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Sriperumbudur KK, Appali R, Gummer AW, van Rienen U. Understanding the impact of modiolus porosity on stimulation of spiral ganglion neurons by cochlear implants. Sci Rep 2024; 14:9593. [PMID: 38671022 PMCID: PMC11053021 DOI: 10.1038/s41598-024-59347-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Moderate-to-profound sensorineural hearing loss in humans is treatable by electrically stimulating the auditory nerve (AN) with a cochlear implant (CI). In the cochlea, the modiolus presents a porous bony interface between the CI electrode and the AN. New bone growth caused by the presence of the CI electrode or neural degeneration inflicted by ageing or otological diseases might change the effective porosity of the modiolus and, thereby, alter its electrical material properties. Using a volume conductor description of the cochlea, with the aid of a 'mapped conductivity' method and an ad-hoc 'regionally kinetic' equation system, we show that even a slight variation in modiolus porosity or pore distribution can disproportionately affect AN stimulation. Hence, because of porosity changes, an inconsistent CI performance might occur if neural degeneration or new bone growth progress after implantation. Appropriate electrical material properties in accordance with modiolar morphology and pathology should be considered in patient-specific studies. The present first-of-its-kind in-silico study advocates for contextual experimental studies to further explore the utility of modiolus porous morphology in optimising the CI outcome.
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Affiliation(s)
- Kiran K Sriperumbudur
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany.
- Research and Development, MED-EL Medical Electronics GmbH, Innsbruck, Austria.
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Anthony W Gummer
- Department of Otolaryngology, University of Tübingen, Tübingen, Germany.
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia.
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
- Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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2
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Montazeri K, Farhadi M, Akbarnejad Z, Asadpour A, Majdabadi A, Fekrazad R, Mahmoudian S. Acoustic and optoacoustic stimulations in auditory brainstem response test in salicylate induced tinnitus. Sci Rep 2023; 13:11930. [PMID: 37488197 PMCID: PMC10366222 DOI: 10.1038/s41598-023-39033-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023] Open
Abstract
As a common debilitating disorder worldwide, tinnitus requires objective assessment. In the auditory brainstem response (ABR) test, auditory potentials can be evoked by acoustic or optoacoustic (induced by laser light) stimulations. In order to use the ABR test in the objective assessment of tinnitus, in this study, acoustic ABR (aABR) and optoacoustic ABR (oABR) were compared in the control and tinnitus groups to determine the changes caused by sodium salicylate (SS)-induced tinnitus in rat. In both aABR and oABR, wave II was the most prominent waveform, and the amplitude of wave II evoked by oABR was significantly higher than that of aABR. Brainstem transmission time (BTT), which represents the time required for a neural stimulation to progress from the auditory nerve ending to the inferior colliculus, was significantly shorter in oABR. In the tinnitus group, there was a significant increase in the threshold of both ABRs and a significant decrease in the amplitude of wave II only in the oABR. Based on our findings, the ABR test has the potential to be used in the assessment of SS-induced tinnitus, but oABR has the advantages of producing more prominent waveforms and significantly reducing the amplitude of wave II in tinnitus.
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Affiliation(s)
- Katayoon Montazeri
- ENT and Head and Neck Research Center, The Five Senses Health Institute, School of Medicine, Hazrate Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, 1445613131, Iran
| | - Mohammad Farhadi
- ENT and Head and Neck Research Center, The Five Senses Health Institute, School of Medicine, Hazrate Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, 1445613131, Iran
| | - Zeinab Akbarnejad
- ENT and Head and Neck Research Center, The Five Senses Health Institute, School of Medicine, Hazrate Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, 1445613131, Iran
| | - Abdoreza Asadpour
- Intelligent Systems Research Centre, Ulster University, Derry Campus, Derry~Londonderry, Northern Ireland, UK
| | - Abbas Majdabadi
- Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Fekrazad
- Radiation Sciences Research Center, Laser Research Center in Medical Sciences, AJA University of Medical Sciences, Tehran, Iran
| | - Saeid Mahmoudian
- ENT and Head and Neck Research Center, The Five Senses Health Institute, School of Medicine, Hazrate Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, 1445613131, Iran.
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3
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Tian L, Zeng M, Tian G, Xu J. In-vitro quantitative measurement and analysis of the photosensitivity of cells to a weak pulse laser. BIOMEDICAL OPTICS EXPRESS 2023; 14:3584-3596. [PMID: 37497496 PMCID: PMC10368051 DOI: 10.1364/boe.494620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/05/2023] [Accepted: 06/13/2023] [Indexed: 07/28/2023]
Abstract
Light can trigger electrical activity in certain types of cells, and is considered to be a better means of biological regulation than electrical stimulation in the future. Due to the specificity and selectivity of natural cells' photoresponse to optical signals, constructing an applicable method to explore which kinds of cells have photosensitivity and which bands of light could induce its photoresponse most effectively, is of great significance for lights' medical applications. This paper firstly proposed a universal and operable system and corresponding method to quantitatively measure and analyze photosensitivity of cells in vitro to weak pulse laser, which is constructed with Ca2+ imaging module, adjustable laser lights module and laser positioning module. With the measurement system and method, the photosensitive effects of the natural spiral ganglion cells (SGCs) of mice are tested systemantically. Then a new photoresponse band of light (453 nm, 300 µs) is found for SGCs, and its minimum threshold is measured as 5.3 mJ/cm2. The results verify that the proposed method is applicable to screen the cells with photosensitive response, as well as to measure and analyze the working optical parameters, thus is beneficial for the optical biophysics and photobiology.
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Affiliation(s)
- Lan Tian
- School of Microelectronics, Shandong University, Jinan 250100, Shandong, China
| | - Ming Zeng
- School of Microelectronics, Shandong University, Jinan 250100, Shandong, China
| | - Geng Tian
- School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China
| | - Jingjing Xu
- School of Microelectronics, Shandong University, Jinan 250100, Shandong, China
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4
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Cutri RM, Lin J, Nguyen NV, Shakya D, Shibata SB. Neomycin-Induced Deafness in Neonatal Mice. J Neurosci Methods 2023; 391:109852. [PMID: 37031766 DOI: 10.1016/j.jneumeth.2023.109852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/26/2023] [Accepted: 04/06/2023] [Indexed: 04/11/2023]
Abstract
BACKGROUND Hearing impairment is a rising public health issue, and current therapeutics fail to restore normal auditory sensation. Animal models are essential to a better understanding of the pathophysiology of deafness and developing therapeutics to restore hearing. NEW METHODS Wild-type CBA/CaJ neonatal mice P2-5 were used in this study. Neomycin suspension (500nl of 50 or 100mg/ml) was micro-injected into the endolymphatic space. Cochlear morphology was examined 3 and 7 days after injection; hair cell (HC) loss, supporting cell morphology, and neurite denervation pattern were assessed with whole-mounts. At 2 and 4 weeks post-injection, the spiral ganglion neuron (SGN) density was analyzed with cryostat sections. Audiometric responses were measured with auditory brain response (ABR) at 4 weeks. RESULTS Rapid and complete degeneration of the inner and outer HCs occurred as early as 3 days post-injection. Subsequently, time- and dose-dependent degeneration patterns were observed along the axis of the cochlear membranous labyrinth forming a flat epithelium. Likewise, the SGN histology demonstrated significant cell density reduction at 2 and 4 weeks. The ABR threshold measurements confirmed profound deafness at 4 weeks. COMPARISON WITH EXISTING METHODS Compared to previously described local and systemic aminoglycoside injections, this method provides a reliable, robust, and rapid deafening model with a single infusion of neomycin in neonatal mice. This model also allows for investigating the effects of inner ear damage during auditory maturation. CONCLUSIONS A single injection of neomycin into the endolymphatic space induces robust HC loss and denervation in neonatal mice.
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Affiliation(s)
- Raffaello M Cutri
- Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Joshua Lin
- Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Nhi V Nguyen
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Dejan Shakya
- Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Seiji B Shibata
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA.
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5
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Ping A, Pan L, Zhang J, Xu K, Schriver KE, Zhu J, Roe AW. Targeted Optical Neural Stimulation: A New Era for Personalized Medicine. Neuroscientist 2023; 29:202-220. [PMID: 34865559 DOI: 10.1177/10738584211057047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Targeted optical neural stimulation comprises infrared neural stimulation and optogenetics, which affect the nervous system through induced thermal transients and activation of light-sensitive proteins, respectively. The main advantage of this pair of optical tools is high functional selectivity, which conventional electrical stimulation lacks. Over the past 15 years, the mechanism, safety, and feasibility of optical stimulation techniques have undergone continuous investigation and development. When combined with other methods like optical imaging and high-field functional magnetic resonance imaging, the translation of optical stimulation to clinical practice adds high value. We review the theoretical foundations and current state of optical stimulation, with a particular focus on infrared neural stimulation as a potential bridge linking optical stimulation to personalized medicine.
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Affiliation(s)
- An Ping
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Li Pan
- Qiushi Academy for Advanced Studies (QAAS), Key Laboratory of Biomedical Engineering of Education Ministry & Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Kedi Xu
- Qiushi Academy for Advanced Studies (QAAS), Key Laboratory of Biomedical Engineering of Education Ministry & Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, Zhejiang, China.,Zhejiang Lab, Hangzhou, Zhejiang, China
| | - Kenneth E Schriver
- Zhejiang University Interdisciplinary Institute of Neuroscience and Technology (ZIINT), School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Junming Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Anna Wang Roe
- Zhejiang University Interdisciplinary Institute of Neuroscience and Technology (ZIINT), School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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6
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Xiao T, Wu K, Wang P, Ding Y, Yang X, Chang C, Yang Y. Sensory input-dependent gain modulation of the optokinetic nystagmus by mid-infrared stimulation in pigeons. eLife 2023; 12:78729. [PMID: 36853228 PMCID: PMC9977280 DOI: 10.7554/elife.78729] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 02/12/2023] [Indexed: 03/01/2023] Open
Abstract
Neuromodulation serves as a cornerstone for brain sciences and clinical applications. Recent reports suggest that mid-infrared stimulation (MIRS) causes non-thermal modulation of brain functions. Current understanding of its mechanism hampers the routine application of MIRS. Here, we examine how MIRS influences the sensorimotor transformation in awaking-behaving pigeons, from neuronal signals to behavior. We applied MIRS and electrical stimulation (ES) to the pretectal nucleus lentiformis mesencephali (nLM), an essential retinorecipient structure in the pretectum, and examined their influences on the optokinetic nystagmus, a visually guided eye movement. We found MIRS altered eye movements by modulating a specific gain depending on the strength of visual inputs, in a manner different than the effect of ES. Simultaneous extracellular recordings and stimulation showed that MIRS could either excite and inhibit the neuronal activity in the same pretectal neuron depending on its ongoing sensory responsiveness levels in awake-behaving animals. Computational simulations suggest that MIRS modulates the resonance of a carbonyl group of the potassium channel, critical to the action potential generation, altering neuronal responses to sensory inputs and as a consequence, guiding behavior. Our findings suggest that MIRS could be a promising approach toward modulating neuronal functions for brain research and treating neurological diseases.
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Affiliation(s)
- Tong Xiao
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Kaijie Wu
- Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense TechnologyBeijingChina
| | - Peiliang Wang
- University of Chinese Academy of SciencesBeijingChina
- Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense TechnologyBeijingChina
- Key Laboratory of Electromagnetic Radiation and Sensing Technology, Aerospace Information Research Institute, Chinese Academy of sciencesBeijingChina
| | - Yali Ding
- University of Chinese Academy of SciencesBeijingChina
| | - Xiao Yang
- Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense TechnologyBeijingChina
| | - Chao Chang
- Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense TechnologyBeijingChina
- School of Physics, Peking UniversityBeijingChina
| | - Yan Yang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
- Institute of Artificial Intelligence, Hefei Comprehensive National Science CenterHefeiChina
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7
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Pan L, Ping A, Schriver KE, Roe AW, Zhu J, Xu K. Infrared neural stimulation in human cerebral cortex. Brain Stimul 2023; 16:418-430. [PMID: 36731770 DOI: 10.1016/j.brs.2023.01.1678] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 01/28/2023] [Accepted: 01/28/2023] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Modulation of brain circuits by electrical stimulation has led to exciting and powerful therapies for diseases such as Parkinson's. Because human brain organization is based in mesoscale (millimeter-scale) functional nodes, having a method that can selectively target such nodes could enable more precise, functionally specific stimulation therapies. Infrared Neural Stimulation (INS) is an emerging stimulation technology that stimulates neural tissue via delivery of tiny heat pulses. In nonhuman primates, this optical method provides focal intensity-dependent stimulation of the brain without tissue damage. However, whether INS application to the human central nervous system (CNS) is similarly effective is unknown. OBJECTIVE To examine the effectiveness of INS on human cerebral cortex in intraoperative setting and to evaluate INS damage threshholds. METHODS Five epileptic subjects undergoing standard lobectomy for epilepsy consented to this study. Cortical response to INS was assessed by intrinsic signal optical imaging (OI, a method that detects changes in tissue reflectance due to neuronal activity). A custom integrated INS and OI system was developed specifically for short-duration INS and OI acquisition during surgical procedures. Single pulse trains of INS with intensities from 0.2 to 0.8 J/cm2 were delivered to the somatosensory cortex and responses were recorded via optical imaging. Following tissue resection, histological analysis was conducted to evaluate damage threshholds. RESULTS As assessed by OI, and similar to results in monkeys, INS induced responses in human cortex were highly focal (millimeter sized) and led to relative suppression of nearby cortical sites. Intensity dependence was observed at both stimulated and functionally connected sites. Histological analysis of INS-stimulated human cortical tissue provided damage threshold estimates. CONCLUSION This is the first study demonstrating application of INS to human CNS and shows feasibility for stimulating single cortical nodes and associated sites and provided INS damage threshold estimates for cortical tissue. Our results suggest that INS is a promising tool for stimulation of functionally selective mesoscale circuits in the human brain, and may lead to advances in the future of precision medicine.
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Affiliation(s)
- Li Pan
- Qiushi Academy for Advanced Studies (QAAS), Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China.
| | - An Ping
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
| | - Kenneth E Schriver
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
| | - Anna Wang Roe
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; Interdisciplinary Institute of Neuroscience and Technology (ZIINT), School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China.
| | - Junming Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China.
| | - Kedi Xu
- Qiushi Academy for Advanced Studies (QAAS), Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, Zhejiang University, Hangzhou, China.
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8
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Uenaka M, Nagamura H, Okamoto A, Hiryu S, Kobayasi KI, Tamai Y. Feasibility evaluation of transtympanic laser stimulation of the cochlea from the outer ear. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:1850. [PMID: 36182303 DOI: 10.1121/10.0014241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
Infrared laser stimulation has been studied as an alternative approach to auditory prostheses. This study evaluated the feasibility of infrared laser stimulation of the cochlea from the outer ear, bypassing the middle ear function. An optic fiber was inserted into the ear canal, and a laser was used to irradiate the cochlea through the tympanic membrane in Mongolian gerbils. A pulsed infrared laser (6.9 mJ/cm2) and clicking sound (70 peak-to-peak equivalent sound pressure level) were presented to the animals. The amplitude of the laser-evoked cochlear response was systematically decreased following insertion of a filter between the tympanic membrane and cochlea; however, the auditory-evoked cochlear response did not decrease. The filter was removed, and the laser-evoked response returned to around the original level. The amplitude ratio and the relative change in response amplitude before and during filter insertion significantly decreased as the absorbance of the infrared filter increased. These results indicate that laser irradiation could bypass the function of the middle ear and directly activate the cochlea. Therefore, laser irradiation from the outer ear is a possible alternative for stimulating the cochlea, circumventing the middle ear.
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Affiliation(s)
- Miku Uenaka
- Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Hidekazu Nagamura
- Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Aya Okamoto
- Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Shizuko Hiryu
- Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Kohta I Kobayasi
- Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Yuta Tamai
- Organization for Research Initiatives and Development, Doshisha University, Kyotanabe, Kyoto, Japan
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9
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Theoretical simulation of the selective stimulation of axons in different areas of a nerve bundle by multichannel near-infrared lasers. Med Biol Eng Comput 2021; 60:205-220. [PMID: 34807355 DOI: 10.1007/s11517-021-02475-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 09/07/2021] [Indexed: 10/19/2022]
Abstract
Damaged nerve function can be repaired by applying external stimuli, and the selective stimulation of nerve fibers is the highest goal of nerve functional repair. This paper proposes a method of using multichannel near-infrared lasers to achieve the selective stimulation of axons in different areas in a mixed nerve bundle. An exposed bullfrog sciatic nerve was considered the object of study to realize the selective stimulation. A model was established by using COMSOL Multiphysics to simulate the temperature distribution of nerves under multichannel near-infrared laser stimulation. The results of this model showed that by changing the distance between the laser fiber and the nerve (d) or the power of the 4 lasers (P), the axons at different parts of the nerve bundle may be selectively stimulated. If only the axons located in the center are selected to be activated, it is necessary to set the d and P value in the four directions to the same value. If only axons on the nerve edge are selected for activation, we can reduce the d value of the nearest laser (or increase P) and increase the d value of lasers in other directions (or decrease P). If only axons in the shallow area below the surface between the two lasers are selected for activation, it is necessary to reduce the d value of the laser in two directions close there (or increase P) and increase the d value of the laser in the other two directions (or decrease P). If only the axons of the superficial region on the coordinate axis are activated, the d value of the laser in the farthest direction can be increased (or decrease P) and the d value of the other three lasers can be reduced (or increase P). Moreover, the results of animal experiments further verify the feasibility of our method to realize selective activation of the axons.
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10
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Park Y, Park SY, Eom K. Current Review of Optical Neural Interfaces for Clinical Applications. MICROMACHINES 2021; 12:925. [PMID: 34442547 PMCID: PMC8400671 DOI: 10.3390/mi12080925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Neural interfaces, which enable the recording and stimulation of living neurons, have emerged as valuable tools in understanding the brain in health and disease, as well as serving as neural prostheses. While neural interfaces are typically based on electrical transduction, alternative energy modalities have been explored to create safe and effective approaches. Among these approaches, optical methods of linking neurons to the outside world have gained attention because light offers high spatial selectivity and decreased invasiveness. Here, we review the current state-of-art of optical neural interfaces and their clinical applications. Optical neural interfaces can be categorized into optical control and optical readout, each of which can be divided into intrinsic and extrinsic approaches. We discuss the advantages and disadvantages of each of these methods and offer a comparison of relative performance. Future directions, including their clinical opportunities, are discussed with regard to the optical properties of biological tissue.
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Affiliation(s)
| | - Sung-Yun Park
- Department of Electronics Engineering, College of Engineering, Pusan National University, Busan 46241, Korea;
| | - Kyungsik Eom
- Department of Electronics Engineering, College of Engineering, Pusan National University, Busan 46241, Korea;
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11
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Xu J, Zeng M, Xu X, Liu J, Huo X, Han D, Wang Z, Tian L. A Micron-Sized Laser Photothermal Effect Evaluation System and Method. SENSORS (BASEL, SWITZERLAND) 2021; 21:5133. [PMID: 34372369 PMCID: PMC8348586 DOI: 10.3390/s21155133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 11/17/2022]
Abstract
The photothermal effects of lasers have played an important role in both medical laser applications and the development of cochlear implants with optical stimulation. However, there are few methods to evaluate the thermal effect of micron-sized laser spots interacting with other tissues. Here, we present a multi-wavelength micro-scale laser thermal effect measuring system that has high temporal, spatial and temperature resolutions, and can quantitatively realize evaluations in real time. In this system, with accurate 3D positioning and flexible pulsed laser parameter adjustments, groups of temperature changes are systematically measured when the micron-sized laser spots from six kinds of wavelengths individually irradiate the Pd/Cr thermocouple junction area, and reference data of laser spot thermal effects are obtained. This work develops a stable, reliable and universal tool for quantitatively exploring the thermal effect of micron-sized lasers, and provides basic reference data for research on light-stimulated neuron excitement in the future.
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Affiliation(s)
- Jingjing Xu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
- Shenzhen Research Institute, Shandong University, Shenzhen 518057, China
| | - Ming Zeng
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Xin Xu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Junhui Liu
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Xinyu Huo
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
| | - Danhong Han
- Beijing Research Institute of Mechanical Equipment, Beijing 100854, China; (D.H.); (Z.W.)
| | - Zhenhai Wang
- Beijing Research Institute of Mechanical Equipment, Beijing 100854, China; (D.H.); (Z.W.)
| | - Lan Tian
- Institute of Microelectronics, Shandong University, Jinan 250102, China; (J.X.); (M.Z.); (X.X.); (J.L.); (X.H.)
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12
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Viral-mediated transduction of auditory neurons with opsins for optical and hybrid activation. Sci Rep 2021; 11:11229. [PMID: 34045604 PMCID: PMC8160204 DOI: 10.1038/s41598-021-90764-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/13/2021] [Indexed: 12/15/2022] Open
Abstract
Optical stimulation is a paradigm-shifting approach to modulating neural activity that has the potential to overcome the issue of current spread that occurs with electrical stimulation by providing focused stimuli. But optical stimulation either requires high power infrared light or genetic modification of neurons to make them responsive to lower power visible light. This work examines optical activation of auditory neurons following optogenetic modification via AAV injection in two species (mouse and guinea pig). An Anc80 viral vector was used to express the channelrhodopsin variant ChR2-H134R fused to a fluorescent reporter gene under the control of the human synapsin-1 promoter. The AAV was administered directly to the cochlea (n = 33) or posterior semi-circular canal of C57BL/6 mice (n = 4) or to guinea pig cochleae (n = 6). Light (488 nm), electrical stimuli or the combination of these (hybrid stimulation) was delivered to the cochlea via a laser-coupled optical fibre and co-located platinum wire. Activation thresholds, spread of activation and stimulus interactions were obtained from multi-unit recordings from the central nucleus of the inferior colliculus of injected mice, as well as ChR2-H134R transgenic mice (n = 4). Expression of ChR2-H134R was examined by histology. In the mouse, transduction of auditory neurons by the Anc80 viral vector was most successful when injected at a neonatal age with up to 89% of neurons transduced. Auditory neuron transductions were not successful in guinea pigs. Inferior colliculus responses to optical stimuli were detected in a cochleotopic manner in all mice with ChR2-H134R expression. There was a significant correlation between lower activation thresholds in mice and higher proportions of transduced neurons. There was no difference in spread of activation between optical stimulation and electrical stimulation provided by the light/electrical delivery system used here (optical fibre with bonded 25 µm platinum/iridium wire). Hybrid stimulation, comprised of sub-threshold optical stimulation to 'prime' or raise the excitability of the neurons, lowered the threshold for electrical activation in most cases, but the impact on excitation width was more variable compared to transgenic mice. This study demonstrates the impact of opsin expression levels and expression pattern on optical and hybrid stimulation when considering optical or hybrid stimulation techniques for neuromodulation.
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Kaszas A, Szalay G, Slézia A, Bojdán A, Vanzetta I, Hangya B, Rózsa B, O'Connor R, Moreau D. Two-photon GCaMP6f imaging of infrared neural stimulation evoked calcium signals in mouse cortical neurons in vivo. Sci Rep 2021; 11:9775. [PMID: 33963220 PMCID: PMC8105372 DOI: 10.1038/s41598-021-89163-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/22/2021] [Indexed: 02/07/2023] Open
Abstract
Infrared neural stimulation is a promising tool for stimulating the brain because it can be used to excite with high spatial precision without the need of delivering or inserting any exogenous agent into the tissue. Very few studies have explored its use in the brain, as most investigations have focused on sensory or motor nerve stimulation. Using intravital calcium imaging with the genetically encoded calcium indicator GCaMP6f, here we show that the application of infrared neural stimulation induces intracellular calcium signals in Layer 2/3 neurons in mouse cortex in vivo. The number of neurons exhibiting infrared-induced calcium response as well as the amplitude of those signals are shown to be both increasing with the energy density applied. By studying as well the spatial extent of the stimulation, we show that reproducibility of the stimulation is achieved mainly in the central part of the infrared beam path. Stimulating in vivo at such a degree of precision and without any exogenous chromophores enables multiple applications, from mapping the brain's connectome to applications in systems neuroscience and the development of new therapeutic tools for investigating the pathological brain.
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Affiliation(s)
- Attila Kaszas
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - Gergely Szalay
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Andrea Slézia
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Alexandra Bojdán
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Ivo Vanzetta
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, 1083, Hungary
| | - Balázs Rózsa
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, 1083, Hungary
- Two-Photon Laboratory, Faculty of Information Technology, Pázmány Péter Catholic University, Budapest, 1083, Hungary
| | - Rodney O'Connor
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005, Marseille, France
| | - David Moreau
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541, Gardanne, France.
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Cury J, Vande Perre L, Smets H, Stumpp L, Vespa S, Vanhoestenberghe A, Doguet P, Delbeke J, El Tahry R, Gorza SP, Nonclercq A. Infrared neurostimulation in ex-vivorat sciatic nerve using 1470 nm wavelength. J Neural Eng 2021; 18. [PMID: 33770780 DOI: 10.1088/1741-2552/abf28f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 03/26/2021] [Indexed: 12/22/2022]
Abstract
Objective.To design and implement a setup forex-vivooptical stimulation for exploring the effect of several key parameters (optical power and pulse duration), activation features (threshold, spatial selectivity) and recovery characteristics (repeated stimuli) in peripheral nerves.Approach.A nerve chamber allowing ex-vivo electrical and optical stimulation was designed and built. A 1470 nm light source was chosen to stimulate the nerve. A photodiode module was implemented for synchronization of the electrical and optical channels.Main results. Compound neural action potentials (CNAPs) were successfully generated with infrared light pulses of 200-2000µs duration and power in the range of 3-10 W. These parameters determine a radiant exposure for stimulation in the range 1.59-4.78 J cm-2. Recruitment curves were obtained by increasing durations at a constant power level. Neural activation threshold is reached at a mean radiant exposure of 3.16 ± 0.68 J cm-2and mean pulse energy of 3.79 ± 0.72 mJ. Repetition rates of 2-10 Hz have been explored. In eight out of ten sciatic nerves (SNs), repeated light stimuli induced a sensitization effect in that the CNAP amplitude progressively grows, representing an increasing number of recruited fibres. In two out of ten SNs, CNAPs were composed of a succession of peaks corresponding to different conduction velocities.Significance.The reported sensitization effect could shed light on the mechanism underlying infrared neurostimulation. Our results suggest that, in sharp contrast with electrical stimuli, optical pulses could recruit slow fibres early on. This more physiological order of recruitment opens the perspective for specific neuromodulation of fibre population who remained poorly accessible until now. Short high-power light pulses at wavelengths below 1.5µm offer interesting perspectives for neurostimulation.
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Affiliation(s)
- Joaquin Cury
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium.,Opera Photonics, Université libre de Bruxelles, Brussels, Belgium
| | - Louis Vande Perre
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
| | - Lars Stumpp
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Simone Vespa
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, University College London, London, United Kingdom
| | | | - Jean Delbeke
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Riëm El Tahry
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | | | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
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Littlefield PD, Richter C. Near-infrared stimulation of the auditory nerve: A decade of progress toward an optical cochlear implant. Laryngoscope Investig Otolaryngol 2021; 6:310-319. [PMID: 33869763 PMCID: PMC8035937 DOI: 10.1002/lio2.541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 12/14/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES We provide an appraisal of recent research on stimulation of the auditory system with light. In particular, we discuss direct infrared stimulation and ongoing controversies regarding the feasibility of this modality. We also discuss advancements and barriers to the development of an optical cochlear implant. METHODS This is a review article that covers relevant animal studies. RESULTS The auditory system has been stimulated with infrared light, and in a much more spatially selective manner than with electrical stimulation. However, there are experiments from other labs that have not been able to reproduce these results. This has resulted in an ongoing controversy regarding the feasibility of infrared stimulation, and the reasons for these experimental differences still require explanation. The neural response characteristics also appear to be much different than with electrical stimulation. The electrical stimulation paradigms used for modern cochlear implants do not apply well to optical stimulation and new coding strategies are under development. Stimulation with infrared light brings the risk of heat accumulation in the tissue at high pulse repetition rates, so optimal pulse shapes and combined optical/electrical stimulation are being investigated to mitigate this. Optogenetics is another promising technique, which makes neurons more sensitive to light stimulation by inserting light sensitive ion channels via viral vectors. Challenges of optogenetics include the expression of light sensitive channels in sufficient density in the target neurons, and the risk of damaging neurons by the expression of a foreign protein. CONCLUSION Optical stimulation of the nervous system is a promising new field, and there has been progress toward the development of a cochlear implant that takes advantage of the benefits of optical stimulation. There are barriers, and controversies, but so far none that seem intractable. LEVEL OF EVIDENCE NA (animal studies and basic research).
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Affiliation(s)
| | - Claus‐Peter Richter
- Department of OtolaryngologyNorthwestern UniversityChicagoIllinoisUSA
- Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
- Department of Biomedical EngineeringNorthwestern UniversityEvanstonIllinoisUSA
- The Hugh Knowles Center, Department of Communication Sciences and DisordersNorthwestern UniversityEvanstonIllinoisUSA
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Brown WGA, Needham K, Begeng JM, Thompson AC, Nayagam BA, Kameneva T, Stoddart PR. Response of primary auditory neurons to stimulation with infrared light in vitro. J Neural Eng 2021; 18:046003. [PMID: 33724234 DOI: 10.1088/1741-2552/abe7b8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. APPROACH Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2-5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. MAIN RESULTS The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. SIGNIFICANCE This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.
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Affiliation(s)
- William G A Brown
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn VIC 3122, Australia
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Thompson AC, Wise AK, Hart WL, Needham K, Fallon JB, Gunewardene N, Stoddart PR, Richardson RT. Hybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation. J Neural Eng 2020; 17:056046. [PMID: 33036009 DOI: 10.1088/1741-2552/abbff0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. APPROACH Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Response thresholds, spread of activation and entrainment data were obtained from multi-unit recordings from the auditory midbrain. MAIN RESULTS Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p < 0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p < 0.05). SIGNIFICANCE By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.
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18
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Tamai Y, Ito Y, Furuyama T, Horinouchi K, Murashima N, Michimoto I, Hishida R, Shibuki K, Hiryu S, Kobayasi KI. Auditory cortical activity elicited by infrared laser irradiation from the outer ear in Mongolian gerbils. PLoS One 2020; 15:e0240227. [PMID: 33057339 PMCID: PMC7561108 DOI: 10.1371/journal.pone.0240227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/22/2020] [Indexed: 12/16/2022] Open
Abstract
Infrared neural stimulation has been studied for its potential to replace an electrical stimulation of a cochlear implant. No studies, however, revealed how the technic reliably evoke auditory cortical activities. This research investigated the effects of cochlear laser stimulation from the outer ear on auditory cortex using brain imaging of activity-dependent changes in mitochondrial flavoprotein fluorescence signal. An optic fiber was inserted into the gerbil’s ear canal to stimulate the lateral side of the cochlea with an infrared laser. Laser stimulation was found to activate the identified primary auditory cortex. In addition, the temporal profile of the laser-evoked responses was comparable to that of the auditory responses. Our results indicate that infrared laser irradiation from the outer ear has the capacity to evoke, and possibly manipulate, the neural activities of the auditory cortex and may substitute for the present cochlear implants in future.
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Affiliation(s)
- Yuta Tamai
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Yuki Ito
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Takafumi Furuyama
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
- Department of Physiology, Kanazawa Medical University, Uchinada, Ishikawa, Japan
| | - Kensuke Horinouchi
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Nagomi Murashima
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Itsuki Michimoto
- Faculty of Science and Engineering, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Ryuichi Hishida
- Department of Neurophysiology, Brain Research Institute, Niigata University, Niigata, Niigata, Japan
| | - Katsuei Shibuki
- Department of Neurophysiology, Brain Research Institute, Niigata University, Niigata, Niigata, Japan
| | - Shizuko Hiryu
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Kohta I. Kobayasi
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto, Japan
- * E-mail:
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19
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Richardson RT, Ibbotson MR, Thompson AC, Wise AK, Fallon JB. Optical stimulation of neural tissue. Healthc Technol Lett 2020; 7:58-65. [PMID: 32754339 PMCID: PMC7353819 DOI: 10.1049/htl.2019.0114] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/08/2020] [Accepted: 05/15/2020] [Indexed: 12/23/2022] Open
Abstract
Electrical stimulation has been used for decades in devices such as pacemakers, cochlear implants and more recently for deep brain and retinal stimulation and electroceutical treatment of disease. However, current spread from the electrodes limits the precision of neural activation, leading to a low quality therapeutic outcome or undesired side-effects. Alternative methods of neural stimulation such as optical stimulation offer the potential to deliver higher spatial resolution of neural activation. Direct optical stimulation is possible with infrared light, while visible light can be used to activate neurons if the neural tissue is genetically modified with a light sensitive ion channel. Experimentally, both methods have resulted in highly precise stimulation with little spread of activation at least in the cochlea, each with advantages and disadvantages. Infrared neural stimulation does not require modification of the neural tissue, but has very high power requirements. Optogenetics can achieve precision of activation with lower power, but only in conjunction with targeted insertion of a light sensitive ion channel into the nervous system via gene therapy. This review will examine the advantages and limitations of optical stimulation of neural tissue, using the cochlea as an exemplary model and recent developments for retinal and deep brain stimulation.
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Affiliation(s)
- Rachael Theresa Richardson
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - Michael R Ibbotson
- National Vision Research Institute, Australian College of Optometry, and Department of Optometry and Vision Science, University of Melbourne, Melbourne, Australia
| | | | - Andrew K Wise
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
| | - James B Fallon
- Bionics Institute, Melbourne 3002, Australia.,University of Melbourne, Medical Bionics Department, Melbourne, 3002, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), Melbourne, 3002, Australia
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20
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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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Efferent Inputs Are Required for Normal Function of Vestibular Nerve Afferents. J Neurosci 2019; 39:6922-6935. [PMID: 31285300 DOI: 10.1523/jneurosci.0237-19.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 01/09/2023] Open
Abstract
A group of vestibular afferent nerve fibers with irregular-firing resting discharges are thought to play a prominent role in responses to fast head movements and vestibular plasticity. We show that, in C57BL/6 mice (either sex, 4-5 weeks old), normal activity in the efferent vestibular pathway is required for function of these irregular afferents. Thermal inhibition of efferent fibers results in a profound inhibition of irregular afferents' resting discharges, rendering them inadequate for signaling head movements. In this way, efferent inputs adjust the contribution of the peripheral irregular afferent pathway that plays a critical role in peripheral vestibular signaling and plasticity.SIGNIFICANCE STATEMENT Vestibular end organs in the inner ear receive efferent inputs from the brainstem. Previously, electrical stimulation of efferents was linked to an increase in resting discharges of afferents and a decrease in their sensitivities. Here, we show that localized thermal inhibition of unmyelinated efferents results in a significant decrease in the activity of afferent nerve fibers, particularly those with irregular resting discharges implicated in responses to fast head movements and vestibular compensation. Thus, by upregulating and downregulating of afferent firing, particularly irregular afferents, efferents adjust neural activity sensitive to rapid head movements. These findings support the notion that peripheral vestibular end organs are not passive transducers of head movements and their sensory signal transmission is modulated by efferent inputs.
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Jiang B, Hou W, Xia N, Peng F, Wang X, Chen C, Zhou Y, Zheng X, Wu X. Inhibitory effect of 980-nm laser on neural activity of the rat's cochlear nucleus. NEUROPHOTONICS 2019; 6:035009. [PMID: 31482103 PMCID: PMC6710856 DOI: 10.1117/1.nph.6.3.035009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Near-infrared radiation (NIR) has been described as one of the highest-resolution tools for neuromodulation. However, the poor tissue penetration depth of NIR has limited its further application on some of the deeper layer neurons in vivo. A 980-nm short-wavelength NIR (SW-NIR) with high penetration depth was employed, and its inhibitory effect on neurons was investigated in vivo. In experiments, SW-NIR was implemented on the rat's cochlear nucleus (CN), the auditory pathway was activated by pure-tones through the rat's external auditory canal, and the neural responses were recorded in the inferior colliculus by a multichannel electrode array. Neural firing rate (FR) and the first spike latency (FSL) were analyzed to evaluate the optically induced neural inhibition. Meanwhile, a two-layered finite element, consisting of a fluid layer and a gray matter layer, was established to model the optically induced temperature changes in CN; different stimulation paradigms were used to compare the inhibitory efficiency of SW-NIR. Results showed that SW-NIR could reversibly inhibit acoustically induced CN neural activities: with the increase of laser radiant exposures energy, neural FR decreased significantly and FSL lengthened steadily. Significant inhibition occurred when the optical pulse stimulated prior to the acoustic stimulus. Results indicated that the inhibition relies on the establishment time of the temperature field. Moreover, our preliminary results suggest that short-wavelength infrared could regulate the activities of neurons beyond the neural tissues laser irradiated through neural networks and conduction in vivo. These findings may provide a method for accurate neuromodulation in vivo.
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Affiliation(s)
- Bin Jiang
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
| | - Wensheng Hou
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Chongqing University, Chongqing Collaborative Innovation Center for Brain Science, China
- Chongqing University, Chongqing Key Laboratory of Artificial Intelligence and Service Robot Control Technology, Chongqing, China
| | - Nan Xia
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Qingdao University, Shandong Provincial Key Laboratory of Digital Medicine and Computer-assisted Surgery, Qingdao, Shandong, China
| | - Fei Peng
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
| | - Xing Wang
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Chongqing University, Chongqing Collaborative Innovation Center for Brain Science, China
| | - Chunye Chen
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Chongqing University, Chongqing Collaborative Innovation Center for Brain Science, China
| | - Yi Zhou
- Chinese Army Medical University, Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Chongqing, China
| | - Xiaolin Zheng
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Chongqing University, Chongqing Collaborative Innovation Center for Brain Science, China
- Chongqing University, Chongqing Key Laboratory of Artificial Intelligence and Service Robot Control Technology, Chongqing, China
| | - Xiaoying Wu
- Chongqing University, Ministry of Education, Key Laboratory of Biorheological Science and Technology, Chongqing, China
- Chongqing University, Chongqing Collaborative Innovation Center for Brain Science, China
- Chongqing University, Chongqing Key Laboratory of Artificial Intelligence and Service Robot Control Technology, Chongqing, China
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23
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Xu Y, Xia N, Lim M, Tan X, Tran MH, Boulger E, Peng F, Young H, Rau C, Rack A, Richter CP. Multichannel optrodes for photonic stimulation. NEUROPHOTONICS 2018; 5:045002. [PMID: 30397630 PMCID: PMC6197865 DOI: 10.1117/1.nph.5.4.045002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/24/2018] [Indexed: 05/27/2023]
Abstract
An emerging method in the field of neural stimulation is the use of photons to activate neurons. The possible advantage of optical stimulation over electrical is attributable to its spatially selective activation of small neuron populations, which is promising in generating superior spatial resolution in neural interfaces. Two principal methods are explored for cochlear prostheses: direct stimulation of nerves with infrared light and optogenetics. This paper discusses basic requirements for developing a light delivery system (LDS) for the cochlea and provides examples for building such devices. The proposed device relies on small optical sources, which are assembled in an array to be inserted into the cochlea. The mechanical properties, the biocompatibility, and the efficacy of optrodes have been tested in animal models. The force required to insert optrodes into a model of the human scala tympani was comparable to insertion forces obtained for contemporary cochlear implant electrodes. Side-emitting diodes are powerful enough to evoke auditory responses in guinea pigs. Chronic implantation of the LDS did not elevate auditory brainstem responses over 26 weeks.
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Affiliation(s)
- Yingyue Xu
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
| | - Nan Xia
- Qingdao University, Institute for Digital Medicine and Computer-assisted Surgery, Qingdao, China
| | - Michelle Lim
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Minh Ha Tran
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Erin Boulger
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Fei Peng
- Chongqing University, Bioengineering College, Chongqing, China
| | - Hunter Young
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Christoph Rau
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Alexander Rack
- Structure of Materials Group-ID19, European Synchrotron Radiation Facility, Cedex 9, France
| | - Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Hugh Knowles Center for Clinical and Basic Sciences in Hearing, Evanston, Illinois, United States
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Moreau D, Lefort C, Pas J, Bardet SM, Leveque P, O'Connor RP. Infrared neural stimulation induces intracellular Ca 2+ release mediated by phospholipase C. JOURNAL OF BIOPHOTONICS 2018; 11:e201700020. [PMID: 28700117 DOI: 10.1002/jbio.201700020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/29/2017] [Accepted: 07/01/2017] [Indexed: 05/18/2023]
Abstract
The influence of infrared laser pulses on intracellular Ca2+ signaling was investigated in neural cell lines with fluorescent live cell imaging. The probe Fluo-4 was used to measure Ca2+ in HT22 mouse hippocampal neurons and nonelectrically excitable U87 human glioblastoma cells exposed to 50 to 500 ms infrared pulses at 1470 nm. Fluorescence recordings of Fluo-4 demonstrated that infrared stimulation induced an instantaneous intracellular Ca2+ transient with similar dose-response characteristics in hippocampal neurons and glioblastoma cells (half-maximal effective energy density EC50 of around 58 J.cm-2 ). For both type of cells, the source of the infrared-induced Ca2+ transients was found to originate from intracellular stores and to be mediated by phospholipase C and IP3 -induced Ca2+ release from the endoplasmic reticulum. The activation of phosphoinositide signaling by IR light is a new mechanism of interaction relevant to infrared neural stimulation that will also be widely applicable to nonexcitable cell types. The prospect of infrared optostimulation of the PLC/IP3 cell signaling cascade has many potential applications including the development of optoceutical therapeutics.
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Affiliation(s)
- David Moreau
- CNRS, XLIM, University of Limoges, UMR 7252, Limoges, France
| | - Claire Lefort
- CNRS, XLIM, University of Limoges, UMR 7252, Limoges, France
| | - Jolien Pas
- Bioelectronics Department, École Nationale Supérieure des Mines de Saint-Étienne, Centre Microélectronique de Provence - Georges Charpak Campus, 880 route de Mimet, 13541 Gardanne, France
| | - Sylvia M Bardet
- CNRS, XLIM, University of Limoges, UMR 7252, Limoges, France
| | | | - Rodney P O'Connor
- Bioelectronics Department, École Nationale Supérieure des Mines de Saint-Étienne, Centre Microélectronique de Provence - Georges Charpak Campus, 880 route de Mimet, 13541 Gardanne, France
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Tan X, Jahan I, Xu Y, Stock S, Kwan CC, Soriano C, Xiao X, García-Añoveros J, Fritzsch B, Richter CP. Auditory Neural Activity in Congenitally Deaf Mice Induced by Infrared Neural Stimulation. Sci Rep 2018; 8:388. [PMID: 29321651 PMCID: PMC5762820 DOI: 10.1038/s41598-017-18814-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/11/2017] [Indexed: 11/16/2022] Open
Abstract
To determine whether responses during infrared neural stimulation (INS) result from the direct interaction with spiral ganglion neurons (SGNs), we tested three genetically modified deaf mouse models: Atoh1-cre; Atoh1f/f (Atoh1 conditional knockout, CKO), Atoh1-cre; Atoh1f/kiNeurog1 (Neurog1 knockin, KI), and the Vglut3 knockout (Vglut3−/−) mice. All animals were exposed to tone bursts and clicks up to 107 dB (re 20 µPa) and to INS, delivered with a 200 µm optical fiber. The wavelength (λ) was 1860 nm, the radiant energy (Q) 0-800 µJ/pulse, and the pulse width (PW) 100–500 µs. No auditory responses to acoustic stimuli could be evoked in any of these animals. INS could not evoke auditory brainstem responses in Atoh1 CKO mice but could in Neurog1 KI and Vglut3−/− mice. X-ray micro-computed tomography of the cochleae showed that responses correlated with the presence of SGNs and hair cells. Results in Neurog1 KI mice do not support a mechanical stimulation through the vibration of the basilar membrane, but cannot rule out the direct activation of the inner hair cells. Results in Vglut3−/− mice, which have no synaptic transmission between inner hair cells and SGNs, suggested that hair cells are not required.
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Affiliation(s)
- Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Israt Jahan
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Stuart Stock
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL, 60611, USA
| | - Changyow Claire Kwan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Carmen Soriano
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Jaime García-Añoveros
- Departments of Anesthesiology, Physiology, and Neurology, Northwestern University Institute for Neuroscience, Ward 10-070, 303 East Chicago Avenue, Chicago, IL, 60611, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA. .,Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA. .,The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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Wu XY, Hou WS. Auditory responses to short-wavelength infrared neural stimulation of the rat cochlear nucleus. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:1942-1945. [PMID: 29060273 DOI: 10.1109/embc.2017.8037229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pulsed Infrared laser is well-known for its high spatial resolution and contact-free stimulation mode. In order to improve the current auditory brainstem implants (ABI), 980 nm-short-wavelength infrared light was applied to stimulate the cochlear nucleus of rats. Single neural activity from contralateral inferior colliculus was recorded during laser stimulation. Animal experimental results showed that 980 nm laser could not directly activate neurons in cochlear nucleus and a photo-acoustic response was observed during stimulation, however, 980 nm laser produces an inhibitory effect on neural responses to sounds; After we added carbon nanoparticles onto the surface of animal cochlear nucleus, 980 nm laser could directly stimulate neurons and no interference between adjacent recording channels was observed. These findings indicated that with the enhancement of carbon nanoparticles, short-wavelength infrared neural stimulation (SW-INS) might be an effective method to overcome the defects of current ABIs. With this method, a new type of optical ABI with transcutaneous stimulating method is quite promising.
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Xu Y, Chen M, LaFaire P, Tan X, Richter CP. Distorting temporal fine structure by phase shifting and its effects on speech intelligibility and neural phase locking. Sci Rep 2017; 7:13387. [PMID: 29042580 PMCID: PMC5645416 DOI: 10.1038/s41598-017-12975-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 09/13/2017] [Indexed: 11/27/2022] Open
Abstract
Envelope (E) and temporal fine structure (TFS) are important features of acoustic signals and their corresponding perceptual function has been investigated with various listening tasks. To further understand the underlying neural processing of TFS, experiments in humans and animals were conducted to demonstrate the effects of modifying the TFS in natural speech sentences on both speech recognition and neural coding. The TFS of natural speech sentences was modified by distorting the phase and maintaining the magnitude. Speech intelligibility was then tested for normal-hearing listeners using the intact and reconstructed sentences presented in quiet and against background noise. Sentences with modified TFS were then used to evoke neural activity in auditory neurons of the inferior colliculus in guinea pigs. Our study demonstrated that speech intelligibility in humans relied on the periodic cues of speech TFS in both quiet and noisy listening conditions. Furthermore, recordings of neural activity from the guinea pig inferior colliculus have shown that individual auditory neurons exhibit phase locking patterns to the periodic cues of speech TFS that disappear when reconstructed sounds do not show periodic patterns anymore. Thus, the periodic cues of TFS are essential for speech intelligibility and are encoded in auditory neurons by phase locking.
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Affiliation(s)
- Yingyue Xu
- Northwestern University, Department of Otolaryngology, 320 E. Superior Street, Searle 12-561, Chicago, IL, 60611, USA
| | - Maxin Chen
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA
| | - Petrina LaFaire
- Northwestern University, Department of Otolaryngology, 320 E. Superior Street, Searle 12-561, Chicago, IL, 60611, USA
| | - Xiaodong Tan
- Northwestern University, Department of Otolaryngology, 320 E. Superior Street, Searle 12-561, Chicago, IL, 60611, USA
| | - Claus-Peter Richter
- Northwestern University, Department of Otolaryngology, 320 E. Superior Street, Searle 12-561, Chicago, IL, 60611, USA. .,Northwestern University, The Hugh Knowles Center, Department of Communication Sciences and Disorders, 2240 Campus Drive, Evanston, IL, 60208, USA.
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Richardson RT, Thompson AC, Wise AK, Needham K. Challenges for the application of optical stimulation in the cochlea for the study and treatment of hearing loss. Expert Opin Biol Ther 2016; 17:213-223. [PMID: 27960585 DOI: 10.1080/14712598.2017.1271870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Electrical stimulation has long been the most effective strategy for evoking neural activity from bionic devices and has been used with great success in the cochlear implant to allow deaf people to hear speech and sound. Despite its success, the spread of electrical current stimulates a broad region of neural tissue meaning that contemporary devices have limited precision. Optical stimulation as an alternative has attracted much recent interest for its capacity to provide highly focused stimuli, and therefore, potentially improved sensory perception. Given its specificity of activation, optical stimulation may also provide a useful tool in the study of fundamental neuroanatomy and neurophysiological processes. Areas covered: This review examines the advances in optical stimulation - infrared, nanoparticle-enhanced, and optogenetic-based - and its application in the inner ear for the restoration of auditory function following hearing loss. Expert opinion: Initial outcomes suggest that optogenetic-based approaches hold the greatest potential and viability amongst optical techniques for application in the cochlea. The future success of this approach will be governed by advances in the targeted delivery of opsins to auditory neurons, improvements in channel kinetics, development of optical arrays, and innovation of opsins that activate within the optimal near-infrared therapeutic window.
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Affiliation(s)
- Rachael T Richardson
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | | | - Andrew K Wise
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | - Karina Needham
- d Department of Surgery (Otolaryngology) , University of Melbourne, Royal Victorian Eye & Ear Hospital , East Melbourne , Australia
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Effect of shorter pulse duration in cochlear neural activation with an 810-nm near-infrared laser. Lasers Med Sci 2016; 32:389-396. [PMID: 27995385 DOI: 10.1007/s10103-016-2129-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
Optical neural stimulation in the cochlea has been presented as an alternative technique to the electrical stimulation due to its potential in spatially selectivity enhancement. So far, few studies have selected the near-infrared (NIR) laser in cochlear neural stimulation and limited optical parameter space has been examined. This paper focused on investigating the optical parameter effect on NIR stimulation of auditory neurons, especially under shorter pulse durations. The spiral ganglion neurons in the cochlea of deafened guinea pigs were stimulated with a pulsed 810-nm NIR laser in vivo. The laser radiation was delivered by an optical fiber and irradiated towards the modiolus. Optically evoked auditory brainstem responses (OABRs) with various optical parameters were recorded and investigated. The OABRs could be elicited with the cochlear deafened animals by using the 810-nm laser in a wide pulse duration ranged from 20 to 1000 μs. Results showed that the OABR intensity increased along with the increasing laser radiant exposure of limited range at each specific pulse duration. In addition, for the pulse durations from 20 to 300 μs, the OABR intensity increased monotonically along with the pulse duration broadening. While for pulse durations above 300 μs, the OABR intensity basically kept stable with the increasing pulse duration. The 810-nm NIR laser could be an effective stimulus in evoking the cochlear neuron response. Our experimental data provided evidence to optimize the pulse duration range, and the results suggested that the pulse durations from 20 to 300 μs could be the optimized range in cochlear neural activation with the 810-nm-wavelength laser.
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Xia N, Tan X, Xu Y, Hou W, Mao T, Richter CP. Pressure in the Cochlea During Infrared Irradiation. IEEE Trans Biomed Eng 2016; 65:1575-1584. [PMID: 27959792 DOI: 10.1109/tbme.2016.2636149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The purpose of the study is to demonstrate laser-evoked pressure waves in small confined volumes such as the cochlea. METHODS Custom-fabricated pressure probes were used to determine the pressure in front of the optical fiber in a small dish and patch pipettes to measure temperature changes. Pressure probes were inserted into scala tympani (ST) or vestibuli during laser stimulation. With a sensitive microphone the pressure was measured in the outer ear canal. RESULTS Heating was spatially confined. The heat relaxation time was 35 ms. During laser stimulation in the cochlea at 17 μJ/pulse, the pressure in the outer ear canal (EC) was 43.5 dB (re 20 μPa). The corresponding intracochlear pressure was calculated to be about 78.5 dB (re 20 μPa) using the middle ear reverse transfer function of -35 dB. At 164 μJ/pulse, the pressure in the EC was on average 63 dB (re 20 μPa) and the intracochlear pressure was estimated to be 98 dB (re 20 μPa), which is similar to the value obtained with the pressure probe, 100 dB (re 20 μPa). Side-emitting optical fibers were used to steer the beam path. The pressure values were independent of the orientation of the beam path. Evoked compound action potentials of the auditory nerve were maximum when spiral ganglion neurons were in the beam path. CONCLUSION Pressure waves are generated during infrared laser stimulation. The intracochlear pressure was independent from the orientation of the beam path. SIGNIFICANCE Neural responses required the spiral ganglion neurons to be directly irradiated.
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Wiegner A, Wright CG, Vollmer M. Multichannel cochlear implant for selective neuronal activation and chronic use in the free-moving Mongolian gerbil. J Neurosci Methods 2016; 273:40-54. [PMID: 27519925 DOI: 10.1016/j.jneumeth.2016.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND Animal models for chronic multichannel cochlear implant stimulation and selective neuronal activation contribute to a better understanding of auditory signal processing and central neural plasticity. NEW METHOD This paper describes the design and surgical implantation of a multichannel cochlear implant (CI) system for chronic use in the free-moving gerbil. For chronic stimulation, adult-deafened gerbils were connected to a multichannel commutator that allowed low resistance cable rotation and stable electric connectivity to the current source. RESULTS Despite the small scale of the gerbil cochlea and auditory brain regions, final electrophysiological mapping experiments revealed selective and tonotopically organized neuronal activation in the auditory cortex. Contact impedances and electrically evoked auditory brainstem responses were stable over several weeks demonstrating the long-term integrity of the implant and the efficacy of the stimulation. COMPARISON WITH EXISTING METHODS Most animal models on multichannel signal processing and stimulation-induced plasticity are limited to larger animals such as ferrets, cats and primates. Multichannel CI stimulation in the free-moving rodent and evidence for selective neuronal activation in gerbil auditory cortex have not been previously reported. CONCLUSIONS Overall, our results show that the gerbil is a robust rodent model for selective and tonotopically organized multichannel CI stimulation. We anticipate that this model provides a useful tool to develop and test both passive stimulation and behavioral training strategies for plastic reorganization and restoration of degraded unilateral and bilateral central auditory signal processing in the hearing impaired and deaf central auditory system.
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Affiliation(s)
- Armin Wiegner
- Comprehensive Hearing Center, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany.
| | - Charles G Wright
- Department of Otolaryngology-Head and Neck Surgery, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States.
| | - Maike Vollmer
- Comprehensive Hearing Center, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany.
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Optoacoustic effect is responsible for laser-induced cochlear responses. Sci Rep 2016; 6:28141. [PMID: 27301846 PMCID: PMC4908384 DOI: 10.1038/srep28141] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/27/2016] [Indexed: 12/17/2022] Open
Abstract
Optical stimulation of the cochlea with laser light has been suggested as an alternative to conventional treatment of sensorineural hearing loss with cochlear implants. The underlying mechanisms are controversially discussed: The stimulation can either be based on a direct excitation of neurons, or it is a result of an optoacoustic pressure wave acting on the basilar membrane. Animal studies comparing the intra-cochlear optical stimulation of hearing and deafened guinea pigs have indicated that the stimulation requires intact hair cells. Therefore, optoacoustic stimulation seems to be the underlying mechanism. The present study investigates optoacoustic characteristics using pulsed laser stimulation for in vivo experiments on hearing guinea pigs and pressure measurements in water. As a result, in vivo as well as pressure measurements showed corresponding signal shapes. The amplitude of the signal for both measurements depended on the absorption coefficient and on the maximum of the first time-derivative of laser pulse power (velocity of heat deposition). In conclusion, the pressure measurements directly demonstrated that laser light generates acoustic waves, with amplitudes suitable for stimulating the (partially) intact cochlea. These findings corroborate optoacoustic as the basic mechanism of optical intra-cochlear stimulation.
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Guan T, Wang J, Yang M, Zhu K, Wang Y, Nie G. Near-Infrared Laser Stimulation of the Auditory Nerve in Guinea Pigs. ACTA ACUST UNITED AC 2016. [DOI: 10.3807/josk.2016.20.2.269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wang MQ, Xia QL, Wu XY, Wang X, Zheng XL, Hou WS. Optical stimulation of primary motor cortex with 980nm infrared neural stimulation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:6143-6. [PMID: 25571399 DOI: 10.1109/embc.2014.6945031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To explore the penetration depth with short-wavelength infrared light, 980 nm pulse infrared light was used to stimulate the primary motor cortex of rat. The heating model was created to simulate the temperature distribution for 1875 nm and 980 nm infrared neural stimulation. Post-stimulus time histogram was used to observe the neural response induced by Infrared neural stimulation on primary motor cortex. The model predicted the penetration depth of 980 nm was deep into 1.2 mm. Cortical neural located between 500 μm to 1000 μm were successfully activated by 980 nm INS. The preliminary results suggested that, 980 nm pulse INS could serve as a candidate for deep tissue stimulation.
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Wang J, Lu J, Li C, Xu L, Li X, Tian L. Pulsed 980 nm short wavelength infrared neural stimulation in cochlea and laser parameter effects on auditory response characteristics. Biomed Eng Online 2015; 14:89. [PMID: 26445884 PMCID: PMC4597400 DOI: 10.1186/s12938-015-0084-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/22/2015] [Indexed: 11/10/2022] Open
Abstract
Background Auditory neural stimulation with pulsed infrared radiation has been proposed as an alternative method to activate the auditory nerves in vivo. Infrared wavelengths from 1800–2150 nm with high water absorption were mainly selected in previous studies. However, few researchers have used the short-wavelength infrared (SWIR) for auditory nerve stimulation and limited pulse parameters variability has been investigated so far. Methods In this paper, we pioneered to use the 980 nm SWIR laser with adjustable pulse parameter as a stimulus to act on the deafened guinea pigs’ cochlea in vivo. Pulsed laser light was guided through the cochlear round window to irradiate the spiral ganglion cells via a 105 μm optical fiber, and then the laser pulse parameters variability and its influence to auditory response characteristics were studied. Results The results showed that the optically evoked auditory brainstem response (OABR) had a similar waveform to the acoustically induced ABR with click sound stimulus. And the evoked OABR amplitude had a positive correlation, while the OABR latency period showed a negative correlation, with the laser pulse energy increase. However, when holding the laser peak power constant, the pulse width variability ranged from 100 to 800 μs showed little influence on the evoked OABR amplitude and its latency period. Conclusions Our study suggests that 980 nm SWIR laser is an effective stimulus for auditory neurons activation in vivo. The evoked OABR amplitude and latency are highly affected by the laser pulse energy, while not sensitive to the pulse width variability in 100–800 μs range.
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Affiliation(s)
- Jingxuan Wang
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Jianren Lu
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Chen Li
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
| | - Lei Xu
- Shandong Artificial Auditory Engineering Centre, 250022, Jinan, Shandong, China.
| | - Xiaofei Li
- Shandong Artificial Auditory Engineering Centre, 250022, Jinan, Shandong, China.
| | - Lan Tian
- School of Information Science and Engineering, Shandong University, 250100, Jinan, Shandong, China.
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Xie B, Dai C, Li H. Attenuated infrared neuron stimulation response in cochlea of deaf animals may associate with the degeneration of spiral ganglion neurons. BIOMEDICAL OPTICS EXPRESS 2015; 6:1990-2005. [PMID: 26114024 PMCID: PMC4473739 DOI: 10.1364/boe.6.001990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 05/13/2023]
Abstract
HYPOTHESIS We hypothesize that degenerated spiral ganglion neurons (SGNs) in guinea pigs reduces auditory brainstem responses evoked by pulsed infrared stimulation. BACKGROUND Pulsed infrared laser excitation can directly evoke physiological responses in neuronal and other excitable cells in vivo and in vitro. Laser pulses could benefit patients with cochlear implants to stimulate the auditory system. METHODS Pulsed infrared lasers were used to study evoked optical auditory brainstem responses (oABRs) in normal hearing and deafened animals. Aslo, the morphology and anatomy of SGNs in normal hearing and deafened guinea pigs were compared. RESULTS By recording oABRs evoked by varying infrared laser pulse durations, it is suggested that degeneration of SGNs in deafened guinea pigs was associated with an elevated oABR threshold and with lower amplitudes. Moreover, oABR threshold decreased while amplitudes increased in both normal hearing and deafened animals as the pulse duration prolonged. Electron microscopy revealed that SGNs in deafened guinea pigs had swollen and vacuolar mitochondria, as well as demyelinated soma and axons. CONCLUSION Infrared laser pulses can stimulate SGNs to evoke oABRs in guinea pigs. Deafened guinea pigs have elevated thresholds and smaller amplitude responses, likely a result of degenerated SGNs. Short pulse durations are more suitable to evoke responses in both normal hearing and deafened animals.
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Affiliation(s)
- Bingbin Xie
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China
| | - Chunfu Dai
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
| | - Huawei Li
- Department of Otology and Skull Base Surgery, Hearing Research Key Lab of Health Ministry of China, Eye and ENT Hospital, Fudan University, Shanghai, 200031, China ;
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Minocycline protection of neomycin induced hearing loss in gerbils. BIOMED RESEARCH INTERNATIONAL 2015; 2015:934158. [PMID: 25950003 PMCID: PMC4407513 DOI: 10.1155/2015/934158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/20/2015] [Accepted: 03/21/2015] [Indexed: 12/03/2022]
Abstract
This animal study was designed to determine if minocycline ameliorates cochlear damage is caused by intratympanic injection of the ototoxic aminoglycoside antibiotic neomycin. Baseline auditory-evoked brainstem responses were measured in gerbils that received 40 mM intratympanic neomycin either with 0, 1.2, or 1.5 mg/kg intraperitoneal minocycline. Four weeks later auditory-evoked brainstem responses were measured and compared to the baseline measurements. Minocycline treatments of 1.2 mg/kg and 1.5 mg/kg resulted in significantly lower threshold increases compared to 0 mg/kg, indicating protection of hearing loss between 6 kHz and 19 kHz. Cochleae were processed for histology and sectioned to allow quantification of the spiral ganglion neurons and histological evaluation of organ of Corti. Significant reduction of spiral ganglion neuron density was demonstrated in animals that did not receive minocycline, indicating that those receiving minocycline demonstrated enhanced survival of spiral ganglion neurons, enhanced survival of sensory hairs cells and spiral ganglion neurons, and reduced hearing threshold elevation correlates with minocycline treatment demonstrating that neomycin induced hearing loss can be reduced by the simultaneous application of minocycline.
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Young HK, Tan X, Xia N, Richter CP. Target structures for cochlear infrared neural stimulation. NEUROPHOTONICS 2015; 2:025002. [PMID: 26158006 PMCID: PMC4478722 DOI: 10.1117/1.nph.2.2.025002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/21/2015] [Indexed: 05/13/2023]
Abstract
Infrared neural stimulation (INS) is a method to depolarize neurons with infrared light. While consensus exists that heating of the target structure is essential, subsequent steps that result in the generation of an action potential are controversially discussed in the literature. The question of whether cochlear INS is an acoustic event has not been clarified. Results have been published that could be explained solely by an acoustic event. However, data exist that do not support an acoustical stimulus as the dominant factor in cochlear INS. We review the different findings that have been suggested for the mechanism of INS. Furthermore, we present the data that clarify the role of an acoustical event in cochlear INS. Masking experiments have been performed in hearing, hearing impaired, and severely hearing impaired animals. In normal hearing animals, the laser response could be masked by the acoustic stimulus. Once thresholds to acoustic stimuli were elevated, the ability to acoustically mask the INS response gradually disappeared. Thresholds for acoustic stimuli were significantly elevated in animals with compromised cochlear function, while the thresholds for optical stimulation remained largely unchanged. The results suggest that the direct interaction between the radiation and the target structure dominates cochlear INS.
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Affiliation(s)
- Hunter K. Young
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Xiaodong Tan
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Nan Xia
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Chongqing University, Key Laboratory of Biorheological Science and Technology, Ministry of Education, 174 Shazheng Street, Chongqing 400044, China
| | - Claus-Peter Richter
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Tech E310, Evanston, Illinois 60208, United States
- Northwestern University, The Hugh Knowles Center, Department of Communication Sciences and Disorders, 2240 Campus Drive, Evanston, Illinois 60208, United States
- Address all correspondence to: Claus-Peter Richter, E-mail:
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Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea. Hear Res 2015; 324:46-53. [PMID: 25796297 DOI: 10.1016/j.heares.2015.03.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 11/23/2022]
Abstract
At present there is some debate as to the processes by which infrared neural stimulation (INS) activates neurons in the cochlea, as the lasers used for INS can potentially generate a range of secondary stimuli e.g. an acoustic stimulus is produced when the light is absorbed by water. To clarify whether INS in the cochlea requires functioning hair cells and to explore the potential relevance to cochlear implants, experiments using INS were performed in the cochleae of both normal hearing and profoundly deaf guinea pigs. A response to laser stimulation was readily evoked in normal hearing cochlea. However, no response was evoked in any profoundly deaf cochleae, for either acute or chronic deafening, contrary to previous work where a response was observed after acute deafening with ototoxic drugs. A neural response to electrical stimulation was readily evoked in all cochleae after deafening. The absence of a response from optical stimuli in profoundly deaf cochleae suggests that the response from INS in the cochlea is hair cell mediated.
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Thompson AC, Stoddart PR, Jansen ED. Optical Stimulation of Neurons. ACTA ACUST UNITED AC 2015; 3:162-177. [PMID: 26322269 PMCID: PMC4541079 DOI: 10.2174/2211555203666141117220611] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/26/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023]
Abstract
Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central and peripheral nervous systems. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury and the subsequent inflammatory response. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device, while also avoiding the electrical artefacts that complicate recordings of electrically stimulated neuronal activity. This review explores the current status of optical stimulation techniques, including optogenetic methods, photoactive molecule approaches and infrared neural stimulation, together with emerging techniques such as hybrid optical-electrical stimulation, nanoparticle enhanced stimulation and optoelectric methods. Infrared neural stimulation is particularly emphasised, due to the potential for direct activation of neural tissue by infrared light, as opposed to techniques that rely on the introduction of exogenous light responsive materials. However, infrared neural stimulation remains imperfectly understood, and techniques for accurately delivering light are still under development. While the various techniques reviewed here confirm the overall feasibility of optical stimulation, a number of challenges remain to be overcome before they can deliver their full potential.
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Affiliation(s)
- Alexander C Thompson
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Jeschke M, Moser T. Considering optogenetic stimulation for cochlear implants. Hear Res 2015; 322:224-34. [PMID: 25601298 DOI: 10.1016/j.heares.2015.01.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/09/2014] [Accepted: 01/08/2015] [Indexed: 02/04/2023]
Abstract
Electrical cochlear implants are by far the most successful neuroprostheses and have been implanted in over 300,000 people worldwide. Cochlear implants enable open speech comprehension in most patients but are limited in providing music appreciation and speech understanding in noisy environments. This is generally considered to be due to low frequency resolution as a consequence of wide current spread from stimulation contacts. Accordingly, the number of independently usable stimulation channels is limited to less than a dozen. As light can be conveniently focused, optical stimulation might provide an alternative approach to cochlear implants with increased number of independent stimulation channels. Here, we focus on summarizing recent work on optogenetic stimulation as one way to develop optical cochlear implants. We conclude that proof of principle has been presented for optogenetic stimulation of the cochlea and central auditory neurons in rodents as well as for the technical realization of flexible μLED-based multichannel cochlear implants. Still, much remains to be done in order to advance the technique for auditory research and even more for eventual clinical translation. This article is part of a Special Issue entitled <Lasker Award>.
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Affiliation(s)
- Marcus Jeschke
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany.
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Goettingen, Germany; Auditory Neuroscience Group, German Primate Center, Goettingen, Germany; Bernstein Focus for Neurotechnology, University of Göttingen, Goettingen, Germany; Collaborative Research Center 889, University of Goettingen Medical Center, Goettingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University of Goettingen, Goettingen, Germany.
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Mou ZX, Hou WS, Zheng XL, Yao JP, Shang GB, Yin ZQ. Pulsed near infrared laser stimulates the rat visual cortex in vivo. Biocybern Biomed Eng 2015. [DOI: 10.1016/j.bbe.2015.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Eom K, Kim J, Choi JM, Kang T, Chang JW, Byun KM, Jun SB, Kim SJ. Enhanced infrared neural stimulation using localized surface plasmon resonance of gold nanorods. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:3853-7. [PMID: 24975778 DOI: 10.1002/smll.201400599] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/06/2014] [Indexed: 05/23/2023]
Abstract
An advanced optical activation of neural tissues is demonstrated using pulsed infrared light and plasmonic gold nanorods. Photothermal effect localized in plasma membrane triggers action potentials of in vivo neural tissues. Compared with conventional infrared stimulation, the suggested method can increase a neural responsivity and lower a threshold stimulation level significantly, thereby reducing a requisite radiant exposure and the concern of tissue damage.
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Affiliation(s)
- Kyungsik Eom
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 151-744, Republic of Korea
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Abstract
The success of conventional hearing aids and electrical auditory prostheses for hearing impaired patients is still limited in noisy environments and for sounds more complex than speech (e. g. music). This is partially due to the difficulty of frequency-specific activation of the auditory system using these devices. Stimulation of the auditory system using light pulses represents an alternative to mechanical and electrical stimulation. Light is a source of energy that can be very exactly focused and applied with little scattering, thus offering perspectives for optimal activation of the auditory system. Studies investigating light stimulation of sectors along the auditory pathway have shown stimulation of the auditory system is possible using light pulses. However, further studies and developments are needed before a new generation of light stimulation-based auditory prostheses can be made available for clinical application.
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Abstract
The exceptional sensitivity of mammalian hearing organs is attributed to an active process, where force produced by sensory cells boost sound-induced vibrations, making soft sounds audible. This process is thought to be local, with each section of the hearing organ capable of amplifying sound-evoked movement, and nearly instantaneous, since amplification can work for sounds at frequencies up to 100 kHz in some species. To test these fundamental precepts, we developed a method for focally stimulating the living hearing organ with light. Light pulses caused intense and highly damped mechanical responses followed by traveling waves that developed with considerable delay. The delayed response was identical to movements evoked by click-like sounds. This shows that the active process is neither local nor instantaneous, but requires mechanical waves traveling from the cochlear base toward its apex. A physiologically-based mathematical model shows that such waves engage the active process, enhancing hearing sensitivity.
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46
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Bareket-Keren L, Hanein Y. Novel interfaces for light directed neuronal stimulation: advances and challenges. Int J Nanomedicine 2014; 9 Suppl 1:65-83. [PMID: 24872704 PMCID: PMC4024977 DOI: 10.2147/ijn.s51193] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Light activation of neurons is a growing field with applications ranging from basic investigation of neuronal systems to the development of new therapeutic methods such as artificial retina. Many recent studies currently explore novel methods for optical stimulation with temporal and spatial precision. Novel materials in particular provide an opportunity to enhance contemporary approaches. Here we review recent advances towards light directed interfaces for neuronal stimulation, focusing on state-of-the-art nanoengineered devices. In particular, we highlight challenges and prospects towards improved retinal prostheses.
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Affiliation(s)
- Lilach Bareket-Keren
- School of Electrical Engineering, Tel-Aviv University, Tel-Aviv University, Tel-Aviv, Israel ; Tel-Aviv University Center for Nanoscience and Nanotechnology, Tel-Aviv University, Tel-Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel-Aviv University, Tel-Aviv University, Tel-Aviv, Israel ; Tel-Aviv University Center for Nanoscience and Nanotechnology, Tel-Aviv University, Tel-Aviv, Israel
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Abstract
Methods to control neural activity by light have been introduced to the field of neuroscience. During the last decade, several techniques have been established, including optogenetics, thermogenetics, and infrared neural stimulation. The techniques allow investigators to turn-on or turn-off neural activity. This review is an attempt to show the importance of the techniques for the auditory field and provide insight in the similarities, overlap, and differences of the techniques. Discussing the mechanism of each of the techniques will shed light on the abilities and challenges for each of the techniques. The field has been grown tremendously and a review cannot be complete. However, efforts are made to summarize the important points and to refer the reader to excellent papers and reviews to specific topics. This article is part of a Special Issue entitled .
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Affiliation(s)
- Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA; Dept. of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA; The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA.
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA
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48
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Rettenmaier A, Lenarz T, Reuter G. Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells. BIOMEDICAL OPTICS EXPRESS 2014; 5:1014-25. [PMID: 24761285 PMCID: PMC3986005 DOI: 10.1364/boe.5.001014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/26/2013] [Accepted: 01/13/2014] [Indexed: 05/18/2023]
Abstract
Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.
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Verma RU, Guex AA, Hancock KE, Durakovic N, McKay CM, Slama MCC, Brown MC, Lee DJ. Auditory responses to electric and infrared neural stimulation of the rat cochlear nucleus. Hear Res 2014; 310:69-75. [PMID: 24508368 DOI: 10.1016/j.heares.2014.01.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/11/2014] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
Abstract
In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported "optophonic" effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach.
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Affiliation(s)
- Rohit U Verma
- School of Medicine, University of Manchester, UK; Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA; Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA
| | - Amélie A Guex
- Ecole Polytechnique Fédérale de Lausanne, Switzerland
| | - Kenneth E Hancock
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA
| | - Nedim Durakovic
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA
| | - Colette M McKay
- School of Psychological Sciences, University of Manchester, UK; The Bionics Institute of Australia, Melbourne, Australia
| | - Michaël C C Slama
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA; Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA
| | - M Christian Brown
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA; Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA.
| | - Daniel J Lee
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, USA; Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA
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Xia N, Peng F, Wang X, Zheng XL, Wan XP, Yuan W, Hou WS. Short-wavelength near infrared stimulation of the inner ear hair cells. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2014; 2014:2633-2636. [PMID: 25570531 DOI: 10.1109/embc.2014.6944163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To explore whether the short wavelength near infrared laser can stimulate the functional hair cells, pulsed laser with wavelength of 808-nm was used to stimulate guinea pigs cochlea. Compound action potential (CAP) and auditory brainstem responses (ABR) were recorded during the experiments. We successfully recorded photomechanical responses from normal hearing animals and demonstrated the responses were not induced by optical acoustic events. Furthermore, we studied the effect of different stimulation parameters on neural response. The results show that cochlear activation can be modulated with different optical parameters.
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