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Enayati S, Chang K, Lennikov A, Yang M, Lee C, Ashok A, Elzaridi F, Yen C, Gunes K, Xie J, Cho KS, Utheim TP, Chen DF. Optimal transcorneal electrical stimulation parameters for preserving photoreceptors in a mouse model of retinitis pigmentosa. Neural Regen Res 2024; 19:2543-2552. [PMID: 38526290 PMCID: PMC11090438 DOI: 10.4103/1673-5374.392888] [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: 12/31/2022] [Revised: 11/21/2023] [Accepted: 12/29/2023] [Indexed: 03/26/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202419110-00034/figure1/v/2024-03-08T184507Z/r/image-tiff Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors, leading to progressive photoreceptor loss. Previous research supports the beneficial effect of electrical stimulation on photoreceptor survival. This study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation (tcES) in mice affected by inherited retinal degeneration. Additionally, the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem humans. In this study, we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular, sine, and ramp waveforms. To investigate the functional effects of electrical stimulation on photoreceptors, we used human retinal explant cultures and rhodopsin knockout (Rho-/-) mice, demonstrating progressive photoreceptor degeneration with age. Human retinal explants isolated from the donors' eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in vitro. Photoreceptor density was evaluated by rhodopsin immunolabeling. In vivo Rho-/- mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp waveforms. Retinal function and visual perception of mice were evaluated by electroretinography and optomotor response (OMR), respectively. Immunolabeling was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse retinas. Oscilloscope recordings indicated effective delivery of rectangular, sine, and ramp waveforms to the retina by transcorneal electrical stimulation, of which the ramp waveform required the lowest voltage. Evaluation of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human eyes. The temperature recordings during and after electrical stimulation indicated no significant temperature change in vivo and only a subtle temperature increase in vitro (~0.5-1.5°C). Electrical stimulation increased photoreceptor survival in human retinal explant cultures, particularly at the ramp waveform. Transcorneal electrical stimulation (rectangular + ramp) waveforms significantly improved the survival and function of S and M-cones and enhanced visual acuity based on the optomotor response results. Histology and immunolabeling demonstrated increased photoreceptor survival, improved outer nuclear layer thickness, and increased bipolar cell sprouting in Rho-/- mice. These results indicate that transcorneal electrical stimulation effectively delivers the electrical field to the retina, improves photoreceptor survival in both human and mouse retinas, and increases visual function in Rho-/- mice. Combined rectangular and ramp waveform stimulation can promote photoreceptor survival in a minimally invasive fashion.
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Affiliation(s)
- Sam Enayati
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Institute of clinical medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway
| | - Karen Chang
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Anton Lennikov
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Menglu Yang
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Cherin Lee
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Ajay Ashok
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Farris Elzaridi
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Christina Yen
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Kasim Gunes
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Department of Histology and Embryology, School of Medicine, Marmara University, Istanbul, Turkiye
| | - Jia Xie
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Kin-Sang Cho
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Tor Paaske Utheim
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Institute of clinical medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway
| | - Dong Feng Chen
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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Amini S, Choi H, Seche W, Blagojevic A, May N, Lefler BM, Davis SL, Elyahoodayan S, Tavousi P, May SJ, Caputo GA, Lowe TC, Hettinger J, Shahbazmohamadi S. Sustainability inspired fabrication of next generation neurostimulation and cardiac rhythm management electrodes via reactive hierarchical surface restructuring. MICROSYSTEMS & NANOENGINEERING 2024; 10:125. [PMID: 39251609 PMCID: PMC11384795 DOI: 10.1038/s41378-024-00754-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 06/05/2024] [Accepted: 06/23/2024] [Indexed: 09/11/2024]
Abstract
Over the last two decades, platinum group metals (PGMs) and their alloys have dominated as the materials of choice for electrodes in long-term implantable neurostimulation and cardiac rhythm management devices due to their superior conductivity, mechanical and chemical stability, biocompatibility, corrosion resistance, radiopacity, and electrochemical performance. Despite these benefits, PGM manufacturing processes are extremely costly, complex, and challenging with potential health hazards. Additionally, the volatility in PGM prices and their high supply risk, combined with their scarce concentration of approximately 0.01 ppm in the earth's upper crust and limited mining geographical areas, underscores their classification as critical raw materials, thus, their effective recovery or substitution worldwide is of paramount importance. Since postmortem recovery from deceased patients and/or refining of PGMs that are used in the manufacturing of the electrodes and microelectrode arrays is extremely rare, challenging, and highly costly, therefore, substitution of PGM-based electrodes with other biocompatible materials that can yield electrochemical performance values equal or greater than PGMs is the only viable and sustainable solution to reduce and ultimately substitute the use of PGMs in long-term implantable neurostimulation and cardiac rhythm management devices. In this article, we demonstrate for the first time how the novel technique of "reactive hierarchical surface restructuring" can be utilized on titanium-that is widely used in many non-stimulation medical device and implant applications-to manufacture biocompatible, low-cost, sustainable, and high-performing neurostimulation and cardiac rhythm management electrodes. We have shown how the surface of titanium electrodes with extremely poor electrochemical performance undergoes compositional and topographical transformations that result in electrodes with outstanding electrochemical performance.
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Affiliation(s)
- Shahram Amini
- Research and Development, Pulse Technologies Inc., Quakertown, PA, USA.
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, USA.
| | - Hongbin Choi
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, USA
| | - Wesley Seche
- Research and Development, Pulse Technologies Inc., Quakertown, PA, USA
| | | | - Nicholas May
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, USA
| | - Benjamin M Lefler
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
| | - Skyler L Davis
- Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, USA
| | - Sahar Elyahoodayan
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Pouya Tavousi
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, USA
| | - Steven J May
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
| | - Gregory A Caputo
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, USA
| | - Terry C Lowe
- Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO, USA
| | - Jeffrey Hettinger
- Department of Physics and Astronomy, Rowan University, Glassboro, NJ, USA
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Niederhoffer T, Vanhoestenberghe A, Lancashire HT. Extending the understanding of Shannon's safe stimulation limit for platinum electrodes: biphasic charge-balanced pulse trains in unbuffered saline at pH = 1 to pH = 12. J Neural Eng 2024; 21:056007. [PMID: 38579740 DOI: 10.1088/1741-2552/ad3b6a] [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: 10/21/2023] [Accepted: 04/05/2024] [Indexed: 04/07/2024]
Abstract
Objective.In neural electrical stimulation, safe stimulation guidelines are essential to deliver efficient treatment while avoiding neural damage and electrode degradation. The widely used Shannon's limit,k, gives conditions on the stimulation parameters to avoid neural damage, however, underlying damage mechanisms are not fully understood. Moreover, the translation from bench testing toin vivoexperiments still presents some challenges, including the increased polarisation observed, which may influence charge-injection mechanisms. In this work, we studied the influence on damage mechanisms of two electrolyte parameters that are differentin vivocompared to usual bench tests: solution pH and electrolyte gelation.Approach.The potential of a platinum macroelectrode was monitored in a three-electrode setup during current-controlled biphasic charge-balanced cathodic-first pulse trains. Maximum anodic and cathodic potential excursions during pulse trains were projected on cyclic voltammograms to infer possible electrochemical reactions.Main results.In unbuffered saline of pH ranging from 1 to 12, the maximum anodic potential was systematically located in the oxide formation region, while the cathodic potential was located the molecular oxygen and oxide reduction region whenkapproached Shannon's damage limit, independent of solution pH. The results support the hypothesis that Shannon's limit corresponds to the beginning of platinum dissolution following repeated cycles of platinum oxidation and reduction, for which the cathodic excursion is a key tipping point. Despite similar potential excursions between solution and gel electrolytes, we found a joint influence of pH and gelation on the cathodic potential alone, while we observed no effect on the anodic potential. We hypothesise that gelation creates a positive feedback loop exacerbating the effects of pH ; however, the extent of that influence needs to be examined further.Significance.This work supports the hypothesis of charge injection mechanisms associated with stimulation-induced damage at platinum electrodes. The validity of a major hypothesis explaining stimulation-induced damage was tested and supported on a range of electrolytes representing potential electrode environments, calling for further characterisation of platinum dissolution during electrical stimulation in various testing conditions.
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Affiliation(s)
- Thomas Niederhoffer
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Anne Vanhoestenberghe
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Henry T Lancashire
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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Chen YY, Chang CJ, Liang YW, Tseng HY, Li SJ, Chang CW, Wu YT, Shao HH, Chen PC, Lai ML, Deng WC, Hsu R, Lo YC. Utilizing diffusion tensor imaging as an image biomarker in exploring the therapeutic efficacy of forniceal deep brain stimulation in a mice model of Alzheimer's disease. J Neural Eng 2024; 21:056003. [PMID: 39230033 DOI: 10.1088/1741-2552/ad7322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 08/15/2024] [Indexed: 09/05/2024]
Abstract
Objective.With prolonged life expectancy, the incidence of memory deficits, especially in Alzheimer's disease (AD), has increased. Although multiple treatments have been evaluated, no promising treatment has been found to date. Deep brain stimulation (DBS) of the fornix area was explored as a possible treatment because the fornix is intimately connected to memory-related areas that are vulnerable in AD; however, a proper imaging biomarker for assessing the therapeutic efficiency of forniceal DBS in AD has not been established.Approach.This study assessed the efficacy and safety of DBS by estimating the optimal intersection volume between the volume of tissue activated and the fornix. Utilizing a gold-electroplating process, the microelectrode's surface area on the neural probe was increased, enhancing charge transfer performance within potential water window limits. Bilateral fornix implantation was conducted in triple-transgenic AD mice (3 × Tg-AD) and wild-type mice (strain: B6129SF1/J), with forniceal DBS administered exclusively to 3 × Tg-AD mice in the DBS-on group. Behavioral tasks, diffusion tensor imaging (DTI), and immunohistochemistry (IHC) were performed in all mice to assess the therapeutic efficacy of forniceal DBS.Main results.The results illustrated that memory deficits and increased anxiety-like behavior in 3 × Tg-AD mice were rescued by forniceal DBS. Furthermore, forniceal DBS positively altered DTI indices, such as increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD), together with reducing microglial cell and astrocyte counts, suggesting a potential causal relationship between revised FA/MD and reduced cell counts in the anterior cingulate cortex, hippocampus, fornix, amygdala, and entorhinal cortex of 3 × Tg-AD mice following forniceal DBS.Significance.The efficacy of forniceal DBS in AD can be indicated by alterations in DTI-based biomarkers reflecting the decreased activation of glial cells, suggesting reduced neural inflammation as evidenced by improvements in memory and anxiety-like behavior.
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Affiliation(s)
- You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
- Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, 12F., Education & Research Building, Shuang-Ho Campus, No. 301, Yuantong Rd., New Taipei City 23564, Taiwan, Republic of China
| | - Chih-Ju Chang
- Department of Neurosurgery, Cathay General Hospital, No. 280, Sec. 4, Renai Rd., Taipei 10629, Taiwan, Republic of China
- School of Medicine, Fu Jen Catholic University, No.510, Zhongzheng Rd., New Taipei City 242062, Taiwan, Republic of China
| | - Yao-Wen Liang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
| | - Hsin-Yi Tseng
- Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, 12F., Education & Research Building, Shuang-Ho Campus, No. 301, Yuantong Rd., New Taipei City 23564, Taiwan, Republic of China
| | - Ssu-Ju Li
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
| | - Ching-Wen Chang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
| | - Yen-Ting Wu
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
| | - Huai-Hsuan Shao
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, No.155, Sec.2, Linong St., Taipei 11221, Taiwan, Republic of China
| | - Po-Chun Chen
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan, Republic of China
| | - Ming-Liang Lai
- Graduate Institute of Intellectual Property, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan, Republic of China
| | - Wen-Chun Deng
- Departments of Neurosurgery, Keelung Chang Gung Memorial Hospital, Chang Gung University, No.222, Maijin Rd., Keelung 20400, Taiwan, Republic of China
| | - RuSiou Hsu
- Department of Ophthalmology, Stanford University, 1651 Page Mill Rd., Palo Alto, CA 94304, United States of America
| | - Yu-Chun Lo
- Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University, 12F., Education & Research Building, Shuang-Ho Campus, No. 301, Yuantong Rd., New Taipei City 23564, Taiwan, Republic of China
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Opančar A, Głowacki ED, Đerek V. Choosing the right electrode representation for modeling real bioelectronic interfaces: a comprehensive guide. J Neural Eng 2024; 21:046049. [PMID: 39094614 DOI: 10.1088/1741-2552/ad6a8b] [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: 02/28/2024] [Accepted: 08/01/2024] [Indexed: 08/04/2024]
Abstract
Objective.Producing realistic numerical models of neurostimulation electrodes in contact with the electrolyte and tissue, for use in time-domain finite element method simulations while maintaining a reasonable computational burden remains a challenge. We aim to provide a straightforward experimental-theoretical hybrid approach for common electrode materials (Ti, TiN, ITO, Au, Pt, IrOx) that are relevant to the research field of bioelectronics, along with all the information necessary to replicate our approach in arbitrary geometry for real-life experimental applications.Approach.We used electrochemical impedance spectroscopy (EIS) to extract the electrode parameters in the AC regime under different DC biases. The pulsed electrode response was obtained by fast amperometry (FA) to optimize and verify the previously obtained electrode parameters in a COMSOL Multiphysics model. For optimization of the electrode parameters a constant phase element (CPE) needed to be implemented in time-domain.Main results.We find that the parameters obtained by EIS can be used to accurately simulate pulsed response only close to the electrode open circuit potential, while at other potentials we give corrections to the obtained parameters, based on FA measurements. We also find that for many electrodes (Au, TiN, Pt, and IrOx), it is important to implement a distributed CPE rather than an ideal capacitor for estimating the electrode double-layer capacitance. We outline and provide examples for the novel time-domain implementation of the CPE for finite element method simulations in COMSOL Multiphysics.Significance.An overview of electrode parameters for some common electrode materials can be a valuable and useful tool in numerical bioelectronics models. A provided FEM implementation model can be readily adapted to arbitrary electrode geometries and used for various applications. Finally, the presented methodology for parametrization of electrode materials can be used for any materials of interest which were not covered by this work.
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Affiliation(s)
- Aleksandar Opančar
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, 10000 Zagreb, Croatia
- Bioelectronics Materials and Devices Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Eric Daniel Głowacki
- Bioelectronics Materials and Devices Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Vedran Đerek
- Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, 10000 Zagreb, Croatia
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Gunes K, Chang K, Lennikov A, Tai WL, Chen J, ElZaridi F, Cho KS, Utheim TP, Dong Feng C. Preservation of vision by transpalpebral electrical stimulation in mice with inherited retinal degeneration. Front Cell Dev Biol 2024; 12:1412909. [PMID: 39206091 PMCID: PMC11349514 DOI: 10.3389/fcell.2024.1412909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/02/2024] [Indexed: 09/04/2024] Open
Abstract
Introduction The potential neuroprotective and regenerative properties of electrical stimulation (ES) were studied in rhodopsin knockout mice (Rho -/- ), a murine model of inherited retinal degeneration. The study focused on assessing the impact of varying ES frequencies on visual functions and photoreceptor cell survival in Rho -/- mice. Methods To elucidate the impact of electrical stimulation on cone survival, Rho -/- mice received either sham or transpalpebral ES using biphasic ramp or rectangular waveforms at 100 µA amplitude, starting at six weeks of age. The treatment duration spanned from one to three weeks. The optimal treatment frequency of ES sessions was determined by applying ES every one, two, or three days in three separate groups of Rho -/- mice. The sham group received daily treatments without the application of ES. Results Our study revealed significant improvement of visual function in Rho -/- mice following daily or every-other-day noninvasive transpalpebral ES, as evidenced by electroretinogram and optomotor response-based visual behavior assays. Concurrently, assessment of outer nuclear thickness and immunohistochemistry for the cone photoreceptor cell marker PNA demonstrated pronounced increases in the survival of rods and cones and improvement in the morphology of the inner and outer segments. Discussion This study underscores the protective effect of non-invasive ES in rhodopsin knockout-induced retinal degenerative disorders, providing a foundation for developing targeted therapeutic interventions for retinitis pigmentosa.
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Affiliation(s)
- Kasim Gunes
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
- Department of Histology and Embryology, School of Medicine, Marmara University, Istanbul, Türkiye
| | - Karen Chang
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Anton Lennikov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Wai Lydia Tai
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Julie Chen
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Farris ElZaridi
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Kin-Sang Cho
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Tor Paaske Utheim
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
| | - Chen Dong Feng
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
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Silkunas M, Pakhomova ON, Silkuniene G, Pakhomov AG. Dynamics of cell membrane lesions and adaptive conductance under the electrical stress. Cell Stress 2024; 8:69-82. [PMID: 39135750 PMCID: PMC11318148 DOI: 10.15698/cst2024.08.298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 07/24/2024] [Accepted: 08/06/2024] [Indexed: 08/15/2024] Open
Abstract
Exceeding physiological limits of the cell membrane potential compromises structural integrity, enabling the passage of normally impermeant solutes and disrupting cell function. Electropermeabilization has been studied extensively at the cellular scale, but not at the individual membrane lesion level. We employed fast total internal reflection fluorescence (TIRF) imaging of Ca2+ entry transients to discern individual lesions in a hyperpolarized cell membrane and characterize their focality, thresholds, electrical conductance, and the lifecycle. A diffuse and momentary membrane permeabilization without a distinct pore formation was observed already at a -100 mV threshold. Polarizing down to -200 mV created focal pores with a low 50- to 300-pS conductance, which disappeared instantly once the hyperpolarization was removed. Charging to -240 mV created high-conductance (> 1 nS) pores which persisted for seconds even at zero membrane potential. With incremental hyperpolarization steps, persistent pores often emerged at locations different from those where the short-lived, low-conductance pores or diffuse permeabilization were previously observed. Attempts to polarize membrane beyond the threshold for the formation of persistent pores increased their conductance adaptively, preventing further potential build-up and "clamping" it at a certain limit (-270 ± 6 mV in HEK cells, -284 ± 5 mV in CHO cells, and -243 ± 9 mV in neurons). The data suggest a previously unknown role of electroporative lesions as a protective mechanism against a potentially fatal membrane overcharging and cell disintegration.
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Affiliation(s)
- Mantas Silkunas
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Giedre Silkuniene
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
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Wu S, Issa NP, Rose SL, Haider HA, Nordli DR, Towle VL, Warnke PC, Tao JX. Depth versus surface: A critical review of subdural and depth electrodes in intracranial electroencephalographic studies. Epilepsia 2024; 65:1868-1878. [PMID: 38722693 DOI: 10.1111/epi.18002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/05/2024] [Accepted: 04/24/2024] [Indexed: 07/17/2024]
Abstract
Intracranial electroencephalographic (IEEG) recording, using subdural electrodes (SDEs) and stereoelectroencephalography (SEEG), plays a pivotal role in localizing the epileptogenic zone (EZ). SDEs, employed for superficial cortical seizure foci localization, provide information on two-dimensional seizure onset and propagation. In contrast, SEEG, with its three-dimensional sampling, allows exploration of deep brain structures, sulcal folds, and bihemispheric networks. SEEG offers the advantages of fewer complications, better tolerability, and coverage of sulci. Although both modalities allow electrical stimulation, SDE mapping can tessellate cortical gyri, providing the opportunity for a tailored resection. With SEEG, both superficial gyri and deep sulci can be stimulated, and there is a lower risk of afterdischarges and stimulation-induced seizures. Most systematic reviews and meta-analyses have addressed the comparative effectiveness of SDEs and SEEG in localizing the EZ and achieving seizure freedom, although discrepancies persist in the literature. The combination of SDEs and SEEG could potentially overcome the limitations inherent to each technique individually, better delineating seizure foci. This review describes the strengths and limitations of SDE and SEEG recordings, highlighting their unique indications in seizure localization, as evidenced by recent publications. Addressing controversies in the perceived usefulness of the two techniques offers insights that can aid in selecting the most suitable IEEG in clinical practice.
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Affiliation(s)
- Shasha Wu
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
| | - Naoum P Issa
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
| | - Sandra L Rose
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
| | - Hiba A Haider
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
| | - Douglas R Nordli
- Department of Pediatrics, University of Chicago, Chicago, Illinois, USA
| | - Vernon L Towle
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
| | - Peter C Warnke
- Department of Neurological Surgery, University of Chicago, Chicago, Illinois, USA
| | - James X Tao
- Department of Neurology, University of Chicago, Chicago, Illinois, USA
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Li Y, Frederick RA, George D, Cogan SF, Pancrazio JJ, Bleris L, Hernandez-Reynoso AG. NeurostimML: a machine learning model for predicting neurostimulation-induced tissue damage. J Neural Eng 2024; 21:036054. [PMID: 38885676 DOI: 10.1088/1741-2552/ad593e] [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: 10/18/2023] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
Objective. The safe delivery of electrical current to neural tissue depends on many factors, yet previous methods for predicting tissue damage rely on only a few stimulation parameters. Here, we report the development of a machine learning approach that could lead to a more reliable method for predicting electrical stimulation-induced tissue damage by incorporating additional stimulation parameters.Approach. A literature search was conducted to build an initial database of tissue response information after electrical stimulation, categorized as either damaging or non-damaging. Subsequently, we used ordinal encoding and random forest for feature selection, and investigated four machine learning models for classification: Logistic Regression, K-nearest Neighbor, Random Forest, and Multilayer Perceptron. Finally, we compared the results of these models against the accuracy of the Shannon equation.Main Results. We compiled a database with 387 unique stimulation parameter combinations collected from 58 independent studies conducted over a period of 47 years, with 195 (51%) categorized as non-damaging and 190 (49%) categorized as damaging. The features selected for building our model with a Random Forest algorithm were: waveform shape, geometric surface area, pulse width, frequency, pulse amplitude, charge per phase, charge density, current density, duty cycle, daily stimulation duration, daily number of pulses delivered, and daily accumulated charge. The Shannon equation yielded an accuracy of 63.9% using akvalue of 1.79. In contrast, the Random Forest algorithm was able to robustly predict whether a set of stimulation parameters was classified as damaging or non-damaging with an accuracy of 88.3%.Significance. This novel Random Forest model can facilitate more informed decision making in the selection of neuromodulation parameters for both research studies and clinical practice. This study represents the first approach to use machine learning in the prediction of stimulation-induced neural tissue damage, and lays the groundwork for neurostimulation driven by machine learning models.
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Affiliation(s)
- Yi Li
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States of America
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Rebecca A Frederick
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR, United States of America
| | - Daniel George
- Department of Computer Science, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Leonidas Bleris
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States of America
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX, United States of America
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Ana G Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States of America
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10
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Ng KKW, So A, Fang JY, Birznieks I, Vickery RM. Multiplexing intensity and frequency sensations for artificial touch by modulating temporal features of electrical pulse trains. Front Neurosci 2024; 18:1125597. [PMID: 38894940 PMCID: PMC11183272 DOI: 10.3389/fnins.2024.1125597] [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: 12/16/2022] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
In neural prostheses, intensity modulation of a single channel (i.e., through a single stimulating electrode) has been achieved by increasing the magnitude or width of each stimulation pulse, which risks eliciting pain or paraesthesia; and by changing the stimulation rate, which leads to concurrent changes in perceived frequency. In this study, we sought to render a perception of tactile intensity and frequency independently, by means of temporal pulse train patterns of fixed magnitude, delivered non-invasively. Our psychophysical study exploits a previously discovered frequency coding mechanism, where the perceived frequency of stimulus pulses grouped into periodic bursts depends on the duration of the inter-burst interval, rather than the mean pulse rate or periodicity. When electrical stimulus pulses were organised into bursts, perceived intensity was influenced by the number of pulses within a burst, while perceived frequency was determined by the time between the end of one burst envelope and the start of the next. The perceived amplitude was modulated by 1.6× while perceived frequency was varied independently by 2× within the tested range (20-40 Hz). Thus, the sensation of intensity might be controlled independently from frequency through a single stimulation channel without having to vary the injected electrical current. This can form the basis for improving strategies in delivering more complex and natural sensations for prosthetic hand users.
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Affiliation(s)
- Kevin K. W. Ng
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- School of Biomedical Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Alwin So
- School of Biomedical Sciences, UNSW Sydney, Sydney, NSW, Australia
- Neuroscience Research Australia, Sydney, NSW, Australia
| | - Jun Yi Fang
- School of Biomedical Sciences, UNSW Sydney, Sydney, NSW, Australia
- Neuroscience Research Australia, Sydney, NSW, Australia
| | - Ingvars Birznieks
- School of Biomedical Sciences, UNSW Sydney, Sydney, NSW, Australia
- Neuroscience Research Australia, Sydney, NSW, Australia
- Bionics and Bio-robotics, Tyree Foundation Institute of Health Engineering, UNSW Sydney, Sydney, NSW, Australia
| | - Richard M. Vickery
- School of Biomedical Sciences, UNSW Sydney, Sydney, NSW, Australia
- Neuroscience Research Australia, Sydney, NSW, Australia
- Bionics and Bio-robotics, Tyree Foundation Institute of Health Engineering, UNSW Sydney, Sydney, NSW, Australia
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11
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Wang S, Yan X, Jiao X, Yang H. Experimental Study of the Implantation Process for Array Electrodes into Highly Transparent Agarose Gel. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2334. [PMID: 38793401 PMCID: PMC11123045 DOI: 10.3390/ma17102334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/09/2024] [Accepted: 05/11/2024] [Indexed: 05/26/2024]
Abstract
Brain-computer interface (BCI) technology is currently a cutting-edge exploratory problem in the field of human-computer interaction. However, in experiments involving the implantation of electrodes into brain tissue, particularly high-speed or array implants, existing technologies find it challenging to observe the damage in real time. Considering the difficulties in obtaining biological brain tissue and the challenges associated with real-time observation of damage during the implantation process, we have prepared a transparent agarose gel that closely mimics the mechanical properties of biological brain tissue for use in electrode implantation experiments. Subsequently, we developed an experimental setup for synchronized observation of the electrode implantation process, utilizing the Digital Gradient Sensing (DGS) method. In the single electrode implantation experiments, with the increase in implantation speed, the implantation load increases progressively, and the tissue damage region around the electrode tip gradually diminishes. In the array electrode implantation experiments, compared to a single electrode, the degree of tissue indentation is more severe due to the coupling effect between adjacent electrodes. As the array spacing increases, the coupling effect gradually diminishes. The experimental results indicate that appropriately increasing the velocity and array spacing of the electrodes can enhance the likelihood of successful implantation. The research findings of this article provide valuable guidance for the damage assessment and selection of implantation parameters during the process of electrode implantation into real brain tissue.
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Affiliation(s)
| | - Xuan Yan
- Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures, Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China; (S.W.); (X.J.)
| | | | - Heng Yang
- Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures, Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China; (S.W.); (X.J.)
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12
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Gupta B, Saxena A, Perillo ML, Wade-Kleyn LC, Thompson CH, Purcell EK. Structural, Functional, and Genetic Changes Surrounding Electrodes Implanted in the Brain. Acc Chem Res 2024; 57:1346-1359. [PMID: 38630432 PMCID: PMC11079975 DOI: 10.1021/acs.accounts.4c00057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 05/08/2024]
Abstract
Implantable neurotechnology enables monitoring and stimulating of the brain signals responsible for performing cognitive, motor, and sensory tasks. Electrode arrays implanted in the brain are increasingly used in the clinic to treat a variety of sources of neurological diseases and injuries. However, the implantation of a foreign body typically initiates a tissue response characterized by physical disruption of vasculature and the neuropil as well as the initiation of inflammation and the induction of reactive glial states. Likewise, electrical stimulation can induce damage to the surrounding tissue depending on the intensity and waveform parameters of the applied stimulus. These phenomena, in turn, are likely influenced by the surface chemistry and characteristics of the materials employed, but further information is needed to effectively link the biological responses observed to specific aspects of device design. In order to inform improved design of implantable neurotechnology, we are investigating the basic science principles governing device-tissue integration. We are employing multiple techniques to characterize the structural, functional, and genetic changes that occur in the cells surrounding implanted electrodes. First, we have developed a new "device-in-slice" technique to capture chronically implanted electrodes within thick slices of live rat brain tissue for interrogation with single-cell electrophysiology and two-photon imaging techniques. Our data revealed several new observations of tissue remodeling surrounding devices: (a) there was significant disruption of dendritic arbors in neurons near implants, where losses were driven asymmetrically on the implant-facing side. (b) There was a significant loss of dendritic spine densities in neurons near implants, with a shift toward more immature (nonfunctional) morphologies. (c) There was a reduction in excitatory neurotransmission surrounding implants, as evidenced by a reduction in the frequency of excitatory postsynaptic currents (EPSCs). Lastly, (d) there were changes in the electrophysiological underpinnings of neuronal spiking regularity. In parallel, we initiated new studies to explore changes in gene expression surrounding devices through spatial transcriptomics, which we applied to both recording and stimulating arrays. We found that (a) device implantation is associated with the induction of hundreds of genes associated with neuroinflammation, glial reactivity, oligodendrocyte function, and cellular metabolism and (b) electrical stimulation induces gene expression associated with damage or plasticity in a manner dependent upon the intensity of the applied stimulus. We are currently developing computational analysis tools to distill biomarkers of device-tissue interactions from large transcriptomics data sets. These results improve the current understanding of the biological response to electrodes implanted in the brain while producing new biomarkers for benchmarking the effects of novel electrode designs on responses. As the next generation of neurotechnology is developed, it will be increasingly important to understand the influence of novel materials, surface chemistries, and implant architectures on device performance as well as the relationship with the induction of specific cellular signaling pathways.
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Affiliation(s)
- Bhavna Gupta
- Neuroscience
Program, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Akash Saxena
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Department
of Electrical and Computer Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Mason L. Perillo
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Lauren C. Wade-Kleyn
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Cort H. Thompson
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
| | - Erin K. Purcell
- Department
of Biomedical Engineering, Michigan State
University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Neuroscience
Program, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Institute
for Quantitative Health Science and Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
- Department
of Electrical and Computer Engineering, Michigan State University, 775 Woodlot Dr., East Lansing, Michigan 48824, United States
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13
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Wang X, Jiang W, Yang H, Ye Y, Zhou Z, Sun L, Nie Y, Tao TH, Wei X. Ultraflexible PEDOT:PSS/IrO x-Modified Electrodes: Applications in Behavioral Modulation and Neural Signal Recording in Mice. MICROMACHINES 2024; 15:447. [PMID: 38675259 PMCID: PMC11051784 DOI: 10.3390/mi15040447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024]
Abstract
Recent advancements in neural probe technology have become pivotal in both neuroscience research and the clinical management of neurological disorders. State-of-the-art developments have led to the advent of multichannel, high-density bidirectional neural interfaces that are adept at both recording and modulating neuronal activity within the central nervous system. Despite this progress, extant bidirectional probes designed for simultaneous recording and stimulation are beset with limitations, including elicitation of inflammatory responses and insufficient charge injection capacity. In this paper, we delineate the design and application of an innovative ultraflexible bidirectional neural probe engineered from polyimide. This probe is distinguished by its ability to facilitate high-resolution recordings and precise stimulation control in deep brain regions. Electrodes enhanced with a PEDOT:PSS/IrOx composite exhibit a substantial increase in charge storage capacity, escalating from 0.14 ± 0.01 mC/cm2 to an impressive 24.75 ± 0.18 mC/cm2. This augmentation significantly bolsters the electrodes' charge transfer efficacy. In tandem, we observed a notable reduction in electrode impedance, from 3.47 ± 1.77 MΩ to a mere 41.88 ± 4.04 kΩ, while the phase angle exhibited a positive shift from -72.61 ± 1.84° to -34.17 ± 0.42°. To substantiate the electrodes' functional prowess, we conducted in vivo experiments, where the probes were surgically implanted into the bilateral motor cortex of mice. These experiments involved the synchronous recording and meticulous analysis of neural signal fluctuations during stimulation and an assessment of the probes' proficiency in modulating directional turning behaviors in the subjects. The empirical evidence corroborates that targeted stimulation within the bilateral motor cortex of mice can modulate the intensity of neural signals in the stimulated locale, enabling the directional control of the mice's turning behavior to the contralateral side of the stimulation site.
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Affiliation(s)
- Xueying Wang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wanqi Jiang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huiran Yang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
| | - Yifei Ye
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Zhitao Zhou
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liuyang Sun
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
- 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Yanyan Nie
- Shanghai Laboratory Animal Research Center, Shanghai 201203, China;
| | - Tiger H. Tao
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
- 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- Neuroxess Co., Ltd. (Jiangxi), Nanchang 330029, China
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai 519031, China
- Tianqiao and Chrissy Chen Institute for Translational Research, Shanghai 200040, China
| | - Xiaoling Wei
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (X.W.); (W.J.); (H.Y.); (Y.Y.); (Z.Z.); (L.S.); (T.H.T.)
- School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Seo HW, Cha S, Jeong Y, Ahn J, Lee KJ, Kim S, Goo YS. Focal stimulation of retinal ganglion cells using subretinal 3D microelectrodes with peripheral electrodes of opposite current. Biomed Eng Lett 2024; 14:355-365. [PMID: 38374901 PMCID: PMC10874361 DOI: 10.1007/s13534-023-00342-3] [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: 06/13/2023] [Revised: 10/10/2023] [Accepted: 12/07/2023] [Indexed: 02/21/2024] Open
Abstract
Subretinal prostheses have been developed to stimulate survived retinal ganglion cells (RGCs), indirectly following the physiological visual pathways. However, current spreading from the prosthesis electrode causes the activation of unintended RGCs, thereby limiting the spatial resolution of artificial vision. This study proposes a strategy for focal stimulation of RGCs using a subretinal electrode array, in which six hexagonally arranged peripheral electrodes surround a stimulating electrode. RGCs in an in-vitro condition were subretinally stimulated using a fabricated electrode array coated with iridium oxide, following the three different stimulation configurations (with no peripheral, six electrodes of opposite current, and six ground). In-vitro experiments showed that the stimulation with six electrodes of opposite current was most effective in controlling RGC responses with a high spatial resolution. The results suggest that the effective utilization of return electrodes, such as by applying an opposite current to them, could help reduce current spreading beyond the local area targeted for stimulation and elicit RGC responses only in the vicinity of the stimulating electrode. Supplementary Information The online version contains supplementary material available at 10.1007/s13534-023-00342-3.
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Affiliation(s)
- Hee Won Seo
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Republic of Korea
| | - Yurim Jeong
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Republic of Korea
| | - Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Republic of Korea
| | - Kyeong Jae Lee
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Sohee Kim
- Department of Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Republic of Korea
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15
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Wu Q, Xue R, Zhao Y, Ramsay K, Wang EY, Savoji H, Veres T, Cartmell SH, Radisic M. Automated fabrication of a scalable heart-on-a-chip device by 3D printing of thermoplastic elastomer nanocomposite and hot embossing. Bioact Mater 2024; 33:46-60. [PMID: 38024233 PMCID: PMC10654006 DOI: 10.1016/j.bioactmat.2023.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
The successful translation of organ-on-a-chip devices requires the development of an automated workflow for device fabrication, which is challenged by the need for precise deposition of multiple classes of materials in micro-meter scaled configurations. Many current heart-on-a-chip devices are produced manually, requiring the expertise and dexterity of skilled operators. Here, we devised an automated and scalable fabrication method to engineer a Biowire II multiwell platform to generate human iPSC-derived cardiac tissues. This high-throughput heart-on-a-chip platform incorporated fluorescent nanocomposite microwires as force sensors, produced from quantum dots and thermoplastic elastomer, and 3D printed on top of a polystyrene tissue culture base patterned by hot embossing. An array of built-in carbon electrodes was embedded in a single step into the base, flanking the microwells on both sides. The facile and rapid 3D printing approach efficiently and seamlessly scaled up the Biowire II system from an 8-well chip to a 24-well and a 96-well format, resulting in an increase of platform fabrication efficiency by 17,5000-69,000% per well. The device's compatibility with long-term electrical stimulation in each well facilitated the targeted generation of mature human iPSC-derived cardiac tissues, evident through a positive force-frequency relationship, post-rest potentiation, and well-aligned sarcomeric apparatus. This system's ease of use and its capacity to gauge drug responses in matured cardiac tissue make it a powerful and reliable platform for rapid preclinical drug screening and development.
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Affiliation(s)
- Qinghua Wu
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Ruikang Xue
- Department of Materials, School of Natural Sciences, Faculty of Science and Engineering and The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester, UK
| | - Yimu Zhao
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Kaitlyn Ramsay
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
| | - Erika Yan Wang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Houman Savoji
- Institute of Biomedical Engineering and Department of Pharmacology and Physiology, University of Montreal, Montreal, Quebec, H3T 1J4, Canada
- Research Center, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Quebec, H3T 1C5, Canada
- Montreal TransMedTech Institute, Montreal, Quebec, H3T 1J4, Canada
| | - Teodor Veres
- National Research Council of Canada, Boucherville, QC, J4B 6Y4, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, M5S 3G8, Canada
| | - Sarah H. Cartmell
- Department of Materials, School of Natural Sciences, Faculty of Science and Engineering and The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester, UK
| | - Milica Radisic
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3E5, Canada
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
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16
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González-González MA, Conde SV, Latorre R, Thébault SC, Pratelli M, Spitzer NC, Verkhratsky A, Tremblay MÈ, Akcora CG, Hernández-Reynoso AG, Ecker M, Coates J, Vincent KL, Ma B. Bioelectronic Medicine: a multidisciplinary roadmap from biophysics to precision therapies. Front Integr Neurosci 2024; 18:1321872. [PMID: 38440417 PMCID: PMC10911101 DOI: 10.3389/fnint.2024.1321872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/10/2024] [Indexed: 03/06/2024] Open
Abstract
Bioelectronic Medicine stands as an emerging field that rapidly evolves and offers distinctive clinical benefits, alongside unique challenges. It consists of the modulation of the nervous system by precise delivery of electrical current for the treatment of clinical conditions, such as post-stroke movement recovery or drug-resistant disorders. The unquestionable clinical impact of Bioelectronic Medicine is underscored by the successful translation to humans in the last decades, and the long list of preclinical studies. Given the emergency of accelerating the progress in new neuromodulation treatments (i.e., drug-resistant hypertension, autoimmune and degenerative diseases), collaboration between multiple fields is imperative. This work intends to foster multidisciplinary work and bring together different fields to provide the fundamental basis underlying Bioelectronic Medicine. In this review we will go from the biophysics of the cell membrane, which we consider the inner core of neuromodulation, to patient care. We will discuss the recently discovered mechanism of neurotransmission switching and how it will impact neuromodulation design, and we will provide an update on neuronal and glial basis in health and disease. The advances in biomedical technology have facilitated the collection of large amounts of data, thereby introducing new challenges in data analysis. We will discuss the current approaches and challenges in high throughput data analysis, encompassing big data, networks, artificial intelligence, and internet of things. Emphasis will be placed on understanding the electrochemical properties of neural interfaces, along with the integration of biocompatible and reliable materials and compliance with biomedical regulations for translational applications. Preclinical validation is foundational to the translational process, and we will discuss the critical aspects of such animal studies. Finally, we will focus on the patient point-of-care and challenges in neuromodulation as the ultimate goal of bioelectronic medicine. This review is a call to scientists from different fields to work together with a common endeavor: accelerate the decoding and modulation of the nervous system in a new era of therapeutic possibilities.
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Affiliation(s)
- María Alejandra González-González
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
- Department of Pediatric Neurology, Baylor College of Medicine, Houston, TX, United States
| | - Silvia V. Conde
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NOVA University, Lisbon, Portugal
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stéphanie C. Thébault
- Laboratorio de Investigación Traslacional en salud visual (D-13), Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Marta Pratelli
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Nicholas C. Spitzer
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
- International Collaborative Center on Big Science Plan for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Cuneyt G. Akcora
- Department of Computer Science, University of Central Florida, Orlando, FL, United States
| | | | - Melanie Ecker
- Department of Biomedical Engineering, University of North Texas, Denton, TX, United States
| | | | - Kathleen L. Vincent
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, United States
| | - Brandy Ma
- Stanley H. Appel Department of Neurology, Houston Methodist Hospital, Houston, TX, United States
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17
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Barra B, Kumar R, Gopinath C, Mirzakhalili E, Lempka SF, Gaunt RA, Fisher LE. High-frequency amplitude-modulated sinusoidal stimulation induces desynchronized yet controllable neural firing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580219. [PMID: 38405798 PMCID: PMC10888888 DOI: 10.1101/2024.02.14.580219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Regaining sensory feedback is pivotal for people living with limb amputation. Electrical stimulation of sensory fibers in peripheral nerves has been shown to restore focal percepts in the missing limb. However, conventional rectangular current pulses induce sensations often described as unnatural. This is likely due to the synchronous and periodic nature of activity evoked by these pulses. Here we introduce a fast-oscillating amplitude-modulated sinusoidal (FAMS) stimulation waveform that desynchronizes evoked neural activity. We used a computational model to show that sinusoidal waveforms evoke asynchronous and irregular firing and that firing patterns are frequency dependent. We designed the FAMS waveform to leverage both low- and high-frequency effects and found that membrane non-linearities enhance neuron-specific differences when exposed to FAMS. We implemented this waveform in a feline model of peripheral nerve stimulation and demonstrated that FAMS-evoked activity is more asynchronous than activity evoked by rectangular pulses, while being easily controllable with simple stimulation parameters. These results represent an important step towards biomimetic stimulation strategies useful for clinical applications to restore sensory feedback.
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Affiliation(s)
- Beatrice Barra
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Neuroscience Institute, New York University Langone Health, New York, USA
| | - Ritesh Kumar
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA
| | - Chaitanya Gopinath
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ehsan Mirzakhalili
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, 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
| | - Robert A. Gaunt
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, USA
| | - Lee E Fisher
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, USA
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18
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Sridhar K, Evers J, Lowery M. Nonlinear effects at the electrode-tissue interface of deep brain stimulation electrodes. J Neural Eng 2024; 21:016024. [PMID: 38306713 DOI: 10.1088/1741-2552/ad2582] [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: 05/31/2023] [Accepted: 02/02/2024] [Indexed: 02/04/2024]
Abstract
Objective.The electrode-tissue interface provides the critical path for charge transfer in neurostimulation therapies and exhibits well-established nonlinear properties at high applied currents or voltages. These nonlinear properties may influence the efficacy and safety of applied stimulation but are typically neglected in computational models. In this study, nonlinear behavior of the electrode-tissue interface impedance was incorporated in a computational model of deep brain stimulation (DBS) to simulate the impact on neural activation and safety considerations.Approach.Nonlinear electrode-tissue interface properties were incorporated in a finite element model of DBS electrodesin vitroandin vivo,in the rat subthalamic nucleus, using an iterative approach. The transition point from linear to nonlinear behavior was determined for voltage and current-controlled stimulation. Predicted levels of neural activation during DBS were examined and the region of linear operation of the electrode was compared with the Shannon safety limit.Main results.A clear transition of the electrode-tissue interface impedance to nonlinear behavior was observed for both current and voltage-controlled stimulation. The transition occurred at lower values of activation overpotential for simulatedin vivothanin vitroconditions (91 mV and 165 mV respectively for current-controlled stimulation; 110 mV and 275 mV for voltage-controlled stimulation), corresponding to an applied current of 30μA and 45μA, or voltage of 330 mV at 1 kHz. The onset of nonlinearity occurred at lower values of the overpotential as frequency was increased. Incorporation of nonlinear properties resulted in activation of a higher proportion of neurons under voltage-controlled stimulation. Under current-controlled stimulation, the predicted transition to nonlinear behavior and Faradaic charge transfer at stimulation amplitudes of 30μA, corresponds to a charge density of 2.29μC cm-2and charge of 1.8 nC, well-below the Shannon safety limit.Significance.The results indicate that DBS electrodes may operate within the nonlinear region at clinically relevant stimulation amplitudes. This affects the extent of neural activation under voltage-controlled stimulation and the transition to Faradaic charge transfer for both voltage- and current-controlled stimulation with important implications for targeting of neural populations and the design of safe stimulation protocols.
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Affiliation(s)
- K Sridhar
- Neuromuscular Systems Lab, School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland
| | - J Evers
- Neuromuscular Systems Lab, School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland
| | - M Lowery
- Neuromuscular Systems Lab, School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland
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19
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Morales AW, Du J, Warren DJ, Fernández-Jover E, Martinez-Navarrete G, Bouteiller JMC, McCreery DC, Lazzi G. Machine learning enables non-Gaussian investigation of changes to peripheral nerves related to electrical stimulation. Sci Rep 2024; 14:2795. [PMID: 38307915 PMCID: PMC10837107 DOI: 10.1038/s41598-024-53284-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 01/30/2024] [Indexed: 02/04/2024] Open
Abstract
Electrical stimulation of the peripheral nervous system (PNS) is becoming increasingly important for the therapeutic treatment of numerous disorders. Thus, as peripheral nerves are increasingly the target of electrical stimulation, it is critical to determine how, and when, electrical stimulation results in anatomical changes in neural tissue. We introduce here a convolutional neural network and support vector machines for cell segmentation and analysis of histological samples of the sciatic nerve of rats stimulated with varying current intensities. We describe the methodologies and present results that highlight the validity of the approach: machine learning enabled highly efficient nerve measurement collection, while multivariate analysis revealed notable changes to nerves' anatomy, even when subjected to levels of stimulation thought to be safe according to the Shannon current limits.
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Affiliation(s)
- Andres W Morales
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Jinze Du
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - David J Warren
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | | | | | - Jean-Marie C Bouteiller
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | | | - Gianluca Lazzi
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, 90089, USA
- Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
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20
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Rabbani M, Rahman E, Powner MB, Triantis IF. Making Sense of Electrical Stimulation: A Meta-analysis for Wound Healing. Ann Biomed Eng 2024; 52:153-177. [PMID: 37743460 PMCID: PMC10808217 DOI: 10.1007/s10439-023-03371-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
Electrical stimulation as a mode of external enhancement factor in wound healing has been explored widely. It has proven to have multidimensional effects in wound healing including antibacterial, galvanotaxis, growth factor secretion, proliferation, transdifferentiation, angiogenesis, etc. Despite such vast exploration, this modality has not yet been established as an accepted method for treatment. This article reviews and analyzes the approaches of using electrical stimulation to modulate wound healing and discusses the incoherence in approaches towards reporting the effect of stimulation on the healing process. The analysis starts by discussing various processes adapted in in vitro, in vivo, and clinical practices. Later it is focused on in vitro approaches directed to various stages of wound healing. Based on the analysis, a protocol is put forward for reporting in vitro works in such a way that the outcomes of the experiment are replicable and scalable in other setups. This work proposes a ground of unification for all the in vitro approaches in a more sensible manner, which can be further explored for translating in vitro approaches to complex tissue stimulation to establish electrical stimulation as a controlled clinical method for modulating wound healing.
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Affiliation(s)
- Mamun Rabbani
- Research Centre for Biomedical Engineering, School of Science and Technology, City University of London, Northampton Square, London, ECIV 0HB, UK
| | - Enayetur Rahman
- Research Centre for Biomedical Engineering, School of Science and Technology, City University of London, Northampton Square, London, ECIV 0HB, UK
| | - Michael B Powner
- Centre for Applied Vision Research, School of Health and Psychological Sciences, City University of London, Northampton Square, London, ECIV 0HB, UK
| | - Iasonas F Triantis
- Research Centre for Biomedical Engineering, School of Science and Technology, City University of London, Northampton Square, London, ECIV 0HB, UK.
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21
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Harris AR. Limitations in the electrochemical analysis of voltage transients. J Neural Eng 2024; 21:013003. [PMID: 38215494 DOI: 10.1088/1741-2552/ad1e23] [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: 08/29/2023] [Accepted: 01/12/2024] [Indexed: 01/14/2024]
Abstract
Objective. Chronopotentiometric voltage transients (VTs) are used to assess the performance of bionic electrodes. The data obtained from VTs are used to define the safe operating conditions of clinical devices. Various approaches to analysing VTs have been reported, and a number of limitations in the accuracy of the measurements in relation to electrode size have been noted previously.Approach. The impact of electronic hardware and electrode configuration on VTs is discussed.Main results. The slew rate, rise time, sample time, minimum pulse length and waveform averaging characteristics of the electronic hardware, and electrode configuration will impact on VT measurement accuracy. Subsequently, activation and polarisation voltage measurements, and the definition of safe stimulation levels can be affected by the electronic hardware and electrode configuration.Significance. This article has identified some limitations in the previous literature related to the measurement and reporting of VTs and subsequent analysis of access and polarisation voltages. Furthermore, the commonly used Shannon plot used to define safe stimulation protocols does not correct for uncompensated resistance, account for electrode roughness or changes in electrode configuration. The creation of a safe stimulation plot which has been corrected for uncompensated resistance would generate more widely applicable stimulation guidelines for clinical devices used in different anatomical locations such as endovascular neural interfaces.
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Affiliation(s)
- Alexander R Harris
- Department of Biomedical Engineering, University of Melbourne, Melbourne 3010, Australia
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22
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Sivanesan E, North RB, Russo MA, Levy RM, Linderoth B, Hayek SM, Eldabe S, Lempka SF. A Definition of Neuromodulation and Classification of Implantable Electrical Modulation for Chronic Pain. Neuromodulation 2024; 27:1-12. [PMID: 37952135 DOI: 10.1016/j.neurom.2023.10.004] [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: 08/16/2023] [Revised: 09/24/2023] [Accepted: 10/09/2023] [Indexed: 11/14/2023]
Abstract
OBJECTIVES Neuromodulation therapies use a variety of treatment modalities (eg, electrical stimulation) to treat chronic pain. These therapies have experienced rapid growth that has coincided with escalating confusion regarding the nomenclature surrounding these neuromodulation technologies. Furthermore, studies are often published without a complete description of the effective stimulation dose, making it impossible to replicate the findings. To improve clinical care and facilitate dissemination among the public, payors, research groups, and regulatory bodies, there is a clear need for a standardization of terms. APPROACH We formed an international group of authors comprising basic scientists, anesthesiologists, neurosurgeons, and engineers with expertise in neuromodulation. Because the field of neuromodulation is extensive, we chose to focus on creating a taxonomy and standardized definitions for implantable electrical modulation of chronic pain. RESULTS We first present a consensus definition of neuromodulation. We then describe a classification scheme based on the 1) intended use (the site of modulation and its indications) and 2) physical properties (waveforms and dose) of a neuromodulation therapy. CONCLUSIONS This framework will help guide future high-quality studies of implantable neuromodulatory treatments and improve reporting of their findings. Standardization with this classification scheme and clear definitions will help physicians, researchers, payors, and patients better understand the applications of implantable electrical modulation for pain and guide informed treatment decisions.
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Affiliation(s)
- Eellan Sivanesan
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| | - Richard B North
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
| | - Marc A Russo
- Hunter Pain Specialists, Broadmeadow, New South Wales, Australia
| | - Robert M Levy
- Neurosurgical Services, Clinical Research, Anesthesia Pain Care Consultants, Tamarac, FL, USA
| | - Bengt Linderoth
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Salim M Hayek
- Division of Pain Medicine, University Hospitals, Cleveland Medical Center, Cleveland, OH, USA
| | - Sam Eldabe
- Department of Pain Medicine, The James Cook University Hospital, Middlesbrough, UK
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
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23
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Wu GK, Ardeshirpour Y, Mastracchio C, Kent J, Caiola M, Ye M. Amplitude- and frequency-dependent activation of layer II/III neurons by intracortical microstimulation. iScience 2023; 26:108140. [PMID: 37915592 PMCID: PMC10616374 DOI: 10.1016/j.isci.2023.108140] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/27/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
Intracortical microstimulation (ICMS) has been used for the development of brain machine interfaces. However, further understanding about the spatiotemporal responses of neurons to different electrical stimulation parameters is necessary to inform the design of optimal therapies. In this study, we employed in vivo electrophysiological recording, two-photon calcium imaging, and electric field simulation to evaluate the acute effect of ICMS on layer II/III neurons. Our results show that stimulation frequency non-linearly modulates neuronal responses, whereas the magnitude of responses is linearly correlated to the electric field strength and stimulation amplitude before reaching a steady state. Temporal dynamics of neurons' responses depends more on stimulation frequency and their distance to the stimulation electrode. In addition, amplitude-dependent post-stimulation suppression was observed within ∼500 μm of the stimulation electrode, as evidenced by both calcium imaging and local field potentials. These findings provide insights for selecting stimulation parameters to achieve desirable spatiotemporal specificity of ICMS.
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Affiliation(s)
- Guangying K. Wu
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Yasaman Ardeshirpour
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Christina Mastracchio
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Jordan Kent
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
- Scientific Publications Department, Society for Neuroscience, Washington DC, USA
| | - Michael Caiola
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
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24
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Ahn J, Yoo Y, Goo YS. Multiple consecutive-biphasic pulse stimulation improves spatially localized firing of retinal ganglion cells in the degenerate retina. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2023; 27:541-553. [PMID: 37884286 PMCID: PMC10613570 DOI: 10.4196/kjpp.2023.27.6.541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/08/2023] [Accepted: 08/22/2023] [Indexed: 10/28/2023]
Abstract
Retinal prostheses have shown some clinical success in restoring vision in patients with retinitis pigmentosa. However, the post-implantation visual acuity does not exceed that of legal blindness. The reason for the poor visual acuity might be that (1) degenerate retinal ganglion cells (RGCs) are less responsive to electrical stimulation than normal RGCs, and (2) electrically-evoked RGC spikes show a more widespread not focal response. The single-biphasic pulse electrical stimulation, commonly used in artificial vision, has limitations in addressing these issues. In this study, we propose the benefit of multiple consecutive-biphasic pulse stimulation. We used C57BL/6J mice and C3H/HeJ (rd1) mice for the normal retina and retinal degeneration model. An 8 × 8 multi-electrode array was used to record electrically-evoked RGC spikes. We compared RGC responses when increasing the amplitude of a single biphasic pulse versus increasing the number of consecutive biphasic pulses at the same stimulus charge. Increasing the amplitude of a single biphasic pulse induced more RGC spike firing while the spatial resolution of RGC populations decreased. For multiple consecutive-biphasic pulse stimulation, RGC firing increased as the number of pulses increased, and the spatial resolution of RGC populations was well preserved even up to 5 pulses. Multiple consecutive-biphasic pulse stimulation using two or three pulses in degenerate retinas induced as much RGC spike firing as in normal retinas. These findings suggest that the newly proposed multiple consecutive-biphasic pulse stimulation can improve the visual acuity in prosthesis-implanted patients.
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Affiliation(s)
- Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Yongseok Yoo
- School of Computer Science and Engineering, Soongsil University, Seoul 06978, Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
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25
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Girges C, Krüger MT, Xu SS, Akram H, Hyam J, Limousin P, Zrinzo L, Foltynie T. Brain Oedema Associated with Deep Brain Stimulation through a Single Directional Contact. Mov Disord Clin Pract 2023; 10:1695-1697. [PMID: 37982107 PMCID: PMC10654822 DOI: 10.1002/mdc3.13871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/02/2023] [Accepted: 08/14/2023] [Indexed: 11/21/2023] Open
Affiliation(s)
- Christine Girges
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Marie T. Krüger
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
- Department of Neurosurgery, University Medical Centre Freiburg, Faculty of Medicine, University of FreiburgFreiburg im BreisgauGermany
| | - San San Xu
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Harith Akram
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Jonathan Hyam
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Patricia Limousin
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Ludvic Zrinzo
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
| | - Thomas Foltynie
- Department of Clinical and Movement NeurosciencesUniversity College LondonLondonUK
- UCL Functional Neurosurgery UnitNational Hospital for Neurology and NeurosurgeryLondonUK
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26
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Li Y, Frederick RA, George D, Cogan SF, Pancrazio JJ, Bleris L, Hernandez-Reynoso AG. NeurostimML: A machine learning model for predicting neurostimulation-induced tissue damage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562980. [PMID: 37905012 PMCID: PMC10614958 DOI: 10.1101/2023.10.18.562980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Objective The safe delivery of electrical current to neural tissue depends on many factors, yet previous methods for predicting tissue damage rely on only a few stimulation parameters. Here, we report the development of a machine learning approach that could lead to a more reliable method for predicting electrical stimulation-induced tissue damage by incorporating additional stimulation parameters. Approach A literature search was conducted to build an initial database of tissue response information after electrical stimulation, categorized as either damaging or non-damaging. Subsequently, we used ordinal encoding and random forest for feature selection, and investigated four machine learning models for classification: Logistic Regression, K-nearest Neighbor, Random Forest, and Multilayer Perceptron. Finally, we compared the results of these models against the accuracy of the Shannon equation. Main Results We compiled a database with 387 unique stimulation parameter combinations collected from 58 independent studies conducted over a period of 47 years, with 195 (51%) categorized as non-damaging and 190 (49%) categorized as damaging. The features selected for building our model with a Random Forest algorithm were: waveform shape, geometric surface area, pulse width, frequency, pulse amplitude, charge per phase, charge density, current density, duty cycle, daily stimulation duration, daily number of pulses delivered, and daily accumulated charge. The Shannon equation yielded an accuracy of 63.9% using a k value of 1.79. In contrast, the Random Forest algorithm was able to robustly predict whether a set of stimulation parameters was classified as damaging or non-damaging with an accuracy of 88.3%. Significance This novel Random Forest model can facilitate more informed decision making in the selection of neuromodulation parameters for both research studies and clinical practice. This study represents the first approach to use machine learning in the prediction of stimulation-induced neural tissue damage, and lays the groundwork for neurostimulation driven by machine learning models.
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Affiliation(s)
- Yi Li
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX, USA
| | - Rebecca A. Frederick
- Phil and Penny Knight Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR, USA
| | - Daniel George
- Department of Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Stuart F. Cogan
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Joseph J. Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Leonidas Bleris
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
- Center for Systems Biology, The University of Texas at Dallas, Richardson, TX, USA
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
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27
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Ojeda Valencia G, Gregg NM, Huang H, Lundstrom BN, Brinkmann BH, Pal Attia T, Van Gompel JJ, Bernstein MA, In MH, Huston J, Worrell GA, Miller KJ, Hermes D. Signatures of Electrical Stimulation Driven Network Interactions in the Human Limbic System. J Neurosci 2023; 43:6697-6711. [PMID: 37620159 PMCID: PMC10538586 DOI: 10.1523/jneurosci.2201-22.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023] Open
Abstract
Stimulation-evoked signals are starting to be used as biomarkers to indicate the state and health of brain networks. The human limbic network, often targeted for brain stimulation therapy, is involved in emotion and memory processing. Previous anatomic, neurophysiological, and functional studies suggest distinct subsystems within the limbic network (Rolls, 2015). Studies using intracranial electrical stimulation, however, have emphasized the similarities of the evoked waveforms across the limbic network. We test whether these subsystems have distinct stimulation-driven signatures. In eight patients (four male, four female) with drug-resistant epilepsy, we stimulated the limbic system with single-pulse electrical stimulation. Reliable corticocortical evoked potentials (CCEPs) were measured between hippocampus and the posterior cingulate cortex (PCC) and between the amygdala and the anterior cingulate cortex (ACC). However, the CCEP waveform in the PCC after hippocampal stimulation showed a unique and reliable morphology, which we term the "limbic Hippocampus-Anterior nucleus of the thalamus-Posterior cingulate, HAP-wave." This limbic HAP-wave was visually distinct and separately decoded from the CCEP waveform in ACC after amygdala stimulation. Diffusion MRI data show that the measured end points in the PCC overlap with the end points of the parolfactory cingulum bundle rather than the parahippocampal cingulum, suggesting that the limbic HAP-wave may travel through fornix, mammillary bodies, and the anterior nucleus of the thalamus (ANT). This was further confirmed by stimulating the ANT, which evoked the same limbic HAP-wave but with an earlier latency. Limbic subsystems have unique stimulation-evoked signatures that may be used in the future to help network pathology diagnosis.SIGNIFICANCE STATEMENT The limbic system is often compromised in diverse clinical conditions, such as epilepsy or Alzheimer's disease, and characterizing its typical circuit responses may provide diagnostic insight. Stimulation-evoked waveforms have been used in the motor system to diagnose circuit pathology. We translate this framework to limbic subsystems using human intracranial stereo EEG (sEEG) recordings that measure deeper brain areas. Our sEEG recordings describe a stimulation-evoked waveform characteristic to the memory and spatial subsystem of the limbic network that we term the "limbic HAP-wave." The limbic HAP-wave follows anatomic white matter pathways from hippocampus to thalamus to the posterior cingulum and shows promise as a distinct biomarker of signaling in the human brain memory and spatial limbic network.
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Affiliation(s)
- Gabriela Ojeda Valencia
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Nicholas M Gregg
- Department of Neurology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Harvey Huang
- Mayo Clinic Medical Scientist Training Program, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Brian N Lundstrom
- Department of Neurology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | | | - Tal Pal Attia
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Jamie J Van Gompel
- Department of Neurologic Surgery, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Matt A Bernstein
- Department of Radiology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Myung-Ho In
- Department of Radiology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - John Huston
- Department of Radiology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Gregory A Worrell
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, Rochester, Minnesota 55902
- Department of Neurology, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Kai J Miller
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, Rochester, Minnesota 55902
- Department of Neurologic Surgery, Mayo Clinic Rochester, Rochester, Minnesota 55902
| | - Dora Hermes
- Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, Rochester, Minnesota 55902
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Matter L, Harland B, Raos B, Svirskis D, Asplund M. Generation of direct current electrical fields as regenerative therapy for spinal cord injury: A review. APL Bioeng 2023; 7:031505. [PMID: 37736015 PMCID: PMC10511262 DOI: 10.1063/5.0152669] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
Electrical stimulation (ES) shows promise as a therapy to promote recovery and regeneration after spinal cord injury. ES therapy establishes beneficial electric fields (EFs) and has been investigated in numerous studies, which date back nearly a century. In this review, we discuss the various engineering approaches available to generate regenerative EFs through direct current electrical stimulation and very low frequency electrical stimulation. We highlight the electrode-tissue interface, which is important for the appropriate choice of electrode material and stimulator circuitry. We discuss how to best estimate and control the generated field, which is an important measure for comparability of studies. Finally, we assess the methods used in these studies to measure functional recovery after the injury and treatment. This work reviews studies in the field of ES therapy with the goal of supporting decisions regarding best stimulation strategy and recovery assessment for future work.
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Affiliation(s)
- Lukas Matter
- Author to whom correspondence should be addressed:
| | - Bruce Harland
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Brad Raos
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, The University of Auckland, NZ 1023 Auckland, New Zealand
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Gilbert Z, Mason X, Sebastian R, Tang AM, Martin Del Campo-Vera R, Chen KH, Leonor A, Shao A, Tabarsi E, Chung R, Sundaram S, Kammen A, Cavaleri J, Gogia AS, Heck C, Nune G, Liu CY, Kellis SS, Lee B. A review of neurophysiological effects and efficiency of waveform parameters in deep brain stimulation. Clin Neurophysiol 2023; 152:93-111. [PMID: 37208270 DOI: 10.1016/j.clinph.2023.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 02/09/2023] [Accepted: 04/15/2023] [Indexed: 05/21/2023]
Abstract
Neurostimulation has diverse clinical applications and potential as a treatment for medically refractory movement disorders, epilepsy, and other neurological disorders. However, the parameters used to program electrodes-polarity, pulse width, amplitude, and frequency-and how they are adjusted have remained largely untouched since the 1970 s. This review summarizes the state-of-the-art in Deep Brain Stimulation (DBS) and highlights the need for further research to uncover the physiological mechanisms of neurostimulation. We focus on studies that reveal the potential for clinicians to use waveform parameters to selectively stimulate neural tissue for therapeutic benefit, while avoiding activating tissue associated with adverse effects. DBS uses cathodic monophasic rectangular pulses with passive recharging in clinical practice to treat neurological conditions such as Parkinson's Disease. However, research has shown that stimulation efficiency can be improved, and side effects reduced, through modulating parameters and adding novel waveform properties. These developments can prolong implantable pulse generator lifespan, reducing costs and surgery-associated risks. Waveform parameters can stimulate neurons based on axon orientation and intrinsic structural properties, providing clinicians with more precise targeting of neural pathways. These findings could expand the spectrum of diseases treatable with neuromodulation and improve patient outcomes.
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Affiliation(s)
- Zachary Gilbert
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States.
| | - Xenos Mason
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Rinu Sebastian
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Austin M Tang
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Roberto Martin Del Campo-Vera
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Kuang-Hsuan Chen
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Andrea Leonor
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Arthur Shao
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Emiliano Tabarsi
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Ryan Chung
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Shivani Sundaram
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Alexandra Kammen
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Jonathan Cavaleri
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Angad S Gogia
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States
| | - Christi Heck
- Department of Neurology, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - George Nune
- Department of Neurology, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Charles Y Liu
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; Department of Neurology, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Spencer S Kellis
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
| | - Brian Lee
- Department of Neurological Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, United States; USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, United States
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30
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Whalen AJ, Fried SI. Thermal safety considerations for implantable micro-coil design. J Neural Eng 2023; 20:10.1088/1741-2552/ace79a. [PMID: 37451256 PMCID: PMC10467159 DOI: 10.1088/1741-2552/ace79a] [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: 03/03/2023] [Accepted: 07/14/2023] [Indexed: 07/18/2023]
Abstract
Micro magnetic stimulation of the brain via implantable micro-coils is a promising novel technology for neuromodulation. Careful consideration of the thermodynamic profile of such devices is necessary for effective and safe designs.Objective.We seek to quantify the thermal profile of bent wire micro-coils in order to understand and mitigate thermal impacts of micro-coil stimulation.Approach. In this study, we use fine wire thermocouples and COMSOL finite element modeling to examine the profile of the thermal gradients generated near bent wire micro-coils submerged in a water bath during stimulation. We tested a range of stimulation parameters previously reported in the literature such as voltage amplitude, stimulus frequency, stimulus repetition rate and coil wire materials.Main results. We found temperature increases ranging from <1 °C to 8.4 °C depending upon the stimulation parameters tested and coil wire materials used. Numerical modeling of the thermodynamics identified hot spots of the highest temperatures along the micro-coil contributing to the thermal gradients and demonstrated that these thermal gradients can be mitigated by the choice of wire conductor material and construction geometry.Significance. ISO standard 14708-1 designates a thermal safety limit of 2 °C temperature increase for active implantable medical devices. By switching the coil wire material from platinum/iridium to gold, our study achieved a 5-6-fold decrease in the thermal impact of coil stimulation. The thermal gradients generated from the gold wire coil were measured below the 2 °C safety limit for all stimulation parameters tested.
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Affiliation(s)
- Andrew J. Whalen
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Shelley I. Fried
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, USA
- Boston VA Medical Center, Boston, USA
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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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Peressotti S, Lara RP, Goding J, Green R. An Electrical Stimulation Device For In Vitro Neural Engineering. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38082758 DOI: 10.1109/embc40787.2023.10339942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Due to the intrinsically low turnover of neural tissues, regenerative therapies have gained significant interest in the context of degenerative diseases and injury to the central and peripheral nervous systems. Although a range of neuroregenerative strategies involving cell transplants and drugs have been explored, these are often limited by low efficacy and unwanted side effects. Electrical stimulation (ES) is thought to modulate the proliferation and differentiation of neural stem cells (NSCs), and thus it represents a promising strategy for neuroregenerative therapies. However, its influence on the biology of endogenous and exogenous NSCs, and the effect of different stimulation paradigms remains unexplored. Additionally, the variability of stimulation platforms and parameters employed in previous studies prevents reliable and reproducible discoveries. Therefore, there is a need to develop versatile and robust tools to study the effect of electrical stimulation on NSC fate in vitro. This paper outlines the development and functional application of a standardised, electrically stable, and easily reproducible ES platform for in vitro neuroregeneration applications.Clinical Relevance- The elucidation of the cellular and molecular mechanisms underlying the effect of ES paradigms on NSCs proliferation and differentiation holds great potential for the development of neuroregenerative therapies.
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33
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Webb T, Cheeniyil R, Wilson M, Kubanek J. Remote targeted electrical stimulation. J Neural Eng 2023; 20:036030. [PMID: 37236172 PMCID: PMC10251736 DOI: 10.1088/1741-2552/acd95c] [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: 12/24/2022] [Revised: 04/26/2023] [Accepted: 05/26/2023] [Indexed: 05/28/2023]
Abstract
Objective:The ability to generate electric fields in specific targets remotely would transform manipulations of processes that rest on electrical signaling.Approach:This article shows that focal electric fields are generated from distance by combining two orthogonal, remotely applied energies-magnetic and focused ultrasonic fields. The effect derives from the Lorentz force equation applied to magnetic and ultrasonic fields.Main results:We elicited this effect using standard hardware and confirmed that the generated electric fields align with the Lorentz equation. The effect significantly and safely modulated human peripheral nerves and deep brain regions of non-human primates.Significance:This approach opens a new set of applications in which electric fields are generated at high spatiotemporal resolution within intact biological tissues or materials, thus circumventing the limitations of traditional electrode-based procedures.
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Affiliation(s)
- Taylor Webb
- University of Utah, 36 S Wasatch Dr, Salt Lake City, UT, 84112, United States of America
| | - Rahul Cheeniyil
- University of Utah, 36 S Wasatch Dr, Salt Lake City, UT, 84112, United States of America
| | - Matthew Wilson
- University of Utah, 36 S Wasatch Dr, Salt Lake City, UT, 84112, United States of America
| | - Jan Kubanek
- University of Utah, 36 S Wasatch Dr, Salt Lake City, UT, 84112, United States of America
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34
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Aungaroon G, Vedala K, Byars AW, Ervin B, Rozhkov L, Horn PS, Ihnen S, Holland KD, Tenney JR, Kremer K, Fong SL, Lin N, Liu W, Arthur TM, Fujiwara H, Skoch J, Leach JL, Mangano FT, Greiner HM, Arya R. Comparing electrical stimulation functional mapping with subdural electrodes and stereoelectroencephalography. Epilepsia 2023; 64:1527-1540. [PMID: 36872854 PMCID: PMC10239361 DOI: 10.1111/epi.17575] [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: 01/06/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/07/2023]
Abstract
OBJECTIVE Electrical stimulation mapping (ESM) is the clinical standard for functional localization with subdural electrodes (SDE). As stereoelectroencephalography (SEEG) has emerged as an alternative option, we compared functional responses, afterdischarges (ADs), and unwanted ESM-induced seizures (EISs) between the two electrode types. METHODS Incidence and current thresholds for functional responses (sensory, motor, speech/language), ADs, and EISs were compared between SDE and SEEG using mixed models incorporating relevant covariates. RESULTS We identified 67 SEEG ESM and 106 SDE ESM patients (7207 and 4980 stimulated contacts, respectively). We found similar incidence of language and motor responses between electrode types; however, more SEEG patients reported sensory responses. ADs and EISs occurred less commonly with SEEG than SDE. Current thresholds for language, face motor, and upper extremity (UE) motor responses and EIS significantly decreased with age. However, they were not affected by electrode type, premedication, or dominant hemispheric stimulation. AD thresholds were higher with SEEG than with SDE. For SEEG ESM, language thresholds remained below AD thresholds up to 26 years of age, whereas this relationship was inverse for SDE. Also, face and UE motor thresholds fell below AD thresholds at earlier ages for SEEG than SDE. AD and EIS thresholds were not affected by premedication. SIGNIFICANCE SEEG and SDE have clinically relevant differences for functional brain mapping with electrical stimulation. Although evaluation of language and motor regions is comparable between SEEG and SDE, SEEG offers a higher likelihood of identifying sensory areas. A lower incidence of ADs and EISs, and a favorable relationship between functional and AD thresholds suggest superior safety and neurophysiologic validity for SEEG ESM than SDE ESM.
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Affiliation(s)
- Gewalin Aungaroon
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Kishore Vedala
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Anna W. Byars
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Brian Ervin
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, Ohio, U.S.A
| | - Leonid Rozhkov
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Paul S. Horn
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - S.K.Z. Ihnen
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Katherine D. Holland
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Jeffrey R. Tenney
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Kelly Kremer
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Susan L. Fong
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Nan Lin
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Wei Liu
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Todd M. Arthur
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Hisako Fujiwara
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Jesse Skoch
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
- Division of Pediatric Neurosurgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - James L. Leach
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
- Division of Pediatric Neuroradiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Francesco T. Mangano
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
- Division of Pediatric Neurosurgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Hansel M. Greiner
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Ravindra Arya
- Comprehensive Epilepsy Center, Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, U.S.A
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, Ohio, U.S.A
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Lee JH, Jang TM, Shin JW, Lim BH, Rajaram K, Han WB, Ko GJ, Yang SM, Han S, Kim DJ, Kang H, Lim JH, Lee KS, Park E, Hwang SW. Wireless, Fully Implantable and Expandable Electronic System for Bidirectional Electrical Neuromodulation of the Urinary Bladder. ACS NANO 2023; 17:8511-8520. [PMID: 37070621 DOI: 10.1021/acsnano.3c00755] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Current standard clinical options for patients with detrusor underactivity (DUA) or underactive bladder─the inability to release urine naturally─include the use of medications, voiding techniques, and intermittent catheterization, for which the patient inserts a tube directly into the urethra to eliminate urine. Although those are life-saving techniques, there are still unfavorable side effects, including urinary tract infection (UTI), urethritis, irritation, and discomfort. Here, we report a wireless, fully implantable, and expandable electronic complex that enables elaborate management of abnormal bladder function via seamless integrations with the urinary bladder. Such electronics can not only record multiple physiological parameters simultaneously but also provide direct electrical stimulation based on a feedback control system. Uniform distribution of multiple stimulation electrodes via mesh-type geometry realizes low-impedance characteristics, which improves voiding/urination efficiency at the desired times. In vivo evaluations using live, free-moving animal models demonstrate system-level functionality.
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Affiliation(s)
- Joong Hoon Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Tae-Min Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jeong-Woong Shin
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Bong Hee Lim
- Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Kaveti Rajaram
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Won Bae Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Gwan-Jin Ko
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Seung Min Yang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Sungkeun Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Dong-Je Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Heeseok Kang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jun Hyeon Lim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Kyu-Sung Lee
- Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Eunkyoung Park
- Department of Biomedical Engineering, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Suk-Won Hwang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
- Department of Integrative Energy Engineering, Korea University, Seoul 02841, Republic of Korea
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36
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Ahn J, Jeong Y, Cha S, Lee JY, Yoo Y, Goo YS. High amplitude pulses on the same charge condition efficiently elicit bipolar cell-mediated retinal ganglion cell responses in the degenerate retina. Biomed Eng Lett 2023; 13:129-140. [PMID: 37124107 PMCID: PMC10130300 DOI: 10.1007/s13534-023-00260-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/19/2022] [Accepted: 01/09/2023] [Indexed: 02/01/2023] Open
Abstract
Retinal pigmentosa (RP) patients lose vision due to the loss of photoreceptors. Retinal prostheses bypass the dead photoreceptors by electrically stimulating surviving retinal neurons, such as bipolar cells or retinal ganglion cells (RGCs). In previous studies, stimulus charge has been mainly optimized to maximize the RGC response to electrical stimulation. This study aimed to investigate the effect of amplitude and duration even under the same charge condition on eliciting RGC spikes in the wild-type and degenerate retinas. Wild-type (WT) Sprague-Dawley rats were used as the normal retinal model, and Pde6b knockout rats were used as a retinal degeneration (RD) model. Electrically-evoked RGC spikes were recorded from isolated rat retinas using an 8 × 8 multielectrode array. The same charge was maintained (10 or 20 nC), and electrical stimulation was applied to WT and RD retinas, adjusting the amplitude and duration of the 1st phase of biphasic pulses. In the pulse modulation of the 1st phase, high amplitude (short duration) pulses induced more RGC spikes than low amplitude (long duration) pulses. Both WT and RD retinas showed a significant reduction in the number of RGC spikes upon stimulation with lower amplitude (longer duration) pulses. In clinical trials where stimulus charges are delivered to the degenerate retina of blind patients, high amplitude (short duration) pulses would help elicit more RGC spikes.
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Affiliation(s)
- Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
| | - Yurim Jeong
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
| | - Joo Yong Lee
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Yongseok Yoo
- School of Computer Science and Engineering, Soongsil University, Seoul, South Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, South Korea
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Shen K, Chen O, Edmunds JL, Piech DK, Maharbiz MM. Translational opportunities and challenges of invasive electrodes for neural interfaces. Nat Biomed Eng 2023; 7:424-442. [PMID: 37081142 DOI: 10.1038/s41551-023-01021-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/15/2023] [Indexed: 04/22/2023]
Abstract
Invasive brain-machine interfaces can restore motor, sensory and cognitive functions. However, their clinical adoption has been hindered by the surgical risk of implantation and by suboptimal long-term reliability. In this Review, we highlight the opportunities and challenges of invasive technology for clinically relevant electrophysiology. Specifically, we discuss the characteristics of neural probes that are most likely to facilitate the clinical translation of invasive neural interfaces, describe the neural signals that can be acquired or produced by intracranial electrodes, the abiotic and biotic factors that contribute to their failure, and emerging neural-interface architectures.
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Affiliation(s)
- Konlin Shen
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA.
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.
| | - Oliver Chen
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - Jordan L Edmunds
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - David K Piech
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA
| | - Michel M Maharbiz
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, CA, USA
- Chan-Zuckerberg Biohub, San Francisco, CA, USA
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Halgren AS, Siegel Z, Golden R, Bazhenov M. Multielectrode Cortical Stimulation Selectively Induces Unidirectional Wave Propagation of Excitatory Neuronal Activity in Biophysical Neural Model. J Neurosci 2023; 43:2482-2496. [PMID: 36849415 PMCID: PMC10082457 DOI: 10.1523/jneurosci.1784-21.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/27/2022] [Accepted: 01/13/2023] [Indexed: 03/01/2023] Open
Abstract
Cortical stimulation is emerging as an experimental tool in basic research and a promising therapy for a range of neuropsychiatric conditions. As multielectrode arrays enter clinical practice, the possibility of using spatiotemporal patterns of electrical stimulation to induce desired physiological patterns has become theoretically possible, but in practice can only be implemented by trial-and-error because of a lack of predictive models. Experimental evidence increasingly establishes traveling waves as fundamental to cortical information-processing, but we lack an understanding of how to control wave properties despite rapidly improving technologies. This study uses a hybrid biophysical-anatomical and neural-computational model to predict and understand how a simple pattern of cortical surface stimulation could induce directional traveling waves via asymmetric activation of inhibitory interneurons. We found that pyramidal cells and basket cells are highly activated by the anodal electrode and minimally activated by the cathodal electrodes, while Martinotti cells are moderately activated by both electrodes but exhibit a slight preference for cathodal stimulation. Network model simulations found that this asymmetrical activation results in a traveling wave in superficial excitatory cells that propagates unidirectionally away from the electrode array. Our study reveals how asymmetric electrical stimulation can easily facilitate traveling waves by relying on two distinct types of inhibitory interneuron activity to shape and sustain the spatiotemporal dynamics of endogenous local circuit mechanisms.SIGNIFICANCE STATEMENT Electrical brain stimulation is becoming increasingly useful to probe the workings of brain and to treat a variety of neuropsychiatric disorders. However, stimulation is currently performed in a trial-and-error fashion as there are no methods to predict how different electrode arrangements and stimulation paradigms will affect brain functioning. In this study, we demonstrate a hybrid modeling approach, which makes experimentally testable predictions that bridge the gap between the microscale effects of multielectrode stimulation and the resultant circuit dynamics at the mesoscale. Our results show how custom stimulation paradigms can induce predictable, persistent changes in brain activity, which has the potential to restore normal brain function and become a powerful therapy for neurological and psychiatric conditions.
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Affiliation(s)
- Alma S Halgren
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Department of Integrative Biology, University of California - Berkeley, Berkeley, California 94720
| | - Zarek Siegel
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
| | - Ryan Golden
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
| | - Maxim Bazhenov
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
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Monroy GL, Erfanzadeh M, Tao M, DePaoli DT, Saytashev I, Nam SA, Rafi H, Kwong KC, Shea K, Vakoc BJ, Vasudevan S, Hammer DX. Development of polarization-sensitive optical coherence tomography imaging platform and metrics to quantify electrostimulation-induced peripheral nerve injury in vivo in a small animal model. NEUROPHOTONICS 2023; 10:025004. [PMID: 37077218 PMCID: PMC10109528 DOI: 10.1117/1.nph.10.2.025004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 03/28/2023] [Indexed: 05/03/2023]
Abstract
Significance Neuromodulation devices are rapidly evolving for the treatment of neurological diseases and conditions. Injury from implantation or long-term use without obvious functional losses is often only detectable through terminal histology. New technologies are needed that assess the peripheral nervous system (PNS) under normal and diseased or injured conditions. Aim We aim to demonstrate an imaging and stimulation platform that can elucidate the biological mechanisms and impacts of neurostimulation in the PNS and apply it to the sciatic nerve to extract imaging metrics indicating electrical overstimulation. Approach A sciatic nerve injury model in a 15-rat cohort was observed using a newly developed imaging and stimulation platform that can detect electrical overstimulation effects with polarization-sensitive optical coherence tomography. The sciatic nerve was electrically stimulated using a custom-developed nerve holder with embedded electrodes for 1 h, followed by a 1-h recovery period, delivered at above-threshold Shannon model k -values in experimental groups: sham control (SC, n = 5 , 0.0 mA / 0 Hz ), stimulation level 1 (SL1, n = 5 , 3.4 mA / 50 Hz , and k = 2.57 ), and stimulation level 2 (SL2, n = 5 , 6.8 mA / 100 Hz , and k = 3.17 ). Results The stimulation and imaging system successfully captured study data across the cohort. When compared to a SC after a 1-week recovery, the fascicle closest to the stimulation lead showed an average change of + 4 % / - 309 % (SL1/SL2) in phase retardation and - 79 % / - 148 % in optical attenuation relative to SC. Analysis of immunohistochemistry (IHC) shows a + 1 % / - 36 % difference in myelin pixel counts and - 13 % / + 29 % difference in axon pixel counts, and an overall increase in cell nuclei pixel count of + 20 % / + 35 % . These metrics were consistent with IHC and hematoxylin/eosin tissue section analysis. Conclusions The poststimulation changes observed in our study are manifestations of nerve injury and repair, specifically degeneration and angiogenesis. Optical imaging metrics quantify these processes and may help evaluate the safety and efficacy of neuromodulation devices.
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Affiliation(s)
- Guillermo L. Monroy
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Mohsen Erfanzadeh
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Michael Tao
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Damon T. DePaoli
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Ilyas Saytashev
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Stephanie A. Nam
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Harmain Rafi
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Kasey C. Kwong
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
| | - Katherine Shea
- U. S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Clinical Pharmacology, Office of Translational Science, Division of Applied Regulatory Science, Silver Spring, Maryland, United States
| | - Benjamin J. Vakoc
- Massachusetts General Hospital, Harvard Medical School, Wellman Center for Photomedicine, Boston, Massachusetts, United States
- Harvard Medical School, Boston, Massachusetts, United States
- Massachusetts Institute of Technology, Division of Health Science and Technology, Cambridge, Massachusetts, United States
| | - Srikanth Vasudevan
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
- Address all correspondence to Srikanth Vasudevan, ; Daniel X. Hammer,
| | - Daniel X. Hammer
- U. S. Food and Drug Administration, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
- Address all correspondence to Srikanth Vasudevan, ; Daniel X. Hammer,
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Ersöz A, Kim I, Han M. Charge Injection Enhancement Comparisons of Iridium Oxide Microelectrodes In Vitro and In Vivo Using a Portable Neurostimulator. INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING : [PROCEEDINGS]. INTERNATIONAL IEEE EMBS CONFERENCE ON NEURAL ENGINEERING 2023; 2023:10.1109/ner52421.2023.10123832. [PMID: 38590827 PMCID: PMC11000213 DOI: 10.1109/ner52421.2023.10123832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Microelectrodes are desired to deliver more charges to neural tissues while under electrochemical safety limits. Applying anodic bias potential during neurostimulation is a known technique for charge enhancement. Here, we investigated the levels of charge enhancement with anodic bias potential in vitro and in vivo using a custom-designed portable neurostimulator. We immersed our custom microelectrode probe in saline and measured voltage transients in response to constant current stimulation with and without a 500 mV anodic bias potential. We then inserted the same microelectrode probe into the primary motor cortex of the rat brain and measured voltage transients with the same electronics. Results showed that the charge injection capacity of the activated iridium oxide microelectrode site (with 2000 μm2 geometric surface areas (GSAs)) increased by the use of the anodic bias potentials in both in vitro and in vivo: from 10 nC/phase to 32 nC/phase for 200 μs pulse widths, and from 2 nC/phase to 8 nC/phase, respectively. Thus, the order of charge injection capacities of the four cases tested in this study is as follows (from the lowest to the highest): in vivo without anodic bias, in vivo with anodic bias, in vitro without anodic bias, and in vitro with anodic bias. This work also validated in vivo use of our new portable neurostimulator which received stimulation waveforms wirelessly.
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Affiliation(s)
- Alpaslan Ersöz
- A. Ersӧz is with the Mechanical Engineering Department, Carnegie Mellon University, Pittsburgh, PA 15213 USA
| | - Insoo Kim
- I. Kim is with the Department of Medicine and Division of Occupational and Environmental Medicine, University of Connecticut, Farmington, CT 06030 USA
| | - Martin Han
- M. Han is with the Biomedical Engineering Department, University of Connecticut, Storrs, CT 06269 USA
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A novel ex vivo assay to define charge-balanced electrical stimulation parameters for neural precursor cell activation in vivo. Brain Res 2023; 1804:148263. [PMID: 36702184 DOI: 10.1016/j.brainres.2023.148263] [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: 10/20/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 01/25/2023]
Abstract
Endogenous neural stem cells and their progeny (together termed neural precursor cells (NPCs)) are promising candidates to facilitate neuroregeneration. Charge-balanced biphasic monopolar stimulation (BPMP) is a clinically relevant approach that can activate NPCs both in vitro and in vivo. Herein, we established a novel ex vivo stimulation system to optimize the efficacy of BPMP electric field (EF) application in activating endogenous NPCs. Using the ex vivo system, we discerned that cathodal amplitude of 200 μA resulted in the greatest NPC pool expansion and enhanced cathodal migration. Application of the same stimulation parameters in vivo resulted in the same NPC activation in the mouse brain. The design and implementation of the novel ex vivo model bridges the gap between in vitro and in vivo systems, enabling a moderate throughput stimulation system to explore and optimize EF parameters that can be applied to clinically relevant brain injury/disease models.
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Sun T, Tsaava T, Peragine J, Crosfield C, Lopez MF, Modi R, Sharma R, Li C, Sohal H, Chang EH, Rieth L. Flexible IrO x neural electrode for mouse vagus nerve stimulation. Acta Biomater 2023; 159:394-409. [PMID: 36669547 PMCID: PMC10823593 DOI: 10.1016/j.actbio.2023.01.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/26/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023]
Abstract
Vagus nerve stimulation (VNS) is being actively explored as a treatment for multiple conditions as part of bioelectronic medicine research. Reliable and safe VNS in mouse models is a critical need for understanding mechanisms of these. We report on the development and evaluation of a microfabricated cuff electrode (MouseFlex) constructed of polyimide (PI) and with iridium oxide (IrOx) electrodes that is thermoformed to 86 µm ± 12 µm radius to interface the mouse cervical vagus nerve (r ≈ 50 µm). Innovative bench-top methods were used to evaluate the stimulation stability and electrochemical properties of electrodes. Our aggressive stimulation stability (Stim-Stab) test utilized 1 billion pulses at a 1000 Hz with a current density of 6.28 A/cm2 (1.51 mC/cm2/phase) delivering 3023 × 103 C/cm2 to evaluate electrode lifetimes, and all electrodes remained functional. We also investigated the effects of thermoforming on their impedance, charge storage capacity (CSC), and charge injection capacity (CIC). The modest changes in electrochemical properties indicate that the thermoforming process was well tolerated. Thermoformed electrode safety and efficacy were evaluated in-vivo by performing acute VNS in mice and monitoring their heart and respiration rate as biomarkers. Their electrochemical properties were also measured before, during and after VNS. Bradycardia and bradypnea were reliably induced at stimulation currents of 100 to 200 µA, well below the in-vivo CIC of ∼1250 µA (∼0.5 mC/cm2), supporting their safety and efficacy. The electrode impedance increased and CIC decreased during in-vivo use, but largely reversed these changes in in-vitro testing after enzymatic cleaning, supporting their tolerance for surgical use. STATEMENT OF SIGNIFICANCE: Vagus nerve stimulation (VNS) is a rapidly growing aspect of healthcare and bioelectronic medicine research. Reliable and safe VNS in mice with small diameter (d ≈ 100 µm) nerves has been a challenge due to achieving intimate contact with the nerve, and the stimulation stability of commonly used electrodes. We demonstrate a microfabricated (MouseFlex) cuff electrode constructed of polyimide with IrOx electrodes that is thermoformed to contact the mouse cervical vagus. Bench studies highlight the stimulation stability exceeded 109 pulses at 6.28 A/cm2 and their electrochemical properties were measured before, during, and after bench and nerve stimulation. Nerve stimulation induced bradycardia and bradypnea at currents below the in-vivo charge injection capacity, supporting their safety, efficacy, and tolerance for surgical handling.
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Affiliation(s)
- Tao Sun
- Mechanical & Aerospace Engineering Department, Benjamin M. Statler College of Engineering & Mineral Resources, West Virginia University, Morgantown, WV 26505, United States
| | - Téa Tsaava
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Joanne Peragine
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Christine Crosfield
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | | | - Romil Modi
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Rohit Sharma
- Electrical and Computer Engineering Department, University of Utah, Salt Lake City, UT 84112, United States; Applied Biosensors, Salt Lake City, UT 84115, United States
| | - Chunyan Li
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | | | - Eric H Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Loren Rieth
- Mechanical & Aerospace Engineering Department, Benjamin M. Statler College of Engineering & Mineral Resources, West Virginia University, Morgantown, WV 26505, United States.
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Foutz TJ, Rensing N, Han L, Durand DM, Wong M. Spatial and Amplitude Dynamics of Neurostimulation: Insights from the Acute Intrahippocampal Kainate Seizure Mouse Model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.07.531440. [PMID: 36945383 PMCID: PMC10028881 DOI: 10.1101/2023.03.07.531440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Objective Neurostimulation is an emerging treatment for patients with medically refractory epilepsy, which is used to suppress, prevent, and terminate seizure activity. Unfortunately, after implantation and despite best clinical practice, most patients continue to have persistent seizures even after years of empirical optimization. The objective of this study is to determine optimal spatial and amplitude properties of neurostimulation in inhibiting epileptiform activity in an acute hippocampal seizure model. Methods We performed high-throughput testing of high-frequency focal brain stimulation in the acute intrahippocampal kainic acid mouse model of temporal lobe epilepsy. We evaluated combinations of six anatomic targets and three stimulus amplitudes. Results We found that the spike-suppressive effects of high-frequency neurostimulation are highly dependent on the stimulation amplitude and location, with higher amplitude stimulation being significantly more effective. Epileptiform spiking activity was significantly reduced with ipsilateral 250 μA stimulation of the CA1 and CA3 hippocampal regions with 21.5% and 22.2% reductions, respectively. In contrast, we found that spiking frequency and amplitude significantly increased with stimulation of the ventral hippocampal commissure. We further found spatial differences with broader effects from CA1 versus CA3 stimulation. Significance These findings demonstrate that the effects of therapeutic neurostimulation in an acute hippocampal seizure model are highly dependent on the location of stimulation and stimulus amplitude. We provide a platform to optimize the anti-seizure effects of neurostimulation, and demonstrate that an exploration of the large electrical parameter and location space can improve current modalities for treating epilepsy. Key Points Evaluated spatial and temporal parameters of neurostimulation in a mouse model of acute seizuresBrief bursts of high-frequency (100 Hz) stimulation effectively interrupted epileptiform activity.The suppressive effect was highly dependent on stimulation amplitude and was maximal at the ipsilateral CA1 and CA3 regions.Pro-excitatory effects were identified with high-amplitude high-frequency stimulation at the ventral hippocampal commissure and contralateral CA1.
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Cheah E, Bansal M, Nguyen L, Chalard A, Malmström J, O'Carroll SJ, Connor B, Wu Z, Svirskis D. Electrically responsive release of proteins from conducting polymer hydrogels. Acta Biomater 2023; 158:87-100. [PMID: 36640949 DOI: 10.1016/j.actbio.2023.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/21/2022] [Accepted: 01/05/2023] [Indexed: 01/13/2023]
Abstract
Electrically modulated delivery of proteins provides an avenue to target local tissues specifically and tune the dose to the application. This approach prolongs and enhances activity at the target site whilst reducing off-target effects associated with systemic drug delivery. The work presented here explores an electrically active composite material comprising of a biocompatible hydrogel, gelatin methacryloyl (GelMA) and a conducting polymer, poly(3,4-ethylenedioxythiophene), generating a conducting polymer hydrogel. In this paper, the key characteristics of electroactivity, mechanical properties, and morphology are characterized using electrochemistry techniques, atomic force, and scanning electron microscopy. Cytocompatibility is established through exposure of human cells to the materials. By applying different electrical-stimuli, the short-term release profiles of a model protein can be controlled over 4 h, demonstrating tunable delivery patterns. This is followed by extended-release studies over 21 days which reveal a bimodal delivery mechanism influenced by both GelMA degradation and electrical stimulation events. This data demonstrates an electroactive and cytocompatible material suitable for the delivery of protein payloads over 3 weeks. This material is well suited for use as a treatment delivery platform in tissue engineering applications where targeted and spatio-temporal controlled delivery of therapeutic proteins is required. STATEMENT OF SIGNIFICANCE: Growth factor use in tissue engineering typically requires sustained and tunable delivery to generate optimal outcomes. While conducting polymer hydrogels (CPH) have been explored for the electrically responsive release of small bioactives, we report on a CPH capable of releasing a protein payload in response to electrical stimulus. The composite material combines the benefits of soft hydrogels acting as a drug reservoir and redox-active properties from the conducting polymer enabling electrical responsiveness. The CPH is able to sustain protein delivery over 3 weeks, with electrical stimulus used to modulate release. The described material is well suited as a treatment delivery platform to deliver large quantities of proteins in applications where spatio-temporal delivery patterns are paramount.
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Affiliation(s)
- Ernest Cheah
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Mahima Bansal
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Linh Nguyen
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Anaïs Chalard
- Department of Chemical and Materials Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jenny Malmström
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand; Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Bronwen Connor
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Zimei Wu
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Im C, Kim HI, Jun SC. Are invasive cortical stimulations effective in brain atrophy? Comput Biol Med 2023; 154:106572. [PMID: 36706567 DOI: 10.1016/j.compbiomed.2023.106572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/23/2022] [Accepted: 01/22/2023] [Indexed: 01/25/2023]
Abstract
Electrical brain stimulation is a treatment method for brain disorder patients. The majority of patients with a severe brain disorder have brain atrophy. However, it is not clearly understood if electrical brain stimulation is effective even to brain atrophy. In this work, we developed anatomical head models with varying degrees of brain atrophy, so that we could investigate the effects of subdural/epidural cortical stimulations. The correlation between brain atrophy and cortical stimulation was quantified by calculating the effective volume that cortical stimulation influenced in this brain atrophy simulation study. The results showed that the effective volumes in both cortical stimulations decreased significantly with brain atrophy. There was also a strong correlation (0.9989) between the cerebrospinal fluid (CSF) and brain atrophy. The increase in CSF volume following brain atrophy reinforced the shunting effect between the brain and CSF and appeared to be the cause of a decrease in the stimulation effect on the brain. Overall, the epidural cortical stimulation was more sensitive (up to 57%) to the severity of the brain atrophy than the subdural cortical stimulation.
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Affiliation(s)
- Cheolki Im
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Hyoung-Ihl Kim
- Department of Medical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Sung Chan Jun
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
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Niederhoffer T, Vanhoestenberghe A, Lancashire HT. Methods of poly(3,4)-ethylenedioxithiophene (PEDOT) electrodeposition on metal electrodes for neural stimulation and recording. J Neural Eng 2023; 20. [PMID: 36603213 DOI: 10.1088/1741-2552/acb084] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 01/05/2023] [Indexed: 01/06/2023]
Abstract
Conductive polymers are of great interest in the field of neural electrodes because of their potential to improve the interfacial properties of electrodes. In particular, the conductive polymer poly (3,4)-ethylenedioxithiophene (PEDOT) has been widely studied for neural applications.Objective:This review compares methods for electrodeposition of PEDOT on metal neural electrodes, and analyses the effects of deposition methods on morphology and electrochemical performance.Approach:Electrochemical performances were analysed against several deposition method choices, including deposition charge density and co-ion, and correlations were explained to morphological and structural arguments as well as characterisation methods choices.Main results:Coating thickness and charge storage capacity are positively correlated with PEDOT electrodeposition charge density. We also show that PEDOT coated electrode impedance at 1 kHz, the only consistently reported impedance quantity, is strongly dependent upon electrode radius across a wide range of studies, because PEDOT coatings reduces the reactance of the complex impedance, conferring a more resistive behaviour to electrodes (at 1 kHz) dominated by the solution resistance and electrode geometry. This review also summarises how PEDOT co-ion choice affects coating structure and morphology and shows that co-ions notably influence the charge injection limit but have a limited influence on charge storage capacity and impedance. Finally we discuss the possible influence of characterisation methods to assess the robustness of comparisons between published results using different methods of characterisation.Significance:This review aims to serve as a common basis for researchers working with PEDOT by showing the effects of deposition methods on electrochemical performance, and aims to set a standard for accurate and uniform reporting of methods.
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Affiliation(s)
- Thomas Niederhoffer
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Anne Vanhoestenberghe
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Henry T Lancashire
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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Segar DJ, Bernstock JD, Arnaout O, Bi WL, Friedman GK, Langer R, Traverso G, Rampersad SM. Modeling of intracranial tumor treating fields for the treatment of complex high-grade gliomas. Sci Rep 2023; 13:1636. [PMID: 36717682 PMCID: PMC9886948 DOI: 10.1038/s41598-023-28769-9] [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: 09/21/2022] [Accepted: 01/24/2023] [Indexed: 02/01/2023] Open
Abstract
Increasing the intensity of tumor treating fields (TTF) within a tumor bed improves clinical efficacy, but reaching sufficiently high field intensities to achieve growth arrest remains challenging due in part to the insulating nature of the cranium. Using MRI-derived finite element models (FEMs) and simulations, we optimized an exhaustive set of intracranial electrode locations to obtain maximum TTF intensities in three clinically challenging high-grade glioma (HGG) cases (i.e., thalamic, left temporal, brainstem). Electric field strengths were converted into therapeutic enhancement ratios (TER) to evaluate the predicted impact of stimulation on tumor growth. Concurrently, conventional transcranial configurations were simulated/optimized for comparison. Optimized intracranial TTF were able to achieve field strengths that have previously been shown capable of inducing complete growth arrest, in 98-100% of the tumor volumes using only 0.54-0.64 A current. The reconceptualization of TTF as a targeted, intracranial therapy has the potential to provide a meaningful survival benefit to patients with HGG and other brain tumors, including those in surgically challenging, deep, or anatomically eloquent locations which may preclude surgical resection. Accordingly, such an approach may ultimately represent a paradigm shift in the use of TTFs for the treatment of brain cancer.
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Affiliation(s)
- David J Segar
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Joshua D Bernstock
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. .,David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Omar Arnaout
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Wenya Linda Bi
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Gregory K Friedman
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, USA
| | - Robert Langer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Giovanni Traverso
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sumientra M Rampersad
- Department of Physics, University of Massachusetts, Boston, MA, USA.,Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, USA
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48
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Mendes AX, do Nascimento AT, Duchi S, Quigley AF, Caballero Aguilar LM, Dekiwadia C, Kapsa RMI, Silva SM, Moulton SE. The impact of electrical stimulation protocols on neuronal cell survival and proliferation using cell-laden GelMA/graphene oxide hydrogels. J Mater Chem B 2023; 11:581-593. [PMID: 36533419 DOI: 10.1039/d2tb02387c] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The development of electroactive cell-laden hydrogels (bioscaffolds) has gained interest in neural tissue engineering research due to their inherent electrical properties that can induce the regulation of cell behaviour. Hydrogels combined with electrically conducting materials can respond to external applied electric fields, where these stimuli can promote electro-responsive cell growth and proliferation. A successful neural interface for electrical stimulation should present the desired stable electrical properties, such as high conductivity, low impedance, increased charge storage capacity and similar mechanical properties related to a target neural tissue. We report how different electrical stimulation protocols can impact neuronal cells' survival and proliferation when using cell-laden GelMA/GO hydrogels. The rat pheochromocytoma cell line, PC12s encapsulated into hydrogels showed an increased proliferation behaviour with increasing current amplitudes applied. Furthermore, the presence of GO in GelMA hydrogels enhanced the metabolic activity and DNA content of PC12s compared with GelMA alone. Similarly, hydrogels provided survival of encapsulated cells at higher current amplitudes when compared to cells seeded onto ITO flat surfaces, which expressed significant cell death at a current amplitude of 2.50 mA. Our findings provide new rational choices for electroactive hydrogels and electrical stimulation with broad potential applications in neural tissue engineering research.
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Affiliation(s)
- Alexandre Xavier Mendes
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Adriana Teixeira do Nascimento
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Serena Duchi
- Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia.,Department of Surgery, University of Melbourne, St Vincent's Hospital Melbourne, Victoria 3065, Australia
| | - Anita F Quigley
- Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia.,School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia.,Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne, Victoria 3065, Australia
| | - Lilith M Caballero Aguilar
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Chaitali Dekiwadia
- RMIT Microscopy and MicroAnalysis Facility (RMMF), STEM College, RMIT University, Melbourne, VIC, 3000, Australia
| | - Robert M I Kapsa
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia.,School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia.,Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne, Victoria 3065, Australia
| | - Saimon Moraes Silva
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia.,Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Simon E Moulton
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia. .,Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia.,Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
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49
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Stieve BJ, Richner TJ, Krook-Magnuson C, Netoff TI, Krook-Magnuson E. Optimization of closed-loop electrical stimulation enables robust cerebellar-directed seizure control. Brain 2023; 146:91-108. [PMID: 35136942 DOI: 10.1093/brain/awac051] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/17/2021] [Accepted: 01/11/2022] [Indexed: 01/11/2023] Open
Abstract
Additional treatment options for temporal lobe epilepsy are needed, and potential interventions targeting the cerebellum are of interest. Previous animal work has shown strong inhibition of hippocampal seizures through on-demand optogenetic manipulation of the cerebellum. However, decades of work examining electrical stimulation-a more immediately translatable approach-targeting the cerebellum has produced very mixed results. We were therefore interested in exploring the impact that stimulation parameters may have on seizure outcomes. Using a mouse model of temporal lobe epilepsy, we conducted on-demand electrical stimulation of the cerebellar cortex, and varied stimulation charge, frequency and pulse width, resulting in over 1000 different potential combinations of settings. To explore this parameter space in an efficient, data-driven, manner, we utilized Bayesian optimization with Gaussian process regression, implemented in MATLAB with an Expected Improvement Plus acquisition function. We examined three different fitting conditions and two different electrode orientations. Following the optimization process, we conducted additional on-demand experiments to test the effectiveness of selected settings. Regardless of experimental setup, we found that Bayesian optimization allowed identification of effective intervention settings. Additionally, generally similar optimal settings were identified across animals, suggesting that personalized optimization may not always be necessary. While optimal settings were effective, stimulation with settings predicted from the Gaussian process regression to be ineffective failed to provide seizure control. Taken together, our results provide a blueprint for exploration of a large parameter space for seizure control and illustrate that robust inhibition of seizures can be achieved with electrical stimulation of the cerebellum, but only if the correct stimulation parameters are used.
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Affiliation(s)
- Bethany J Stieve
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis 55455, USA
| | - Thomas J Richner
- Department of Biomedical Engineering, University of Minnesota, Minneapolis 55455, USA.,Department of Neuroscience, University of Minnesota, Minneapolis 55455, USA
| | | | - Theoden I Netoff
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis 55455, USA.,Department of Biomedical Engineering, University of Minnesota, Minneapolis 55455, USA
| | - Esther Krook-Magnuson
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis 55455, USA.,Department of Neuroscience, University of Minnesota, Minneapolis 55455, USA
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50
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Ye M, Zestos AG, Welle CG, Wu GK, Cui XT. Editorial: Safety and efficacy evaluation of electrical stimulation devices for neural modulation. Front Neurosci 2023; 17:1143989. [PMID: 36824215 PMCID: PMC9941729 DOI: 10.3389/fnins.2023.1143989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Affiliation(s)
- Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, United States
| | - Alexander G Zestos
- Department of Chemistry, American University, Washington, DC, United States
| | - Cristin G Welle
- Department of Physiology and Biophysics, University of Colorado, Anschutz Medical Campus, Denver, CO, United States
| | - Guangying K Wu
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
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