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Coventry BS, Bartlett EL. Practical Bayesian Inference in Neuroscience: Or How I Learned To Stop Worrying and Embrace the Distribution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.19.567743. [PMID: 38045416 PMCID: PMC10690186 DOI: 10.1101/2023.11.19.567743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Typical statistical practices in the biological sciences have been increasingly called into question due to difficulties in replication of an increasing number of studies, many of which are confounded by the relative difficulty of null significance hypothesis testing designs and interpretation of p-values. Bayesian inference, representing a fundamentally different approach to hypothesis testing, is receiving renewed interest as a potential alternative or complement to traditional null significance hypothesis testing due to its ease of interpretation and explicit declarations of prior assumptions. Bayesian models are more mathematically complex than equivalent frequentist approaches, which have historically limited applications to simplified analysis cases. However, the advent of probability distribution sampling tools with exponential increases in computational power now allows for quick and robust inference under any distribution of data. Here we present a practical tutorial on the use of Bayesian inference in the context of neuroscientific studies. We first start with an intuitive discussion of Bayes' rule and inference followed by the formulation of Bayesian-based regression and ANOVA models using data from a variety of neuroscientific studies. We show how Bayesian inference leads to easily interpretable analysis of data while providing an open-source toolbox to facilitate the use of Bayesian tools.
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Affiliation(s)
- Brandon S Coventry
- Department of Neurological Surgery and the Wisconsin Institute for Translational Neuroengineering, University of Wisconsin-Madison, Madison, WI USA 53705
| | - Edward L Bartlett
- Weldon School of Biomedical Engineering, Department of Biological Sciences, and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA 47907
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2
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Coventry BS, Lawlor GL, Bagnati CB, Krogmeier C, Bartlett EL. Characterization and closed-loop control of infrared thalamocortical stimulation produces spatially constrained single-unit responses. PNAS NEXUS 2024; 3:pgae082. [PMID: 38725532 PMCID: PMC11079674 DOI: 10.1093/pnasnexus/pgae082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 02/07/2024] [Indexed: 05/12/2024]
Abstract
Deep brain stimulation (DBS) is a powerful tool for the treatment of circuitopathy-related neurological and psychiatric diseases and disorders such as Parkinson's disease and obsessive-compulsive disorder, as well as a critical research tool for perturbing neural circuits and exploring neuroprostheses. Electrically mediated DBS, however, is limited by the spread of stimulus currents into tissue unrelated to disease course and treatment, potentially causing undesirable patient side effects. In this work, we utilize infrared neural stimulation (INS), an optical neuromodulation technique that uses near to midinfrared light to drive graded excitatory and inhibitory responses in nerves and neurons, to facilitate an optical and spatially constrained DBS paradigm. INS has been shown to provide spatially constrained responses in cortical neurons and, unlike other optical techniques, does not require genetic modification of the neural target. We show that INS produces graded, biophysically relevant single-unit responses with robust information transfer in rat thalamocortical circuits. Importantly, we show that cortical spread of activation from thalamic INS produces more spatially constrained response profiles than conventional electrical stimulation. Owing to observed spatial precision of INS, we used deep reinforcement learning (RL) for closed-loop control of thalamocortical circuits, creating real-time representations of stimulus-response dynamics while driving cortical neurons to precise firing patterns. Our data suggest that INS can serve as a targeted and dynamic stimulation paradigm for both open and closed-loop DBS.
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Affiliation(s)
- Brandon S Coventry
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Georgia L Lawlor
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Christina B Bagnati
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Claudia Krogmeier
- Department of Computer Graphics Technology, Purdue University, West Lafayette, IN 47907, USA
| | - Edward L Bartlett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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3
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Quimby AE, Wei K, Adewole D, Eliades S, Cullen DK, Brant JA. Signal processing and stimulation potential within the ascending auditory pathway: a review. Front Neurosci 2023; 17:1277627. [PMID: 38027521 PMCID: PMC10658786 DOI: 10.3389/fnins.2023.1277627] [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: 08/14/2023] [Accepted: 10/12/2023] [Indexed: 12/01/2023] Open
Abstract
The human auditory system encodes sound with a high degree of temporal and spectral resolution. When hearing fails, existing neuroprosthetics such as cochlear implants may partially restore hearing through stimulation of auditory neurons at the level of the cochlea, though not without limitations inherent to electrical stimulation. Novel approaches to hearing restoration, such as optogenetics, offer the potential of improved performance. We review signal processing in the ascending auditory pathway and the current state of conventional and emerging neural stimulation strategies at various levels of the auditory system.
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Affiliation(s)
- Alexandra E. Quimby
- Department of Otolaryngology and Communication Sciences, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Kimberly Wei
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Dayo Adewole
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Steven Eliades
- Department of Head and Neck Surgery and Communication Sciences, Duke University, Durham, NC, United States
| | - D. Kacy Cullen
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Jason A. Brant
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Otorhinolaryngology – Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, United States
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4
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Coventry BS, Lawlor GL, Bagnati CB, Krogmeier C, Bartlett EL. Spatially specific, closed-loop infrared thalamocortical deep brain stimulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.04.560859. [PMID: 37904955 PMCID: PMC10614743 DOI: 10.1101/2023.10.04.560859] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Deep brain stimulation (DBS) is a powerful tool for the treatment of circuitopathy-related neurological and psychiatric diseases and disorders such as Parkinson's disease and obsessive-compulsive disorder, as well as a critical research tool for perturbing neural circuits and exploring neuroprostheses. Electrically-mediated DBS, however, is limited by the spread of stimulus currents into tissue unrelated to disease course and treatment, potentially causing undesirable patient side effects. In this work, we utilize infrared neural stimulation (INS), an optical neuromodulation technique that uses near to mid-infrared light to drive graded excitatory and inhibitory responses in nerves and neurons, to facilitate an optical and spatially constrained DBS paradigm. INS has been shown to provide spatially constrained responses in cortical neurons and, unlike other optical techniques, does not require genetic modification of the neural target. We show that INS produces graded, biophysically relevant single-unit responses with robust information transfer in thalamocortical circuits. Importantly, we show that cortical spread of activation from thalamic INS produces more spatially constrained response profiles than conventional electrical stimulation. Owing to observed spatial precision of INS, we used deep reinforcement learning for closed-loop control of thalamocortical circuits, creating real-time representations of stimulus-response dynamics while driving cortical neurons to precise firing patterns. Our data suggest that INS can serve as a targeted and dynamic stimulation paradigm for both open and closed-loop DBS.
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Affiliation(s)
- Brandon S Coventry
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA
| | - Georgia L Lawlor
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA
| | - Christina B Bagnati
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN USA
| | - Claudia Krogmeier
- Department of Computer Graphics Technology, Purdue University, West Lafayette, IN USA
| | - Edward L Bartlett
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN USA
- Center for Implantable Devices and the Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA
- Department of Biological Sciences, Purdue University, West Lafayette, IN USA
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5
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Wolf BJ, Kusch K, Hunniford V, Vona B, Kühler R, Keppeler D, Strenzke N, Moser T. Is there an unmet medical need for improved hearing restoration? EMBO Mol Med 2022; 14:e15798. [PMID: 35833443 PMCID: PMC9358394 DOI: 10.15252/emmm.202215798] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/12/2022] [Accepted: 06/02/2022] [Indexed: 12/26/2022] Open
Abstract
Hearing impairment, the most prevalent sensory deficit, affects more than 466 million people worldwide (WHO). We presently lack causative treatment for the most common form, sensorineural hearing impairment; hearing aids and cochlear implants (CI) remain the only means of hearing restoration. We engaged with CI users to learn about their expectations and their willingness to collaborate with health care professionals on establishing novel therapies. We summarize upcoming CI innovations, gene therapies, and regenerative approaches and evaluate the chances for clinical translation of these novel strategies. We conclude that there remains an unmet medical need for improving hearing restoration and that we are likely to witness the clinical translation of gene therapy and major CI innovations within this decade.
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Affiliation(s)
- Bettina Julia Wolf
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Kathrin Kusch
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Functional Auditory Genomics Group, Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
| | - Victoria Hunniford
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Sensory and Motor Neuroscience PhD Program, Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Barbara Vona
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Robert Kühler
- Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Nicola Strenzke
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience & Synaptic Nanophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
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6
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Current Review of Optical Neural Interfaces for Clinical Applications. MICROMACHINES 2021; 12:mi12080925. [PMID: 34442547 PMCID: PMC8400671 DOI: 10.3390/mi12080925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Neural interfaces, which enable the recording and stimulation of living neurons, have emerged as valuable tools in understanding the brain in health and disease, as well as serving as neural prostheses. While neural interfaces are typically based on electrical transduction, alternative energy modalities have been explored to create safe and effective approaches. Among these approaches, optical methods of linking neurons to the outside world have gained attention because light offers high spatial selectivity and decreased invasiveness. Here, we review the current state-of-art of optical neural interfaces and their clinical applications. Optical neural interfaces can be categorized into optical control and optical readout, each of which can be divided into intrinsic and extrinsic approaches. We discuss the advantages and disadvantages of each of these methods and offer a comparison of relative performance. Future directions, including their clinical opportunities, are discussed with regard to the optical properties of biological tissue.
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Xu J, Zeng M, Xu X, Liu J, Huo X, Han D, Wang Z, Tian L. A Micron-Sized Laser Photothermal Effect Evaluation System and Method. SENSORS (BASEL, SWITZERLAND) 2021; 21:5133. [PMID: 34372369 PMCID: PMC8348586 DOI: 10.3390/s21155133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 11/17/2022]
Abstract
The photothermal effects of lasers have played an important role in both medical laser applications and the development of cochlear implants with optical stimulation. However, there are few methods to evaluate the thermal effect of micron-sized laser spots interacting with other tissues. Here, we present a multi-wavelength micro-scale laser thermal effect measuring system that has high temporal, spatial and temperature resolutions, and can quantitatively realize evaluations in real time. In this system, with accurate 3D positioning and flexible pulsed laser parameter adjustments, groups of temperature changes are systematically measured when the micron-sized laser spots from six kinds of wavelengths individually irradiate the Pd/Cr thermocouple junction area, and reference data of laser spot thermal effects are obtained. This work develops a stable, reliable and universal tool for quantitatively exploring the thermal effect of micron-sized lasers, and provides basic reference data for research on light-stimulated neuron excitement in the future.
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Affiliation(s)
- Jingjing Xu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
- Shenzhen Research Institute, Shandong University, Shenzhen 518057, China
| | - Ming Zeng
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Xin Xu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Junhui Liu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Xinyu Huo
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Danhong Han
- Beijing Research Institute of Mechanical Equipment, Beijing 100854, China; (D.H.); (Z.W.)
| | - Zhenhai Wang
- Beijing Research Institute of Mechanical Equipment, Beijing 100854, China; (D.H.); (Z.W.)
| | - Lan Tian
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
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8
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Viral-mediated transduction of auditory neurons with opsins for optical and hybrid activation. Sci Rep 2021; 11:11229. [PMID: 34045604 PMCID: PMC8160204 DOI: 10.1038/s41598-021-90764-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/13/2021] [Indexed: 12/15/2022] Open
Abstract
Optical stimulation is a paradigm-shifting approach to modulating neural activity that has the potential to overcome the issue of current spread that occurs with electrical stimulation by providing focused stimuli. But optical stimulation either requires high power infrared light or genetic modification of neurons to make them responsive to lower power visible light. This work examines optical activation of auditory neurons following optogenetic modification via AAV injection in two species (mouse and guinea pig). An Anc80 viral vector was used to express the channelrhodopsin variant ChR2-H134R fused to a fluorescent reporter gene under the control of the human synapsin-1 promoter. The AAV was administered directly to the cochlea (n = 33) or posterior semi-circular canal of C57BL/6 mice (n = 4) or to guinea pig cochleae (n = 6). Light (488 nm), electrical stimuli or the combination of these (hybrid stimulation) was delivered to the cochlea via a laser-coupled optical fibre and co-located platinum wire. Activation thresholds, spread of activation and stimulus interactions were obtained from multi-unit recordings from the central nucleus of the inferior colliculus of injected mice, as well as ChR2-H134R transgenic mice (n = 4). Expression of ChR2-H134R was examined by histology. In the mouse, transduction of auditory neurons by the Anc80 viral vector was most successful when injected at a neonatal age with up to 89% of neurons transduced. Auditory neuron transductions were not successful in guinea pigs. Inferior colliculus responses to optical stimuli were detected in a cochleotopic manner in all mice with ChR2-H134R expression. There was a significant correlation between lower activation thresholds in mice and higher proportions of transduced neurons. There was no difference in spread of activation between optical stimulation and electrical stimulation provided by the light/electrical delivery system used here (optical fibre with bonded 25 µm platinum/iridium wire). Hybrid stimulation, comprised of sub-threshold optical stimulation to 'prime' or raise the excitability of the neurons, lowered the threshold for electrical activation in most cases, but the impact on excitation width was more variable compared to transgenic mice. This study demonstrates the impact of opsin expression levels and expression pattern on optical and hybrid stimulation when considering optical or hybrid stimulation techniques for neuromodulation.
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Littlefield PD, Richter C. Near-infrared stimulation of the auditory nerve: A decade of progress toward an optical cochlear implant. Laryngoscope Investig Otolaryngol 2021; 6:310-319. [PMID: 33869763 PMCID: PMC8035937 DOI: 10.1002/lio2.541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 12/14/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES We provide an appraisal of recent research on stimulation of the auditory system with light. In particular, we discuss direct infrared stimulation and ongoing controversies regarding the feasibility of this modality. We also discuss advancements and barriers to the development of an optical cochlear implant. METHODS This is a review article that covers relevant animal studies. RESULTS The auditory system has been stimulated with infrared light, and in a much more spatially selective manner than with electrical stimulation. However, there are experiments from other labs that have not been able to reproduce these results. This has resulted in an ongoing controversy regarding the feasibility of infrared stimulation, and the reasons for these experimental differences still require explanation. The neural response characteristics also appear to be much different than with electrical stimulation. The electrical stimulation paradigms used for modern cochlear implants do not apply well to optical stimulation and new coding strategies are under development. Stimulation with infrared light brings the risk of heat accumulation in the tissue at high pulse repetition rates, so optimal pulse shapes and combined optical/electrical stimulation are being investigated to mitigate this. Optogenetics is another promising technique, which makes neurons more sensitive to light stimulation by inserting light sensitive ion channels via viral vectors. Challenges of optogenetics include the expression of light sensitive channels in sufficient density in the target neurons, and the risk of damaging neurons by the expression of a foreign protein. CONCLUSION Optical stimulation of the nervous system is a promising new field, and there has been progress toward the development of a cochlear implant that takes advantage of the benefits of optical stimulation. There are barriers, and controversies, but so far none that seem intractable. LEVEL OF EVIDENCE NA (animal studies and basic research).
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Affiliation(s)
| | - Claus‐Peter Richter
- Department of OtolaryngologyNorthwestern UniversityChicagoIllinoisUSA
- Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
- Department of Biomedical EngineeringNorthwestern UniversityEvanstonIllinoisUSA
- The Hugh Knowles Center, Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
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10
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Agarwal A, Tan X, Xu Y, Richter CP. Channel Interaction During Infrared Light Stimulation in the Cochlea. Lasers Surg Med 2021; 53:986-997. [PMID: 33476051 DOI: 10.1002/lsm.23360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/21/2020] [Accepted: 11/07/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND OBJECTIVES The number of perceptually independent channels to encode acoustic information is limited in contemporary cochlear implants (CIs) because of the current spread in the tissue. It has been suggested that neighboring electrodes have to be separated in humans by a distance of more than 2 mm to eliminate significant overlap of the electric current fields and subsequent interaction between the channels. It has also been argued that an increase in the number of independent channels could improve CI user performance in challenging listening environments, such as speech in noise, tonal languages, or music perception. Optical stimulation has been suggested as an alternative modality for neural stimulation because it is spatially selective. This study reports the results of experiments designed to quantify the interaction between neighboring optical sources in the cochlea during stimulation with infrared radiation. STUDY DESIGN/MATERIALS AND METHODS In seven adult albino guinea pigs, a forward masking method was used to quantify the interaction between two neighboring optical sources during stimulation. Two optical fibers were placed through cochleostomies into the scala tympani of the basal cochlear turn. The radiation beams were directed towards different neuron populations along the spiral ganglion. Optically evoked compound action potentials were recorded for different radiant energies and distances between the optical fibers. The outcome measure was the radiant energy of a masker pulse delivered 3 milliseconds before a probe pulse to reduce the response evoked by the probe pulse by 3 dB. Results were compared for different distances between the fibers placed along the cochlea. RESULTS The energy required to reduce the probe's response by 3 dB increased by 20.4 dB/mm and by 26.0 dB/octave. The inhibition was symmetrical for the masker placed basal to the probe (base-to-apex) and the masker placed apical to the probe (apex-to-base). CONCLUSION The interaction between neighboring optical sources during infrared laser stimulation is less than the interaction between neighboring electrical contacts during electrical stimulation. Previously published data for electrical stimulation reported an average current spread in human and cat cochleae of 2.8 dB/mm. With the increased number of independent channels for optical stimulation, it is anticipated that speech and music performance will improve. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Aditi Agarwal
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, 320 E. Superior Street, Searle 12-561, Chicago, Illinois, 60611
| | - Xiaodong Tan
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, 320 E. Superior Street, Searle 12-561, Chicago, Illinois, 60611
| | - Yingyue Xu
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, 320 E. Superior Street, Searle 12-561, Chicago, Illinois, 60611
| | - Claus-Peter Richter
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, 320 E. Superior Street, Searle 12-561, Chicago, Illinois, 60611.,Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, Illinois, 60208.,Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, 60208.,Department of Communication Sciences and Disorders, The Hugh Knowles Center, Northwestern University, Evanston, Illinois, 60208
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11
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Thompson AC, Wise AK, Hart WL, Needham K, Fallon JB, Gunewardene N, Stoddart PR, Richardson RT. Hybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation. J Neural Eng 2020; 17:056046. [PMID: 33036009 DOI: 10.1088/1741-2552/abbff0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. APPROACH Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Response thresholds, spread of activation and entrainment data were obtained from multi-unit recordings from the auditory midbrain. MAIN RESULTS Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p < 0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p < 0.05). SIGNIFICANCE By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.
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Coventry BS, Sick JT, Talavage TM, Stantz KM, Bartlett EL. Short-wave Infrared Neural Stimulation Drives Graded Sciatic Nerve Activation Across A Continuum of Wavelengths. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:3581-3585. [PMID: 33018777 DOI: 10.1109/embc44109.2020.9176177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Infrared neural stimulation (INS) is an optical stimulation technique which uses coherent light to stimulate nerves and neurons and which shows increased spatial selectivity compared to electrical stimulation. This could improve deep brain, high channel count, or vagus nerve stimulation. In this study, we seek to understand the wavelength dependence of INS in the near-infrared optical window. Rat sciatic nerves were excised ex vivo and stimulated with wavelengths between 700 and 900 nm. Recorded compound nerve action potentials (CNAPs) showed that stimulation was maximized in the 700 nm window despite comparable laser power levels across wavelengths. Computational models demonstrated that wavelength-based activation dependencies were not a result of passive optical properties. This data demonstrates that INS is both wavelength and power level dependent, which inform stimulation systems to actively target neural microcircuits in humans.
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13
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Richardson RT, Ibbotson MR, Thompson AC, Wise AK, Fallon JB. Optical stimulation of neural tissue. Healthc Technol Lett 2020; 7:58-65. [PMID: 32754339 PMCID: PMC7353819 DOI: 10.1049/htl.2019.0114] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/08/2020] [Accepted: 05/15/2020] [Indexed: 12/23/2022] Open
Abstract
Electrical stimulation has been used for decades in devices such as pacemakers, cochlear implants and more recently for deep brain and retinal stimulation and electroceutical treatment of disease. However, current spread from the electrodes limits the precision of neural activation, leading to a low quality therapeutic outcome or undesired side-effects. Alternative methods of neural stimulation such as optical stimulation offer the potential to deliver higher spatial resolution of neural activation. Direct optical stimulation is possible with infrared light, while visible light can be used to activate neurons if the neural tissue is genetically modified with a light sensitive ion channel. Experimentally, both methods have resulted in highly precise stimulation with little spread of activation at least in the cochlea, each with advantages and disadvantages. Infrared neural stimulation does not require modification of the neural tissue, but has very high power requirements. Optogenetics can achieve precision of activation with lower power, but only in conjunction with targeted insertion of a light sensitive ion channel into the nervous system via gene therapy. This review will examine the advantages and limitations of optical stimulation of neural tissue, using the cochlea as an exemplary model and recent developments for retinal and deep brain stimulation.
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Affiliation(s)
- Rachael Theresa Richardson
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - Michael R Ibbotson
- National Vision Research Institute, Australian College of Optometry, and Department of Optometry and Vision Science, University of Melbourne, Melbourne, Australia
| | | | - Andrew K Wise
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - James B Fallon
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
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14
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Dieter A, Keppeler D, Moser T. Towards the optical cochlear implant: optogenetic approaches for hearing restoration. EMBO Mol Med 2020; 12:e11618. [PMID: 32227585 PMCID: PMC7136966 DOI: 10.15252/emmm.201911618] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/08/2020] [Accepted: 01/28/2020] [Indexed: 12/30/2022] Open
Abstract
Cochlear implants (CIs) are considered the most successful neuroprosthesis as they enable speech comprehension in the majority of half a million CI users suffering from sensorineural hearing loss. By electrically stimulating the auditory nerve, CIs constitute an interface re-connecting the brain and the auditory scene, providing the patient with information regarding the latter. However, since electric current is hard to focus in conductive environments such as the cochlea, the precision of electrical sound encoding-and thus quality of artificial hearing-is limited. Recently, optogenetic stimulation of the cochlea has been suggested as an alternative approach for hearing restoration. Cochlear optogenetics promises increased spectral selectivity of artificial sound encoding, hence improved hearing, as light can conveniently be confined in space to activate the auditory nerve within smaller tonotopic ranges. In this review, we discuss the latest experimental and technological developments of cochlear optogenetics and outline the remaining challenges on the way to clinical translation.
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Affiliation(s)
- Alexander Dieter
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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15
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Dombrowski T, Rankovic V, Moser T. Toward the Optical Cochlear Implant. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033225. [PMID: 30323016 DOI: 10.1101/cshperspect.a033225] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
When hearing fails, cochlear implants (CIs) provide open speech perception to most of the currently half a million CI users. CIs bypass the defective sensory organ and stimulate the auditory nerve electrically. The major bottleneck of current CIs is the poor coding of spectral information, which results from wide current spread from each electrode contact. As light can be more conveniently confined, optical stimulation of the auditory nerve presents a promising perspective for a fundamental advance of CIs. Moreover, given the improved frequency resolution of optical excitation and its versatility for arbitrary stimulation patterns the approach also bears potential for auditory research. Here, we review the current state of the art focusing on the emerging concept of optogenetic stimulation of the auditory pathway. Developing optogenetic stimulation for auditory research and future CIs requires efforts toward viral gene transfer to the neurons, design and characterization of appropriate optogenetic actuators, as well as engineering of multichannel optical implants.
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Affiliation(s)
- Tobias Dombrowski
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center, 37075 Göttingen, Germany.,Department of Otorhinolaryngology, Head and Neck Surgery, Ruhr University Bochum, St. Elisabeth Hospital, 44787 Bochum, Germany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center, 37075 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Group, German Primate Center, 37077 Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center, 37075 Göttingen, Germany.,Auditory Neuroscience and Optogenetics Group, German Primate Center, 37077 Göttingen, Germany.,Auditory Neuroscience Group, Max-Planck-Institute for Experimental Medicine, 37075 Göttingen, Germany
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16
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Selective stimulation of bullfrog sciatic nerve by gold nanorod assisted combined electrical and near-infrared stimulation. Biomed Microdevices 2019; 21:76. [DOI: 10.1007/s10544-019-0428-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Xia Q, Nyberg T. Inhibition of cortical neural networks using infrared laser. JOURNAL OF BIOPHOTONICS 2019; 12:e201800403. [PMID: 30859700 DOI: 10.1002/jbio.201800403] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/04/2019] [Accepted: 03/08/2019] [Indexed: 05/18/2023]
Abstract
The aim of the present study is to optimize parameters for inhibiting neuronal activity safely and investigating thermal inhibition of rat cortex neural networks in vitro by continuous infrared (IR) laser. Rat cortex neurons were cultured on multi-electrode arrays until neural networks were formed with spontaneous neural activity. Neurons were then irradiated to inhibit the activity of the networks using different powers of 1550 nm IR laser light. A finite element heating model, calibrated by the open glass pipette method, was used to calculate temperature increases at different laser irradiation intensities. A damage signal ratio (DSR) was evaluated to avoid excessive heating that may damage cells. The DSR predicted that cortex neurons should be safe at temperatures up to 49.6°C for 30 seconds, but experiments suggested that cortex neurons should not be exposed to temperatures over 46°C for 30 seconds. Neural response experiments showed that the inhibition of neural activity is temperature dependent. The normal neural activity could be inhibited safely with an inhibition degree up to 80% and induced epileptiform activity could be suppressed. These results show that continuous IR laser radiations provide a possible way to safely inhibit the neural network activity.
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Affiliation(s)
- Qingling Xia
- Key Laboratory of Biorheological Science and Technology of Ministry of Education, Chongqing University, Chongqing, China
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Tobias Nyberg
- Division of Neuronic Engineering, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
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18
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Near physiological spectral selectivity of cochlear optogenetics. Nat Commun 2019; 10:1962. [PMID: 31036812 PMCID: PMC6488702 DOI: 10.1038/s41467-019-09980-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/28/2019] [Indexed: 01/06/2023] Open
Abstract
Cochlear implants (CIs) electrically stimulate spiral ganglion neurons (SGNs) and partially restore hearing to half a million CI users. However, wide current spread from intracochlear electrodes limits spatial selectivity (i.e. spectral resolution) of electrical CIs. Optogenetic stimulation might become an alternative, since light can be confined in space, promising artificial sound encoding with increased spectral selectivity. Here we compare spectral selectivity of optogenetic, electric, and acoustic stimulation by multi-channel recordings in the inferior colliculus (IC) of gerbils. When projecting light onto tonotopically distinct SGNs, we observe corresponding tonotopically ordered IC activity. An activity-based comparison reveals that spectral selectivity of optogenetic stimulation is indistinguishable from acoustic stimulation for modest intensities. Moreover, optogenetic stimulation outperforms bipolar electric stimulation at medium and high intensities and monopolar electric stimulation at all intensities. In conclusion, we demonstrate better spectral selectivity of optogenetic over electric SGN stimulation, suggesting the potential for improved hearing restoration by optical CIs. Cochlear implant spectral resolution is limited by current spread from each stimulation electrode. Here the authors compare optogenetic, electric and acoustic stimulation in gerbils and demonstrate improved spectral resolution of optogenetic over conventional electric stimulation.
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19
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Jiang J, Hu W, Xie D, Yang J, He J, Gao Y, Wan Q. 2D electric-double-layer phototransistor for photoelectronic and spatiotemporal hybrid neuromorphic integration. NANOSCALE 2019; 11:1360-1369. [PMID: 30604810 DOI: 10.1039/c8nr07133k] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The hardware implementation of neuromorphic computing has attracted growing interest as a promising candidate for confronting the bottleneck of traditional von Neumann computers. However, most previous reports are focusd on emulating the synaptic behaviors by a mono-mode using an electric-driving or photo-driving approach, resulting in a big challenge to synchronously handle the natural photoelectric information. Herein, we report a multifunctional photoelectronic hybrid-integrated synaptic device based on the electric-double-layer (EDL) MoS2 phototransistor. Interestingly, the electric MoS2 synapse exhibits a potentiation filtering effect, while the photonic counterpart can implement both potentiation and depression filtering effects. Most importantly, for the first time, photoelectronic and spatio-temporal four-dimensional (4D) hybrid integration was successfully demonstrated by the synergic interplay between photonic and electric stimuli within a single MoS2 synapse. An energy band model is proposed to further understand such a photoelectronic and spatio-temporal 4D hybrid coupling mechanism. These results might provide an alternative solution for the size-scaling and intellectualization campaign of the post-Moore era, and for more sophisticated photoelectronic hybrid computing in the emerging neuromorphic nanoelectronics.
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Affiliation(s)
- Jie Jiang
- Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, China.
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20
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He HK, Yang R, Zhou W, Huang HM, Xiong J, Gan L, Zhai TY, Guo X. Photonic Potentiation and Electric Habituation in Ultrathin Memristive Synapses Based on Monolayer MoS 2. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1800079. [PMID: 29504245 DOI: 10.1002/smll.201800079] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Indexed: 05/22/2023]
Abstract
Monolayer of 2D transition metal dichalcogenides, with a thickness of less than 1 nm, paves a feasible path to the development of ultrathin memristive synapses, to fulfill the requirements for constructing large-scale high density 3D stacking neuromorphic chips. Herein, memristive devices based on monolayer n-MoS2 on p-Si substrate with a large self-rectification ratio, exhibiting photonic potentiation and electric habituation, are successfully fabricated. Versatile synaptic neuromorphic functions, such as potentiation/habituation, short-term/long-term plasticity, and paired-pulse facilitation, are successfully mimicked based on the inherent persistent photoconductivity performance and the volatile resistive switching behavior. These findings demonstrate the potential applications of ultrathin transition metal dichalcogenides for memristive synapses. These memristive synapses with the combination of photonic and electric neuromorphic functions have prospective in the applications of synthetic retinas and optoelectronic interfaces for integrated photonic circuits based on mixed-mode electro-optical operation.
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Affiliation(s)
- Hui-Kai He
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Rui Yang
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Wen Zhou
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - He-Ming Huang
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Jue Xiong
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Lin Gan
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Tian-You Zhai
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Xin Guo
- School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
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21
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Tan X, Jahan I, Xu Y, Stock S, Kwan CC, Soriano C, Xiao X, García-Añoveros J, Fritzsch B, Richter CP. Auditory Neural Activity in Congenitally Deaf Mice Induced by Infrared Neural Stimulation. Sci Rep 2018; 8:388. [PMID: 29321651 PMCID: PMC5762820 DOI: 10.1038/s41598-017-18814-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/11/2017] [Indexed: 11/16/2022] Open
Abstract
To determine whether responses during infrared neural stimulation (INS) result from the direct interaction with spiral ganglion neurons (SGNs), we tested three genetically modified deaf mouse models: Atoh1-cre; Atoh1f/f (Atoh1 conditional knockout, CKO), Atoh1-cre; Atoh1f/kiNeurog1 (Neurog1 knockin, KI), and the Vglut3 knockout (Vglut3−/−) mice. All animals were exposed to tone bursts and clicks up to 107 dB (re 20 µPa) and to INS, delivered with a 200 µm optical fiber. The wavelength (λ) was 1860 nm, the radiant energy (Q) 0-800 µJ/pulse, and the pulse width (PW) 100–500 µs. No auditory responses to acoustic stimuli could be evoked in any of these animals. INS could not evoke auditory brainstem responses in Atoh1 CKO mice but could in Neurog1 KI and Vglut3−/− mice. X-ray micro-computed tomography of the cochleae showed that responses correlated with the presence of SGNs and hair cells. Results in Neurog1 KI mice do not support a mechanical stimulation through the vibration of the basilar membrane, but cannot rule out the direct activation of the inner hair cells. Results in Vglut3−/− mice, which have no synaptic transmission between inner hair cells and SGNs, suggested that hair cells are not required.
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Affiliation(s)
- Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Israt Jahan
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Stuart Stock
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL, 60611, USA
| | - Changyow Claire Kwan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Carmen Soriano
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Jaime García-Añoveros
- Departments of Anesthesiology, Physiology, and Neurology, Northwestern University Institute for Neuroscience, Ward 10-070, 303 East Chicago Avenue, Chicago, IL, 60611, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA. .,Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA. .,The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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22
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Bazard P, Frisina RD, Walton JP, Bhethanabotla VR. Nanoparticle-based Plasmonic Transduction for Modulation of Electrically Excitable Cells. Sci Rep 2017; 7:7803. [PMID: 28798342 PMCID: PMC5552804 DOI: 10.1038/s41598-017-08141-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 07/05/2017] [Indexed: 11/11/2022] Open
Abstract
There is a compelling need for the development of new sensory and neural prosthetic devices which are capable of more precise point stimulation. Current prosthetic devices suffer from the limitation of low spatial resolution due to the non-specific stimulation characteristics of electrical stimulation, i.e., the spread of electric fields generated. We present a visible light stimulation method for modulating the firing patterns of electrically-excitable cells using surface plasmon resonance phenomena. In in-vitro studies using gold (Au) nanoparticle-coated nanoelectrodes, we show that this method (substrate coated with nanoparticles) has the potential for incorporating this new technology into neural stimulation prosthetics, such as cochlear implants for the deaf, with very high spatial resolution. Au nanoparticles (NPs) were coated on micropipettes using aminosilane linkers; and these micropipettes were used for stimulating and inhibiting the action potential firing patterns of SH-SY5Y human neuroblastoma cells and neonatal cardiomyocytes. Our findings pave the way for development of biomedical implants and neural testing devices using nanoelectrodes capable of temporally and spatially precise excitation and inhibition of electrically-excitable cellular activity.
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Affiliation(s)
- Parveen Bazard
- Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida, Tampa, FL-33620, USA.,Global Center of Hearing and Speech Research, University of South Florida, Tampa, FL-33612, USA
| | - Robert D Frisina
- Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida, Tampa, FL-33620, USA.,Department of Communication Sciences and Disorders, College of Behavioral & Community Sciences, University of South Florida, Tampa, FL-33620, USA.,Global Center of Hearing and Speech Research, University of South Florida, Tampa, FL-33612, USA
| | - Joseph P Walton
- Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida, Tampa, FL-33620, USA.,Department of Communication Sciences and Disorders, College of Behavioral & Community Sciences, University of South Florida, Tampa, FL-33620, USA.,Global Center of Hearing and Speech Research, University of South Florida, Tampa, FL-33612, USA
| | - Venkat R Bhethanabotla
- Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida, Tampa, FL-33620, USA. .,Global Center of Hearing and Speech Research, University of South Florida, Tampa, FL-33612, USA.
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23
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Richardson RT, Thompson AC, Wise AK, Needham K. Challenges for the application of optical stimulation in the cochlea for the study and treatment of hearing loss. Expert Opin Biol Ther 2016; 17:213-223. [PMID: 27960585 DOI: 10.1080/14712598.2017.1271870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Electrical stimulation has long been the most effective strategy for evoking neural activity from bionic devices and has been used with great success in the cochlear implant to allow deaf people to hear speech and sound. Despite its success, the spread of electrical current stimulates a broad region of neural tissue meaning that contemporary devices have limited precision. Optical stimulation as an alternative has attracted much recent interest for its capacity to provide highly focused stimuli, and therefore, potentially improved sensory perception. Given its specificity of activation, optical stimulation may also provide a useful tool in the study of fundamental neuroanatomy and neurophysiological processes. Areas covered: This review examines the advances in optical stimulation - infrared, nanoparticle-enhanced, and optogenetic-based - and its application in the inner ear for the restoration of auditory function following hearing loss. Expert opinion: Initial outcomes suggest that optogenetic-based approaches hold the greatest potential and viability amongst optical techniques for application in the cochlea. The future success of this approach will be governed by advances in the targeted delivery of opsins to auditory neurons, improvements in channel kinetics, development of optical arrays, and innovation of opsins that activate within the optimal near-infrared therapeutic window.
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Affiliation(s)
- Rachael T Richardson
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | | | - Andrew K Wise
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | - Karina Needham
- d Department of Surgery (Otolaryngology) , University of Melbourne, Royal Victorian Eye & Ear Hospital , East Melbourne , Australia
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24
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Effect of shorter pulse duration in cochlear neural activation with an 810-nm near-infrared laser. Lasers Med Sci 2016; 32:389-396. [PMID: 27995385 DOI: 10.1007/s10103-016-2129-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
Optical neural stimulation in the cochlea has been presented as an alternative technique to the electrical stimulation due to its potential in spatially selectivity enhancement. So far, few studies have selected the near-infrared (NIR) laser in cochlear neural stimulation and limited optical parameter space has been examined. This paper focused on investigating the optical parameter effect on NIR stimulation of auditory neurons, especially under shorter pulse durations. The spiral ganglion neurons in the cochlea of deafened guinea pigs were stimulated with a pulsed 810-nm NIR laser in vivo. The laser radiation was delivered by an optical fiber and irradiated towards the modiolus. Optically evoked auditory brainstem responses (OABRs) with various optical parameters were recorded and investigated. The OABRs could be elicited with the cochlear deafened animals by using the 810-nm laser in a wide pulse duration ranged from 20 to 1000 μs. Results showed that the OABR intensity increased along with the increasing laser radiant exposure of limited range at each specific pulse duration. In addition, for the pulse durations from 20 to 300 μs, the OABR intensity increased monotonically along with the pulse duration broadening. While for pulse durations above 300 μs, the OABR intensity basically kept stable with the increasing pulse duration. The 810-nm NIR laser could be an effective stimulus in evoking the cochlear neuron response. Our experimental data provided evidence to optimize the pulse duration range, and the results suggested that the pulse durations from 20 to 300 μs could be the optimized range in cochlear neural activation with the 810-nm-wavelength laser.
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25
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Wang J, Lu J, Tian L. Effect of Fiberoptic Collimation Technique on 808 nm Wavelength Laser Stimulation of Cochlear Neurons. Photomed Laser Surg 2016; 34:252-7. [PMID: 26977557 DOI: 10.1089/pho.2015.4065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVE The purpose of this study was to evaluate the effects of fiberoptic collimation technique on auditory neural stimulation in the cochlea with 808 nm wavelength lasers. BACKGROUND DATA Recently, the pulsed near-infrared lasers in the 800-1000 nm wavelength range have been investigated as an emerging technique to trigger auditory neural response in the cochlea. A laser beam divergence in the optical stimulation pathway exists, which may affect stimulation efficiency and spatial selectivity. METHODS The fiberoptic collimation technique was proposed for cochlear neuron stimulation, and the C-lens element was designed as the collimation structure. The spiral ganglion cells in deafened guinea pigs' cochlea were irradiated with collimated and uncollimated near-infrared lasers. Optically evoked auditory brainstem response (OABR) under the two laser output modes were recorded. RESULTS Laser with the collimation technique evoked an average 58% higher OABR amplitude than the uncollimated laser output. In addition, the collimated laser setup consumed on average 35.2% of laser energy compared with the uncollimated laser when evoking the same OABR amplitude. CONCLUSIONS The fiberoptic collimation technique improved stimulation efficiency and reduced stimulating energy consumption in near-infrared neural stimulation in cochlea. The positive effects of laser collimation technique could benefit further research in optically based cochlear implants.
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Affiliation(s)
- Jingxuan Wang
- School of Information Science and Engineering, Shandong University , Jinan 250100, Shandong, China
| | - Jianren Lu
- School of Information Science and Engineering, Shandong University , Jinan 250100, Shandong, China
| | - Lan Tian
- School of Information Science and Engineering, Shandong University , Jinan 250100, Shandong, China
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26
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Abstract
Cochlear implantation and cochlear implants (CIs) have a long history filled with innovations that have resulted in the high-performing device's currently available. Several promising technologies have been reviewed in this article, which hold the promise to drive performance even higher. Remote CI programming, totally implanted devices, improved neural health and survival through targeted drug therapy and delivery, intraneural electrode placement, electroacoustical stimulation and hybrid CIs, and methods to enhance the neural-prosthesis interface are evolving areas of innovation reviewed in this article.
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Affiliation(s)
- Joseph P Roche
- Department of Otolaryngology - Head and Neck Surgery, The University of Iowa Carver College of Medicine, 21151 Pomerantz Family Pavilion, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
| | - Marlan R Hansen
- Department of Otolaryngology - Head and Neck Surgery, The University of Iowa Carver College of Medicine, 21151 Pomerantz Family Pavilion, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA; Department of Neurosurgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA.
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27
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Wang J, Lu J, Li C, Xu L, Li X, Tian L. Pulsed 980 nm short wavelength infrared neural stimulation in cochlea and laser parameter effects on auditory response characteristics. Biomed Eng Online 2015; 14:89. [PMID: 26445884 PMCID: PMC4597400 DOI: 10.1186/s12938-015-0084-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/22/2015] [Indexed: 11/10/2022] Open
Abstract
Background Auditory neural stimulation with pulsed infrared radiation has been proposed as an alternative method to activate the auditory nerves in vivo. Infrared wavelengths from 1800–2150 nm with high water absorption were mainly selected in previous studies. However, few researchers have used the short-wavelength infrared (SWIR) for auditory nerve stimulation and limited pulse parameters variability has been investigated so far. Methods In this paper, we pioneered to use the 980 nm SWIR laser with adjustable pulse parameter as a stimulus to act on the deafened guinea pigs’ cochlea in vivo. Pulsed laser light was guided through the cochlear round window to irradiate the spiral ganglion cells via a 105 μm optical fiber, and then the laser pulse parameters variability and its influence to auditory response characteristics were studied. Results The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus. And the evoked OABR amplitude had a positive correlation, while the OABR latency period showed a negative correlation, with the laser pulse energy increase. However, when holding the laser peak power constant, the pulse width variability ranged from 100 to 800 μs showed little influence on the evoked OABR amplitude and its latency period. Conclusions Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo. The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100–800 μs range.
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Affiliation(s)
- Jingxuan Wang
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Jianren Lu
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Chen Li
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Lei Xu
- Shandong Artificial Auditory Engineering Centre, 250022, Jinan, Shandong, China.
| | - Xiaofei Li
- Shandong Artificial Auditory Engineering Centre, 250022, Jinan, Shandong, China.
| | - Lan Tian
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
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Xie B, Dai C, Li H. Attenuated infrared neuron stimulation response in cochlea of deaf animals may associate with the degeneration of spiral ganglion neurons. BIOMEDICAL OPTICS EXPRESS 2015; 6:1990-2005. [PMID: 26114024 PMCID: PMC4473739 DOI: 10.1364/boe.6.001990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 05/13/2023]
Abstract
HYPOTHESIS We hypothesize that degenerated spiral ganglion neurons (SGNs) in guinea pigs reduces auditory brainstem responses evoked by pulsed infrared stimulation. BACKGROUND Pulsed infrared laser excitation can directly evoke physiological responses in neuronal and other excitable cells in vivo and in vitro. Laser pulses could benefit patients with cochlear implants to stimulate the auditory system. METHODS Pulsed infrared lasers were used to study evoked optical auditory brainstem responses (oABRs) in normal hearing and deafened animals. Aslo, the morphology and anatomy of SGNs in normal hearing and deafened guinea pigs were compared. RESULTS By recording oABRs evoked by varying infrared laser pulse durations, it is suggested that degeneration of SGNs in deafened guinea pigs was associated with an elevated oABR threshold and with lower amplitudes. Moreover, oABR threshold decreased while amplitudes increased in both normal hearing and deafened animals as the pulse duration prolonged. Electron microscopy revealed that SGNs in deafened guinea pigs had swollen and vacuolar mitochondria, as well as demyelinated soma and axons. CONCLUSION Infrared laser pulses can stimulate SGNs to evoke oABRs in guinea pigs. Deafened guinea pigs have elevated thresholds and smaller amplitude responses, likely a result of degenerated SGNs. Short pulse durations are more suitable to evoke responses in both normal hearing and deafened animals.
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Affiliation(s)
- Bingbin Xie
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China
| | - Chunfu Dai
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
| | - Huawei Li
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
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Wang J, Xia M, Lu J, Li C, Tian X, Tian L. Performance analysis of the beam shaping method on optical auditory neural stimulation in vivo. Lasers Med Sci 2015; 30:1533-40. [PMID: 25947304 DOI: 10.1007/s10103-015-1763-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/28/2015] [Indexed: 11/28/2022]
Abstract
Previous research has shown that infrared neural stimulation (INS) could be an alternative approach to evoke auditory neural activities. The laser beam property of the fiber output is a considerable aspect of INS, and the corresponding effects on auditory responses in vivo deserve further discussions. The paper presents a beam-shaped infrared laser stimulation method of auditory nerves. Pulsed 980-nm fiber-coupled laser systems were used as the radiant sources. The gradient reflective index (GRIN) lens was added at the port of the optical fiber as a beam shaping structure. The laser spot sizes and properties between the beam-shaped output and the bare fiber output were preliminarily analyzed by a laser beam profiler. And further experiments in vivo with four deafened adult guinea pigs were conducted. Optically evoked auditory brainstem responses (OABRs) of the animal samples were recorded and compared under the two output configurations. The results show a decrease of the beam divergence compared to a bare output fiber, and the INS with a beam shaping design evokes above 13 % increase on OABR amplitudes than the bare fiber output, especially when enlarging the distance between the optical fiber and the nerve tissue. The beam shaping design can enhance the effect of INS for evoking auditory nerves, and it could be an optimized design in the future implementation of optical cochlear implants.
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Affiliation(s)
- Jingxuan Wang
- School of Information Science and Engineering, Shandong University, Jinan, Shandong, 250100, China
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30
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Thompson AC, Stoddart PR, Jansen ED. Optical Stimulation of Neurons. ACTA ACUST UNITED AC 2015; 3:162-177. [PMID: 26322269 PMCID: PMC4541079 DOI: 10.2174/2211555203666141117220611] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/26/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023]
Abstract
Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central and peripheral nervous systems. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury and the subsequent inflammatory response. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device, while also avoiding the electrical artefacts that complicate recordings of electrically stimulated neuronal activity. This review explores the current status of optical stimulation techniques, including optogenetic methods, photoactive molecule approaches and infrared neural stimulation, together with emerging techniques such as hybrid optical-electrical stimulation, nanoparticle enhanced stimulation and optoelectric methods. Infrared neural stimulation is particularly emphasised, due to the potential for direct activation of neural tissue by infrared light, as opposed to techniques that rely on the introduction of exogenous light responsive materials. However, infrared neural stimulation remains imperfectly understood, and techniques for accurately delivering light are still under development. While the various techniques reviewed here confirm the overall feasibility of optical stimulation, a number of challenges remain to be overcome before they can deliver their full potential.
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Affiliation(s)
- Alexander C Thompson
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Moser T. Optogenetic stimulation of the auditory pathway for research and future prosthetics. Curr Opin Neurobiol 2015; 34:29-36. [PMID: 25637880 DOI: 10.1016/j.conb.2015.01.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/09/2015] [Indexed: 01/13/2023]
Abstract
Sound is encoded by spiral ganglion neurons (SGNs) in the hearing organ, the cochlea, with great temporal, spectral and intensity resolution. When hearing fails, electric stimulation by implanted prostheses can partially restore hearing. Optical stimulation promises a fundamental advance of hearing restoration over electric prostheses since light can be conveniently focused and hence might dramatically improve frequency resolution of sound encoding. Combining optogenetic manipulation of neurons with innovative optical stimulation technology promises versatile spatiotemporal stimulation patterns in the auditory system. Therefore, using optical stimulation of SGNs also has great potential for auditory research. Here, I review recent progress in optogenetic stimulation of the auditory system and its potential for future application in research and hearing restoration.
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Affiliation(s)
- Tobias Moser
- Institute for Auditory Neuroscience and Collaborative Research Center 889, University Medical Center Göttingen, Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Göttingen, Göttingen, Germany.
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Jeschke M, Moser T. Considering optogenetic stimulation for cochlear implants. Hear Res 2015; 322:224-34. [PMID: 25601298 DOI: 10.1016/j.heares.2015.01.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/09/2014] [Accepted: 01/08/2015] [Indexed: 02/04/2023]
Abstract
Electrical cochlear implants are by far the most successful neuroprostheses and have been implanted in over 300,000 people worldwide. Cochlear implants enable open speech comprehension in most patients but are limited in providing music appreciation and speech understanding in noisy environments. This is generally considered to be due to low frequency resolution as a consequence of wide current spread from stimulation contacts. Accordingly, the number of independently usable stimulation channels is limited to less than a dozen. As light can be conveniently focused, optical stimulation might provide an alternative approach to cochlear implants with increased number of independent stimulation channels. Here, we focus on summarizing recent work on optogenetic stimulation as one way to develop optical cochlear implants. We conclude that proof of principle has been presented for optogenetic stimulation of the cochlea and central auditory neurons in rodents as well as for the technical realization of flexible μLED-based multichannel cochlear implants. Still, much remains to be done in order to advance the technique for auditory research and even more for eventual clinical translation. This article is part of a Special Issue entitled <Lasker Award>.
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Affiliation(s)
- Marcus Jeschke
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany.
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany; Bernstein Focus for Neurotechnology, University of Göttingen, Goettingen, Germany; Collaborative Research Center 889, University of Goettingen Medical Center, Goettingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Goettingen, Goettingen, Germany.
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Mou ZX, Hou WS, Zheng XL, Yao JP, Shang GB, Yin ZQ. Pulsed near infrared laser stimulates the rat visual cortex in vivo. Biocybern Biomed Eng 2015. [DOI: 10.1016/j.bbe.2015.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Eom K, Kim J, Choi JM, Kang T, Chang JW, Byun KM, Jun SB, Kim SJ. Enhanced infrared neural stimulation using localized surface plasmon resonance of gold nanorods. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:3853-7. [PMID: 24975778 DOI: 10.1002/smll.201400599] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/06/2014] [Indexed: 05/23/2023]
Abstract
An advanced optical activation of neural tissues is demonstrated using pulsed infrared light and plasmonic gold nanorods. Photothermal effect localized in plasma membrane triggers action potentials of in vivo neural tissues. Compared with conventional infrared stimulation, the suggested method can increase a neural responsivity and lower a threshold stimulation level significantly, thereby reducing a requisite radiant exposure and the concern of tissue damage.
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Affiliation(s)
- Kyungsik Eom
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 151-744, Republic of Korea
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Abstract
The success of conventional hearing aids and electrical auditory prostheses for hearing impaired patients is still limited in noisy environments and for sounds more complex than speech (e. g. music). This is partially due to the difficulty of frequency-specific activation of the auditory system using these devices. Stimulation of the auditory system using light pulses represents an alternative to mechanical and electrical stimulation. Light is a source of energy that can be very exactly focused and applied with little scattering, thus offering perspectives for optimal activation of the auditory system. Studies investigating light stimulation of sectors along the auditory pathway have shown stimulation of the auditory system is possible using light pulses. However, further studies and developments are needed before a new generation of light stimulation-based auditory prostheses can be made available for clinical application.
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Hernandez VH, Gehrt A, Jing Z, Hoch G, Jeschke M, Strenzke N, Moser T. Optogenetic stimulation of the auditory nerve. J Vis Exp 2014:e52069. [PMID: 25350571 DOI: 10.3791/52069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted deaf subjects(1-) (6). Nonetheless, sound coding with current CIs has poor frequency and intensity resolution due to broad current spread from each electrode contact activating a large number of SGNs along the tonotopic axis of the cochlea(7-) (9). Optical stimulation is proposed as an alternative to electrical stimulation that promises spatially more confined activation of SGNs and, hence, higher frequency resolution of coding. In recent years, direct infrared illumination of the cochlea has been used to evoke responses in the auditory nerve(10). Nevertheless it requires higher energies than electrical stimulation(10,11) and uncertainty remains as to the underlying mechanism(12). Here we describe a method based on optogenetics to stimulate SGNs with low intensity blue light, using transgenic mice with neuronal expression of channelrhodopsin 2 (ChR2)(13) or virus-mediated expression of the ChR2-variant CatCh(14). We used micro-light emitting diodes (µLEDs) and fiber-coupled lasers to stimulate ChR2-expressing SGNs through a small artificial opening (cochleostomy) or the round window. We assayed the responses by scalp recordings of light-evoked potentials (optogenetic auditory brainstem response: oABR) or by microelectrode recordings from the auditory pathway and compared them with acoustic and electrical stimulation.
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Affiliation(s)
- Victor H Hernandez
- InnerEarLab, Department of Otolaryngology, University Medical Center Goettingen; Bernstein Focus for Neurotechnology, University of Goettingen; Department of Chemical, Electronic, and Biomedical Engineering, University of Guanajuato
| | - Anna Gehrt
- InnerEarLab, Department of Otolaryngology, University Medical Center Goettingen; Auditory Systems Physiology Group, Department of Otolaryngology, University Medical Center Goettingen
| | - Zhizi Jing
- Auditory Systems Physiology Group, Department of Otolaryngology, University Medical Center Goettingen
| | - Gerhard Hoch
- InnerEarLab, Department of Otolaryngology, University Medical Center Goettingen
| | - Marcus Jeschke
- InnerEarLab, Department of Otolaryngology, University Medical Center Goettingen
| | - Nicola Strenzke
- Auditory Systems Physiology Group, Department of Otolaryngology, University Medical Center Goettingen
| | - Tobias Moser
- InnerEarLab, Department of Otolaryngology, University Medical Center Goettingen; Bernstein Focus for Neurotechnology, University of Goettingen; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Goettingen;
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Chernov M, Roe AW. Infrared neural stimulation: a new stimulation tool for central nervous system applications. NEUROPHOTONICS 2014; 1:011011. [PMID: 26157967 PMCID: PMC4478761 DOI: 10.1117/1.nph.1.1.011011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 05/08/2023]
Abstract
The traditional approach to modulating brain function (in both clinical and basic science applications) is to tap into the neural circuitry using electrical currents applied via implanted electrodes. However, it suffers from a number of problems, including the risk of tissue trauma, poor spatial specificity, and the inability to selectively stimulate neuronal subtypes. About a decade ago, optical alternatives to electrical stimulation started to emerge in order to address the shortcomings of electrical stimulation. We describe the use of one optical stimulation technique, infrared neural stimulation (INS), during which short (of the order of a millisecond) pulses of infrared light are delivered to the neural tissue. Very focal stimulation is achieved via a thermal mechanism and stimulation location can be quickly adjusted by redirecting the light. After describing some of the work done in the peripheral nervous system, we focus on the use of INS in the central nervous system to investigate functional connectivity in the visual and somatosensory areas, target specific functional domains, and influence behavior of an awake nonhuman primate. We conclude with a positive outlook for INS as a tool for safe and precise targeted brain stimulation.
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Affiliation(s)
- Mykyta Chernov
- Vanderbilt University, Department of Psychology, 111 21st Avenue South, Nashville, Tennessee 37240, United States
| | - Anna Wang Roe
- Vanderbilt University, Department of Psychology, 111 21st Avenue South, Nashville, Tennessee 37240, United States
- Address all correspondence to: Anna Wang Roe, E-mail:
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Lumbreras V, Bas E, Gupta C, Rajguru SM. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling. J Neurophysiol 2014; 112:1246-55. [PMID: 24920028 DOI: 10.1152/jn.00253.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses.
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Affiliation(s)
- Vicente Lumbreras
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and
| | - Esperanza Bas
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Chhavi Gupta
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, Florida; and Department of Otolaryngology, University of Miami, Miami, Florida
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Abstract
Methods to control neural activity by light have been introduced to the field of neuroscience. During the last decade, several techniques have been established, including optogenetics, thermogenetics, and infrared neural stimulation. The techniques allow investigators to turn-on or turn-off neural activity. This review is an attempt to show the importance of the techniques for the auditory field and provide insight in the similarities, overlap, and differences of the techniques. Discussing the mechanism of each of the techniques will shed light on the abilities and challenges for each of the techniques. The field has been grown tremendously and a review cannot be complete. However, efforts are made to summarize the important points and to refer the reader to excellent papers and reviews to specific topics. This article is part of a Special Issue entitled .
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Affiliation(s)
- Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA; Dept. of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA; The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA.
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA
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Zeng FG, Tang Q, Lu T. Abnormal pitch perception produced by cochlear implant stimulation. PLoS One 2014; 9:e88662. [PMID: 24551131 PMCID: PMC3923805 DOI: 10.1371/journal.pone.0088662] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/14/2014] [Indexed: 11/19/2022] Open
Abstract
Contemporary cochlear implants with multiple electrode stimulation can produce good speech perception but poor music perception. Hindered by the lack of a gold standard to quantify electric pitch, relatively little is known about the nature and extent of the electric pitch abnormalities and their impact on cochlear implant performance. Here we overcame this obstacle by comparing acoustic and electric pitch perception in 3 unilateral cochlear-implant subjects who had functionally usable acoustic hearing throughout the audiometric frequency range in the non-implant ear. First, to establish a baseline, we measured and found slightly impaired pure tone frequency discrimination and nearly perfect melody recognition in all 3 subjects' acoustic ear. Second, using pure tones in the acoustic ear to match electric pitch induced by an intra-cochlear electrode, we found that the frequency-electrode function was not only 1-2 octaves lower, but also 2 times more compressed in frequency range than the normal cochlear frequency-place function. Third, we derived frequency difference limens in electric pitch and found that the equivalent electric frequency discrimination was 24 times worse than normal-hearing controls. These 3 abnormalities are likely a result of a combination of broad electric field, distant intra-cochlear electrode placement, and non-uniform spiral ganglion cell distribution and survival, all of which are inherent to the electrode-nerve interface in contemporary cochlear implants. Previous studies emphasized on the "mean" shape of the frequency-electrode function, but the present study indicates that the large "variance" of this function, reflecting poor electric pitch discriminability, is the main factor limiting contemporary cochlear implant performance.
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Affiliation(s)
- Fan-Gang Zeng
- Center for Hearing Research, Departments of Anatomy and Neurobiology, Biomedical Engineering, Cognitive Sciences, and Otolaryngology – Head and Neck Surgery, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| | - Qing Tang
- Center for Hearing Research, Departments of Anatomy and Neurobiology, Biomedical Engineering, Cognitive Sciences, and Otolaryngology – Head and Neck Surgery, University of California Irvine, Irvine, California, United States of America
| | - Thomas Lu
- Center for Hearing Research, Departments of Anatomy and Neurobiology, Biomedical Engineering, Cognitive Sciences, and Otolaryngology – Head and Neck Surgery, University of California Irvine, Irvine, California, United States of America
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Hernandez VH, Gehrt A, Reuter K, Jing Z, Jeschke M, Mendoza Schulz A, Hoch G, Bartels M, Vogt G, Garnham CW, Yawo H, Fukazawa Y, Augustine GJ, Bamberg E, Kügler S, Salditt T, de Hoz L, Strenzke N, Moser T. Optogenetic stimulation of the auditory pathway. J Clin Invest 2014; 124:1114-29. [PMID: 24509078 DOI: 10.1172/jci69050] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 11/21/2013] [Indexed: 12/18/2022] Open
Abstract
Auditory prostheses can partially restore speech comprehension when hearing fails. Sound coding with current prostheses is based on electrical stimulation of auditory neurons and has limited frequency resolution due to broad current spread within the cochlea. In contrast, optical stimulation can be spatially confined, which may improve frequency resolution. Here, we used animal models to characterize optogenetic stimulation, which is the optical stimulation of neurons genetically engineered to express the light-gated ion channel channelrhodopsin-2 (ChR2). Optogenetic stimulation of spiral ganglion neurons (SGNs) activated the auditory pathway, as demonstrated by recordings of single neuron and neuronal population responses. Furthermore, optogenetic stimulation of SGNs restored auditory activity in deaf mice. Approximation of the spatial spread of cochlear excitation by recording local field potentials (LFPs) in the inferior colliculus in response to suprathreshold optical, acoustic, and electrical stimuli indicated that optogenetic stimulation achieves better frequency resolution than monopolar electrical stimulation. Virus-mediated expression of a ChR2 variant with greater light sensitivity in SGNs reduced the amount of light required for responses and allowed neuronal spiking following stimulation up to 60 Hz. Our study demonstrates a strategy for optogenetic stimulation of the auditory pathway in rodents and lays the groundwork for future applications of cochlear optogenetics in auditory research and prosthetics.
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Chernov MM, Chen G, Roe AW. Histological assessment of thermal damage in the brain following infrared neural stimulation. Brain Stimul 2014; 7:476-82. [PMID: 24529644 DOI: 10.1016/j.brs.2014.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/06/2014] [Accepted: 01/09/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Infrared neural stimulation (INS) is a novel technique for modulating neural function. Its advantages over electrical stimulation include high spatial specificity, lack of electrical artifact and contact-free stimulation. INS acts via a rapid, focal increase in temperature. However, in order to become a viable experimental and therapeutic tool, the safety of INS must be demonstrated. OBJECTIVE/HYPOTHESIS Our aim was to determine the upper limit for the radiant exposure of INS in the brain without causing damage, using an INS sequence previously shown to induce both behavioral and electrophysiological effects in rodents and non-human primates. METHODS We stimulated the brains of anesthetized rodents and two squirrel monkeys using an infrared laser, depositing radiant energies from 0.3 to 0.9 J/cm2 per pulse in 0.5 s-long 200 Hz trains. At the end of the experiment, the animals were euthanized, perfused and the brains processed using standard histological techniques. RESULTS Radiant exposures greater than or equal to 0.4 J/cm2 resulted in identifiable lesions in brain sections. The lesions had a shape of a parabola and could further be subdivided into three concentric zones based on the type of damage observed. CONCLUSIONS The thermal damage threshold following our INS paradigm was between 0.3 and 0.4 J/cm2 per pulse. This value is lower than the one found previously in peripheral nerve. The differences are likely due to the structure of the INS sequence itself, particularly the repetition rate. The results warrant further modeling and experimental work in order to delimit the INS parameter space that is both safe and effective.
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Affiliation(s)
- Mykyta Mikhailovich Chernov
- Department of Psychology, Vanderbilt University, 111 21st Ave. South, 301 Wilson Hall, Nashville, TN 37240, USA.
| | - Gang Chen
- Department of Psychology, Vanderbilt University, 111 21st Ave. South, 301 Wilson Hall, Nashville, TN 37240, USA
| | - Anna Wang Roe
- Department of Psychology, Vanderbilt University, 111 21st Ave. South, 301 Wilson Hall, Nashville, TN 37240, USA
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Quantification of a thermal damage threshold for astrocytes using infrared laser generated heat gradients. Ann Biomed Eng 2013; 42:822-32. [PMID: 24259007 DOI: 10.1007/s10439-013-0940-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
Abstract
The response of cells and tissues to elevated temperatures is highly important in several research areas, especially in the area of infrared neural stimulation. So far, only the heat response of neurons has been considered. In this study, primary rat astrocytes were exposed to infrared laser pulses of various pulse lengths and the resulting cell morphology changes and cell migration was studied using light microscopy. By using a finite element model of the experimental setup the temperature distribution was simulated and the temperatures and times to induce morphological changes and migration were extracted. These threshold temperatures were used in the commonly used first-order reaction model according to Arrhenius to extract the kinetic parameters, i.e., the activation energy, E a, and the frequency factor, A c, for the system. A damage signal ratio threshold was defined and calculated to be 6% for the astrocytes to change morphology and start migrating.
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Brown WGA, Needham K, Nayagam BA, Stoddart PR. Whole cell patch clamp for investigating the mechanisms of infrared neural stimulation. J Vis Exp 2013. [PMID: 23929071 DOI: 10.3791/50444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
It has been demonstrated in recent years that pulsed, infrared laser light can be used to elicit electrical responses in neural tissue, independent of any further modification of the target tissue. Infrared neural stimulation has been reported in a variety of peripheral and sensory neural tissue in vivo, with particular interest shown in stimulation of neurons in the auditory nerve. However, while INS has been shown to work in these settings, the mechanism (or mechanisms) by which infrared light causes neural excitation is currently not well understood. The protocol presented here describes a whole cell patch clamp method designed to facilitate the investigation of infrared neural stimulation in cultured primary auditory neurons. By thoroughly characterizing the response of these cells to infrared laser illumination in vitro under controlled conditions, it may be possible to gain an improved understanding of the fundamental physical and biochemical processes underlying infrared neural stimulation.
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Affiliation(s)
- William G A Brown
- Biotactical Engineering, Faculty of Engineering and Industrial Science, Swinburne University of Technology
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Liljemalm R, Nyberg T, von Holst H. Heating during infrared neural stimulation. Lasers Surg Med 2013; 45:469-81. [PMID: 23832680 DOI: 10.1002/lsm.22158] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVE Infrared neural stimulation (INS) has recently evoked interest as an alternative to electrical stimulation. The mechanism of activation is the heating of water, which induces changes in cell membrane potential but may also trigger heat sensitive receptors. To further elucidate the mechanism, which may be dependent on cell type, a detailed description of the temperature distribution is necessary. A good control of the resulting temperature during INS is also necessary to avoid excessive heating that may damage the cells. Here we present a detailed model for the heating during INS and apply it for INS of in vitro neural networks of rat cerebral cortex neurons. STUDY DESIGN/MATERIALS AND METHODS A model of the heating during INS of a cell culture in a non-turbid media was prepared using multiphysics software. Experimental parameters such as initial temperature, beam distribution, pulse length, pulse duration, frequency and laser-cell distance were used. To verify the model, local temperature measurements using open pipette resistance were conducted. Furthermore, cortical neurons in culture were stimulated by a 500 mW pulsed diode laser (wavelength 1,550 nm) launched into a 200 µm multimodal optical fiber positioned 300 µm from the glass surface. The radiant exposure was 5.2 J/cm(2) . RESULTS The model gave detailed information about the spatial and temporal temperature distribution in the heated volume during INS. Temperature measurements using open pipette resistance verified the model. The peak temperature experienced by the cells was 48°C. Cortical neurons were successfully stimulated using the 1,550 nm laser and single cell activation as well as neural network inhibition were observed. CONCLUSION The model shows the spatial and temporal temperature distribution in the heated volume and could serve as a useful tool for future studies of the heating during INS.
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Affiliation(s)
- Rickard Liljemalm
- Royal Institute of Technology, School of Technology and Health, Alfred Nobels Allé 10, 14152, Huddinge, Sweden
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Kadakia S, Young H, Richter CP. Masking of Infrared Neural Stimulation (INS) in hearing and deaf guinea pigs. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2013; 8565:85655V. [PMID: 25075262 DOI: 10.1117/12.2013848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Spatial selective infrared neural stimulation has potential to improve neural prostheses, including cochlear implants. The heating of a confined target volume depolarizes the cell membrane and results in an action potential. Tissue heating may also results in thermal damage or the generation of a stress relaxation wave. Stress relaxation waves may result in a direct mechanical stimulation of remaining hair cells in the cochlea, so called optophony. Data are presented that quantify the effect of an acoustical stimulus (noise masker) on the response obtained with INS in normal hearing, acutely deafened, and chronic deaf animals. While in normal hearing animals an acoustic masker can reduce the response to INS, in acutely deafened animals the masking effect is reduced, and in chronic deaf animals this effect has not been detected. The responses to INS remain stable following the different degrees of cochlear damage.
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Affiliation(s)
- Sama Kadakia
- Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA ; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA
| | - Hunter Young
- Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA ; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA ; The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA
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Matic AI, Robinson AM, Young HK, Badofsky B, Rajguru SM, Stock S, Richter CP. Behavioral and electrophysiological responses evoked by chronic infrared neural stimulation of the cochlea. PLoS One 2013; 8:e58189. [PMID: 23505466 PMCID: PMC3591411 DOI: 10.1371/journal.pone.0058189] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 01/31/2013] [Indexed: 11/18/2022] Open
Abstract
Infrared neural stimulation (INS) has been proposed as a novel method for neural stimulation. In order for INS to translate to clinical use, which would involve the use of implanted devices over years or decades, the efficacy and safety of chronic INS needs to be determined. We examined a population of cats that were chronically implanted with an optical fiber to stimulate the cochlea with infrared radiation, the first known chronic application of INS. Through behavioral responses, the cats demonstrate that stimulation occurs and a perceptual event results. Long-term stimulation did not result in a change in the electrophysiological responses, either optically-evoked or acoustically-evoked. Spiral ganglion neuron counts and post implantation tissue growth, which was localized at the optical fiber, were similar in chronically stimulated and sham implanted cochleae. Results from chronic INS experiments in the cat cochlea support future work toward INS-based neuroprostheses for humans.
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Affiliation(s)
- Agnella Izzo Matic
- Department of Otolaryngology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America.
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Spelman FA. Cochlear Prostheses. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00083-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Crew JD, Galvin JJ, Fu QJ. Channel interaction limits melodic pitch perception in simulated cochlear implants. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2012; 132:EL429-35. [PMID: 23145706 PMCID: PMC3494451 DOI: 10.1121/1.4758770] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In cochlear implants (CIs), melodic pitch perception is limited by the spectral resolution, which in turn is limited by the number of spectral channels as well as interactions between adjacent channels. This study investigated the effect of channel interaction on melodic contour identification (MCI) in normal-hearing subjects listening to novel 16-channel sinewave vocoders that simulated channel interaction in CI signal processing. MCI performance worsened as the degree of channel interaction increased. Although greater numbers of spectral channels may be beneficial to melodic pitch perception, the present data suggest that it is also important to improve independence among spectral channels.
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Affiliation(s)
- Joseph D Crew
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California 90089, USA.
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Eshraghi AA, Nazarian R, Telischi FF, Rajguru SM, Truy E, Gupta C. The cochlear implant: historical aspects and future prospects. Anat Rec (Hoboken) 2012; 295:1967-80. [PMID: 23044644 DOI: 10.1002/ar.22580] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 02/06/2023]
Abstract
The cochlear implant (CI) is the first effective treatment for deafness and severe losses in hearing. As such, the CI is now widely regarded as one of the great advances in modern medicine. This article reviews the key events and discoveries that led up to the current CI systems, and we review and present some among the many possibilities for further improvements in device design and performance. The past achievements include: (1) development of reliable devices that can be used over the lifetime of a patient; (2) development of arrays of implanted electrodes that can stimulate more than one site in the cochlea; and (3) progressive and large improvements in sound processing strategies for CIs. In addition, cooperation between research organizations and companies greatly accelerated the widespread availability and use of safe and effective devices. Possibilities for the future include: (1) use of otoprotective drugs; (2) further improvements in electrode designs and placements; (3) further improvements in sound processing strategies; (4) use of stem cells to replace lost sensory hair cells and neural structures in the cochlea; (5) gene therapy; (6) further reductions in the trauma caused by insertions of electrodes and other manipulations during implant surgeries; and (7) optical rather electrical stimulation of the auditory nerve. Each of these possibilities is the subject of active research. Although great progress has been made to date in the development of the CI, including the first substantial restoration of a human sense, much more progress seems likely and certainly would not be a surprise.
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Affiliation(s)
- Adrien A Eshraghi
- Department of Otolaryngology, University of Miami Ear Institute, University of Miami Miller School of Medicine, Miami, Florida 33136-1015, USA.
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