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Payne SC, Osborne PB, Thompson A, Eiber CD, Keast JR, Fallon JB. Selective recording of physiologically evoked neural activity in a mixed autonomic nerve using a minimally invasive array. APL Bioeng 2023; 7:046110. [PMID: 37928642 PMCID: PMC10625482 DOI: 10.1063/5.0164951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 10/16/2023] [Indexed: 11/07/2023] Open
Abstract
Real-time closed-loop control of neuromodulation devices requires long-term monitoring of neural activity in the peripheral nervous system. Although many signal extraction methods exist, few are both clinically viable and designed for extracting small signals from fragile peripheral visceral nerves. Here, we report that our minimally invasive recording and analysis technology extracts low to negative signal to noise ratio (SNR) neural activity from a visceral nerve with a high degree of specificity for fiber type and class. Complex activity was recorded from the rat pelvic nerve that was physiologically evoked during controlled bladder filling and voiding, in an extensively characterized in vivo model that provided an excellent test bed to validate our technology. Urethane-anesthetized male rats (n = 12) were implanted with a four-electrode planar array and the bladder instrumented for continuous-flow cystometry, which measures urodynamic function by recording bladder pressure changes during constant infusion of saline. We demonstrated that differential bipolar recordings and cross-correlation analyses extracts afferent and efferent activity, and discriminated between subpopulations of fibers based on conduction velocity. Integrated Aδ afferent fiber activity correlated with bladder pressure during voiding (r2: 0.66 ± 0.06) and was not affected by activating nociceptive afferents with intravesical capsaicin (r2: 0.59 ± 0.14, P = 0.54, and n = 3). Collectively, these results demonstrate our minimally invasive recording and analysis technology is selective in extracting mixed neural activity with low/negative SNR. Furthermore, integrated afferent activity reliably correlates with bladder pressure and is a promising first step in developing closed-loop technology for bladder control.
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Affiliation(s)
| | - Peregrine B. Osborne
- Department of Anatomy and Physiology, University of Melbourne, Victoria 3010, Australia
| | | | - Calvin D. Eiber
- Department of Anatomy and Physiology, University of Melbourne, Victoria 3010, Australia
| | - Janet R. Keast
- Department of Anatomy and Physiology, University of Melbourne, Victoria 3010, Australia
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Eiber CD, Aditya Tarigoppula VS, Rind GS. A 'Total Unique Variation Analysis' for Brain-Machine Interfaces. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38083167 DOI: 10.1109/embc40787.2023.10340518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
When designing a fully implantable brain-machine interface (BMI), the primary aim is to detect as much neural information as possible with as few channels as possible. In this paper, we present a total unique variance analysis (TUVA) for evaluating the signal unique to each channel that cannot be predicted by linear combination of signals on other channels. TUVA is a statistical method for determining the total unique variance in multidimensional data, ordering channels from most to least informative, to aid in the design of maximally-efficacious BMIs. We demonstrate how this method can be applied to the design of BMIs by comparing TUVA values computed for simulated lead-field maps for high-channel-count electrocorticography (ECoG) with values computed for recordings in the interictal period in the context of surgery planning for epileptic resection.Clinical Relevance- This paper introduces a new statistical method for comparison of neural interface designs, focused on quantifying recording efficiency by minimizing channel crosstalk, which may help improve the risk-benefit profile of invasive neural recording.
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Lim J, Eiber CD, Sun A, Maples A, Powley TL, Ward MP, Lee H. Fractal Microelectrodes for More Energy-Efficient Cervical Vagus Nerve Stimulation. Adv Healthc Mater 2023; 12:e2202619. [PMID: 36973998 PMCID: PMC10522801 DOI: 10.1002/adhm.202202619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/06/2023] [Indexed: 03/29/2023]
Abstract
Vagus nerve stimulation (VNS) has the potential to treat various peripheral dysfunctions, but the traditional cuff electrodes for VNS are susceptible to off-target effects. Microelectrodes may enable highly selective VNS that can mitigate off-target effects, but they suffer from the increased impedance. Recent studies on microelectrodes with non-Euclidean geometries have reported higher energy efficiency in neural stimulation applications. These previous studies use electrodes with mm/cm-scale dimensions, mostly targeted for myelinated fibers. This study evaluates fractal microelectrodes for VNS in a rodent model (N = 3). A thin-film device with fractal and circle microelectrodes is fabricated to compare their neural stimulation performance on the same radial coordinate of the nerve. The results show that fractal microelectrodes can activate C-fibers with up to 52% less energy (p = 0.012) compared to circle microelectrodes. To the best of the knowledge, this work is the first to demonstrate a geometric advantage of fractal microelectrodes for VNS in vivo.
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Affiliation(s)
- Jongcheon Lim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
| | - Calvin D Eiber
- Synchron Inc., Melbourne, VIC, 3004, Australia
- Department of Medicine (RMH), Faculty of Medicine, Health and Dentistry, the University of Melbourne, Melbourne, VIC, 3050, Australia
| | - Anina Sun
- Department of Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Amanda Maples
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Terry L Powley
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute of Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Matthew P Ward
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Hyowon Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
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Eiber CD, Payne SC, Biscola NP, Havton LA, Keast JR, Osborne PB, Fallon JB. Computational modelling of nerve stimulation and recording with peripheral visceral neural interfaces. J Neural Eng 2021; 18. [PMID: 34740201 DOI: 10.1088/1741-2552/ac36e2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 11/05/2021] [Indexed: 12/30/2022]
Abstract
Objective.Neuromodulation of visceral nerves is being intensively studied for treating a wide range of conditions, but effective translation requires increasing the efficacy and predictability of neural interface performance. Here we use computational models of rat visceral nerve to predict how neuroanatomical variability could affect both electrical stimulation and recording with an experimental planar neural interface.Approach.We developed a hybrid computational pipeline,VisceralNerveEnsembleRecording andStimulation (ViNERS), to couple finite-element modelling of extracellular electrical fields with biophysical simulations of individual axons. Anatomical properties of fascicles and axons in rat pelvic and vagus nerves were measured or obtained from public datasets. To validate ViNERS, we simulated pelvic nerve stimulation and recording with an experimental four-electrode planar array.Main results.Axon diameters measured from pelvic nerve were used to model a population of myelinated and unmyelinated axons and simulate recordings of electrically evoked single-unit field potentials (SUFPs). Across visceral nerve fascicles of increasing size, our simulations predicted an increase in stimulation threshold and a decrease in SUFP amplitude. Simulated threshold changes were dominated by changes in perineurium thickness, which correlates with fascicle diameter. We also demonstrated that ViNERS could simulate recordings of electrically-evoked compound action potentials (ECAPs) that were qualitatively similar to pelvic nerve recording made with the array used for simulation.Significance.We introduce ViNERS as a new open-source computational tool for modelling large-scale stimulation and recording from visceral nerves. ViNERS predicts how neuroanatomical variation in rat pelvic nerve affects stimulation and recording with an experimental planar electrode array. We show ViNERS can simulate ECAPS that capture features of our recordings, but our results suggest the underlying NEURON models need to be further refined and specifically adapted to accurately simulate visceral nerve axons.
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Affiliation(s)
- Calvin D Eiber
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - Sophie C Payne
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, The University of Melbourne, Victoria, Australia
| | - Natalia P Biscola
- Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Leif A Havton
- Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Janet R Keast
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - Peregrine B Osborne
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - James B Fallon
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, The University of Melbourne, Victoria, Australia
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Eiber CD, Delbeke J, Cardoso J, de Neeling M, John SE, Won Lee C, Skefos J, Sun A, Prodanov D, McKinney Z. Preliminary Minimum Reporting Requirements for In-Vivo Neural Interface Research: I. Implantable Neural Interfaces. IEEE Open J Eng Med Biol 2021; 2:74-83. [PMID: 33997788 PMCID: PMC8118094 DOI: 10.1109/ojemb.2021.3060919] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The pace of research and development in neuroscience, neurotechnology, and neurorehabilitation is rapidly accelerating, with the number of publications doubling every 4.2 years. Maintaining this progress requires technological standards and scientific reporting guidelines to provide frameworks for communication and interoperability. The present lack of such neurotechnology standards limits the transparency, repro-ducibility, and meta-analysis of this growing body of literature, posing an ongoing barrier to research, clinical, and commercial objectives. Continued neurotechnological innovation requires the development of some minimal standards to promote integration between this broad spectrum of technologies and therapies. To preserve design freedom and accelerate the translation of research into safe and effective technologies with maximal user benefit, such standards must be collaboratively co-developed by the full range of neuroscience and neurotechnology stakeholders. This paper summarizes the preliminary recommendations of IEEE P2794 Standards Working Group, developing a Reporting Standard for in-vivo Neural Interface Research (RSNIR).
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Affiliation(s)
| | | | - Jorge Cardoso
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon 1649-028, Portugal
| | | | - Sam E John
- University of Melbourne, Melbourne 3010, Australia
| | | | | | - Argus Sun
- University of California, Los Angeles, CA 90095 USA
| | | | - Zach McKinney
- BioRobotics Institute and Center for Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy
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Payne SC, Wiedmann NM, Eiber CD, Wong AW, Senn P, Osborne PB, Keast JR, Fallon JB. Recording of Electrically Evoked Neural Activity and Bladder Pressure Responses in Awake Rats Chronically Implanted With a Pelvic Nerve Array. Front Neurosci 2020; 14:619275. [PMID: 33390899 PMCID: PMC7773906 DOI: 10.3389/fnins.2020.619275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/25/2020] [Indexed: 01/16/2023] Open
Abstract
Bioelectronic medical devices are well established and widely used in the treatment of urological dysfunction. Approved targets include the sacral S3 spinal root and posterior tibial nerve, but an alternate target is the group of pelvic splanchnic nerves, as these contain sacral visceral sensory and autonomic motor pathways that coordinate storage and voiding functions of the bladder. Here, we developed a device suitable for long-term use in an awake rat model to study electrical neuromodulation of the pelvic nerve (homolog of the human pelvic splanchnic nerves). In male Sprague-Dawley rats, custom planar four-electrode arrays were implanted over the distal end of the pelvic nerve, close to the major pelvic ganglion. Electrically evoked compound action potentials (ECAPs) were reliably detected under anesthesia and in chronically implanted, awake rats up to 8 weeks post-surgery. ECAP waveforms showed three peaks, with latencies that suggested electrical stimulation activated several subpopulations of myelinated A-fiber and unmyelinated C-fiber axons. Chronic implantation of the array did not impact on voiding evoked in awake rats by continuous cystometry, where void parameters were comparable to those published in naïve rats. Electrical stimulation with chronically implanted arrays also induced two classes of bladder pressure responses detected by continuous flow cystometry in awake rats: voiding contractions and non-voiding contractions. No evidence of tissue pathology produced by chronically implanted arrays was detected by immunohistochemical visualization of markers for neuronal injury or noxious spinal cord activation. These results demonstrate a rat pelvic nerve electrode array that can be used for preclinical development of closed loop neuromodulation devices targeting the pelvic nerve as a therapy for neuro-urological dysfunction.
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Affiliation(s)
- Sophie C Payne
- Bionics Institute, Fitzroy, VIC, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, VIC, Australia
| | - Nicole M Wiedmann
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia
| | - Calvin D Eiber
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia
| | - Agnes W Wong
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia
| | - Philipp Senn
- Bionics Institute, Fitzroy, VIC, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, VIC, Australia
| | - Peregrine B Osborne
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia
| | - Janet R Keast
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia
| | - James B Fallon
- Bionics Institute, Fitzroy, VIC, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, VIC, Australia.,Department of Otolaryngology, University of Melbourne, Melbourne, VIC, Australia
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Abstract
Bioelectronic neural interfaces that deliver adaptive therapeutic stimulation in an intelligent manner must be able to sense and stimulate activity within the same nerve. Existing minimally-invasive peripheral neural interfaces can provide a read-out of the aggregate level of activity via electrical recordings of nerve activity, but these recordings are limited in terms of their specificity. Computational simulations can provide fine-grained insight into the contributions of different neural populations to the extracellular recording, but integration of the signals from individual nerve fibers requires knowledge of spread of current in the complex (heterogenous, anisotropic) extracellular space. We have developed a model which uses the open-source EIDORS package for extracellular stimulation and recording in the pelvic nerve. The pelvic nerve is the primary source of autonomic innervation to the pelvic organs, and a prime target for electrical stimulation to treat a variety of voiding disorders. We simulated recordings of spontaneous and electrically-evoked activity using biophysical models for myelinated and unmyelinated axons. As expected, stimulus thresholds depended strongly on both fibre type and electrode-fibre distance. In conclusion, EIDORS can be used to accurately simulate extracellular recording in complex, heterogenous neural geometries.
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Eiber CD, Bertrand MB, Keast JR, Osborne PB. SPARC: Modelling a Bidirectional Bioelectric Pelvic Nerve Interface. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Eiber CD, Dokos S, Lovell NH, Suaning GJ. Multipolar Field Shaping in a Suprachoroidal Visual Prosthesis. IEEE Trans Neural Syst Rehabil Eng 2017; 25:2480-2487. [DOI: 10.1109/tnsre.2017.2730880] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Matteucci PB, Barriga-Rivera A, Eiber CD, Lovell NH, Morley JW, Suaning GJ. The Effect of Electric Cross-Talk in Retinal Neurostimulation. ACTA ACUST UNITED AC 2016; 57:1031-7. [DOI: 10.1167/iovs.15-18400] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Paul B. Matteucci
- Graduate School of Biomedical Engineering University of New South Wales, Sydney, Australia
| | | | - Calvin D. Eiber
- Graduate School of Biomedical Engineering University of New South Wales, Sydney, Australia
| | - Nigel H. Lovell
- Graduate School of Biomedical Engineering University of New South Wales, Sydney, Australia
| | - John W. Morley
- School of Medicine, Western Sydney University, Sydney, Australia 3School of Medical Science, University of New South Wales, Sydney, Australia
| | - Gregg J. Suaning
- Graduate School of Biomedical Engineering University of New South Wales, Sydney, Australia
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Barriga-Rivera A, Eiber CD, Dodds CWD, Fung AT, Tatarinoff V, Lovell NH, Suaning GJ. Electrically evoked potentials in an ovine model for the evaluation of visual prosthesis efficacy. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:3359-62. [PMID: 26737012 DOI: 10.1109/embc.2015.7319112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Visual prostheses are becoming a reality as a therapy to restore functional vision to the blind. New stimulation strategies and novel electrode designs are contributing to accelerate the development of such devices triggering the interest of scientists, clinicians and the blind community worldwide. In this scenario, there is a need for large animal models that are suitable for preclinical testing of retinal neuroprostheses. This study presents an electrophysiology assessment of an ovine model for single and simultaneous electrode stimulation from the suprachoroidal space, using symmetric biphasic current pulses with a monopolar return configuration. Visually and electrically evoked potentials were recorded using supradural surface electrodes, showing charge thresholds comparable to those in humans. This model represents an alternative to feline or canine models with analogous activation levels and an eye anatomy similar to that of humans.
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Eiber CD, Morley JW, Lovell NH, Suaning GJ. A cortical integrate-and-fire neural network model for blind decoding of visual prosthetic stimulation. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2014:1715-8. [PMID: 25570306 DOI: 10.1109/embc.2014.6943938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We present a computational model of the optic pathway which has been adapted to simulate cortical responses to visual-prosthetic stimulation. This model reproduces the statistically observed distributions of spikes for cortical recordings of sham and maximum-intensity stimuli, while simultaneously generating cellular receptive fields consistent with those observed using traditional visual neuroscience methods. By inverting this model to generate candidate phosphenes which could generate the responses observed to novel stimulation strategies, we hope to aid the development of said strategies in-vivo before being deployed in clinical settings.
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Abstract
Visual prosthetics is an expanding subfield of functional electrical stimulation which has gained increased interest recently in light of new advances in treatments and technology. These treatments and technology represent a major improvement over prior art, but are still subject to a host of limitations which are dependent on the manner in which one approaches the topic of visual prosthetics. These limitations pose new research challenges whose solutions are directly applicable to the well-being of blind individuals everywhere. In this review, we will outline and critically compare major current approaches to visual prosthetics, and in particular retinal prosthetics. Then, we will engage in an in-depth discussion of the limitations imposed by current technology, physics, and the underlying biology of the retina to highlight several of the challenges currently facing researchers.
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Affiliation(s)
- Calvin D Eiber
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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