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Bestsennaia E, Maslov I, Balandin T, Alekseev A, Yudenko A, Abu Shamseye A, Zabelskii D, Baumann A, Catapano C, Karathanasis C, Gordeliy V, Heilemann M, Gensch T, Borshchevskiy V. Channelrhodopsin-2 Oligomerization in Cell Membrane Revealed by Photo-Activated Localization Microscopy. Angew Chem Int Ed Engl 2024; 63:e202307555. [PMID: 38226794 DOI: 10.1002/anie.202307555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 01/03/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
Microbial rhodopsins are retinal membrane proteins that found a broad application in optogenetics. The oligomeric state of rhodopsins is important for their functionality and stability. Of particular interest is the oligomeric state in the cellular native membrane environment. Fluorescence microscopy provides powerful tools to determine the oligomeric state of membrane proteins directly in cells. Among these methods is quantitative photoactivated localization microscopy (qPALM) allowing the investigation of molecular organization at the level of single protein clusters. Here, we apply qPALM to investigate the oligomeric state of the first and most used optogenetic tool Channelrhodopsin-2 (ChR2) in the plasma membrane of eukaryotic cells. ChR2 appeared predominantly as a dimer in the cell membrane and did not form higher oligomers. The disulfide bonds between Cys34 and Cys36 of adjacent ChR2 monomers were not required for dimer formation and mutations disrupting these bonds resulted in only partial monomerization of ChR2. The monomeric fraction increased when the total concentration of mutant ChR2 in the membrane was low. The dissociation constant was estimated for this partially monomerized mutant ChR2 as 2.2±0.9 proteins/μm2 . Our findings are important for understanding the mechanistic basis of ChR2 activity as well as for improving existing and developing future optogenetic tools.
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Affiliation(s)
- Ekaterina Bestsennaia
- Institute of Biological Information Processing 1, IBI-1 (Molecular and Cellular Physiology), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Ivan Maslov
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and the Biomedical Research Institute, Hasselt University, B3590, Diepenbeek, Belgium
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, 3001, Leuven, Belgium
| | - Taras Balandin
- Institute of Biological Information Processing 7, IBI-7 (Structural Biochemistry), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Alexey Alekseev
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Anna Yudenko
- Department of Biomedical Sciences, University Medical Center Groningen, University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Assalla Abu Shamseye
- Institute of Biological Information Processing 1, IBI-1 (Molecular and Cellular Physiology), Forschungszentrum Jülich, 52428, Jülich, Germany
- Institute of Biological Information Processing 7, IBI-7 (Structural Biochemistry), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Dmitrii Zabelskii
- Institute of Biological Information Processing 7, IBI-7 (Structural Biochemistry), Forschungszentrum Jülich, 52428, Jülich, Germany
- European XFEL, 22869, Schenefeld, Germany
| | - Arnd Baumann
- Institute of Biological Information Processing 1, IBI-1 (Molecular and Cellular Physiology), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Claudia Catapano
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, 60438, Frankfurt, Germany
| | - Christos Karathanasis
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, 60438, Frankfurt, Germany
| | - Valentin Gordeliy
- Institute of Biological Information Processing 7, IBI-7 (Structural Biochemistry), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, 60438, Frankfurt, Germany
| | - Thomas Gensch
- Institute of Biological Information Processing 1, IBI-1 (Molecular and Cellular Physiology), Forschungszentrum Jülich, 52428, Jülich, Germany
| | - Valentin Borshchevskiy
- Institute of Biological Information Processing 7, IBI-7 (Structural Biochemistry), Forschungszentrum Jülich, 52428, Jülich, Germany
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Kunze K, Gossler C, Reinhardt M, Arnold M, Schwenzer F, Helke C, Reuter D, Keppeler D, Moser T, Schwarz UT. Multichannel laser diode to polymer waveguide array coupling with a double-aspheric lens. APPLIED OPTICS 2023; 62:9353-9360. [PMID: 38108707 DOI: 10.1364/ao.505167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023]
Abstract
An optical system for multichannel coupling of laser arrays to polymer waveguide array probes with a single biconvex lens is developed. The developed cylindrical module with 13 mm and 20 mm in diameter and length, respectively, enables coupling of eight individual optical channels using an aspheric lens. Specific coupling with crosstalk below -13d B for each channel and quasi-uniform coupling over all channels is achieved for a waveguide array with 100 µm lateral facet pitch at the incoupling site. The polymer waveguide technology allows for tapering of the lateral waveguide pitch to 25 µm toward the tip of the flexible waveguide array. SU-8 and PMMA are used as the waveguide core and cladding, respectively. The optical coupling module is designed as a prototype for preclinical evaluation of optical neural stimulators.
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Park J, Kim K, Kim Y, Kim TS, Min IS, Li B, Cho YU, Lee C, Lee JY, Gao Y, Kang K, Kim DH, Choi WJ, Shin HB, Kang HK, Song YM, Cheng H, Cho IJ, Yu KJ. A wireless, solar-powered, optoelectronic system for spatial restriction-free long-term optogenetic neuromodulations. SCIENCE ADVANCES 2023; 9:eadi8918. [PMID: 37756405 PMCID: PMC10530225 DOI: 10.1126/sciadv.adi8918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
Numerous wireless optogenetic systems have been reported for practical tether-free optogenetics in freely moving animals. However, most devices rely on battery-powered or coil-powered systems requiring periodic battery replacement or bulky, high-cost charging equipment with delicate antenna design. This leads to spatiotemporal constraints, such as limited experimental duration due to battery life or animals' restricted movement within specific areas to maintain wireless power transmission. In this study, we present a wireless, solar-powered, flexible optoelectronic device for neuromodulation of the complete freely behaving subject. This device provides chronic operation without battery replacement or other external settings including impedance matching technique and radio frequency generators. Our device uses high-efficiency, thin InGaP/GaAs tandem flexible photovoltaics to harvest energy from various light sources, which powers Bluetooth system to facilitate long-term, on-demand use. Observation of sustained locomotion behaviors for a month in mice via secondary motor cortex area stimulation demonstrates the notable capabilities of our device, highlighting its potential for space-free neuromodulating applications.
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Affiliation(s)
- Jaejin Park
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Kyubeen Kim
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Yujin Kim
- Department of Biomedical Sciences, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Tae Soo Kim
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - In Sik Min
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Bowen Li
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Young Uk Cho
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Chanwoo Lee
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Ju Young Lee
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Yuyan Gao
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kyowon Kang
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Do Hyeon Kim
- School of Electrical Engineering and Computer Science (EECS), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Won Jun Choi
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hyun-Beom Shin
- Korea Advanced Nano Fab Center (KANC), Suwon 443-270, Korea
| | - Ho Kwan Kang
- Korea Advanced Nano Fab Center (KANC), Suwon 443-270, Korea
| | - Young Min Song
- School of Electrical Engineering and Computer Science (EECS), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Huanyu Cheng
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Il-Joo Cho
- Department of Biomedical Sciences, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- Department of Anatomy, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Ki Jun Yu
- Functional Bio-integrated Electronics and Energy Management Lab, School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
- Department of Electrical and Electronic Engineering, YU-Korea Institute of Science and Technology (KIST) Institute, Yonsei University, 50, Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
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Rogalla MM, Seibert A, Sleeboom JM, Hildebrandt KJ. Differential optogenetic activation of the auditory midbrain in freely moving behaving mice. Front Syst Neurosci 2023; 17:1222176. [PMID: 37719023 PMCID: PMC10501139 DOI: 10.3389/fnsys.2023.1222176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 08/09/2023] [Indexed: 09/19/2023] Open
Abstract
Introduction In patients with severe auditory impairment, partial hearing restoration can be achieved by sensory prostheses for the electrical stimulation of the central nervous system. However, these state-of-the-art approaches suffer from limited spectral resolution: electrical field spread depends on the impedance of the surrounding medium, impeding spatially focused electrical stimulation in neural tissue. To overcome these limitations, optogenetic activation could be applied in such prostheses to achieve enhanced resolution through precise and differential stimulation of nearby neuronal ensembles. Previous experiments have provided a first proof for behavioral detectability of optogenetic activation in the rodent auditory system, but little is known about the generation of complex and behaviorally relevant sensory patterns involving differential activation. Methods In this study, we developed and behaviorally tested an optogenetic implant to excite two spatially separated points along the tonotopy of the murine inferior colliculus (ICc). Results Using a reward based operant Go/No-Go paradigm, we show that differential optogenetic activation of a sub-cortical sensory pathway is possible and efficient. We demonstrate how animals which were previously trained in a frequency discrimination paradigm (a) rapidly respond to either sound or optogenetic stimulation, (b) generally detect optogenetic stimulation of two different neuronal ensembles, and (c) discriminate between them. Discussion Our results demonstrate that optogenetic excitatory stimulation at different points of the ICc tonotopy elicits a stable response behavior over time periods of several months. With this study, we provide the first proof of principle for sub-cortical differential stimulation of sensory systems using complex artificial cues in freely moving animals.
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Affiliation(s)
- Meike M. Rogalla
- Department of Neuroscience, Division of Auditory Neuroscience, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
- Cluster of Excellence Hearing4all, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
| | - Adina Seibert
- Department of Neuroscience, Division of Auditory Neuroscience, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
| | - Jana M. Sleeboom
- Department of Neuroscience, Division of Auditory Neuroscience, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
| | - K. Jannis Hildebrandt
- Department of Neuroscience, Division of Auditory Neuroscience, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
- Cluster of Excellence Hearing4all, Carl von Ossietzky University, Oldenburg, Lower Saxony, Germany
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Hunniford V, Kühler R, Wolf B, Keppeler D, Strenzke N, Moser T. Patient perspectives on the need for improved hearing rehabilitation: A qualitative survey study of German cochlear implant users. Front Neurosci 2023; 17:1105562. [PMID: 36755736 PMCID: PMC9899842 DOI: 10.3389/fnins.2023.1105562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023] Open
Abstract
Background The electrical cochlear implant (eCI) partially restores hearing in individuals affected by profound hearing impairment (HI) or deafness. However, the limited resolution of sound frequency coding with eCIs limits hearing in daily situations such as group conversations. Current research promises future improvements in hearing restoration which may involve gene therapy and optical stimulation of the auditory nerve, using optogenetics. Prior to the potential clinical translation of these technologies, it is critical that patients are engaged in order to align future research agendas and technological advancements with their needs. Methods Here, we performed a survey study with hearing impaired, using an eCI as a means of hearing rehabilitation. We distributed a questionnaire to 180 adult patients from the University Medical Center Göttingen's Department of Otolaryngology who were actively using an eCI for 6 months or more during the time of the survey period. Questions revolved around patients needs, and willingness to accept hypothetical risks or drawbacks associated with an optical CI (oCI). Results Eighty-one participants responded to the questionnaire; 68% were greater than 60 years of age and 26% had bilateral eCIs. Participants expressed a need for improving the performance beyond that experienced with their current eCI. Primarily, they desired improved speech comprehension in background noise, greater ability to appreciate music, and more natural sound impression. They expressed a willingness for engaging with new technologies for improved hearing restoration. Notably, participants were least concerned about hypothetically receiving a gene therapy necessary for the oCI implant; but expressed greater reluctance to hypothetically receiving an implant that had yet to be evaluated in a human clinical trial. Conclusion This work provides a preliminary step in engaging patients in the development of a new technology that has the potential to address the limitations of electrical hearing rehabilitation.
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Affiliation(s)
- Victoria Hunniford
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany,Sensory and Motor Neuroscience, Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Robert Kühler
- Department of Otolaryngology, University Medical Center Göttingen, Göttingen, Germany
| | - Bettina Wolf
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany,Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 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,Nicola Strenzke,
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, 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,Auditory Neuroscience and Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany,*Correspondence: Tobias Moser,
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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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Wang X, Zhang Y, Bai S, Qi R, Sun H, Li R, Zhu L, Cao X, Jia G, Li X, Gao L. Corticofugal Modulation of Temporal and Rate Representations in the Inferior Colliculus of the Awake Marmoset. Cereb Cortex 2022; 32:4080-4097. [PMID: 35029654 DOI: 10.1093/cercor/bhab467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/12/2021] [Accepted: 11/16/2021] [Indexed: 11/14/2022] Open
Abstract
Temporal processing is crucial for auditory perception and cognition, especially for communication sounds. Previous studies have shown that the auditory cortex and the thalamus use temporal and rate representations to encode slowly and rapidly changing time-varying sounds. However, how the primate inferior colliculus (IC) encodes time-varying sounds at the millisecond scale remains unclear. In this study, we investigated the temporal processing by IC neurons in awake marmosets to Gaussian click trains with varying interclick intervals (2-100 ms). Strikingly, we found that 28% of IC neurons exhibited rate representation with nonsynchronized responses, which is in sharp contrast to the current view that the IC only uses a temporal representation to encode time-varying signals. Moreover, IC neurons with rate representation exhibited response properties distinct from those with temporal representation. We further demonstrated that reversible inactivation of the primary auditory cortex modulated 17% of the stimulus-synchronized responses and 21% of the nonsynchronized responses of IC neurons, revealing that cortico-colliculus projections play a role, but not a crucial one, in temporal processing in the IC. This study has significantly advanced our understanding of temporal processing in the IC of awake animals and provides new insights into temporal processing from the midbrain to the cortex.
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Affiliation(s)
- Xiaohui Wang
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Yuanqing Zhang
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Siyi Bai
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Runze Qi
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Hao Sun
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Rui Li
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Lin Zhu
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Xinyuan Cao
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Guoqiang Jia
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Xinjian Li
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Lixia Gao
- Department of Neurology of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, College of Biomedical Engineering and Instrument Science, School of Medicine, Zhejiang University, Hangzhou 310000, China
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8
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Kießling J. Die Entwicklung der Audiologie - von Helmholtz bis heute. Z Med Phys 2021; 31:238-253. [DOI: 10.1016/j.zemedi.2020.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/12/2020] [Accepted: 08/31/2020] [Indexed: 11/17/2022]
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9
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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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10
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Ayub S, David F, Klein E, Borel M, Paul O, Gentet LJ, Ruther P. Compact Optical Neural Probes With Up to 20 Integrated Thin-Film $\mu$LEDs Applied in Acute Optogenetic Studies. IEEE Trans Biomed Eng 2020; 67:2603-2615. [DOI: 10.1109/tbme.2020.2966293] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Dieter A, Klein E, Keppeler D, Jablonski L, Harczos T, Hoch G, Rankovic V, Paul O, Jeschke M, Ruther P, Moser T. μLED-based optical cochlear implants for spectrally selective activation of the auditory nerve. EMBO Mol Med 2020; 12:e12387. [PMID: 32596983 PMCID: PMC7411546 DOI: 10.15252/emmm.202012387] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/23/2020] [Accepted: 06/02/2020] [Indexed: 01/19/2023] Open
Abstract
Electrical cochlear implants (eCIs) partially restore hearing and enable speech comprehension to more than half a million users, thereby re-connecting deaf patients to the auditory scene surrounding them. Yet, eCIs suffer from limited spectral selectivity, resulting from current spread around each electrode contact and causing poor speech recognition in the presence of background noise. Optogenetic stimulation of the auditory nerve might overcome this limitation as light can be conveniently confined in space. Here, we combined virus-mediated optogenetic manipulation of cochlear spiral ganglion neurons (SGNs) and microsystems engineering to establish acute multi-channel optical cochlear implant (oCI) stimulation in adult Mongolian gerbils. oCIs based on 16 microscale thin-film light-emitting diodes (μLEDs) evoked tonotopic activation of the auditory pathway with high spectral selectivity and modest power requirements in hearing and deaf gerbils. These results prove the feasibility of μLED-based oCIs for spectrally selective activation of the auditory nerve.
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Affiliation(s)
- Alexander Dieter
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Present address:
Synaptic Wiring LabCenter for Molecular Neurobiology HamburgUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Eric Klein
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
| | - Lukasz Jablonski
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Tamas Harczos
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Gerhard Hoch
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Restorative Cochlear Genomics GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Oliver Paul
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
- BrainLinks‐BrainToolsCluster of ExcellenceUniversity of FreiburgFreiburgGermany
| | - Marcus Jeschke
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Cognitive Hearing in Primates GroupAuditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
| | - Patrick Ruther
- Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
- BrainLinks‐BrainToolsCluster of ExcellenceUniversity of FreiburgFreiburgGermany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for Neurosciences and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Neuroscience GroupMax Planck Institute for Experimental MedicineGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GoettingenGoettingenGermany
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12
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White M, Mackay M, Whittaker R. Taking Optogenetics into the Human Brain: Opportunities and Challenges in Clinical Trial Design. OPEN ACCESS JOURNAL OF CLINICAL TRIALS 2020; 2020:33-41. [PMID: 34471390 DOI: 10.2147/oajct.s259702] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Optogenetics, the use of light to control the activity of suitably sensitized cells, has led to major advances in the field of basic neuroscience since it first emerged in 2005. Already, the technique has entered clinical trials for conditions such as Retinitis Pigmentosa. A major focus of interest is the use of optogenetics within the brain, where the ability to precisely control the activity of specific subsets of neurons could lead to novel treatments for a wide range of disorders from epilepsy to schizophrenia. However, since any therapy would require both the use of gene therapy techniques to introduce non-human proteins, and implantable electronic devices to provide optical stimulation, applying this technique in the brain presents a unique set of obstacles and challenges. This review looks at the reasons why researchers are exploring the use of optogenetics within the brain. It then explores the challenges facing scientists, engineers and clinicians wanting to take this technology from the lab into the first human brain, discussing different possibilities for a first-in-human clinical trial from a sponsor, patient and regulatory perspective.
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Affiliation(s)
- Michael White
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Michael Mackay
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Roger Whittaker
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom.,Department of Clinical Neurophysiology, Royal Victoria Hospital, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, United Kingdom
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13
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Liu CH, Lu YS, Chen PC, Lee CF. Effects of different electrodes used in bone-guided extracochlear implants on electrical stimulation of auditory nerves in guinea pigs. Tzu Chi Med J 2020; 33:42-48. [PMID: 33505877 PMCID: PMC7821833 DOI: 10.4103/tcmj.tcmj_46_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/20/2020] [Accepted: 05/08/2020] [Indexed: 11/30/2022] Open
Abstract
Objective: Conventional cochlear implants provide patients who are deaf with hearing via electrical intracochlear stimulations. Stimulation electrodes are inserted into the cochlea through a cochleostomy or round window membrane (RWM) approach. However, these methods might induce cochlear ossificans and loss of residual hearing by damaging inner ear structures. To avoid an invasive electrode insertion, we developed a novel bone-guided extracochlear implant that stimulated the auditory nerves between the cochlear bones and the RWM to prevent cochlea damage. Power consumption plays an important role in wireless implantable electronic devices. Therefore, we aimed to investigate the effects of different electrodes on the stimulating threshold currents of the auditory nerve and the power consumption of bone-guided extracochlear implants using a commercial stimulator. Materials and Methods: Inert aurum (Au) electrodes were compared with biocompatible platinum (Pt) and iridium oxide (IrOx) electrodes in practical implantable applications. IrOx electrodes were used for their high-charge storage capacity, low impedance, and biocompatibility. The electrodes were fabricated via sputtering and were experimentally characterized with cyclic voltammetry and then examined using in vivo tests. Results: Based on electrical auditory brainstem responses, IrOx electrodes yielded lower acoustic nerve-stimulating threshold currents (132 μA) compared with Au electrodes (204 μA). IrOx electrodes also had a lower acoustic nerve stimulating threshold current (132 μA) compared with Pt electrodes (168 μA). Conclusion: As expected, IrOx electrodes were beneficial in the development of multielectrode bone-guided extracochlear implants, with the lowest acoustic nerve-stimulating threshold and current consumptions compared with Au and Pt electrodes.
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Affiliation(s)
- Chien-Hao Liu
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - Yung-Shan Lu
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - Po-Chun Chen
- Department of Materials and Mineral Resource Engineering, Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Chia-Fone Lee
- Department of Otolaryngology, Hualian Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Otolaryngology Head and Neck Surgery, School of Medicine, Tzu Chi University, Hualien, Taiwan
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14
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Recent Advances on Thermal Management of Flexible Inorganic Electronics. MICROMACHINES 2020; 11:mi11040390. [PMID: 32283609 PMCID: PMC7231351 DOI: 10.3390/mi11040390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/27/2020] [Accepted: 04/05/2020] [Indexed: 12/16/2022]
Abstract
Flexible inorganic electronic devices (FIEDs) consisting of functional inorganic components on a soft polymer substrate have enabled many novel applications such as epidermal electronics and wearable electronics, which cannot be realized through conventional rigid electronics. The low thermal dissipation capacity of the soft polymer substrate of FIEDs demands proper thermal management to reduce the undesired thermal influences. The biointegrated applications of FIEDs pose even more stringent requirements on thermal management due to the sensitive nature of biological tissues to temperature. In this review, we take microscale inorganic light-emitting diodes (μ-ILEDs) as an example of functional components to summarize the recent advances on thermal management of FIEDs including thermal analysis, thermo-mechanical analysis and thermal designs of FIEDs with and without biological tissues. These results are very helpful to understand the underlying heat transfer mechanism and provide design guidelines to optimize FIEDs in practical applications.
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15
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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: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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 InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Graduate School for NeurosciencesBiophysics and Molecular BiosciencesUniversity of GöttingenGöttingenGermany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLabUniversity Medical Center GöttingenGöttingenGermany
- Auditory Neuroscience and Optogenetics LaboratoryGerman Primate CenterGöttingenGermany
- Auditory Neuroscience GroupMax Planck Institute of Experimental MedicineGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GöttingenGöttingenGermany
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16
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Zhang C, Yang S, Flossmann T, Gao S, Witte OW, Nagel G, Holthoff K, Kirmse K. Optimized photo-stimulation of halorhodopsin for long-term neuronal inhibition. BMC Biol 2019; 17:95. [PMID: 31775747 PMCID: PMC6882325 DOI: 10.1186/s12915-019-0717-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 10/30/2019] [Indexed: 01/04/2023] Open
Abstract
Background Optogenetic silencing techniques have expanded the causal understanding of the functions of diverse neuronal cell types in both the healthy and diseased brain. A widely used inhibitory optogenetic actuator is eNpHR3.0, an improved version of the light-driven chloride pump halorhodopsin derived from Natronomonas pharaonis. A major drawback of eNpHR3.0 is related to its pronounced inactivation on a time-scale of seconds, which renders it unsuited for applications that require long-lasting silencing. Results Using transgenic mice and Xenopus laevis oocytes expressing an eNpHR3.0-EYFP fusion protein, we here report optimized photo-stimulation techniques that profoundly increase the stability of eNpHR3.0-mediated currents during long-term photo-stimulation. We demonstrate that optimized photo-stimulation enables prolonged hyperpolarization and suppression of action potential discharge on a time-scale of minutes. Conclusions Collectively, our findings extend the utility of eNpHR3.0 to the long-lasting inhibition of excitable cells, thus facilitating the optogenetic dissection of neural circuits.
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Affiliation(s)
- Chuanqiang Zhang
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.,Present Address: Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Shang Yang
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Tom Flossmann
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.,Present Address: Centre for Discovery Brain Sciences, Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Shiqiang Gao
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Otto W Witte
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - Georg Nagel
- Institute for Molecular Plant Physiology and Biophysics, Biocenter, & Institute of Physiology - Neurophysiology, Julius-Maximilians-University of Würzburg, 97070, Würzburg, Germany
| | - Knut Holthoff
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
| | - Knut Kirmse
- Hans-Berger Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany.
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17
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Zhu A, Qureshi AA, Kozin ED, Lee DJ. Concepts in Neural Stimulation: Electrical and Optical Modulation of the Auditory Pathways. Otolaryngol Clin North Am 2019; 53:31-43. [PMID: 31685241 DOI: 10.1016/j.otc.2019.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Understanding the mechanisms of neural stimulation is necessary to improve the management of sensory disorders. Neurons can be artificially stimulated using electrical current, or with newer stimulation modalities, including optogenetics. Electrical stimulation forms the basis for all neuroprosthetic devices that are used clinically. Off-target stimulation and poor implant performance remain concerns for patients with electrically based neuroprosthetic devices. Optogenetic techniques may improve cranial nerve stimulation strategies used by various neuroprostheses and result in better patient outcomes. This article reviews the fundamentals of neural stimulation and provides an overview of recent major advancements in light-based neuromodulation."
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Affiliation(s)
- Angela Zhu
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Ahad A Qureshi
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Elliott D Kozin
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
| | - Daniel J Lee
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA.
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18
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Abstract
Cochlear implant is the first approved cranial nerve stimulator that works by directly stimulating the cochlear nerve. The medical and societal impact of this revolutionary device cannot be understated. This article reviews the evolving indications for cochlear implant, patient assessment, surgical approach, and outcomes for pediatric and adult cochlear implant that demonstrate its impact. Future concepts in cochlear implant are introduced briefly. This article covers a breadth of information; however, it is not intended be entirely comprehensive. Rather, it should serve as a foundation for understanding cochlear implant.
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19
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Sorg K, Stahn P, Pillong L, Hinsberger MP, Heimann L, Foth HJ, Schick B, Wenzel GI. First biocompatibility margins for optical stimulation at the eardrum via 532-nm laser pulses in a mouse model. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-10. [PMID: 31436071 PMCID: PMC6983485 DOI: 10.1117/1.jbo.24.8.085003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Hearing impairment affects ∼460 million people worldwide. Conservative therapies, such as hearing aids, bone conduction systems, and middle ear implants, do not always sufficiently compensate for this deficit. The optical stimulation is currently under investigation as an alternative stimulation strategy for the activation of the hearing system. To assess the biocompatibility margins of this emerging technology, we established a method applicable in whole-mount preparations of murine tympanic membranes (TM). We irradiated the TM of anesthetized mice with 532-nm laser pulses at an average power of 50, 89, 99, and 125 mW at two different locations of the TM and monitored the hearing function with auditory brainstem responses. Laser-power-dependent negative side effects to the TM were observed at power levels exceeding 89 mW. Although we did not find any significant negative effects of optical stimulation on the hearing function in these mice, based on the histology results further studies are necessary for optimization of the used parameters.
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Affiliation(s)
- Katharina Sorg
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Patricia Stahn
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Lukas Pillong
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Marius P. Hinsberger
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Larissa Heimann
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Hans-Jochen Foth
- University of Kaiserslautern, Department of Physics, Kaiserslautern, Germany
| | - Bernhard Schick
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Gentiana I. Wenzel
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
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20
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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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21
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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: 47] [Impact Index Per Article: 9.4] [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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22
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Stahn P, Lim HH, Hinsberger MP, Sorg K, Pillong L, Kannengießer M, Schreiter C, Foth HJ, Langenbucher A, Schick B, Wenzel GI. Frequency-specific activation of the peripheral auditory system using optoacoustic laser stimulation. Sci Rep 2019; 9:4171. [PMID: 30862850 PMCID: PMC6414650 DOI: 10.1038/s41598-019-40860-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 02/22/2019] [Indexed: 11/09/2022] Open
Abstract
Hearing impairment is one of the most common sensory deficits in humans. Hearing aids are helpful to patients but can have poor sound quality or transmission due to insufficient output or acoustic feedback, such as for high frequencies. Implantable devices partially overcome these issues but require surgery with limited locations for device attachment. Here, we investigate a new optoacoustic approach to vibrate the hearing organ with laser stimulation to improve frequency bandwidth, not requiring attachment to specific vibratory structures, and potentially reduce acoustic feedback. We developed a laser pulse modulation strategy and simulated its response at the umbo (1-10 kHz) based on a convolution-based model. We achieved frequency-specific activation in which non-contact laser stimulation of the umbo, as well as within the middle ear at the round window and otic capsule, induced precise shifts in the maximal vibratory response of the umbo and neural activation within the inferior colliculus of guinea pigs, corresponding to the targeted, modelled and then stimulated frequency. There was also no acoustic feedback detected from laser stimulation with our experimental setup. These findings open up the potential for using a convolution-based optoacoustic approach as a new type of laser hearing aid or middle ear implant.
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Affiliation(s)
- Patricia Stahn
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany.
| | - Hubert H Lim
- University of Minnesota, Department of Biomedical Engineering, Department of Otolaryngology, Minnesota, USA
| | - Marius P Hinsberger
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
| | - Katharina Sorg
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
| | - Lukas Pillong
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
| | - Marc Kannengießer
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
- Saarland University, Experimental Ophthalmology, Homburg, Germany
| | - Cathleen Schreiter
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
| | - Hans-Jochen Foth
- Technische Universität Kaiserslautern, Department of Physics, Kaiserslautern, Germany
| | | | - Bernhard Schick
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany
| | - Gentiana I Wenzel
- Saarland University, Faculty of Medicine, Department of Otolaryngology, Kirrbergerstr. 100, 66421, Homburg, Germany.
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23
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Ashmore J. The neuroscience of hearing or how to do a hard job with soft components. Brain Neurosci Adv 2018; 2:2398212818810687. [PMID: 32166156 PMCID: PMC7058193 DOI: 10.1177/2398212818810687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Indexed: 12/02/2022] Open
Abstract
The inner ear is a small and relatively inaccessible structure. The use of multiple biophysical recording techniques from the late 1970s onwards, combined with molecular genetics to identify genes critically involved in cochlear development, has revealed how the cochlea acts as the front end for the central nervous system analysis of the auditory world. Some notable progress has been made in clarifying the mechanisms of frequency coding and cochlear amplification, and of mechano-transduction in hair cells and in establishing molecules necessary for normal (and by implication in abnormal) development of hearing and balance. There has been a parallel growth in understanding some of the neural networks in the brainstem and cortical areas responsible for processing the information derived from the auditory nerve. Informing future technical improvements to hearing aids and cochlear implants (electrically and optogenetically encoded), this chapter concentrates mainly on the neuroscience of peripheral hearing.
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Affiliation(s)
- Jonathan Ashmore
- Department of Neuroscience, Physiology and Pharmacology and UCL Ear Institute, University College London, London, UK
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24
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Goncalves SB, Ribeiro JF, Silva AF, Costa RM, Correia JH. Design and manufacturing challenges of optogenetic neural interfaces: a review. J Neural Eng 2018; 14:041001. [PMID: 28452331 DOI: 10.1088/1741-2552/aa7004] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Optogenetics is a relatively new technology to achieve cell-type specific neuromodulation with millisecond-scale temporal precision. Optogenetic tools are being developed to address neuroscience challenges, and to improve the knowledge about brain networks, with the ultimate aim of catalyzing new treatments for brain disorders and diseases. To reach this ambitious goal the implementation of mature and reliable engineered tools is required. The success of optogenetics relies on optical tools that can deliver light into the neural tissue. Objective/Approach: Here, the design and manufacturing approaches available to the scientific community are reviewed, and current challenges to accomplish appropriate scalable, multimodal and wireless optical devices are discussed. SIGNIFICANCE Overall, this review aims at presenting a helpful guidance to the engineering and design of optical microsystems for optogenetic applications.
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Affiliation(s)
- S B Goncalves
- CMEMS-UMinho, Department of Industrial Electronics, University of Minho, Guimaraes, Portugal
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25
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Zhang W, Kim SM, Wang W, Cai C, Feng Y, Kong W, Lin X. Cochlear Gene Therapy for Sensorineural Hearing Loss: Current Status and Major Remaining Hurdles for Translational Success. Front Mol Neurosci 2018; 11:221. [PMID: 29997477 PMCID: PMC6028713 DOI: 10.3389/fnmol.2018.00221] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/06/2018] [Indexed: 12/19/2022] Open
Abstract
Sensorineural hearing loss (SNHL) affects millions of people. Genetic mutations play a large and direct role in both congenital and late-onset cases of SNHL (e.g., age-dependent hearing loss, ADHL). Although hearing aids can help moderate to severe hearing loss the only effective treatment for deaf patients is the cochlear implant (CI). Gene- and cell-based therapies potentially may preserve or restore hearing with more natural sound perception, since their theoretical frequency resolution power is much higher than that of cochlear implants. These biologically-based interventions also carry the potential to re-establish hearing without the need for implanting any prosthetic device; the convenience and lower financial burden afforded by such biologically-based interventions could potentially benefit far more SNHL patients. Recently major progress has been achieved in preclinical studies of cochlear gene therapy. This review critically evaluates recent advances in the preclinical trials of gene therapies for SNHL and the major remaining challenges for the development and eventual clinical translation of this novel therapy. The cochlea bears many similarities to the eye for translational studies of gene therapies. Experience gained in ocular gene therapy trials, many of which have advanced to clinical phase III, may provide valuable guidance in improving the chance of success for cochlear gene therapy in human trials. A discussion on potential implications of translational knowledge gleaned from large numbers of advanced clinical trials of ocular gene therapy is therefore included.
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Affiliation(s)
- Wenjuan Zhang
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sun Myoung Kim
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
| | - Wenwen Wang
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | | | - Yong Feng
- Xiangya School of Medicine, Changsha, China
| | - Weijia Kong
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
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26
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Leong ATL, Dong CM, Gao PP, Chan RW, To A, Sanes DH, Wu EX. Optogenetic auditory fMRI reveals the effects of visual cortical inputs on auditory midbrain response. Sci Rep 2018; 8:8736. [PMID: 29880842 PMCID: PMC5992211 DOI: 10.1038/s41598-018-26568-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 05/10/2018] [Indexed: 12/20/2022] Open
Abstract
Sensory cortices contain extensive descending (corticofugal) pathways, yet their impact on brainstem processing - particularly across sensory systems - remains poorly understood. In the auditory system, the inferior colliculus (IC) in the midbrain receives cross-modal inputs from the visual cortex (VC). However, the influences from VC on auditory midbrain processing are unclear. To investigate whether and how visual cortical inputs affect IC auditory responses, the present study combines auditory blood-oxygenation-level-dependent (BOLD) functional MRI (fMRI) with cell-type specific optogenetic manipulation of visual cortex. The results show that predominant optogenetic excitation of the excitatory pyramidal neurons in the infragranular layers of the primary VC enhances the noise-evoked BOLD fMRI responses within the IC. This finding reveals that inputs from VC influence and facilitate basic sound processing in the auditory midbrain. Such combined optogenetic and auditory fMRI approach can shed light on the large-scale modulatory effects of corticofugal pathways and guide detailed electrophysiological studies in the future.
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Affiliation(s)
- Alex T L Leong
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Celia M Dong
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Patrick P Gao
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Russell W Chan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Anthea To
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Dan H Sanes
- Center for Neural Science, New York University, New York, NY, 10003, United States
| | - Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China. .,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China. .,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China. .,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Abstract
Drug delivery to the inner ear is an ideal method to treat a wide variety of otologic conditions. A broad range of potential applications is just beginning to be explored. New approaches combine principles of inner ear pharmacokinetics with emerging technologies of drug delivery including novel delivery systems, drug-device combinations, and new categories of drugs. Strategies include cell-specific targeting, manipulation of gene expression, local activation following systemic delivery, and use of stem cells, viral vectors, and gene editing systems. Translation of these therapies to the clinic remains challenging given the potential risks of intracochlear and intralabyrinthine trauma, our limited understanding of the etiologies of particular inner ear disorders, and paucity of accurate diagnostic tools at the cellular level. This review provides an overview of future methods, delivery systems, disease targets, and clinical considerations required for translation to clinical medicine.
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High frequency neural spiking and auditory signaling by ultrafast red-shifted optogenetics. Nat Commun 2018; 9:1750. [PMID: 29717130 PMCID: PMC5931537 DOI: 10.1038/s41467-018-04146-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 04/06/2018] [Indexed: 11/29/2022] Open
Abstract
Optogenetics revolutionizes basic research in neuroscience and cell biology and bears potential for medical applications. We develop mutants leading to a unifying concept for the construction of various channelrhodopsins with fast closing kinetics. Due to different absorption maxima these channelrhodopsins allow fast neural photoactivation over the whole range of the visible spectrum. We focus our functional analysis on the fast-switching, red light-activated Chrimson variants, because red light has lower light scattering and marginal phototoxicity in tissues. We show paradigmatically for neurons of the cerebral cortex and the auditory nerve that the fast Chrimson mutants enable neural stimulation with firing frequencies of several hundred Hz. They drive spiking at high rates and temporal fidelity with low thresholds for stimulus intensity and duration. Optical cochlear implants restore auditory nerve activity in deaf mice. This demonstrates that the mutants facilitate neuroscience research and future medical applications such as hearing restoration. Optogenetic applications would benefit from channelrhodopsins (ChRs) with faster photostimulation, increased tissue transparency and lower phototoxicity. Here, the authors develop fast red-shifted ChR variants and show the abilities for temporal precise spiking of cerebral interneurons and restoring auditory activity in deaf mice.
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Cochlear Implants Meet Regenerative Biology: State of the Science and Future Research Directions. Otol Neurotol 2018; 38:e232-e236. [PMID: 28806331 DOI: 10.1097/mao.0000000000001407] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
: The cochlear implant, the first device to restore a human sense, is an electronic substitute for lost mechanosensory hair cells. It has been successful at providing hearing to people with severe to profound hearing loss and as of 2012, an estimated 324,000 patients worldwide have received cochlear implants. Users of cochlear implants however, suffer from difficulties in processing complex sounds such as music and in discriminating sounds in noisy environments. Recent advances in regenerative biology and medicine are opening new avenues for enhancing the efficacy of cochlear implants by improving the neural interface in the future and offer the possibility of an entirely biological solution for hearing loss in the long term. This report comprises the latest developments presented in the first Symposium on cochlear implants and regenerative biology, held at the 14th International Conference on Cochlear Implants in 2016 in Toronto, Canada.
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Volkov O, Kovalev K, Polovinkin V, Borshchevskiy V, Bamann C, Astashkin R, Marin E, Popov A, Balandin T, Willbold D, Büldt G, Bamberg E, Gordeliy V. Structural insights into ion conduction by channelrhodopsin 2. Science 2018; 358:358/6366/eaan8862. [PMID: 29170206 DOI: 10.1126/science.aan8862] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/30/2017] [Indexed: 11/02/2022]
Abstract
The light-gated ion channel channelrhodopsin 2 (ChR2) from Chlamydomonas reinhardtii is a major optogenetic tool. Photon absorption starts a well-characterized photocycle, but the structural basis for the regulation of channel opening remains unclear. We present high-resolution structures of ChR2 and the C128T mutant, which has a markedly increased open-state lifetime. The structure reveals two cavities on the intracellular side and two cavities on the extracellular side. They are connected by extended hydrogen-bonding networks involving water molecules and side-chain residues. Central is the retinal Schiff base that controls and synchronizes three gates that separate the cavities. Separate from this network is the DC gate that comprises a water-mediated bond between C128 and D156 and interacts directly with the retinal Schiff base. Comparison with the C128T structure reveals a direct connection of the DC gate to the central gate and suggests how the gating mechanism is affected by subtle tuning of the Schiff base's interactions.
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Affiliation(s)
- Oleksandr Volkov
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany
| | - Kirill Kovalev
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany.,Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes-Commissariat à l'Energie Atomique et aux Energies Alternatives-CNRS, Grenoble, France.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Institute of Crystallography, University of Aachen, Aachen, Germany
| | - Vitaly Polovinkin
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany.,Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes-Commissariat à l'Energie Atomique et aux Energies Alternatives-CNRS, Grenoble, France.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,ELI Beamlines, Institute of Physics, Czech Academy of Sciences, 18221 Prague, Czech Republic
| | | | | | - Roman Astashkin
- Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes-Commissariat à l'Energie Atomique et aux Energies Alternatives-CNRS, Grenoble, France.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Egor Marin
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Alexander Popov
- European Synchrotron Radiation Facility, 38027 Grenoble, France
| | - Taras Balandin
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany
| | - Dieter Willbold
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany.,Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes-Commissariat à l'Energie Atomique et aux Energies Alternatives-CNRS, Grenoble, France.,Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Georg Büldt
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| | - Valentin Gordeliy
- Institute of Complex Systems (ICS), ICS-6: Structural Biochemistry, Research Centre Juelich, Juelich, Germany. .,Institut de Biologie Structurale Jean-Pierre Ebel, Université Grenoble Alpes-Commissariat à l'Energie Atomique et aux Energies Alternatives-CNRS, Grenoble, France.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia
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31
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Moser T. [Molecular Understanding of Hearing - How Does This Matter to the Hearing Impaired?]. Laryngorhinootologie 2018; 97:S214-S230. [PMID: 29905358 PMCID: PMC6541096 DOI: 10.1055/s-0043-121595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This review addresses the advances of our molecular understanding of hearing and how this benefits the hearing impaired. Classical biochemical methods usually fall short in contributing to the analysis of the molecular mechanisms of hearing e. g. in the cochlea, the auditory part of the inner ear, due to the scarcity of the cells of interest. Genetics, molecular cell biology, and physiology, on the other hand, have elucidated the intricate molecular and cellular mechanisms that bring about the outstanding performance of the auditory system. Many of those mechanisms are quite unique and specialized to serve the specific needs of hearing. Hence, their defects often spare other organs and lead to specific non-syndromic deafness. High throughput sequencing can reveal causes of sporadic deafness when combined with careful bioinformatics. Molecular approaches are also helpful for understanding more common forms of hearing impairment such as noise-induced hearing impairment. While molecular therapies are not yet clinically available, careful molecular genetic analysis helps to counsel the hearing impaired subjects.
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Affiliation(s)
- Tobias Moser
- Institut für Auditorische Neurowissenschaften, Universitätsmedizin Göttingen
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32
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Affiliation(s)
- Klaus Gerwert
- Department of Biophysics, Ruhr-Universität Bochum, 44780 Bochum, Germany.
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33
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Abstract
Here I identify two gaps in cochlear implants that have been limiting their performance and acceptance. First, cochlear implant performance has remained largely unchanged, despite the number of publications tripling per decade in the last 30 years. Little has been done so far to address a fundamental limitation in the electrode-to-neuron interface, with the electrode size being a thousand times larger than the neuron diameter while the number of electrodes being a thousand times less. Both the small number and the large size of electrodes produce broad spatial activation and poor frequency resolution that limit current cochlear implant performance. Second, a similarly rapid growth in cochlear implant volume has not produced an expected decrease in unit price in the same period. The high cost contributes to low market penetration rate, which is about 20% in developed countries and less than 1% in developing countries. I will discuss changes needed in both research strategy and business practice to close the gap between prosthetic and normal hearing as well as that between haves and have-nots.
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34
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Dinakaran D, Gossler C, Mounir C, Paul O, Schwarz UT, Ruther P. Phosphor-based light conversion for miniaturized optical tools. APPLIED OPTICS 2017; 56:3654-3659. [PMID: 28463249 DOI: 10.1364/ao.56.003654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This paper describes the application of phosphor-based light conversion for its use in optogenetic experiments to tailor the wavelength of light emitted from implantable miniaturized light sources. Gallium-nitride-based blue light-emitting diodes are used in combination with orthosilicate phosphor immersed in an epoxy matrix and emitting in the yellow wavelength range. The miniaturization of the phosphor-containing polymer droplets toward diameters as small as 300 μm provides the compatibility with implantable optical probes. The parameter study applied here varied the concentration of the phosphor material in the polymer matrix as well as the droplet height in order to tailor the characteristics of blue-to-yellow light conversion.
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35
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Wu T, Ramamoorthy S, Wilson T, Chen F, Porsov E, Subhash H, Foster S, Zhang Y, Omelchenko I, Bateschell M, Wang L, Brigande JV, Jiang ZG, Mao T, Nuttall AL. Optogenetic Control of Mouse Outer Hair Cells. Biophys J 2016; 110:493-502. [PMID: 26789771 DOI: 10.1016/j.bpj.2015.11.3521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/15/2015] [Accepted: 11/13/2015] [Indexed: 01/28/2023] Open
Abstract
Normal hearing in mammals depends on sound amplification by outer hair cells (OHCs) presumably by their somatic motility and force production. However, the role of OHC force production in cochlear amplification and frequency tuning are not yet fully understood. Currently, available OHC manipulation techniques for physiological or clinical studies are limited by their invasive nature, lack of precision, and poor temporal-spatial resolution. To overcome these limitations, we explored an optogenetic approach based on channelrhodopsin 2 (ChR-2), a direct light-activated nonselective cation channel originally discovered in Chlamydomonas reinhardtii. Three approaches were compared: 1) adeno-associated virus-mediated in utero transfer of the ChR-2 gene into the developing murine otocyst, 2) expression of ChR-2(H134R) in an auditory cell line (HEI-OC1), and 3) expression of ChR-2 in the OHCs of a mouse line carrying a ChR-2 conditional allele. Whole cell recording showed that blue light (470 nm) elicited the typical nonselective cation current of ChR-2 with reversal potential around zero in both mouse OHCs and HEI-OC1 cells and generated depolarization in both cell types. In addition, pulsed light stimulation (10 Hz) elicited a 1:1 repetitive depolarization and ChR-2 currents in mouse OHCs and HEI-OC1 cells, respectively. The time constant of depolarization in OHCs, 1.45 ms, is 10 times faster than HEI-OC1 cells, which allowed light stimulation up to rates of 10/s to elicit corresponding membrane potential changes. Our study demonstrates that ChR-2 can successfully be expressed in mouse OHCs and HEI-OC1 cells and that these present a typical light-sensitive current and depolarization. However, the amount of ChR-2 current induced in our in vivo experiments was insufficient to result in measurable cochlear effects.
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Affiliation(s)
- Tao Wu
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Sripriya Ramamoorthy
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Teresa Wilson
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Fangyi Chen
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Edward Porsov
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Hrebesh Subhash
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Sarah Foster
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Yuan Zhang
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Irina Omelchenko
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Michael Bateschell
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Lingyan Wang
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - John V Brigande
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Zhi-Gen Jiang
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Tianyi Mao
- The Vollum Institute, Oregon Health & Science University, Portland, Oregon
| | - Alfred L Nuttall
- Oregon Hearing Research Center, NRC04, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon; Kresge Hearing Research Institute, The University of Michigan, Ann Arbor, Michigan.
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36
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Weiss RS, Voss A, Hemmert W. Optogenetic stimulation of the cochlea-A review of mechanisms, measurements, and first models. NETWORK (BRISTOL, ENGLAND) 2016; 27:212-236. [PMID: 27644125 DOI: 10.1080/0954898x.2016.1224944] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This review evaluates the potential of optogenetic methods for the stimulation of the auditory nerve and assesses the feasability of optogenetic cochlear implants (CIs). It provides an overview of all critical steps like opsin targeting strategies, how opsins work, how their function can be modeled and included in neuronal models and the properties of light sources available for optical stimulation. From these foundations, quantitative estimates for the number of independent stimulation channels and the temporal precision of optogenetic stimulation of the auditory nerve are derived and compared with state-of-the-art electrical CIs. We conclude that optogenetic CIs have the potential to increase the number of independent stimulation channels by up to one order of magnitude to about 100, but only if light sources are able to deliver confined illumination patterns independently and parallelly. Already now, opsin variants like ChETA and Chronos enable driving of the auditory nerve up to rates of 200 spikes/s, close to the physiological value of their maximum sustained firing rate. Apart from requiring 10 times more energy than electrical stimulation, optical CIs still face major hurdles concerning the safety of gene transfection and optrode array implantation, for example, before becoming an option to replace electrical CIs.
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Affiliation(s)
- Robin S Weiss
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
| | - Andrej Voss
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
| | - Werner Hemmert
- a Bio-Inspired Information Processing, Faculty of Electrical and Computer Engineering , Technical University of Munich , Garching , Germany
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37
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Depth-specific optogenetic control in vivo with a scalable, high-density μLED neural probe. Sci Rep 2016; 6:28381. [PMID: 27334849 PMCID: PMC4917834 DOI: 10.1038/srep28381] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/03/2016] [Indexed: 01/04/2023] Open
Abstract
Controlling neural circuits is a powerful approach to uncover a causal link between neural activity and behaviour. Optogenetics has been widely adopted by the neuroscience community as it offers cell-type-specific perturbation with millisecond precision. However, these studies require light delivery in complex patterns with cellular-scale resolution, while covering a large volume of tissue at depth in vivo. Here we describe a novel high-density silicon-based microscale light-emitting diode (μLED) array, consisting of up to ninety-six 25 μm-diameter μLEDs emitting at a wavelength of 450 nm with a peak irradiance of 400 mW/mm2. A width of 100 μm, tapering to a 1 μm point, and a 40 μm thickness help minimise tissue damage during insertion. Thermal properties permit a set of optogenetic operating regimes, with ~0.5 °C average temperature increase. We demonstrate depth-dependent activation of mouse neocortical neurons in vivo, offering an inexpensive novel tool for the precise manipulation of neural activity.
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38
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Moritz CT, Ruther P, Goering S, Stett A, Ball T, Burgard W, Chudler EH, Rao RPN. New Perspectives on Neuroengineering and Neurotechnologies: NSF-DFG Workshop Report. IEEE Trans Biomed Eng 2016; 63:1354-67. [PMID: 27008657 DOI: 10.1109/tbme.2016.2543662] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
GOAL To identify and overcome barriers to creating new neurotechnologies capable of restoring both motor and sensory function in individuals with neurological conditions. METHODS This report builds upon the outcomes of a joint workshop between the US National Science Foundation and the German Research Foundation on New Perspectives in Neuroengineering and Neurotechnology convened in Arlington, VA, USA, November 13-14, 2014. RESULTS The participants identified key technological challenges for recording and manipulating neural activity, decoding, and interpreting brain data in the presence of plasticity, and early considerations of ethical and social issues pertinent to the adoption of neurotechnologies. CONCLUSIONS The envisaged progress in neuroengineering requires tightly integrated hardware and signal processing efforts, advances in understanding of physiological adaptations to closed-loop interactions with neural devices, and an open dialog with stakeholders and potential end-users of neurotechnology. SIGNIFICANCE The development of new neurotechnologies (e.g., bidirectional brain-computer interfaces) could significantly improve the quality of life of people living with the effects of brain or spinal cord injury, or other neurodegenerative diseases. Focused efforts aimed at overcoming the remaining barriers at the electrode tissue interface, developing implantable hardware with on-board computation, and refining stimulation methods to precisely activate neural tissue will advance both our understanding of brain function and our ability to treat currently intractable disorders of the nervous system.
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39
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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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40
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McAlinden N, Gu E, Dawson MD, Sakata S, Mathieson K. Optogenetic activation of neocortical neurons in vivo with a sapphire-based micro-scale LED probe. Front Neural Circuits 2015; 9:25. [PMID: 26074778 PMCID: PMC4448043 DOI: 10.3389/fncir.2015.00025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 05/09/2015] [Indexed: 11/20/2022] Open
Abstract
Optogenetics has proven to be a revolutionary technology in neuroscience and has advanced continuously over the past decade. However, optical stimulation technologies for in vivo need to be developed to match the advances in genetics and biochemistry that have driven this field. In particular, conventional approaches for in vivo optical illumination have a limitation on the achievable spatio-temporal resolution. Here we utilize a sapphire-based microscale gallium nitride light-emitting diode (μLED) probe to activate neocortical neurons in vivo. The probes were designed to contain independently controllable multiple μLEDs, emitting at 450 nm wavelength with an irradiance of up to 2 W/mm2. Monte-Carlo stimulations predicted that optical stimulation using a μLED can modulate neural activity within a localized region. To validate this prediction, we tested this probe in the mouse neocortex that expressed channelrhodopsin-2 (ChR2) and compared the results with optical stimulation through a fiber at the cortical surface. We confirmed that both approaches reliably induced action potentials in cortical neurons and that the μLED probe evoked strong responses in deep neurons. Due to the possibility to integrate many optical stimulation sites onto a single shank, the μLED probe is thus a promising approach to control neurons locally in vivo.
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Affiliation(s)
- Niall McAlinden
- Institute of Photonics, Department of Physics, University of Strathclyde Glasgow, UK
| | - Erdan Gu
- Institute of Photonics, Department of Physics, University of Strathclyde Glasgow, UK
| | - Martin D Dawson
- Institute of Photonics, Department of Physics, University of Strathclyde Glasgow, UK
| | - Shuzo Sakata
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde Glasgow, UK ; Centre for Neuroscience, University of Strathclyde Glasgow, UK
| | - Keith Mathieson
- Institute of Photonics, Department of Physics, University of Strathclyde Glasgow, UK
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