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Burwood G, He WX, Fridberger A, Ren TY, Nuttall AL. Outer hair cell driven reticular lamina mechanical distortion in living cochleae. Hear Res 2022; 423:108405. [PMID: 34916081 PMCID: PMC9170269 DOI: 10.1016/j.heares.2021.108405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 10/25/2021] [Accepted: 11/25/2021] [Indexed: 11/17/2022]
Abstract
Cochlear distortions afford researchers and clinicians a glimpse into the conditions and properties of inner ear signal processing mechanisms. Until recently, our examination of these distortions has been limited to measuring the vibration of the basilar membrane or recording acoustic distortion output in the ear canal. Despite its importance, the generation mechanism of cochlear distortion remains a substantial task to understand. The ability to measure the vibration of the reticular lamina in rodent models is a recent experimental advance. Surprising mechanical properties have been revealed. These properties merit both discussion in context with our current understanding of distortion, and appraisal of the significance of new interpretations of cochlear mechanics. This review focusses on some of the recent data from our research groups and discusses the implications of these data on our understanding of vocalization processing in the periphery, and their influence upon future experimental directions. This article is part of the Special Issue Outer hair cell Edited by Joseph Santos-Sacchi and Kumar Navaratnam.
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Affiliation(s)
- G Burwood
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - W X He
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - A Fridberger
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - T Y Ren
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - A L Nuttall
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States.
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2
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Lee JM, Han I, Nam KH, Kim DH, Song S, Park H, Kim H, Kim M, Choi J, Lee JI. Preclinical mouse model of optical coherence tomography for subcortical brain imaging without dissection. JOURNAL OF BIOPHOTONICS 2021; 14:e202100143. [PMID: 34346171 DOI: 10.1002/jbio.202100143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
The purpose of this study was to investigate the feasibility of using optical coherence tomography (OCT) to identify internal brain lesions, specifically intracerebral hemorrhage, without dissection. Mice with artificially injected brain hematomas were used to test the OCT system, and the recorded images were compared with microscopic images of the same mouse brains after hematoxylin and eosin staining. The intracranial structures surrounding the hematomas were clearly visualized by the OCT system without dissection. These images reflect the ability of OCT to determine the extent of a lesion in several planes. OCT is a useful technology, and these findings could be used as a starting point for future research in intraoperative imaging.
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Affiliation(s)
- Jae Meen Lee
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Inho Han
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Kyoung Hyup Nam
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Dong Hwan Kim
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Seunghwan Song
- Department of Thoracic and Cardiovascular Surgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Heejeong Park
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Hongki Kim
- Kohyoung Technology, Inc, Seoul, South Korea
| | - Minkyu Kim
- Kohyoung Technology, Inc, Seoul, South Korea
| | | | - Jae Il Lee
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
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Olson ES, Strimbu CE. Cochlear mechanics: new insights from vibrometry and Optical Coherence Tomography. CURRENT OPINION IN PHYSIOLOGY 2020; 18:56-62. [PMID: 33103018 DOI: 10.1016/j.cophys.2020.08.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The cochlea is a complex biological machine that transduces sound-induced mechanical vibrations to neural signals. Hair cells within the sensory tissue of the cochlea transduce vibrations into electrical signals, and exert electromechanical feedback that enhances the passive frequency separation provided by the cochlea's traveling wave mechanics; this enhancement is termed cochlear amplification. The vibration of the sensory tissue has been studied with many techniques, and the current state of the art is optical coherence tomography (OCT). The OCT technique allows for motion of intra-organ structures to be measured in vivo at many layers within the sensory tissue, at several angles and in previously under-explored species. OCT-based observations are already impacting our understanding of hair cell excitation and cochlear amplification.
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Affiliation(s)
- Elizabeth S Olson
- Department of Otolaryngolgy Head and Neck Surgery, Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th St, New York, NY 10032.,Department Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue,New York, NY 10027
| | - C Elliott Strimbu
- Department of Otolaryngolgy Head and Neck Surgery, Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th St, New York, NY 10032
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Romito M, Pu Y, Stankovic KM, Psaltis D. Imaging hair cells through laser-ablated cochlear bone. BIOMEDICAL OPTICS EXPRESS 2019; 10:5974-5988. [PMID: 31799058 PMCID: PMC6865115 DOI: 10.1364/boe.10.005974] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/29/2019] [Accepted: 10/24/2019] [Indexed: 05/04/2023]
Abstract
We report an innovative technique for the visualization of cells through an overlying scattering medium by combining femtosecond laser bone ablation and two-photon excitation fluorescence (TPEF) microscopy. We demonstrate the technique by imaging hair cells in an intact mouse cochlea ex vivo. Intracochlear imaging is important for the assessment of hearing disorders. However, the small size of the cochlea and its encasement in the densest bone in the body present challenging obstacles, preventing the visualization of the intracochlear microanatomy using standard clinical imaging modalities. The controlled laser ablation reduces the optical scattering of the cochlear bone while the TPEF allows visualization of individual cells behind the bone. We implemented optical coherence tomography (OCT) simultaneously with the laser ablation to enhance the precision of the ablation and prevent inadvertent damage to the cells behind the bone.
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Affiliation(s)
- Marilisa Romito
- Optics Laboratory, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ye Pu
- Optics Laboratory, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Konstantina M. Stankovic
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Demetri Psaltis
- Optics Laboratory, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Burwood GWS, Fridberger A, Wang RK, Nuttall AL. Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography. Quant Imaging Med Surg 2019; 9:858-881. [PMID: 31281781 PMCID: PMC6571188 DOI: 10.21037/qims.2019.05.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 05/09/2019] [Indexed: 01/17/2023]
Abstract
Optical coherence tomography (OCT) has revolutionized physiological studies of the hearing organ, the vibration and morphology of which can now be measured without opening the surrounding bone. In this review, we provide an overview of OCT as used in the otological research, describing advances and different techniques in vibrometry, angiography, and structural imaging.
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Affiliation(s)
- George W. S. Burwood
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
| | - Anders Fridberger
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
- Department of Clinical and Experimental Medicine, Section for Neurobiology, Linköping University, Linköping, Sweden
| | - Ruikang K. Wang
- Department of Bioengineering and Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Alfred L. Nuttall
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
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Guo C, Yang X, Wu JP, Guo X, He Y, Shen Z, Sun Z, Guan T, Chen F. Image-guided vibrometry system integrated with spectral- and time-domain optical coherence tomography. APPLIED OPTICS 2019; 58:1606-1613. [PMID: 30874191 DOI: 10.1364/ao.58.001606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Vibrometry using optical coherence tomography (OCT) can provide valuable information for investigating either the mechanical properties or the physiological function of biological tissues, especially the hearing organs. Real-time imaging of the measured tissues provides structure imaging and spatial guidance for and is thus highly demanded by such vibrometry. However, the traditional time-domain OCT (TD-OCT) systems, although capable of subnanometric vibrometry at large ranges of frequencies, are unable to offer an imaging speed that is high enough to acquire depth-resolved images for guidance. The spectral-domain OCT (SD-OCT) systems, although allowing image-guided vibrometry, are challenged in measuring vibration at high frequencies, particularly for scattering tissue specimens that require longer exposure time to ensure imaging and vibrometry performance. This is because of their limit in the line-scan rate of the CCD, in which the maximum resolvable frequency measured by the SD-OCT is about 1/4 of the CCD line-scan rate in practice. In the present study, we have developed a dual-mode OCT system combining both SD-OCT and TD-OCT modalities for image-guided vibrometry, as the SD-OCT can provide guiding structural images in real-time and, moreover, the TD-OCT can guarantee vibrometry at large ranges of frequencies, including high frequencies. The efficacy of the developed system in image-guided vibrometry has been experimentally demonstrated using both piezoelectric ceramic transducer (PZT) and ex vivo middle-ear samples from guinea pigs. For the vibrometry of PZT, the minimum detectable vibration amplitude was reached at ∼0.01 nm. For the vibrometry of the sound-evoked biological samples, both real-time two-dimensional imaging and subnanometric vibrometry were performed at the frequency ranging from 1 to 40 kHz. These results indicate that our dual-mode OCT system is able to act as an excellent vibrometer enabling image-guided high-frequency measurement.
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Brown DJ, Pastras CJ, Curthoys IS. Electrophysiological Measurements of Peripheral Vestibular Function-A Review of Electrovestibulography. Front Syst Neurosci 2017; 11:34. [PMID: 28620284 PMCID: PMC5450778 DOI: 10.3389/fnsys.2017.00034] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022] Open
Abstract
Electrocochleography (EcochG), incorporating the Cochlear Microphonic (CM), the Summating Potential (SP), and the cochlear Compound Action Potential (CAP), has been used to study cochlear function in humans and experimental animals since the 1930s, providing a simple objective tool to assess both hair cell (HC) and nerve sensitivity. The vestibular equivalent of ECochG, termed here Electrovestibulography (EVestG), incorporates responses of the vestibular HCs and nerve. Few research groups have utilized EVestG to study vestibular function. Arguably, this is because stimulating the cochlea in isolation with sound is a trivial matter, whereas stimulating the vestibular system in isolation requires significantly more technical effort. That is, the vestibular system is sensitive to both high-level sound and bone-conducted vibrations, but so is the cochlea, and gross electrical responses of the inner ear to such stimuli can be difficult to interpret. Fortunately, several simple techniques can be employed to isolate vestibular electrical responses. Here, we review the literature underpinning gross vestibular nerve and HC responses, and we discuss the nomenclature used in this field. We also discuss techniques for recording EVestG in experimental animals and humans and highlight how EVestG is furthering our understanding of the vestibular system.
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Affiliation(s)
- Daniel J Brown
- Neurotology Laboratory, Sydney Medical School, The University of SydneySydney, NSW, Australia
| | - Christopher J Pastras
- Neurotology Laboratory, Sydney Medical School, The University of SydneySydney, NSW, Australia
| | - Ian S Curthoys
- Department of Psychology, The University of SydneySydney, NSW, Australia
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Choi S, Sato K, Ota T, Nin F, Muramatsu S, Hibino H. Multifrequency-swept optical coherence microscopy for highspeed full-field tomographic vibrometry in biological tissues. BIOMEDICAL OPTICS EXPRESS 2017; 8:608-621. [PMID: 28270971 PMCID: PMC5330561 DOI: 10.1364/boe.8.000608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/27/2016] [Accepted: 12/29/2016] [Indexed: 05/03/2023]
Abstract
Because conventional laser Doppler vibrometry or Doppler optical coherence tomography require mechanical scanning probes that cannot simultaneously measure the wide-range dynamics of bio-tissues, a multifrequency-swept optical coherence microscopy with wide-field heterodyne detection technique was developed. A 1024 × 1024 × 2000 voxel volume was acquired with an axial resolution of ~1.8 μm and an acquisition speed of 2 s. Vibration measurements at 10 kHz were performed over a wide field of view. Wide-field tomographic vibration measurements of a mouse tympanic membrane are demonstrated to illustrate the applicability of this method to live animals.
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Affiliation(s)
- Samuel Choi
- Niigata University, Department of Electrical and Electronics Engineering, 8050 Ikarashi-2, Niigata 950-2181, Japan
- AMED-CTRST, AMED, Japan
| | - Keita Sato
- Niigata University, Department of Electrical and Electronics Engineering, 8050 Ikarashi-2, Niigata 950-2181, Japan
| | - Takeru Ota
- AMED-CTRST, AMED, Japan
- Niigata University, School of Medicine, Department of Molecular Physiology, 757 Ichibancho, Asahimachi, Niigata 951-8510, Japan
| | - Fumiaki Nin
- AMED-CTRST, AMED, Japan
- Niigata University, School of Medicine, Department of Molecular Physiology, 757 Ichibancho, Asahimachi, Niigata 951-8510, Japan
- Niigata University, Center for Transdisciplinary Research, 8050 Ikarashi-2, Niigata 950-2181, Japan
| | - Shogo Muramatsu
- Niigata University, Department of Electrical and Electronics Engineering, 8050 Ikarashi-2, Niigata 950-2181, Japan
- AMED-CTRST, AMED, Japan
| | - Hiroshi Hibino
- AMED-CTRST, AMED, Japan
- Niigata University, School of Medicine, Department of Molecular Physiology, 757 Ichibancho, Asahimachi, Niigata 951-8510, Japan
- Niigata University, Center for Transdisciplinary Research, 8050 Ikarashi-2, Niigata 950-2181, Japan
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9
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Micro-optical coherence tomography of the mammalian cochlea. Sci Rep 2016; 6:33288. [PMID: 27633610 PMCID: PMC5025881 DOI: 10.1038/srep33288] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/23/2016] [Indexed: 12/27/2022] Open
Abstract
The mammalian cochlea has historically resisted attempts at high-resolution, non-invasive imaging due to its small size, complex three-dimensional structure, and embedded location within the temporal bone. As a result, little is known about the relationship between an individual’s cochlear pathology and hearing function, and otologists must rely on physiological testing and imaging methods that offer limited resolution to obtain information about the inner ear prior to performing surgery. Micro-optical coherence tomography (μOCT) is a non-invasive, low-coherence interferometric imaging technique capable of resolving cellular-level anatomic structures. To determine whether μOCT is capable of resolving mammalian intracochlear anatomy, fixed guinea pig inner ears were imaged as whole temporal bones with cochlea in situ. Anatomical structures such as the tunnel of Corti, space of Nuel, modiolus, scalae, and cell groupings were visualized, in addition to individual cell types such as neuronal fibers, hair cells, and supporting cells. Visualization of these structures, via volumetrically-reconstructed image stacks and endoscopic perspective videos, represents an improvement over previous efforts using conventional OCT. These are the first μOCT images of mammalian cochlear anatomy, and they demonstrate μOCT’s potential utility as an imaging tool in otology research.
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Landegger LD, Psaltis D, Stankovic KM. Human audiometric thresholds do not predict specific cellular damage in the inner ear. Hear Res 2016; 335:83-93. [PMID: 26924453 PMCID: PMC5970796 DOI: 10.1016/j.heares.2016.02.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 02/23/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION As otology enters the field of gene therapy and human studies commence, the question arises whether audiograms - the current gold standard for the evaluation of hearing function - can consistently predict cellular damage within the human inner ear and thus should be used to define inclusion criteria for trials. Current assumptions rely on the analysis of small groups of human temporal bones post mortem or from psychophysical identification of cochlear "dead regions" in vivo, but a comprehensive study assessing the correlation between audiometric thresholds and cellular damage within the cochlea is lacking. METHODS A total of 131 human temporal bones from 85 adult individuals (ages 19-92 years, median 69 years) with sensorineural hearing loss due to various etiologies were analyzed. Cytocochleograms - which quantify loss of hair cells, neurons, and strial atrophy along the length of the cochlea - were compared with subjects' latest available audiometric tests prior to death (time range 5 h-22 years, median 24 months). The Greenwood function and the equivalent rectangular bandwidth were used to infer, from cytocochleograms, cochlear locations corresponding to frequencies tested in clinical audiograms. Correlation between audiometric thresholds at clinically tested frequencies and cell type-specific damage in those frequency regions was examined by calculating Spearman's correlation coefficients. RESULTS Similar audiometric profiles reflected widely different cellular damage in the cochlea. In our diverse group of patients, audiometric thresholds tended to be more influenced by hair cell loss than by neuronal loss or strial atrophy. Spearman's correlation coefficient across frequencies was at most 0.7 and often below 0.5, with 1.0 indicating perfect correlation. CONCLUSIONS Audiometric thresholds do not predict specific cellular damage in the human inner ear. Our study highlights the need for better non- or minimally-invasive tools, such as cochlear endoscopy, to establish cellular-level diagnosis and thereby guide therapy and monitor response to treatment.
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Affiliation(s)
- Lukas D Landegger
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02141, United States; Department of Otolaryngology, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, United States; Department of Otolaryngology, Vienna General Hospital, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
| | - Demetri Psaltis
- Optics Laboratory, School of Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), BM 4102 (Bâtiment BM), Station 17, 1015 Lausanne, Switzerland.
| | - Konstantina M Stankovic
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02141, United States; Department of Otolaryngology, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, United States; Harvard Program in Speech and Hearing Bioscience and Technology, 260 Longwood Avenue, Boston, MA 02115, United States.
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11
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de Boer E. Physics underlying the physiology of the ear. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:2554-2560. [PMID: 26520338 PMCID: PMC4627937 DOI: 10.1121/1.4932674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/15/2015] [Accepted: 09/22/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Egbert de Boer
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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Choi S, Watanabe T, Suzuki T, Nin F, Hibino H, Sasaki O. Multifrequency swept common-path en-face OCT for wide-field measurement of interior surface vibrations in thick biological tissues. OPTICS EXPRESS 2015; 23:21078-89. [PMID: 26367958 DOI: 10.1364/oe.23.021078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microvibrations that occur in bio-tissues are considered to play pivotal roles in organ function; however techniques for their measurement have remained underdeveloped. To address this issue, in the present study we have developed a novel optical coherence tomography (OCT) method that utilizes multifrequency swept interferometry. The OCT volume data can be acquired by sweeping the multifrequency modes produced by combining a tunable Fabry-Perot filter and an 840 nm super-luminescent diode with a bandwidth of 160 nm. The system employing the wide-field heterodyne method does not require mechanical scanning probes, which are usually incorporated in conventional Doppler OCTs and heterodyne-type interferometers. These arrangements allow obtaining not only 3D tomographic images but also various vibration parameters such as spatial amplitude, phase, and frequency, with high temporal and transverse resolutions over a wide field. Indeed, our OCT achieved the axial resolution of ~2.5 μm when scanning the surface of a glass plate. Moreover, when examining a mechanically resonant multilayered bio-tissue in full-field configuration, we captured 22 nm vibrations of its internal surfaces at 1 kHz by reconstructing temporal phase variations. This so-called "multifrequency swept common-path en-face OCT" can be applied for measuring microdynamics of a variety of biological samples, thus contributing to the progress in life sciences research.
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Teudt IU, Richter CP. Basilar membrane and tectorial membrane stiffness in the CBA/CaJ mouse. J Assoc Res Otolaryngol 2014; 15:675-94. [PMID: 24865766 PMCID: PMC4164692 DOI: 10.1007/s10162-014-0463-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 05/07/2014] [Indexed: 10/25/2022] Open
Abstract
The mouse has become an important animal model in understanding cochlear function. Structures, such as the tectorial membrane or hair cells, have been changed by gene manipulation, and the resulting effect on cochlear function has been studied. To contrast those findings, physical properties of the basilar membrane (BM) and tectorial membrane (TM) in mice without gene mutation are of great importance. Using the hemicochlea of CBA/CaJ mice, we have demonstrated that tectorial membrane (TM) and basilar membrane (BM) revealed a stiffness gradient along the cochlea. While a simple spring mass resonator predicts the change in the characteristic frequency of the BM, the spring mass model does not predict the frequency change along the TM. Plateau stiffness values of the TM were 0.6 ± 0.5, 0.2 ± 0.1, and 0.09 ± 0.09 N/m for the basal, middle, and upper turns, respectively. The BM plateau stiffness values were 3.7 ± 2.2, 1.2 ± 1.2, and 0.5 ± 0.5 N/m for the basal, middle, and upper turns, respectively. Estimations of the TM Young's modulus (in kPa) revealed 24.3 ± 25.2 for the basal turns, 5.1 ± 4.5 for the middle turns, and 1.9 ± 1.6 for the apical turns. Young's modulus determined at the BM pectinate zone was 76.8 ± 72, 23.9 ± 30.6, and 9.4 ± 6.2 kPa for the basal, middle, and apical turns, respectively. The reported stiffness values of the CBA/CaJ mouse TM and BM provide basic data for the physical properties of its organ of Corti.
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Affiliation(s)
- I. U. Teudt
- />Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Searle Building 12-561; 303 East Chicago Avenue, 60611-3008 Chicago, IL USA
- />Department of Otolaryngology—Head and Neck Surgery, University Clinic Hamburg-Eppendorf, Hamburg, Germany
- />Department of Otolaryngology—Head and Neck Surgery, Asklepios Clinic Altona, Hamburg, Germany
| | - C. P. Richter
- />Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Searle Building 12-561; 303 East Chicago Avenue, 60611-3008 Chicago, IL USA
- />Department of Biomedical Engineering, Northwestern University, Evanston, IL USA
- />Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL USA
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Reichenbach T, Hudspeth AJ. The physics of hearing: fluid mechanics and the active process of the inner ear. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:076601. [PMID: 25006839 DOI: 10.1088/0034-4885/77/7/076601] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Most sounds of interest consist of complex, time-dependent admixtures of tones of diverse frequencies and variable amplitudes. To detect and process these signals, the ear employs a highly nonlinear, adaptive, real-time spectral analyzer: the cochlea. Sound excites vibration of the eardrum and the three miniscule bones of the middle ear, the last of which acts as a piston to initiate oscillatory pressure changes within the liquid-filled chambers of the cochlea. The basilar membrane, an elastic band spiraling along the cochlea between two of these chambers, responds to these pressures by conducting a largely independent traveling wave for each frequency component of the input. Because the basilar membrane is graded in mass and stiffness along its length, however, each traveling wave grows in magnitude and decreases in wavelength until it peaks at a specific, frequency-dependent position: low frequencies propagate to the cochlear apex, whereas high frequencies culminate at the base. The oscillations of the basilar membrane deflect hair bundles, the mechanically sensitive organelles of the ear's sensory receptors, the hair cells. As mechanically sensitive ion channels open and close, each hair cell responds with an electrical signal that is chemically transmitted to an afferent nerve fiber and thence into the brain. In addition to transducing mechanical inputs, hair cells amplify them by two means. Channel gating endows a hair bundle with negative stiffness, an instability that interacts with the motor protein myosin-1c to produce a mechanical amplifier and oscillator. Acting through the piezoelectric membrane protein prestin, electrical responses also cause outer hair cells to elongate and shorten, thus pumping energy into the basilar membrane's movements. The two forms of motility constitute an active process that amplifies mechanical inputs, sharpens frequency discrimination, and confers a compressive nonlinearity on responsiveness. These features arise because the active process operates near a Hopf bifurcation, the generic properties of which explain several key features of hearing. Moreover, when the gain of the active process rises sufficiently in ultraquiet circumstances, the system traverses the bifurcation and even a normal ear actually emits sound. The remarkable properties of hearing thus stem from the propagation of traveling waves on a nonlinear and excitable medium.
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Subhash HM, Choudhury N, Chen F, Wang RK, Jacques SL, Nuttall AL. Depth-resolved dual-beamlet vibrometry based on Fourier domain low coherence interferometry. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:036003. [PMID: 23455961 PMCID: PMC3584824 DOI: 10.1117/1.jbo.18.3.036003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We present an optical vibrometer based on delay-encoded, dual-beamlet phase-sensitive Fourier domain interferometric system to provide depth-resolved subnanometer scale vibration information from scattering biological specimens. System characterization, calibration, and preliminary vibrometry with biological specimens were performed. The proposed system has the potential to provide both amplitude and direction of vibration of tissue microstructures on a single two-dimensional plane.
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Affiliation(s)
- Hrebesh M Subhash
- Department of Biomedical Engineering, Oregon Health and Science University, 3303 SW Bond Avenue, Portland, Oregon 97239, USA.
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16
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Zha D, Chen F, Ramamoorthy S, Fridberger A, Choudhury N, Jacques SL, Wang RK, Nuttall AL. In vivo outer hair cell length changes expose the active process in the cochlea. PLoS One 2012; 7:e32757. [PMID: 22496736 PMCID: PMC3322117 DOI: 10.1371/journal.pone.0032757] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/30/2012] [Indexed: 11/28/2022] Open
Abstract
Background Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Methodology/Principal Findings Using in vivo optical coherence tomography, we demonstrate that outer hair cells in living guinea pigs have length changes with unexpected timing and magnitudes that depend on the stimulus level in the sensitive cochlea. Conclusions/Significance The level-dependent length change is a necessary condition for directly validating that power is expended by the active process presumed to underlie normal hearing.
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Affiliation(s)
- Dingjun Zha
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- Department of Otolaryngology/Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Shaanxi, People's Republic of China
| | - Fangyi Chen
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
| | - Sripriya Ramamoorthy
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Anders Fridberger
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- Karolinska Institutet, Center for Hearing and Communication Research, Department of Clinical Science, Intervention, and Technology, M1 Karolinska University Hospital, Stockholm, Sweden
| | - Niloy Choudhury
- Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan, United States of America
| | - Steven L. Jacques
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oregon, United States of America
- Department of Dermatology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Alfred L. Nuttall
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oregon, United States of America
- Kresge Hearing Research Institute, The University of Michigan, Ann Arbor, Michigan, United States of America
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17
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Gao SS, Xia A, Yuan T, Raphael PD, Shelton RL, Applegate BE, Oghalai JS. Quantitative imaging of cochlear soft tissues in wild-type and hearing-impaired transgenic mice by spectral domain optical coherence tomography. OPTICS EXPRESS 2011; 19:15415-28. [PMID: 21934905 PMCID: PMC3482885 DOI: 10.1364/oe.19.015415] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Human hearing loss often occurs as a result of damage or malformations to the functional soft tissues within the cochlea, but these changes are not appreciable with current medical imaging modalities. We sought to determine whether optical coherence tomography (OCT) could assess the soft tissue structures relevant to hearing using mouse models. We imaged excised cochleae with an altered tectorial membrane and during normal development. The soft tissue structures and expected anatomical variations were visible using OCT, and quantitative measurements confirmed the ability to detect critical changes relevant to hearing.
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Affiliation(s)
- Simon S. Gao
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305,
USA
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005,
USA
| | - Anping Xia
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305,
USA
| | - Tao Yuan
- Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030,
USA
| | - Patrick D. Raphael
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305,
USA
| | - Ryan L. Shelton
- Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center, 3120 TAMU, College Station, TX 77843
USA
| | - Brian E. Applegate
- Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center, 3120 TAMU, College Station, TX 77843
USA
| | - John S. Oghalai
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305,
USA
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005,
USA
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18
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Chen F, Zha D, Fridberger A, Zheng J, Choudhury N, Jacques SL, Wang RK, Shi X, Nuttall AL. A differentially amplified motion in the ear for near-threshold sound detection. Nat Neurosci 2011; 14:770-4. [PMID: 21602821 PMCID: PMC3225052 DOI: 10.1038/nn.2827] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 04/08/2011] [Indexed: 11/17/2022]
Abstract
The ear is a remarkably sensitive pressure fluctuation detector. In guinea pigs, behavioral measurements indicate a minimum detectable sound pressure of ∼20 μPa at 16 kHz. Such faint sounds produce 0.1-nm basilar membrane displacements, a distance smaller than conformational transitions in ion channels. It seems that noise within the auditory system would swamp such tiny motions, making weak sounds imperceptible. Here we propose a new mechanism contributing to a resolution of this problem and validate it through direct measurement. We hypothesized that vibration at the apical side of hair cells is enhanced compared with that at the commonly measured basilar membrane side. Using in vivo optical coherence tomography, we demonstrated that apical-side vibrations peaked at a higher frequency, had different timing and were enhanced compared with those at the basilar membrane. These effects depend nonlinearly on the stimulus sound pressure level. The timing difference and enhancement of vibrations are important for explaining how the noise problem is circumvented.
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Affiliation(s)
- Fangyi Chen
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
| | - Dingjun Zha
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
- Department of Otolaryngology/Head & Neck Surgery, Xijing Hospital, Fourth Military Medical University, People’s Republic of China
| | - Anders Fridberger
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
- Karolinska Institutet, Center for Hearing and Communication Research, Department of Clinical Science, Intervention, and Technology, M1 Karolinska University Hospital, Sweden
| | - Jiefu Zheng
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
| | - Niloy Choudhury
- Department of Biomedical Engineering, Oregon Health & Science University, Oregon 97239, USA
| | - Steven L. Jacques
- Department of Biomedical Engineering, Oregon Health & Science University, Oregon 97239, USA
- Department of Dermatology, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5061, USA
| | - Xiaorui Shi
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
- The Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Alfred L. Nuttall
- Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, Oregon, 97239-3098, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Oregon 97239, USA
- Kresge Hearing Research Institute, The University of Michigan, Ann Arbor, Michigan 48109-0506, USA
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19
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Wang RK, Nuttall AL. Phase-sensitive optical coherence tomography imaging of the tissue motion within the organ of Corti at a subnanometer scale: a preliminary study. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:056005. [PMID: 21054099 PMCID: PMC2948044 DOI: 10.1117/1.3486543] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 07/05/2010] [Accepted: 07/23/2010] [Indexed: 05/17/2023]
Abstract
Hearing loss can mean severe impairment to the quality of life. However, the biomechanical mechanisms of how the hearing organ, i.e., the organ of Corti (OC), responds to sound are still elusive, largely because there is currently no means available to image the 3-D motion characteristics of the OC. We present a novel use of the phase-sensitive spectral domain optical coherence tomography (PSOCT) to characterize the motion of cellular compartments within the OC at a subnanometer scale. The PSOCT system operates at 1310 nm with a spatial resolution of ∼16 μm and an imaging speed of 47,000 A-lines/s. The phase changes of the spectral interferograms induced by the localized tissue motion are used to quantify the vibration magnitude. Fourier transform analysis of the phase changes improves the system sensitivity to sense minute vibrations smaller than 1 nm. We demonstrate that the PSOCT system is feasible to image the meaningful vibration of cellular compartments within the OC with an unprecedented sensitivity down to ∼0.5 Å.
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Affiliation(s)
- Ruikang K Wang
- Oregon Health & Science University, Department of Biomedical Engineering, CH13B, 3303 Southwest Bond Avenue, Portland, Oregon 97239, USA.
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