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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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Hamza M, Carron R, Dibué M, Moiraghi A, Barrit S, Filipescu C, Landré E, Gavaret M, Domenech P, Pallud J, Zanello M. Right-sided vagus nerve stimulation for drug-resistant epilepsy: A systematic review of the literature and perspectives. Seizure 2024; 117:298-304. [PMID: 38615369 DOI: 10.1016/j.seizure.2024.02.011] [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: 12/16/2023] [Revised: 02/11/2024] [Accepted: 02/18/2024] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND Right-sided vagus nerve stimulation (RS-VNS) is indicated when the procedure was deemed not technically feasible or too risky on the indicated left side. OBJECTIVE The present study aims to systematically review the literature on RS-VNS, assessing its effectiveness and safety. METHODS A systematic review following PRISMA guidelines was conducted: Pubmed/MEDLINE, The Cochrane Library, Scopus, Embase and Web of science databases were searched from inception to August 13th,2023. Gray literature was searched in two libraries. Eligible studies included all studies reporting, at least, one single case of RS-VNS in patients for the treatment of drug-resistant epilepsy. RESULTS Out of 2333 initial results, 415 studies were screened by abstract. Only four were included in the final analysis comprising seven patients with RS-VNS for a drug-resistant epilepsy. One patient experienced nocturnal asymptomatic bradycardia whereas the other six patients did not display any cardiac symptom. RS-VNS was discontinued in one case due to exercise-induced airway disease exacerbation. Decrease of epileptic seizure frequency after RS-VNS ranged from 25 % to 100 % in six cases. In the remaining case, VNS effectiveness was unclear. In one case, RS-VNS was more efficient than left-sided VNS (69 % vs 50 %, respectively) whereas in another case, RS-VNS was less efficient (50 % vs 95 %, respectively). CONCLUSION Literature on the present topic is limited. In six out of seven patients, RS-VNS for drug-resistant epilepsy displayed reasonable effectiveness with a low complication rate. Further research, including prospective studies, is necessary to assess safety and effectiveness of RS-VNS for drug-resistant epilepsy patients.
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Affiliation(s)
- Meissa Hamza
- Department of Neurosurgery, GHU Paris - Sainte-Anne Hospital, Paris, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France
| | - Romain Carron
- Aix Marseille Université, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France; Department of Functional and Stereotactic Neurosurgery, Timone University Hospital, Marseille, France
| | - Maxine Dibué
- Department of Neurosurgery, Friedrich-Schiller University, Jena, Germany; Medical Affairs Neuromodulation International, LivaNova PLC, London United Kingdom
| | - Alessandro Moiraghi
- Department of Neurosurgery, GHU Paris - Sainte-Anne Hospital, Paris, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France; Université Paris Cité, INSERM UMR1266, IPNP, Paris, France
| | - Sami Barrit
- Department of Neurosurgery, Erasmus Hospital, Free University of Brussels, Belgium
| | - Cristina Filipescu
- Neurophysiology Department, GHU Paris Psychiatrie et Neurosciences, Sainte-Anne Hospital, Paris, France
| | - Elisabeth Landré
- Neurophysiology Department, GHU Paris Psychiatrie et Neurosciences, Sainte-Anne Hospital, Paris, France
| | - Martine Gavaret
- Paris Descartes University, Sorbonne Paris Cité, Paris, France; Université Paris Cité, INSERM UMR1266, IPNP, Paris, France; Neurophysiology Department, GHU Paris Psychiatrie et Neurosciences, Sainte-Anne Hospital, Paris, France
| | - Philippe Domenech
- Neuromodulation Institute, GHU Paris, Psychiatrie et neurosciences, Hôpital Saint-Anne, Université Paris Cité, Paris, France; Cognitive Neuroimaging Unit, INSERM, CEA, CNRS, Université Paris-Saclay, NeuroSpin Center, France
| | - Johan Pallud
- Department of Neurosurgery, GHU Paris - Sainte-Anne Hospital, Paris, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France; Université Paris Cité, INSERM UMR1266, IPNP, Paris, France
| | - Marc Zanello
- Department of Neurosurgery, GHU Paris - Sainte-Anne Hospital, Paris, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France; Université Paris Cité, INSERM UMR1266, IPNP, Paris, France.
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Tovbis D, Lee E, Koh RGL, Jeong R, Agur A, Yoo PB. Enhancing the selective electrical activation of human vagal nerve fibers: a comparative computational modeling study with validation in a rat sciatic model. J Neural Eng 2023; 20:066012. [PMID: 37963401 DOI: 10.1088/1741-2552/ad0c60] [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: 03/15/2023] [Accepted: 11/14/2023] [Indexed: 11/16/2023]
Abstract
Objective.Vagus nerve stimulation (VNS) is an emerging treatment option for a myriad of medical disorders, where the method of delivering electrical pulses can vary depending on the clinical indication. In this study, we investigated the relative effectiveness of electrically activating the cervical vagus nerve among three different approaches: nerve cuff electrode stimulation (NCES), transcutaneous electrical nerve stimulation (TENS), and enhanced TENS (eTENS). The objectives were to characterize factors that influenced nerve activation and to compare the nerve recruitment properties as a function of nerve fiber diameter.Methods.The Finite Element Model, based on data from the Visible Human Project, was implemented in COMSOL. The three simulation types were compared under a range of vertical and horizontal displacements relative to the location of the vagus nerve. Monopolar anodic stimulation was examined, along with latency and activation of different fiber sizes. Nerve activation was determined via the activating function and McIntyre-Richardson-Grill models, and activation thresholds were validated in anin-vivorodent model.Results.While NCES produced the lowest activation thresholds, eTENS generally performed superior to TENS under the range of conditions and fiber diameters, producing activation thresholds up to three times lower than TENS. eTENS also preserved its enhancement when surface electrodes were displaced away from the nerve. Anodic stimulation revealed an inhibitory region that removed eTENS benefits. eTENS also outperformed TENS by up to four times when targeting smaller diameter nerve fibers, scaling similar to a cuff electrode. In latency and activation of smaller diameter nerve fibers, eTENS results resembled those of NCES more than a TENS electrode. Activation threshold ratios were consistent inin-vivovalidation.Significance.Our findings expand upon previously identified mechanisms for eTENS and further demonstrate how eTENS emulates a nerve cuff electrode to achieve lower activation thresholds. This work further characterizes considerations required for VNS under the three stimulation methods.
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Affiliation(s)
- Daniel Tovbis
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Eugene Lee
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
| | - Ryan G L Koh
- KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
| | - Rania Jeong
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
| | - Anne Agur
- Division of Anatomy, Department of Surgery, University of Toronto, Toronto, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
| | - Paul B Yoo
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
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Villalobos J, Payne SC, Ward GM, Andrikopoulos S, Hyakumura T, MacIsaac RJ, Fallon JB. Stimulation parameters for directional vagus nerve stimulation. Bioelectron Med 2023; 9:16. [PMID: 37464423 DOI: 10.1186/s42234-023-00117-2] [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: 05/05/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND Autonomic nerve stimulation is used as a treatment for a growing number of diseases. We have previously demonstrated that application of efferent vagus nerve stimulation (eVNS) has promising glucose lowering effects in a rat model of type 2 diabetes. This paradigm combines high frequency pulsatile stimulation to block nerve activation in the afferent direction with low frequency stimulation to activate the efferent nerve section. In this study we explored the effects of the parameters for nerve blocking on the ability to inhibit nerve activation in the afferent direction. The overarching aim is to establish a blocking stimulation strategy that could be applied using commercially available implantable pulse generators used in the clinic. METHODS Male rats (n = 20) had the anterior abdominal vagus nerve implanted with a multi-electrode cuff. Evoked compound action potentials (ECAP) were recorded at the proximal end of the electrode cuff. The efficacy of high frequency stimulation to block the afferent ECAP was assessed by changes in the threshold and saturation level of the response. Blocking frequency and duty cycle of the blocking pulses were varied while maintaining a constant 4 mA current amplitude. RESULTS During application of blocking at lower frequencies (≤ 4 kHz), the ECAP threshold increased (ANOVA, p < 0.001) and saturation level decreased (p < 0.001). Application of higher duty cycles (> 70%) led to an increase in evoked neural response threshold (p < 0.001) and a decrease in saturation level (p < 0.001). During the application of a constant pulse width and frequency (1 or 1.6 kHz, > 70% duty cycle), the charge delivered per pulse had a significant influence on the magnitude of the block (ANOVA, p = 0.003), and was focal (< 2 mm range). CONCLUSIONS This study has determined the range of frequencies, duty cycles and currents of high frequency stimulation that generate an efficacious, focal axonal block of a predominantly C-fiber tract. These findings could have potential application for the treatment of type 2 diabetes.
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Affiliation(s)
- Joel Villalobos
- Bionics Institute, East Melbourne, Vic, Australia
- Department of Medical Bionics, University of Melbourne, Parkville, Vic, Australia
| | - Sophie C Payne
- Bionics Institute, East Melbourne, Vic, Australia
- Department of Medical Bionics, University of Melbourne, Parkville, Vic, Australia
| | - Glenn M Ward
- Bionics Institute, East Melbourne, Vic, Australia
- Department of Endocrinology and Diabetes, St Vincent's Hospital Melbourne, Fitzroy, Vic, Australia
- Department of Medicine, St Vincent's Hospital Melbourne, University of Melbourne, Fitzroy, Vic, Australia
| | - Sofianos Andrikopoulos
- Australian Centre for Accelerating Diabetes Innovations, University of Melbourne, Parkville, Australia
- Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Vic, Australia
| | - Tomoko Hyakumura
- Bionics Institute, East Melbourne, Vic, Australia
- Department of Medical Bionics, University of Melbourne, Parkville, Vic, Australia
| | - Richard J MacIsaac
- Bionics Institute, East Melbourne, Vic, Australia
- Department of Endocrinology and Diabetes, St Vincent's Hospital Melbourne, Fitzroy, Vic, Australia
- Department of Medicine, St Vincent's Hospital Melbourne, University of Melbourne, Fitzroy, Vic, Australia
- Australian Centre for Accelerating Diabetes Innovations, University of Melbourne, Parkville, Australia
| | - James B Fallon
- Bionics Institute, East Melbourne, Vic, Australia.
- Department of Medical Bionics, University of Melbourne, Parkville, Vic, Australia.
- Australian Diabetes Society, Sydney, NSW, Australia.
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Tamura K, Sasaki R, Sakakibara T, Dahal R, Takeshima Y, Matsuda R, Yamada S, Nishimura F, Nakagawa I, Park YS, Hirabayashi H, Nakase H. Additional Effect of High-output Current and/or High-duty Cycle in Vagus Nerve Stimulation for Adolescent/Adult Intractable Epilepsy. Neurol Med Chir (Tokyo) 2023; 63:273-282. [PMID: 37045770 PMCID: PMC10406457 DOI: 10.2176/jns-nmc.2022-0280] [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: 08/31/2022] [Accepted: 02/20/2023] [Indexed: 04/14/2023] Open
Abstract
A vagus nerve stimulation (VNS) device delivers electrical pulses to the vagus nerve at a rhythm defined by the duty cycle. The standard therapeutic range is advocated for an output current of 1.5-2.25 mA and a duty cycle of 10%. As the optimal settings vary from patient to patient, some patients may benefit from additional seizure reduction when stimulated beyond the standard range. A total of 74 patients (15 children aged <12 years and 59 adolescents/adults) who underwent VNS implantation between 2011 and 2020 and who were followed up for at least 2 years were included in this retrospective study. Stimulation parameters exceeding 2.25 mA of output current, 25% of duty cycle, and 0.5625 (2.25 mA × 25%) of current × duty cycle were defined as high stimulation. The proportion achieved an additional seizure reduction of 20%, and the 50% seizure reduction rate at the last follow-up was compared between adolescents/adults and children. Approximately 40% of patients in adolescents/adults treated with high stimulation experienced an additional acute effect, resulting in a 50% or greater reduction in seizures in almost all patients. Moreover, in adolescents/adults, 22.2%-41.9% of the patients were treated with high stimulation, and the responder rate was 69.5%. Conversely, the responder rate in children was 26.7%, significantly worse than that in adolescents/adults, despite higher stimulation. VNS with high-stimulation settings is effective for adolescent and adult patients with intractable epilepsy. Even high stimulation may not be effective in extremely refractory pediatric epilepsy with a high seizure frequency.
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Affiliation(s)
- Kentaro Tamura
- Department of Neurosurgery, Nara Medical University
- Epilepsy Center, National Hospital Organization Nara Medical Center
| | - Ryota Sasaki
- Department of Neurosurgery, Nara Medical University
- Epilepsy Center, National Hospital Organization Nara Medical Center
| | - Takafumi Sakakibara
- Epilepsy Center, National Hospital Organization Nara Medical Center
- Department of Pediatrics, Nara Medical University
| | - Riju Dahal
- Department of Neurosurgery, Nara Medical University
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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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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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Elia A, Fossati S. Autonomic nervous system and cardiac neuro-signaling pathway modulation in cardiovascular disorders and Alzheimer's disease. Front Physiol 2023; 14:1060666. [PMID: 36798942 PMCID: PMC9926972 DOI: 10.3389/fphys.2023.1060666] [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: 10/03/2022] [Accepted: 01/19/2023] [Indexed: 01/31/2023] Open
Abstract
The heart is a functional syncytium controlled by a delicate and sophisticated balance ensured by the tight coordination of its several cell subpopulations. Accordingly, cardiomyocytes together with the surrounding microenvironment participate in the heart tissue homeostasis. In the right atrium, the sinoatrial nodal cells regulate the cardiac impulse propagation through cardiomyocytes, thus ensuring the maintenance of the electric network in the heart tissue. Notably, the central nervous system (CNS) modulates the cardiac rhythm through the two limbs of the autonomic nervous system (ANS): the parasympathetic and sympathetic compartments. The autonomic nervous system exerts non-voluntary effects on different peripheral organs. The main neuromodulator of the Sympathetic Nervous System (SNS) is norepinephrine, while the principal neurotransmitter of the Parasympathetic Nervous System (PNS) is acetylcholine. Through these two main neurohormones, the ANS can gradually regulate cardiac, vascular, visceral, and glandular functions by turning on one of its two branches (adrenergic and/or cholinergic), which exert opposite effects on targeted organs. Besides these neuromodulators, the cardiac nervous system is ruled by specific neuropeptides (neurotrophic factors) that help to preserve innervation homeostasis through the myocardial layers (from epicardium to endocardium). Interestingly, the dysregulation of this neuro-signaling pathway may expose the cardiac tissue to severe disorders of different etiology and nature. Specifically, a maladaptive remodeling of the cardiac nervous system may culminate in a progressive loss of neurotrophins, thus leading to severe myocardial denervation, as observed in different cardiometabolic and neurodegenerative diseases (myocardial infarction, heart failure, Alzheimer's disease). This review analyzes the current knowledge on the pathophysiological processes involved in cardiac nervous system impairment from the perspectives of both cardiac disorders and a widely diffused and devastating neurodegenerative disorder, Alzheimer's disease, proposing a relationship between neurodegeneration, loss of neurotrophic factors, and cardiac nervous system impairment. This overview is conducive to a more comprehensive understanding of the process of cardiac neuro-signaling dysfunction, while bringing to light potential therapeutic scenarios to correct or delay the adverse cardiovascular remodeling, thus improving the cardiac prognosis and quality of life in patients with heart or neurodegenerative disorders.
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VNS parameters for clinical response in Epilepsy. Brain Stimul 2022; 15:814-821. [DOI: 10.1016/j.brs.2022.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/14/2022] [Accepted: 05/22/2022] [Indexed: 01/11/2023] Open
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Afra P, Adamolekun B, Aydemir S, Watson GDR. Evolution of the Vagus Nerve Stimulation (VNS) Therapy System Technology for Drug-Resistant Epilepsy. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:696543. [PMID: 35047938 PMCID: PMC8757869 DOI: 10.3389/fmedt.2021.696543] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/10/2021] [Indexed: 12/14/2022] Open
Abstract
The vagus nerve stimulation (VNS) Therapy® System is the first FDA-approved medical device therapy for the treatment of drug-resistant epilepsy. Over the past two decades, the technology has evolved through multiple iterations resulting in software-related updates and implantable lead and generator hardware improvements. Healthcare providers today commonly encounter a range of single- and dual-pin generators (models 100, 101, 102, 102R, 103, 104, 105, 106, 1000) and related programming systems (models 250, 3000), all of which have their own subtle, but practical differences. It can therefore be a daunting task to go through the manuals of these implant models for comparison, some of which are not readily available. In this review, we highlight the technological evolution of the VNS Therapy System with respect to device approval milestones and provide a comparison of conventional open-loop vs. the latest closed-loop generator models. Battery longevity projections and an in-depth examination of stimulation mode interactions are also presented to further differentiate amongst generator models.
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Affiliation(s)
- Pegah Afra
- Department of Neurology, Weill-Cornell Medicine, New York, NY, United States.,Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Bola Adamolekun
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Seyhmus Aydemir
- Department of Neurology, Weill-Cornell Medicine, New York, NY, United States
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Broncel A, Bocian R, Konopacki J. Vagal Nerve Stimulation: The Effect on the Brain Oscillatory Field Potential. Neuroscience 2021; 483:127-138. [PMID: 34952159 DOI: 10.1016/j.neuroscience.2021.12.023] [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: 09/03/2021] [Revised: 12/03/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
More than thirty years of medical treatment with the use of vagal nerve stimulation (VNS) has shown that this therapeutic procedure works in a number of homeostatic disturbances. Although the clinical usage of VNS has a long history, our knowledge about the central mechanisms underlying this treatment is still limited. In the present paper we review the effects of VNS on brain oscillations as a possible electrophysiological bio-marker of VNS efficacy. The review was prepared mainly on the basis of data delivered from clinical observations and the outcomes of electrophysiological experiments conducted on laboratory animals that are available in PubMed. We consciously did not focus on epileptiform activity understood as a pathologic oscillatory activity, which was widely discussed in the numerous previously published reviews. The main conclusion of the present paper is that further, well-designed experiments on laboratory animals are absolutely necessary to address the electrophysiological issues. These will fill a number of gaps in our present knowledge of the central mechanisms underlying VNS therapy.
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Affiliation(s)
- Adam Broncel
- Medical Technology Centre, Natolin 15, 92-701 Lodz, Poland.
| | - Renata Bocian
- Department of Neurobiology, Faculty of Biology and Environmental Protection, The University of Lodz, Pomorska St. No. 141/143, 90-236 Lodz, Poland.
| | - Jan Konopacki
- Department of Neurobiology, Faculty of Biology and Environmental Protection, The University of Lodz, Pomorska St. No. 141/143, 90-236 Lodz, Poland.
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12
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ASCENT (Automated Simulations to Characterize Electrical Nerve Thresholds): A pipeline for sample-specific computational modeling of electrical stimulation of peripheral nerves. PLoS Comput Biol 2021; 17:e1009285. [PMID: 34492004 PMCID: PMC8423288 DOI: 10.1371/journal.pcbi.1009285] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 07/18/2021] [Indexed: 12/04/2022] Open
Abstract
Electrical stimulation and block of peripheral nerves hold great promise for treatment of a range of disease and disorders, but promising results from preclinical studies often fail to translate to successful clinical therapies. Differences in neural anatomy across species require different electrodes and stimulation parameters to achieve equivalent nerve responses, and accounting for the consequences of these factors is difficult. We describe the implementation, validation, and application of a standardized, modular, and scalable computational modeling pipeline for biophysical simulations of electrical activation and block of nerve fibers within peripheral nerves. The ASCENT (Automated Simulations to Characterize Electrical Nerve Thresholds) pipeline provides a suite of built-in capabilities for user control over the entire workflow, including libraries for parts to assemble electrodes, electrical properties of biological materials, previously published fiber models, and common stimulation waveforms. We validated the accuracy of ASCENT calculations, verified usability in beta release, and provide several compelling examples of ASCENT-implemented models. ASCENT will enable the reproducibility of simulation data, and it will be used as a component of integrated simulations with other models (e.g., organ system models), to interpret experimental results, and to design experimental and clinical interventions for the advancement of peripheral nerve stimulation therapies. Despite promising results from preclinical studies, novel therapies using electrical stimulation of peripheral nerves often fail to produce successful clinical outcomes due to differences in neural anatomy across species. These differences often require different electrodes to interface with the nerves and/or different stimulation parameters to achieve equivalent nerve responses. Further, differences in nerve anatomy across a population contribute to differences in nerve responses to stimulation. These inter-species and inter-individual differences can be studied using computational modeling of individual-specific peripheral nerve morphology and biophysical properties. To accelerate the process of computational modeling of individual nerve anatomy, we developed ASCENT, a software platform for simulating the responses of sample-specific nerves to electrical stimulation with custom electrodes and stimulation parameters. ASCENT automates the complex, multi-step process required to build computational models of preclinical and clinical studies and to design novel stimulation protocols using biophysically realistic simulations. The ASCENT pipeline will be used to develop technologies that increase the selectivity and efficiency of stimulation and to accelerate the translation of novel peripheral nerve stimulation therapies to the clinic.
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13
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Ahmed U, Chang YC, Lopez MF, Wong J, Datta-Chaudhuri T, Rieth L, Al-Abed Y, Zanos S. Implant- and anesthesia-related factors affecting cardiopulmonary threshold intensities for vagus nerve stimulation. J Neural Eng 2021; 18. [PMID: 34036940 DOI: 10.1088/1741-2552/ac048a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 05/24/2021] [Indexed: 11/11/2022]
Abstract
Objective.Vagus nerve stimulation (VNS) is typically delivered at increasing stimulus intensity until a neurological or physiological response is observed ('threshold') for dose calibration, preclinically and therapeutically. Factors affecting VNS thresholds have not been studied systematically. In a rodent model of VNS we measured neural and physiological responses to increasing VNS intensity, determined neurological and physiological thresholds and examined the effect of implant- and anesthesia-related factors on thresholds.Approach.In acute and chronic vagus implants (45 and 20 rats, respectively) VNS was delivered under isoflurane, ketamine-xylazine, or awake conditions. Evoked compound action potentials (CAPs) were recorded and activation of different fiber types was extracted. Elicited physiological responses were registered, including changes in heart rate (HR), breathing rate (BR), and blood pressure (BP). CAP and physiological thresholds were determined.Main results. The threshold for evoking discernable CAPs (>10µV) (CAP threshold) is significantly lower than what elicits 5%-10% drop in heart rate (heart rate threshold, HRT) (25µA ± 1.8 vs. 80µA ± 5.1, respectively; mean ± SEM). Changes in BP and small changes in BR (bradypnea) occur at lowest intensities (70µA ± 8.3), followed by HR changes (80µA ± 5.1) and finally significant changes in BR (apnea) (310μA ± 32.5). HRT and electrode impedance are correlated in chronic (Pearson correlationr= 0.47;p< 0.001) but not in acute implants (r= -0.34;pNS); HRT and impedance both increase with implant age (r= 0.44;p< 0.001 andr= 0.64;p< 0.001, respectively). HRT is lowest when animals are awake (200µA ± 35.5), followed by ketamine-xylazine (640µA ± 151.5), and isoflurane (1000µA ± 139.5). The sequence of physiological responses with increasing VNS intensity is the same in anesthetized and awake animals. Pulsing frequency affects physiological responses but not CAPs.Significance. Implant age, electrode impedance, and type of anesthesia affect VNS thresholds and should be accounted for when calibrating stimulation dose.
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Affiliation(s)
- Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Maria F Lopez
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Jason Wong
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Timir Datta-Chaudhuri
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Loren Rieth
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, 350 Community Drive, Manhasset, NY 11030, United States of America
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14
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Fisher B, DesMarteau JA, Koontz EH, Wilks SJ, Melamed SE. Responsive Vagus Nerve Stimulation for Drug Resistant Epilepsy: A Review of New Features and Practical Guidance for Advanced Practice Providers. Front Neurol 2021; 11:610379. [PMID: 33584511 PMCID: PMC7874068 DOI: 10.3389/fneur.2020.610379] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/14/2020] [Indexed: 01/17/2023] Open
Abstract
Vagus nerve stimulation (VNS) is a safe and effective therapy that has been available for over 20 years for adults and children with drug resistant epilepsy (DRE). Since U.S. Food and Drug Administration approval in 1997, VNS has been implanted in over 100,000 patients including over 30,000 children as an adjunctive therapy in reducing the frequency of seizures in patients 4 years of age and older with focal seizures that are refractory to antiseizure medications. VNS Therapy® has evolved over time and currently offers closed-loop, responsive stimulation as well as advanced features that streamline dosing and patient management. Advanced Practice Providers (APPs) such as nurse practitioners, physician assistants and clinical nurse specialists are integral in a comprehensive healthcare team, and dedicated VNS clinics have formed at comprehensive epilepsy centers across the world that are often managed by APPs. This approach improves access, education, and continuity of care for those with VNS or those considering VNS. Here we provide a review for APPs on the VNS Therapy® system focused on new features, dosing, and troubleshooting strategies with the goal to provide guidance to those managing VNS patients.
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Affiliation(s)
- Breanne Fisher
- Division of Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Julie A DesMarteau
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Elizabeth H Koontz
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States
| | - Seth J Wilks
- Neuromodulation Division, LivaNova, Houston, TX, United States
| | - Susan E Melamed
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
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15
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Hadaya J, Ardell JL. Autonomic Modulation for Cardiovascular Disease. Front Physiol 2020; 11:617459. [PMID: 33414727 PMCID: PMC7783451 DOI: 10.3389/fphys.2020.617459] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Dysfunction of the autonomic nervous system has been implicated in the pathogenesis of cardiovascular disease, including congestive heart failure and cardiac arrhythmias. Despite advances in the medical and surgical management of these entities, progression of disease persists as does the risk for sudden cardiac death. With improved knowledge of the dynamic relationships between the nervous system and heart, neuromodulatory techniques such as cardiac sympathetic denervation and vagal nerve stimulation (VNS) have emerged as possible therapeutic approaches for the management of these disorders. In this review, we present the structure and function of the cardiac nervous system and the remodeling that occurs in disease states, emphasizing the concept of increased sympathoexcitation and reduced parasympathetic tone. We review preclinical evidence for vagal nerve stimulation, and early results of clinical trials in the setting of congestive heart failure. Vagal nerve stimulation, and other neuromodulatory techniques, may improve the management of cardiovascular disorders, and warrant further study.
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Affiliation(s)
- Joseph Hadaya
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States.,Molecular, Cellular, and Integrative Physiology Program, UCLA, Los Angeles, CA, United States
| | - Jeffrey L Ardell
- University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, CA, United States.,UCLA Neurocardiology Research Program of Excellence, UCLA, Los Angeles, CA, United States
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16
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Pelot NA, Goldhagen GB, Cariello JE, Musselman ED, Clissold KA, Ezzell JA, Grill WM. Quantified Morphology of the Cervical and Subdiaphragmatic Vagus Nerves of Human, Pig, and Rat. Front Neurosci 2020; 14:601479. [PMID: 33250710 PMCID: PMC7672126 DOI: 10.3389/fnins.2020.601479] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/13/2020] [Indexed: 12/27/2022] Open
Abstract
It is necessary to understand the morphology of the vagus nerve (VN) to design and deliver effective and selective vagus nerve stimulation (VNS) because nerve morphology influences fiber responses to electrical stimulation. Specifically, nerve diameter (and thus, electrode-fiber distance), fascicle diameter, fascicular organization, and perineurium thickness all significantly affect the responses of nerve fibers to electrical signals delivered through a cuff electrode. We quantified the morphology of cervical and subdiaphragmatic VNs in humans, pigs, and rats: effective nerve diameter, number of fascicles, effective fascicle diameters, proportions of endoneurial, perineurial, and epineurial tissues, and perineurium thickness. The human and pig VNs were comparable sizes (∼2 mm cervically; ∼1.6 mm subdiaphragmatically), while the rat nerves were ten times smaller. The pig nerves had ten times more fascicles-and the fascicles were smaller-than in human nerves (47 vs. 7 fascicles cervically; 38 vs. 5 fascicles subdiaphragmatically). Comparing the cervical to the subdiaphragmatic VNs, the nerves and fascicles were larger at the cervical level for all species and there were more fascicles for pigs. Human morphology generally exhibited greater variability across samples than pigs and rats. A prior study of human somatic nerves indicated that the ratio of perineurium thickness to fascicle diameter was approximately constant across fascicle diameters. However, our data found thicker human and pig VN perineurium than those prior data: the VNs had thicker perineurium for larger fascicles and thicker perineurium normalized by fascicle diameter for smaller fascicles. Understanding these differences in VN morphology between preclinical models and the clinical target, as well as the variability across individuals of a species, is essential for designing suitable cuff electrodes and stimulation parameters and for informing translation of preclinical results to clinical application to advance the therapeutic efficacy of VNS.
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Affiliation(s)
- Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Gabriel B. Goldhagen
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Jake E. Cariello
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Eric D. Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Kara A. Clissold
- Histology Research Core, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - J. Ashley Ezzell
- Histology Research Core, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States
- Department of Neurobiology, Duke University, Durham, NC, United States
- Department of Neurosurgery, School of Medicine, Duke University, Durham, NC, United States
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17
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Nicolai EN, Settell ML, Knudsen BE, McConico AL, Gosink BA, Trevathan JK, Baumgart IW, Ross EK, Pelot NA, Grill WM, Gustafson KJ, Shoffstall AJ, Williams JC, Ludwig KA. Sources of off-target effects of vagus nerve stimulation using the helical clinical lead in domestic pigs. J Neural Eng 2020; 17:046017. [PMID: 32554888 PMCID: PMC7717671 DOI: 10.1088/1741-2552/ab9db8] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Objective Clinical data suggest that efficacious vagus nerve stimulation (VNS) is limited by side effects such as cough and dyspnea that have stimulation thresholds lower than those for therapeutic outcomes. VNS side effects are putatively caused by activation of nearby muscles within the neck, via direct muscle activation or activation of nerve fibers innervating those muscles. Our goal was to determine the thresholds at which various VNS-evoked effects occur in the domestic pig—an animal model with vagus anatomy similar to human—using the bipolar helical lead deployed clinically. Approach Intrafascicular electrodes were placed within the vagus nerve to record electroneurographic (ENG) responses, and needle electrodes were placed in the vagal-innervated neck muscles to record electromyographic (EMG) responses. Main results Contraction of the cricoarytenoid muscle occurred at low amplitudes (~0.3 mA) and resulted from activation of motor nerve fibers in the cervical vagus trunk within the electrode cuff which bifurcate into the recurrent laryngeal branch of the vagus. At higher amplitudes (~1.4 mA), contraction of the cricoarytenoid and cricothyroid muscles was generated by current leakage outside the cuff to activate motor nerve fibers running within the nearby superior laryngeal branch of the vagus. Activation of these muscles generated artifacts in the ENG recordings that may be mistaken for compound action potentials representing slowly conducting Aδ-, B-, and C-fibers. Significance Our data resolve conflicting reports of the stimulation amplitudes required for C-fiber activation in large animal studies (>10 mA) and human studies (<250 μA). After removing muscle-generated artifacts, ENG signals with post-stimulus latencies consistent with Aδ- and B-fibers occurred in only a small subset of animals, and these signals had similar thresholds to those that caused bradycardia. By identifying specific neuroanatomical pathways that cause off-target effects and characterizing the stimulation dose-response curves for on- and off-target effects, we hope to guide interpretation and optimization of clinical VNS.
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Affiliation(s)
- Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Andrea L McConico
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America
| | - Brian A Gosink
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-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 of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Ian W Baumgart
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Erika K Ross
- Abbott Neuromodulation, Plano, TX, 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
| | - Kenneth J Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
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18
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Ahmed U, Chang YC, Cracchiolo M, Lopez MF, Tomaio JN, Datta-Chaudhuri T, Zanos TP, Rieth L, Al-Abed Y, Zanos S. Anodal block permits directional vagus nerve stimulation. Sci Rep 2020; 10:9221. [PMID: 32513973 PMCID: PMC7280203 DOI: 10.1038/s41598-020-66332-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/14/2020] [Indexed: 11/10/2022] Open
Abstract
Vagus nerve stimulation (VNS) is a bioelectronic therapy for disorders of the brain and peripheral organs, and a tool to study the physiology of autonomic circuits. Selective activation of afferent or efferent vagal fibers can maximize efficacy and minimize off-target effects of VNS. Anodal block (ABL) has been used to achieve directional fiber activation in nerve stimulation. However, evidence for directional VNS with ABL has been scarce and inconsistent, and it is unknown whether ABL permits directional fiber activation with respect to functional effects of VNS. Through a series of vagotomies, we established physiological markers for afferent and efferent fiber activation by VNS: stimulus-elicited change in breathing rate (ΔBR) and heart rate (ΔHR), respectively. Bipolar VNS trains of both polarities elicited mixed ΔHR and ΔBR responses. Cathode cephalad polarity caused an afferent pattern of responses (relatively stronger ΔBR) whereas cathode caudad caused an efferent pattern (stronger ΔHR). Additionally, left VNS elicited a greater afferent and right VNS a greater efferent response. By analyzing stimulus-evoked compound nerve potentials, we confirmed that such polarity differences in functional responses to VNS can be explained by ABL of A- and B-fiber activation. We conclude that ABL is a mechanism that can be leveraged for directional VNS.
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Affiliation(s)
- Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Marina Cracchiolo
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
- Biorobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Maria F Lopez
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Jacquelyn N Tomaio
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Timir Datta-Chaudhuri
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Theodoros P Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Loren Rieth
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, 11030, USA.
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19
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Capogrosso M, Lempka SF. A computational outlook on neurostimulation. Bioelectron Med 2020; 6:10. [PMID: 32490037 PMCID: PMC7247210 DOI: 10.1186/s42234-020-00047-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/08/2020] [Indexed: 12/16/2022] Open
Abstract
Efficient identification of effective neurostimulation strategies is critical due to the growing number of clinical applications and the increasing complexity of the corresponding technology. In consequence, investigators are encouraged to accelerate translational research of neurostimulation technologies and move quickly to clinical applications. However, this process is hampered by rigorous, but necessary, regulations and lack of a mechanistic understanding of the interactions between electric fields and neural circuits. Here we discuss how computational models have influenced the field of neurostimulation for pain and movement recovery, deep brain stimulation, and even device regulations. Finally, we propose our vision on how computational models will be key to accelerate clinical developments through mechanistic understanding.
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Affiliation(s)
- Marco Capogrosso
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA USA.,Rehabilitation Neural Engineering Laboratories, University of Pittsburgh, Pittsburgh, PA USA
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI USA.,Department of Anesthesiology, University of Michigan, Ann Arbor, MI USA
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20
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Adair D, Truong D, Esmaeilpour Z, Gebodh N, Borges H, Ho L, Bremner JD, Badran BW, Napadow V, Clark VP, Bikson M. Electrical stimulation of cranial nerves in cognition and disease. Brain Stimul 2020; 13:717-750. [PMID: 32289703 PMCID: PMC7196013 DOI: 10.1016/j.brs.2020.02.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.
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Affiliation(s)
- Devin Adair
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Dennis Truong
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
| | - Nigel Gebodh
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Helen Borges
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - Libby Ho
- Department of Biomedical Engineering, City College of New York, New York, NY, USA
| | - J Douglas Bremner
- Department of Psychiatry & Behavioral Sciences and Radiology, Emory University School of Medicine, Atlanta, GA, USA; Atlanta VA Medical Center, Decatur, GA, USA
| | - Bashar W Badran
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
| | - Vitaly Napadow
- Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Harvard medical school, Boston, MA, USA
| | - Vincent P Clark
- Psychology Clinical Neuroscience Center, Dept. Psychology, MSC03-2220, University of New Mexico, Albuquerque, NM, 87131, USA; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA; The Mind Research Network of the Lovelace Biomedical Research Institute, 1101 Yale Blvd. NE, Albuquerque, NM, 87106, USA
| | - Marom Bikson
- Department of Biomedical Engineering, City College of New York, New York, NY, USA.
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21
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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] [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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22
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Arle JE, Iftimia N, Shils JL, Mei L, Carlson KW. Dynamic Computational Model of the Human Spinal Cord Connectome. Neural Comput 2018; 31:388-416. [PMID: 30576619 DOI: 10.1162/neco_a_01159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Connectomes abound, but few for the human spinal cord. Using anatomical data in the literature, we constructed a draft connectivity map of the human spinal cord connectome, providing a template for the many calibrations of specialized behavior to be overlaid on it and the basis for an initial computational model. A thorough literature review gleaned cell types, connectivity, and connection strength indications. Where human data were not available, we selected species that have been studied. Cadaveric spinal cord measurements, cross-sectional histology images, and cytoarchitectural data regarding cell size and density served as the starting point for estimating numbers of neurons. Simulations were run using neural circuitry simulation software. The model contains the neural circuitry in all ten Rexed laminae with intralaminar, interlaminar, and intersegmental connections, as well as ascending and descending brain connections and estimated neuron counts for various cell types in every lamina of all 31 segments. We noted the presence of highly interconnected complex networks exhibiting several orders of recurrence. The model was used to perform a detailed study of spinal cord stimulation for analgesia. This model is a starting point for workers to develop and test hypotheses across an array of biomedical applications focused on the spinal cord. Each such model requires additional calibrations to constrain its output to verifiable predictions. Future work will include simulating additional segments and expanding the research uses of the model.
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Affiliation(s)
- Jeffrey E Arle
- Department of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA 02215; Department of Neurosurgery, Harvard Medical School, Boston, MA 02115; and Department of Neurosurgery, Mt. Auburn Hospital, Cambridge, MA 02138, U.S.A.
| | - Nicolae Iftimia
- Molecular Pathology Department, Massachusetts General Hospital, Charlestown, MA 02114, U.S.A.
| | - Jay L Shils
- Department of Anesthesiology, Rush Medical Center, Chicago, IL 60612, U.S.A.
| | - Longzhi Mei
- Department of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, U.S.A.
| | - Kristen W Carlson
- Department of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, U.S.A.
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23
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Barth BB, Shen X. Computational motility models of neurogastroenterology and neuromodulation. Brain Res 2018; 1693:174-179. [PMID: 29903620 PMCID: PMC6671680 DOI: 10.1016/j.brainres.2018.02.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/18/2018] [Accepted: 02/24/2018] [Indexed: 01/15/2023]
Abstract
The success of neuromodulation therapies, particularly in the brain, spinal cord, and peripheral nerves, has been greatly aided by computational, biophysical models. However, treating gastrointestinal disorders with electrical stimulation has been much less explored, partly because the mode of action of such treatments is unclear, and selection of stimulation parameters is often empirical. Progress in gut neuromodulation is limited by the comparative lack of biophysical models capable of simulating neuromodulation of gastrointestinal function. Here, we review the recently developed biophysical models of electrically-active cells in the gastrointestinal system that contribute to motility. Biophysical models are replacing phenomenologically-defined models due to advancements in electrophysiological characterization of key players in the gut: enteric neurons, smooth muscle fibers, and interstitial cells of Cajal. In this review, we explore existing biophysically-defined cellular and network models that contribute to gastrointestinal motility. We focus on recent models that are laying the groundwork for modeling electrical stimulation of the gastrointestinal system. Developing models of gut neuromodulation will improve our mechanistic understanding of these treatments, leading to better parameterization, selectivity, and efficacy of neuromodulation to treat gastrointestinal disorders. Such models may have direct clinical translation to current neuromodulation therapies, such as sacral nerve stimulation.
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Affiliation(s)
- Bradley B Barth
- Department of Biomedical Engineering, Duke University, Room 2141, CIEMAS, 101 Science Drive, Durham, NC, USA.
| | - Xiling Shen
- Department of Biomedical Engineering, Duke University, Room 2167, CIEMAS, 101 Science Drive, Durham, NC, USA.
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24
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Pelot NA, Thio BJ, Grill WM. Modeling Current Sources for Neural Stimulation in COMSOL. Front Comput Neurosci 2018; 12:40. [PMID: 29937722 PMCID: PMC6002501 DOI: 10.3389/fncom.2018.00040] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/17/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Computational modeling provides an important toolset for designing and analyzing neural stimulation devices to treat neurological disorders and diseases. Modeling enables efficient exploration of large parameter spaces, where preclinical and clinical studies would be infeasible. Current commercial finite element method software packages enable straightforward calculation of the potential distributions, but it is not always clear how to implement boundary conditions to appropriately represent metal stimulating electrodes. By quantifying the effects of different electrode representations on activation thresholds for model axons, we provide recommendations for accurate and efficient modeling of neural stimulating electrodes. Methods: We quantified the effects of different representations of current sources for neural stimulation in COMSOL Multiphysics for monopolar, bipolar, and multipolar electrode designs. Results: We recommend modeling each electrode contact as a thin platinum domain, modeling the electrode substrate with the conductivity of silicone, and either using a point current source in the center of each electrode contact or using a boundary current source. Alternatively, to avoid possible numerical instabilities associated with a large range of conductivity values (i.e., platinum and silicone) and to eliminate the small mesh elements required for thin electrode contacts, the electrode substrate can be assigned the conductivity of platinum by using insulating boundaries between the substrate and surrounding medium, and within the substrate to isolate the contacts from each other. When modeling more than one contact, we recommend using superposition by solving the model once for each contact, leaving inactive contacts floating, and superposing the resulting potentials. We computed comparable errors in activation thresholds across the different implementations in a simplified model (electrode in a homogeneous, isotropic medium), and in realistic models of rat spinal cord stimulation (SCS) and human deep brain stimulation, indicating that the recommended approaches are applicable to different stimulation targets.
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Affiliation(s)
- Nicole A Pelot
- Department of Biomedical Engineering, Duke University Durham, NC, United States
| | - Brandon J Thio
- Department of Biomedical Engineering, Duke University Durham, NC, United States
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University Durham, NC, United States.,Department of Electrical and Computer Engineering, Duke University Durham, NC, United States.,Department of Neurobiology, Duke University Durham, NC, United States.,Department of Neurosurgery, Duke University School of Medicine Durham, NC, United States
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25
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Mourdoukoutas AP, Truong DQ, Adair DK, Simon BJ, Bikson M. High-Resolution Multi-Scale Computational Model for Non-Invasive Cervical Vagus Nerve Stimulation. Neuromodulation 2018; 21:261-268. [PMID: 29076212 PMCID: PMC5895480 DOI: 10.1111/ner.12706] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/26/2017] [Accepted: 08/25/2017] [Indexed: 12/28/2022]
Abstract
OBJECTIVES To develop the first high-resolution, multi-scale model of cervical non-invasive vagus nerve stimulation (nVNS) and to predict vagus fiber type activation, given clinically relevant rheobase thresholds. METHODS An MRI-derived Finite Element Method (FEM) model was developed to accurately simulate key macroscopic (e.g., skin, soft tissue, muscle) and mesoscopic (cervical enlargement, vertebral arch and foramen, cerebral spinal fluid [CSF], nerve sheath) tissue components to predict extracellular potential, electric field (E-Field), and activating function along the vagus nerve. Microscopic scale biophysical models of axons were developed to compare axons of varying size (Aα-, Aβ- and Aδ-, B-, and C-fibers). Rheobase threshold estimates were based on a step function waveform. RESULTS Macro-scale accuracy was found to determine E-Field magnitudes around the vagus nerve, while meso-scale precision determined E-field changes (activating function). Mesoscopic anatomical details that capture vagus nerve passage through a changing tissue environment (e.g., bone to soft tissue) profoundly enhanced predicted axon sensitivity while encapsulation in homogenous tissue (e.g., nerve sheath) dulled axon sensitivity to nVNS. CONCLUSIONS These findings indicate that realistic and precise modeling at both macroscopic and mesoscopic scales are needed for quantitative predictions of vagus nerve activation. Based on this approach, we predict conventional cervical nVNS protocols can activate A- and B- but not C-fibers. Our state-of-the-art implementation across scales is equally valuable for models of spinal cord stimulation, cortex/deep brain stimulation, and other peripheral/cranial nerve models.
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Affiliation(s)
- Antonios P. Mourdoukoutas
- Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY
| | - Dennis Q. Truong
- Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY
| | - Devin K. Adair
- Department of Psychology, The Graduate Center, City University of New York, New York, New York
| | | | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, City University of New York, New York, NY
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26
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Lu XX, Hong ZQ, Tan Z, Sui MH, Zhuang ZQ, Liu HH, Zheng XY, Yan TB, Geng DF, Jin DM. Nicotinic Acetylcholine Receptor Alpha7 Subunit Mediates Vagus Nerve Stimulation-Induced Neuroprotection in Acute Permanent Cerebral Ischemia by a7nAchR/JAK2 Pathway. Med Sci Monit 2017; 23:6072-6081. [PMID: 29274273 PMCID: PMC5747934 DOI: 10.12659/msm.907628] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Background The role of nicotinic acetylcholine receptor alpha7 subunit (a7nAchR) in the treatment of acute cerebral ischemia by VNS has not been thoroughly clarified to date. Therefore, this study aimed to investigate the specific role of a7nAchR and explore whether this process is involved in the mechanisms of VNS-induced neuroprotection in rats undergoing permanent middle cerebral artery occlusion (PMCAO) surgery. Material/Methods Rats received a7nAChR antagonist (A) or antagonist placebo injection for control (AC), followed by PMCAO and VNS treatment, whereas the a7nAChR agonist (P) was utilized singly without VNS treatment but only with PMCAO pretreatment. The rats were randomly divided into 6 groups: sham PMCAO, PMCAO, PMCAO+VNS, PMCAO+VNS+A, PMCAO+VNS+AC, and PMCAO+P. Neurological function and cerebral infarct volume were measured to evaluate the level of brain injury at 24 h after PMCAO or PMCAO-sham. Moreover, the related proteins levels of a7nAChR, p-JAK2, and p-STAT3 in the ischemic penumbra were assessed by Western blot analysis. Results Rats pretreated with VNS had significantly improved neurological function and reduced cerebral infarct volume after PMCAO injury (p<0.05). In addition, VNS enhanced the levels of a7nAchR, p-JAK2, and p-STAT3 in the ischemic penumbra (p<0.05). However, inhibition of a7nAchR not only attenuated the beneficial neuroprotective effects induced by VNS, but also decreased levels of p-JAK2 and p-STAT3. Strikingly, pharmacological activation of a7nAchR can partially substitute for VNS-induced beneficial neurological protection. Conclusions These results suggest that a7nAchR is a pivotal mediator of VNS-induced neuroprotective effects on PMCAO injury, which may be related to suppressed inflammation via activation of the a7nAchR/JAK2 anti-inflammatory pathway.
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Affiliation(s)
- Xin-Xin Lu
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Department of Rehabilitation Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Zhong-Qiu Hong
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland)
| | - Zhi Tan
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland)
| | - Ming-Hong Sui
- Department of Rehabilitation Medicine, Shenzhen Nanshan People's Hospital (The Sixth People's Hospital of Shenzhen), Shenzhen University, Shenzhen, Guangdong, China (mainland)
| | - Zhi-Qiang Zhuang
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Engineering Technology Research Center for Rehabilitation and Elderly Care, Guangdong, China (mainland)
| | - Hui-Hua Liu
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Engineering Technology Research Center for Rehabilitation and Elderly Care, Guangdong, China (mainland)
| | - Xiu-Yuan Zheng
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Engineering Technology Research Center for Rehabilitation and Elderly Care, Guangdong, China (mainland)
| | - Tie-Bin Yan
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Engineering Technology Research Center for Rehabilitation and Elderly Care, Guangdong, China (mainland)
| | - Deng-Feng Geng
- Department of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland)
| | - Dong-Mei Jin
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China (mainland).,Guangdong Engineering Technology Research Center for Rehabilitation and Elderly Care, Guangdong, China (mainland)
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27
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Ardell JL, Nier H, Hammer M, Southerland EM, Ardell CL, Beaumont E, KenKnight BH, Armour JA. Defining the neural fulcrum for chronic vagus nerve stimulation: implications for integrated cardiac control. J Physiol 2017; 595:6887-6903. [PMID: 28862330 PMCID: PMC5685838 DOI: 10.1113/jp274678] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/14/2017] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS The evoked cardiac response to bipolar cervical vagus nerve stimulation (VNS) reflects a dynamic interaction between afferent mediated decreases in central parasympathetic drive and suppressive effects evoked by direct stimulation of parasympathetic efferent axons to the heart. The neural fulcrum is defined as the operating point, based on frequency-amplitude-pulse width, where a null heart rate response is reproducibly evoked during the on-phase of VNS. Cardiac control, based on the principal of the neural fulcrum, can be elicited from either vagus. Beta-receptor blockade does not alter the tachycardia phase to low intensity VNS, but can increase the bradycardia to higher intensity VNS. While muscarinic cholinergic blockade prevented the VNS-induced bradycardia, clinically relevant doses of ACE inhibitors, beta-blockade and the funny channel blocker ivabradine did not alter the VNS chronotropic response. While there are qualitative differences in VNS heart control between awake and anaesthetized states, the physiological expression of the neural fulcrum is maintained. ABSTRACT Vagus nerve stimulation (VNS) is an emerging therapy for treatment of chronic heart failure and remains a standard of therapy in patients with treatment-resistant epilepsy. The objective of this work was to characterize heart rate (HR) responses (HRRs) during the active phase of chronic VNS over a wide range of stimulation parameters in order to define optimal protocols for bidirectional bioelectronic control of the heart. In normal canines, bipolar electrodes were chronically implanted on the cervical vagosympathetic trunk bilaterally with anode cephalad to cathode (n = 8, 'cardiac' configuration) or with electrode positions reversed (n = 8, 'epilepsy' configuration). In awake state, HRRs were determined for each combination of pulse frequency (2-20 Hz), intensity (0-3.5 mA) and pulse widths (130-750 μs) over 14 months. At low intensities and higher frequency VNS, HR increased during the VNS active phase owing to afferent modulation of parasympathetic central drive. When functional effects of afferent and efferent fibre activation were balanced, a null HRR was evoked (defined as 'neural fulcrum') during which HRR ≈ 0. As intensity increased further, HR was reduced during the active phase of VNS. While qualitatively similar, VNS delivered in the epilepsy configuration resulted in more pronounced HR acceleration and reduced HR deceleration during VNS. At termination, under anaesthesia, transection of the vagi rostral to the stimulation site eliminated the augmenting response to VNS and enhanced the parasympathetic efferent-mediated suppressing effect on electrical and mechanical function of the heart. In conclusion, VNS activates central then peripheral aspects of the cardiac nervous system. VNS control over cardiac function is maintained during chronic therapy.
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Affiliation(s)
- Jeffrey L. Ardell
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los AngelesLos AngelesCAUSA
| | - Heath Nier
- Biomedical SciencesEast Tennessee State UniversityJohnson CityTNUSA
| | - Matthew Hammer
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los AngelesLos AngelesCAUSA
| | | | | | - Eric Beaumont
- Biomedical SciencesEast Tennessee State UniversityJohnson CityTNUSA
| | | | - J. Andrew Armour
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los AngelesLos AngelesCAUSA
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28
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Cutsforth-Gregory JK, Benarroch EE. Nucleus of the solitary tract, medullary reflexes, and clinical implications. Neurology 2017; 88:1187-1196. [PMID: 28202704 DOI: 10.1212/wnl.0000000000003751] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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29
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Zhang L, Ma J, Jin X, Jia G, Jiang Y, Li C. L-PGDS Mediates Vagus Nerve Stimulation-Induced Neuroprotection in a Rat Model of Ischemic Stroke by Suppressing the Apoptotic Response. Neurochem Res 2016; 42:644-655. [PMID: 27900597 DOI: 10.1007/s11064-016-2121-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/25/2016] [Accepted: 11/21/2016] [Indexed: 12/18/2022]
Abstract
The role of lipocalin prostaglandin D2 synthase (L-PGDS) in brain ischemia has not been fully clarified to date. Vagus nerve stimulation (VNS) protects against cerebral ischemia/reperfusion (I/R) injury, but the mechanisms involved need further exploration. This study investigated the role of L-PGDS in cerebral I/R and whether this process was involved in the mechanism of VNS-mediated neuroprotection. Male Sprague-Dawley rats were pretreated with a lentiviral vector (LV) through intracerebroventricular injection, followed by middle cerebral artery occlusion (MCAO) and VNS treatment. The expression of L-PGDS in the peri-infarct cortex was examined. The localization of L-PGDS was determined using double immunofluorescence staining. Neurologic scores, infarct volume and neuronal apoptosis were evaluated at 24 h after reperfusion. The expression of apoptosis-related molecules was measured by western blot analysis. The expression of L-PGDS in the peri-infarct cortex increased at 12 h, reached a peak at 24 h after reperfusion, and lasted up to 3 days. VNS treatment further enhanced the expression of L-PGDS following ischemic stroke. L-PGDS was mainly expressed in neurons in the peri-infarct cortex. I/R rats treated with VNS showed better neurological deficit scores, reduced infarct volume, and decreased neuronal apoptosis as indicated by the decreased levels of Bax and cleaved caspase-3 as well as increased levels of Bcl-2. Strikingly, the beneficial effects of VNS were weakened after L-PGDS down-regulation. In general, our results suggest that L-PGDS is a potential mediator of VNS-induced neuroprotection against I/R injury.
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Affiliation(s)
- Lina Zhang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, #76 Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Jingxi Ma
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, #76 Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Xinhao Jin
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, #76 Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Gongwei Jia
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, #76 Linjiang Road, Yuzhong District, Chongqing, 400010, China
| | - Ying Jiang
- Department of Neurology, Center for Neurodegenerative Disease, Beijing Tiantan Hospital, Capital Medical University, #6 Tian Tan Xi Li Street, Beijing, 100050, China
| | - Changqing Li
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, #76 Linjiang Road, Yuzhong District, Chongqing, 400010, China.
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