, depression, and to facilitate rehabilitation in stroke. VNS at surgically implanted electrodes is often limited by activation of motor nerve fibers near and within the VN that cause neck muscle contraction. In this study we investigated endovascular VNS that may allow activation of the VN at locations where the motor nerve fibers are not localized.Approach. We used endovascular electrodes within the nearby internal jugular vein (IJV) to electrically stimulate the VN while recording VN compound action potentials (CAPs) and neck muscle motor evoked potentials (MEPs) in an acute intraoperative swine experiment.Main Results. We show that the stimulation electrode position within the IJV is critical for efficient activation of the VN. We also demonstrate use of fluoroscopy (cone beam CT mode) and ultrasound to determine the position of the endovascular stimulation electrode with respect to the VN and IJV. At the most effective endovascular stimulation locations tested, thresholds for VN activation were several times higher than direct stimulation of the nerve using a cuff electrode; however, this work demonstrates the feasibility of VNS with endovascular electrodes and provides tools to optimize endovascular electrode positions for VNS.Significance. This work lays the foundation to develop endovascular VNS strategies to stimulate at VN locations that would be otherwise too invasive and at VN locations where structures such as motor nerve fibers do not exist.
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Affiliation(s)
- Evan N. Nicolai
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
| | - Jorge Arturo Larco
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA
| | - Sarosh I. Madhani
- Department of Neurosurgery, University of California-San Francisco, San Francisco, CA, USA
| | | | - Su-youne Chang
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, USA
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Luis E. Savastano
- Department of Neurosurgery, University of California-San Francisco, San Francisco, CA, USA
| | - Gregory A. Worrell
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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11
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Riley M, Tala F, Johnson KJ, Johnson BC. Fully Customizable, Low-Cost, Multi-Contact Nerve Cuffs for Spatially Selective Neuromodulation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38082709 DOI: 10.1109/embc40787.2023.10340814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Selective neuromodulation of peripheral nerves is an emerging treatment for neurological diseases that are resistant to traditional drug therapy. While nerve cuffs with multichannel stimulation can be made by many varied methods, they usually require specialized microfabrication or additive manufacturing equipment. A truly low-cost and effective method of creating a custom cuff has not been accessible to researchers to prototype new methodologies and therapies in acute studies. Here, we present an inexpensive, highly repeatable method to create multi-contact nerve cuffs that require a simple postproduction PEDOT:PSS coating to improve the tissue/electrode interface. We demonstrate spatially selective neuromodulation with the proposed cuff design on the rat sciatic by preferentially activating the tibialis anterior (TA) and the lateral gastrocnemius (LG) in longitudinal and transverse stimulation patterns. This demonstrates that the proposed cuff fabrication method was not only effective for selective neuromodulation, but it is also significantly lower in cost, fully-customizable, and easily manufactured for future selective neuromodulation studies.
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12
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Musselman ED, Pelot NA, Grill WM. Validated computational models predict vagus nerve stimulation thresholds in preclinical animals and humans. J Neural Eng 2023; 20:10.1088/1741-2552/acda64. [PMID: 37257454 PMCID: PMC10324064 DOI: 10.1088/1741-2552/acda64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/31/2023] [Indexed: 06/02/2023]
Abstract
Objective.We demonstrated how automated simulations to characterize electrical nerve thresholds, a recently published open-source software for modeling stimulation of peripheral nerves, can be applied to simulate accurately nerve responses to electrical stimulation.Approach.We simulated vagus nerve stimulation (VNS) for humans, pigs, and rats. We informed our models using histology from sample-specific or representative nerves, device design features (i.e. cuff, waveform), published material and tissue conductivities, and realistic fiber models.Main results.Despite large differences in nerve size, cuff geometry, and stimulation waveform, the models predicted accurate activation thresholds across species and myelinated fiber types. However, our C fiber model thresholds overestimated thresholds across pulse widths, suggesting that improved models of unmyelinated nerve fibers are needed. Our models of human VNS yielded accurate thresholds to activate laryngeal motor fibers and captured the inter-individual variability for both acute and chronic implants. For B fibers, our small-diameter fiber model underestimated threshold and saturation for pulse widths >0.25 ms. Our models of pig VNS consistently captured the range ofin vivothresholds across all measured nerve and physiological responses (i.e. heart rate, Aδ/B fibers, Aγfibers, electromyography, and Aαfibers). In rats, our smallest diameter myelinated fibers accurately predicted fast fiber thresholds across short and intermediate pulse widths; slow unmyelinated fiber thresholds overestimated thresholds across shorter pulse widths, but there was overlap for pulse widths >0.3 ms.Significance.We elevated standards for models of peripheral nerve stimulation in populations of models across species, which enabled us to model accurately nerve responses, demonstrate that individual-specific differences in nerve morphology produce variability in neural and physiological responses, and predict mechanisms of VNS therapeutic and side effects.
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Affiliation(s)
- Eric D Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
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13
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Buyukcelik ON, Lapierre-Landry M, Kolluru C, Upadhye AR, Marshall DP, Pelot NA, Ludwig KA, Gustafson KJ, Wilson DL, Jenkins MW, Shoffstall AJ. Deep-learning segmentation of fascicles from microCT of the human vagus nerve. Front Neurosci 2023; 17:1169187. [PMID: 37332862 PMCID: PMC10275336 DOI: 10.3389/fnins.2023.1169187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/12/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction MicroCT of the three-dimensional fascicular organization of the human vagus nerve provides essential data to inform basic anatomy as well as the development and optimization of neuromodulation therapies. To process the images into usable formats for subsequent analysis and computational modeling, the fascicles must be segmented. Prior segmentations were completed manually due to the complex nature of the images, including variable contrast between tissue types and staining artifacts. Methods Here, we developed a U-Net convolutional neural network (CNN) to automate segmentation of fascicles in microCT of human vagus nerve. Results The U-Net segmentation of ~500 images spanning one cervical vagus nerve was completed in 24 s, versus ~40 h for manual segmentation, i.e., nearly four orders of magnitude faster. The automated segmentations had a Dice coefficient of 0.87, a measure of pixel-wise accuracy, thus suggesting a rapid and accurate segmentation. While Dice coefficients are a commonly used metric to assess segmentation performance, we also adapted a metric to assess fascicle-wise detection accuracy, which showed that our network accurately detects the majority of fascicles, but may under-detect smaller fascicles. Discussion This network and the associated performance metrics set a benchmark, using a standard U-Net CNN, for the application of deep-learning algorithms to segment fascicles from microCT images. The process may be further optimized by refining tissue staining methods, modifying network architecture, and expanding the ground-truth training data. The resulting three-dimensional segmentations of the human vagus nerve will provide unprecedented accuracy to define nerve morphology in computational models for the analysis and design of neuromodulation therapies.
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Affiliation(s)
- Ozge N. Buyukcelik
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Maryse Lapierre-Landry
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Aniruddha R. Upadhye
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Daniel P. Marshall
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin Madison, Madison, WI, United States
- Department of Neurological Surgery, University of Wisconsin Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering, Madison, WI, United States
| | - Kenneth J. Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Functional Electrical Stimulation Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - David L. Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
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14
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Suminski AJ, Rajala AZ, Birn RM, Mueller EM, Malone ME, Ness JP, Filla C, Brunner K, McMillan AB, Poore SO, Williams JC, Murali D, Brzeczkowski A, Hurley SA, Dingle AM, Zeng W, Lake WB, Ludwig KA, Populin LC. Vagus nerve stimulation in the non-human primate: implantation methodology, characterization of nerve anatomy, target engagement and experimental applications. Bioelectron Med 2023; 9:9. [PMID: 37118841 PMCID: PMC10148417 DOI: 10.1186/s42234-023-00111-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 04/19/2023] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Vagus nerve stimulation (VNS) is a FDA approved therapy regularly used to treat a variety of neurological disorders that impact the central nervous system (CNS) including epilepsy and stroke. Putatively, the therapeutic efficacy of VNS results from its action on neuromodulatory centers via projections of the vagus nerve to the solitary tract nucleus. Currently, there is not an established large animal model that facilitates detailed mechanistic studies exploring how VNS impacts the function of the CNS, especially during complex behaviors requiring motor action and decision making. METHODS We describe the anatomical organization, surgical methodology to implant VNS electrodes on the left gagus nerve and characterization of target engagement/neural interface properties in a non-human primate (NHP) model of VNS that permits chronic stimulation over long periods of time. Furthermore, we describe the results of pilot experiments in a small number of NHPs to demonstrate how this preparation might be used in an animal model capable of performing complex motor and decision making tasks. RESULTS VNS electrode impedance remained constant over months suggesting a stable interface. VNS elicited robust activation of the vagus nerve which resulted in decreases of respiration rate and/or partial pressure of carbon dioxide in expired air, but not changes in heart rate in both awake and anesthetized NHPs. CONCLUSIONS We anticipate that this preparation will be very useful to study the mechanisms underlying the effects of VNS for the treatment of conditions such as epilepsy and depression, for which VNS is extensively used, as well as for the study of the neurobiological basis underlying higher order functions such as learning and memory.
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Affiliation(s)
- Aaron J Suminski
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Abigail Z Rajala
- Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Rasmus M Birn
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | - Ellie M Mueller
- Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Margaret E Malone
- Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Jared P Ness
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Caitlyn Filla
- Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Kevin Brunner
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Alan B McMillan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Samuel O Poore
- Division of Plastic Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Justin C Williams
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Dhanabalan Murali
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Andrea Brzeczkowski
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Samuel A Hurley
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Aaron M Dingle
- Division of Plastic Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Weifeng Zeng
- Division of Plastic Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Wendell B Lake
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Kip A Ludwig
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Luis C Populin
- Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, 53705, USA.
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15
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Verma N, Knudsen B, Gholston A, Skubal A, Blanz S, Settell M, Frank J, Trevathan J, Ludwig K. Microneurography as a minimally invasive method to assess target engagement during neuromodulation. J Neural Eng 2023; 20:10.1088/1741-2552/acc35c. [PMID: 36898148 PMCID: PMC10587909 DOI: 10.1088/1741-2552/acc35c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 03/10/2023] [Indexed: 03/12/2023]
Abstract
Objective.Peripheral neural signals recorded during neuromodulation therapies provide insights into local neural target engagement and serve as a sensitive biomarker of physiological effect. Although these applications make peripheral recordings important for furthering neuromodulation therapies, the invasive nature of conventional nerve cuffs and longitudinal intrafascicular electrodes (LIFEs) limit their clinical utility. Furthermore, cuff electrodes typically record clear asynchronous neural activity in small animal models but not in large animal models. Microneurography, a minimally invasive technique, is already used routinely in humans to record asynchronous neural activity in the periphery. However, the relative performance of microneurography microelectrodes compared to cuff and LIFE electrodes in measuring neural signals relevant to neuromodulation therapies is not well understood.Approach.To address this gap, we recorded cervical vagus nerve electrically evoked compound action potentials (ECAPs) and spontaneous activity in a human-scaled large animal model-the pig. Additionally, we recorded sensory evoked activity and both invasively and non-invasively evoked CAPs from the great auricular nerve. In aggregate, this study assesses the potential of microneurography electrodes to measure neural activity during neuromodulation therapies with statistically powered and pre-registered outcomes (https://osf.io/y9k6j).Main results.The cuff recorded the largest ECAP signal (p< 0.01) and had the lowest noise floor amongst the evaluated electrodes. Despite the lower signal to noise ratio, microneurography electrodes were able to detect the threshold for neural activation with similar sensitivity to cuff and LIFE electrodes once a dose-response curve was constructed. Furthermore, the microneurography electrodes recorded distinct sensory evoked neural activity.Significance.The results show that microneurography electrodes can measure neural signals relevant to neuromodulation therapies. Microneurography could further neuromodulation therapies by providing a real-time biomarker to guide electrode placement and stimulation parameter selection to optimize local neural fiber engagement and study mechanisms of action.
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Affiliation(s)
- Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Bruce Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron Gholston
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron Skubal
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Stephan Blanz
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Megan Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Jennifer Frank
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
| | - James Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Kip Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
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16
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Davis CJ, Musselman ED, Grill WM, Pelot NA. Fibers in smaller fascicles have lower activation thresholds with cuff electrodes due to thinner perineurium and smaller cross-sectional area. J Neural Eng 2023; 20:10.1088/1741-2552/acc42b. [PMID: 36917856 PMCID: PMC10410695 DOI: 10.1088/1741-2552/acc42b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/14/2023] [Indexed: 03/15/2023]
Abstract
Objective. In nerve stimulation therapies, fibers in larger fascicles generally have higher activation thresholds, but the mechanisms are not well understood. We implemented and analyzed computational models to uncover the effects of morphological parameters on activation thresholds.Approach. We implemented finite element models of human vagus nerve stimulation to quantify the effects of morphological parameters on thresholds in realistic nerves. We also implemented simplified models to isolate effects of perineurium thickness, endoneurium diameter, fiber diameter, and fascicle location on current density, potential distributions (Ve), and activation thresholds across cuff geometries and stimulation waveforms. UsingVefrom each finite element model, we simulated activation thresholds in biophysical cable models of mammalian axons.Main results. Perineurium thickness increases with fascicle diameter, and both thicker perineurium and larger endoneurial diameter contributed to higher activation thresholds via lower peak and broader longitudinal potentials. Thicker perineurium caused less current to enter the fascicle transversely, decreasing peakVe. Thicker perineurium also inhibited current from leaving the fascicle, causing more constant longitudinal current density, broadeningVe. With increasing endoneurial diameter, intrafascicular volume increased faster than surface area, thereby decreasing intrafascicular current density and peakVe. Additionally, larger fascicles have greater cross-sectional area, thereby facilitating longitudinal intrafascicular current flow and broadeningVe. A large neighboring fascicle could increase activation thresholds, and for a given fascicle, fiber diameter had the greatest effect on thresholds, followed by fascicle diameter, and lastly, fascicle location within the epineurium. The circumneural cuff elicited robust activation across the nerve, whereas a bipolar transverse cuff with small contacts delivering a pseudo-monophasic waveform enabled more selective activation across fiber diameters and locations.Significance. Our computational studies provide mechanistic understanding of neural responses across relevant morphological parameters of peripheral nerves, thereby informing rational design of effective therapies.
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Affiliation(s)
- Christopher J Davis
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Eric D Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Neurobiology, Duke University, Durham, NC 27708, United States of America
- Department of Neurosurgery, Duke University, Durham, NC 27708, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
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