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Jha RH, Piker EG, Clinard CG. Effects of Age on the Bone-Conduction Amplitude-Modulated cVEMP Temporal Modulation Transfer Function. Ear Hear 2025; 46:696-706. [PMID: 39726105 DOI: 10.1097/aud.0000000000001614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2024]
Abstract
OBJECTIVES Cervical vestibular evoked myogenic potentials (cVEMPs) reflect saccular stimulation that results in an inhibitory muscle reflex recorded over the sternocleidomastoid muscle. These responses are utilized to study basic vestibular functions and are also applied clinically. Traditionally, cVEMPs have utilized transient stimuli such as clicks and tonebursts to evoke onset responses. Recently, amplitude-modulated tones have been used to elicit cVEMPs (AMcVEMPs). These AMcVEMP responses can provide information about the magnitude, phase synchrony, and nonlinearities from the vestibulo-collic reflexes that cannot be captured using other existing testing techniques. Although temporal modulation transfer functions (TMTFs) of AMcVEMPs for young, healthy adults have been established using different analysis techniques, there is currently no information regarding the effects of age on these responses. Thus, the current study aimed to examine the effects of age on AMcVEMPs across a broad range of modulation frequencies (MFs) using various AMcVEMP metrics including amplitude, signal to noise ratio (SNR), and phase coherence (PC). DESIGN The study included 16 (aged 20 to 39 years) young, 17 (aged 40 to 59 years) mid-age, and 16 (60 to 75 years) older adults with no history of neurological, vestibular, or middle-ear complaints. The stimuli consisted of amplitude-modulated tones with a carrier frequency of 500 Hz and 10 MFs ranging from 11 to 397 Hz. These stimuli were presented using a B81 transducer at 123 dB FL. AMcVEMPs were recorded from the sternocleidomastoid muscle (ipsilateral to the stimulating mastoid) using surface electrodes. Response analysis was performed using an FFT-based approach with analyses including amplitude, SNR, and PC. RESULTS AMcVEMP waveforms exhibited periodicity corresponding to the stimulus MF, consistent with previous observations. Furthermore, significant age-related degradation in AMcVEMP amplitude, SNR, and PC measures were observed across a broad range of MFs. While AMcVEMPs were elicited across a wide range of MFs (11 to 263 Hz) for young adults, in mid-age and older adults, these metrics were robust only across a narrower range of MFs, resulting in a reduced TMTF. In addition, the MF eliciting the most robust AMcVEMP varied across different AMcVEMP analysis metrics and age groups. CONCLUSIONS A significant decline in the AMcVEMP response is seen as an effect of aging; however, the effect of aging is not uniform across measures or across MFs. The TMTF of AMcVEMP gets flatter, and the overall range is reduced as an effect of aging. Results from this study enhance our understanding of age-related changes in the vestibular system. Expansion of AMcVEMP to clinical populations may lead to a deeper understanding of the pathophysiology of vestibular disorders.
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Affiliation(s)
- Raghav H Jha
- School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, USA
| | - Erin G Piker
- Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia, USA
| | - Christopher G Clinard
- Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia, USA
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2
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Horii K, Ogawa B, Nagase N, Morimoto I, Abe C, Ogawa T, Choi S, Nin F. The cochlear hook region detects harmonics beyond the canonical hearing range. PNAS NEXUS 2024; 3:pgae280. [PMID: 39055687 PMCID: PMC11272074 DOI: 10.1093/pnasnexus/pgae280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 07/03/2024] [Indexed: 07/27/2024]
Abstract
Ultrasound, or sound at frequencies exceeding the conventional range of human hearing, is not only audible to mice, microbats, and dolphins, but also creates an auditory sensation when delivered through bone conduction in humans. Although ultrasound is utilized for brain activation and in hearing aids, the physiological mechanism of ultrasonic hearing remains unknown. In guinea pigs, we found that ultrasound above the hearing range delivered through ossicles of the middle ear evokes an auditory brainstem response and a mechano-electrical transduction current through hair cells, as shown by the local field potential called the cochlear microphonic potential (CM). The CM synchronizes with ultrasound, and like the response to audible sounds is actively and nonlinearly amplified. In vivo optical nano-vibration analysis revealed that the sensory epithelium in the hook region, the basal extreme of the cochlear turns, resonates in response both to ultrasound within the hearing range and to harmonics beyond the hearing range. The results indicate that hair cells can respond to stimulation at the optimal frequency and its harmonics, and the hook region detects ultrasound stimuli with frequencies more than two octaves higher than the upper limit of the ordinary hearing range.
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Affiliation(s)
- Kazuhiro Horii
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Bakushi Ogawa
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
- Division of Sensorimotor Medicine, Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Noriko Nagase
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
- Division of Sensorimotor Medicine, Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Iori Morimoto
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Chikara Abe
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Takenori Ogawa
- Division of Sensorimotor Medicine, Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Samuel Choi
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, Nishi-ku, Niigata, 950-2181, Japan
| | - Fumiaki Nin
- Division of Biological Principles, Department of Physiology and Biophysics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan
- Center for One Medicine Innovative Translational Research (COMIT), Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
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Quimby AE, Wei K, Adewole D, Eliades S, Cullen DK, Brant JA. Signal processing and stimulation potential within the ascending auditory pathway: a review. Front Neurosci 2023; 17:1277627. [PMID: 38027521 PMCID: PMC10658786 DOI: 10.3389/fnins.2023.1277627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/12/2023] [Indexed: 12/01/2023] Open
Abstract
The human auditory system encodes sound with a high degree of temporal and spectral resolution. When hearing fails, existing neuroprosthetics such as cochlear implants may partially restore hearing through stimulation of auditory neurons at the level of the cochlea, though not without limitations inherent to electrical stimulation. Novel approaches to hearing restoration, such as optogenetics, offer the potential of improved performance. We review signal processing in the ascending auditory pathway and the current state of conventional and emerging neural stimulation strategies at various levels of the auditory system.
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Affiliation(s)
- Alexandra E. Quimby
- Department of Otolaryngology and Communication Sciences, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Kimberly Wei
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Dayo Adewole
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Steven Eliades
- Department of Head and Neck Surgery and Communication Sciences, Duke University, Durham, NC, United States
| | - D. Kacy Cullen
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Jason A. Brant
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Otorhinolaryngology – Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, United States
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4
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The reticular lamina and basilar membrane vibrations in the transverse direction in the basal turn of the living gerbil cochlea. Sci Rep 2022; 12:19810. [PMID: 36396720 PMCID: PMC9671912 DOI: 10.1038/s41598-022-24394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022] Open
Abstract
The prevailing theory of cochlear function states that outer hair cells amplify sound-induced vibration to improve hearing sensitivity and frequency specificity. Recent micromechanical measurements in the basal turn of gerbil cochleae through the round window have demonstrated that the reticular lamina vibration lags the basilar membrane vibration, and it is physiologically vulnerable not only at the best frequency but also at the low frequencies. These results suggest that outer hair cells from a broad cochlear region enhance hearing sensitivity through a global hydromechanical mechanism. However, the time difference between the reticular lamina and basilar membrane vibration has been thought to result from a systematic measurement error caused by the optical axis non-perpendicular to the cochlear partition. To address this concern, we measured the reticular lamina and basilar membrane vibrations in the transverse direction through an opening in the cochlear lateral wall in this study. Present results show that the phase difference between the reticular lamina and basilar membrane vibration decreases with frequency by ~ 180 degrees from low frequencies to the best frequency, consistent with those measured through the round window. Together with the round-window measurement, the low-coherence interferometry through the cochlear lateral wall demonstrates that the time difference between the reticular lamina and basilar membrane vibration results from the cochlear active processing rather than a measurement error.
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Dewey JB. Cubic and quadratic distortion products in vibrations of the mouse cochlear apex. JASA EXPRESS LETTERS 2022; 2:114402. [PMID: 36456371 PMCID: PMC9704500 DOI: 10.1121/10.0015244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
When the ear is stimulated by two tones presented at frequencies f1 and f2, nonlinearity in the cochlea's vibratory response leads to the generation of distortion products (DPs), with the cubic 2f1-f2 DP commonly viewed as the most prominent. While the quadratic f2-f1 DP is also evident in numerous physiological and perceptual studies, its presence in the cochlea's mechanical response has been less well documented. Here, examination of vibratory DPs within the mouse cochlea confirmed that f2-f1 was a significant and sometimes dominant component, whether DPs were measured near their generation site, or after having propagated from more basal locations.
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Affiliation(s)
- James B Dewey
- Caruso Department of Otolaryngology-Head & Neck Surgery, University of Southern California, Los Angeles, California 90033, USA
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6
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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: 0.7] [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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He W, Burwood G, Fridberger A, Nuttall AL, Ren T. An outer hair cell-powered global hydromechanical mechanism for cochlear amplification. Hear Res 2022; 423:108407. [PMID: 34922772 PMCID: PMC9156726 DOI: 10.1016/j.heares.2021.108407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 11/04/2022]
Abstract
It is a common belief that the mammalian cochlea achieves its exquisite sensitivity, frequency selectivity, and dynamic range through an outer hair cell-based active process, or cochlear amplification. As a sound-induced traveling wave propagates from the cochlear base toward the apex, outer hair cells at a narrow region amplify the low level sound-induced vibration through a local feedback mechanism. This widely accepted theory has been tested by measuring sound-induced sub-nanometer vibrations within the organ of Corti in the sensitive living cochleae using heterodyne low-coherence interferometry and optical coherence tomography. The aim of this short review is to summarize experimental findings on the cochlear active process by the authors' group. Our data show that outer hair cells are able to generate substantial forces for driving the cochlear partition at all audible frequencies in vivo. The acoustically induced reticular lamina vibration is larger and more broadly tuned than the basilar membrane vibration. The reticular lamina and basilar membrane vibrate approximately in opposite directions at low frequencies and in the same direction at the best frequency. The group delay of the reticular lamina is larger than that of the basilar membrane. The magnitude and phase differences between the reticular lamina and basilar membrane vibration are physiologically vulnerable. These results contradict predictions based on the local feedback mechanism but suggest a global hydromechanical mechanism for cochlear amplification. 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)
- Wenxuan He
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - George Burwood
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - Anders Fridberger
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Alfred L Nuttall
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States
| | - Tianying Ren
- Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland OR, United States.
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8
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Easwar V, Purcell D, Eeckhoutte MV, Aiken SJ. The Influence of Male- and Female-Spoken Vowel Acoustics on Envelope-Following Responses. Semin Hear 2022; 43:223-239. [PMID: 36313043 PMCID: PMC9605803 DOI: 10.1055/s-0042-1756165] [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: 06/16/2023] Open
Abstract
The influence of male and female vowel characteristics on the envelope-following responses (EFRs) is not well understood. This study explored the role of vowel characteristics on the EFR at the fundamental frequency (f0) in response to the vowel /ε/ (as in "head"). Vowel tokens were spoken by five males and five females and EFRs were measured in 25 young adults (21 females). An auditory model was used to estimate changes in auditory processing that might account for talker effects on EFR amplitude. There were several differences between male and female vowels in relation to the EFR. For male talkers, EFR amplitudes were correlated with the bandwidth and harmonic count of the first formant, and the amplitude of the trough below the second formant. For female talkers, EFR amplitudes were correlated with the range of f0 frequencies and the amplitude of the trough above the second formant. The model suggested that the f0 EFR reflects a wide distribution of energy in speech, with primary contributions from high-frequency harmonics mediated from cochlear regions basal to the peaks of the first and second formants, not from low-frequency harmonics with energy near f0. Vowels produced by female talkers tend to produce lower-amplitude EFR, likely because they depend on higher-frequency harmonics where speech sound levels tend to be lower. This work advances auditory electrophysiology by showing how the EFR evoked by speech relates to the acoustics of speech, for both male and female voices.
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Affiliation(s)
- Vijayalakshmi Easwar
- Department of Communication Sciences and Disorders & Waisman Center, University of Wisconsin, Madison
- Department of Communication Sciences, National Acoustic Laboratories, Sydney, Australia
| | - David Purcell
- National Center for Audiology, School of Communication Sciences and Disorders, Western University, London, Canada
| | - Maaike Van Eeckhoutte
- Division of Hearing Systems, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
- Copenhagen Hearing and Balance Centre - Ear, Nose, Throat and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- National Center for Audiology, Western University, London, Canada
| | - Steven J. Aiken
- School of Communication Sciences and Disorders, Departments of Surgery and Psychology and Neuroscience, Dalhousie University, Halifax, Canada
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9
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Signatures of cochlear processing in neuronal coding of auditory information. Mol Cell Neurosci 2022; 120:103732. [PMID: 35489636 DOI: 10.1016/j.mcn.2022.103732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 11/22/2022] Open
Abstract
The vertebrate ear is endowed with remarkable perceptual capabilities. The faintest sounds produce vibrations of magnitudes comparable to those generated by thermal noise and can nonetheless be detected through efficient amplification of small acoustic stimuli. Two mechanisms have been proposed to underlie such sound amplification in the mammalian cochlea: somatic electromotility and active hair-bundle motility. These biomechanical mechanisms may work in concert to tune auditory sensitivity. In addition to amplitude sensitivity, the hearing system shows exceptional frequency discrimination allowing mammals to distinguish complex sounds with great accuracy. For instance, although the wide hearing range of humans encompasses frequencies from 20 Hz to 20 kHz, our frequency resolution extends to one-thirtieth of the interval between successive keys on a piano. In this article, we review the different cochlear mechanisms underlying sound encoding in the auditory system, with a particular focus on the frequency decomposition of sounds. The relation between peak frequency of activation and location along the cochlea - known as tonotopy - arises from multiple gradients in biophysical properties of the sensory epithelium. Tonotopic mapping represents a major organizational principle both in the peripheral hearing system and in higher processing levels and permits the spectral decomposition of complex tones. The ribbon synapses connecting sensory hair cells to auditory afferents and the downstream spiral ganglion neurons are also tuned to process periodic stimuli according to their preferred frequency. Though sensory hair cells and neurons necessarily filter signals beyond a few kHz, many animals can hear well beyond this range. We finally describe how the cochlear structure shapes the neural code for further processing in order to send meaningful information to the brain. Both the phase-locked response of auditory nerve fibers and tonotopy are key to decode sound frequency information and place specific constraints on the downstream neuronal network.
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Berger J, Rubinstein J. A flexible anatomical set of mechanical models for the organ of Corti. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210016. [PMID: 34540242 PMCID: PMC8441134 DOI: 10.1098/rsos.210016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
We build a flexible platform to study the mechanical operation of the organ of Corti (OoC) in the transduction of basilar membrane (BM) vibrations to oscillations of an inner hair cell bundle (IHB). The anatomical components that we consider are the outer hair cells (OHCs), the outer hair cell bundles, Deiters cells, Hensen cells, the IHB and various sections of the reticular lamina. In each of the components we apply Newton's equations of motion. The components are coupled to each other and are further coupled to the endolymph fluid motion in the subtectorial gap. This allows us to obtain the forces acting on the IHB, and thus study its motion as a function of the parameters of the different components. Some of the components include a nonlinear mechanical response. We find that slight bending of the apical ends of the OHCs can have a significant impact on the passage of motion from the BM to the IHB, including critical oscillator behaviour. In particular, our model implies that the components of the OoC could cooperate to enhance frequency selectivity, amplitude compression and signal to noise ratio in the passage from the BM to the IHB. Since the model is modular, it is easy to modify the assumptions and parameters for each component.
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Affiliation(s)
- Jorge Berger
- Department of Physics and Optical Engineering, Ort Braude College, Karmiel, Israel
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He W, Ren T. The origin of mechanical harmonic distortion within the organ of Corti in living gerbil cochleae. Commun Biol 2021; 4:1008. [PMID: 34433876 PMCID: PMC8387486 DOI: 10.1038/s42003-021-02540-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022] Open
Abstract
Although auditory harmonic distortion has been demonstrated psychophysically in humans and electrophysiologically in experimental animals, the cellular origin of the mechanical harmonic distortion remains unclear. To demonstrate the outer hair cell-generated harmonics within the organ of Corti, we measured sub-nanometer vibrations of the reticular lamina from the apical ends of the outer hair cells in living gerbil cochleae using a custom-built heterodyne low-coherence interferometer. The harmonics in the reticular lamina vibration are significantly larger and have broader spectra and shorter latencies than those in the basilar membrane vibration. The latency of the second harmonic is significantly greater than that of the fundamental at low stimulus frequencies. These data indicate that the mechanical harmonics are generated by the outer hair cells over a broad cochlear region and propagate from the generation sites to their own best-frequency locations.
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Affiliation(s)
- Wenxuan He
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, USA
| | - Tianying Ren
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, USA.
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12
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Quon RJ, Leslie GA, Camp EJ, Meisenhelter S, Steimel SA, Song Y, Ettinger AB, Bujarski KA, Casey MA, Jobst BC. 40-Hz auditory stimulation for intracranial interictal activity: A pilot study. Acta Neurol Scand 2021; 144:192-201. [PMID: 33893999 DOI: 10.1111/ane.13437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/08/2021] [Accepted: 04/11/2021] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To study the effects of auditory stimuli on interictal epileptiform discharge (IED) rates evident with intracranial monitoring. MATERIALS AND METHODS Eight subjects undergoing intracranial EEG monitoring for refractory epilepsy participated in this study. Auditory stimuli consisted of a 40-Hz tone, a 440-Hz tone modulated by a 40-Hz sinusoid, Mozart's Sonata for Two Pianos in D Major (K448), and K448 modulated by a 40-Hz sinusoid (modK448). Subjects were stratified into high- and low-IED rate groups defined by baseline IED rates. Subject-level analyses identified individual responses to auditory stimuli, discerned specific brain regions with significant reductions in IED rates, and examined the influence auditory stimuli had on whole-brain sigma power (12-16 Hz). RESULTS All subjects in the high baseline IED group had a significant 35.25% average reduction in IEDs during the 40-Hz tone; subject-level reductions localized to mesial and lateral temporal regions. Exposure to Mozart K448 showed significant yet less homogeneous responses. A post hoc analysis demonstrated two of the four subjects with positive IED responses had increased whole-brain power at the sigma frequency band during 40-Hz stimulation. CONCLUSIONS Our study is the first to evaluate the relationship between 40-Hz auditory stimulation and IED rates in refractory epilepsy. We reveal that 40-Hz auditory stimuli may be a noninvasive adjunctive intervention to reduce IED burden. Our pilot study supports the future examination of 40-Hz auditory stimuli in a larger population of subjects with high baseline IED rates.
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Affiliation(s)
- Robert J. Quon
- Department of Neurology Geisel School of Medicine at Dartmouth Hanover NH USA
| | - Grace A. Leslie
- Department of Music Georgia Institute of Technology Atlanta GA USA
| | - Edward J. Camp
- Department of Neurology Dartmouth‐Hitchcock Medical Center Lebanon NH USA
| | | | - Sarah A. Steimel
- Department of Neurology Geisel School of Medicine at Dartmouth Hanover NH USA
| | - Yinchen Song
- Department of Neurology Geisel School of Medicine at Dartmouth Hanover NH USA
- Department of Neurology Dartmouth‐Hitchcock Medical Center Lebanon NH USA
| | | | - Krzysztof A. Bujarski
- Department of Neurology Geisel School of Medicine at Dartmouth Hanover NH USA
- Department of Neurology Dartmouth‐Hitchcock Medical Center Lebanon NH USA
| | - Michael A. Casey
- Department of Music at Dartmouth College Hanover NH USA
- Department of Computer Science at Dartmouth College Hanover NH USA
| | - Barbara C. Jobst
- Department of Neurology Geisel School of Medicine at Dartmouth Hanover NH USA
- Department of Neurology Dartmouth‐Hitchcock Medical Center Lebanon NH USA
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13
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Easwar V, Boothalingam S, Flaherty R. Fundamental frequency-dependent changes in vowel-evoked envelope following responses. Hear Res 2021; 408:108297. [PMID: 34229221 DOI: 10.1016/j.heares.2021.108297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 06/03/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
Scalp-recorded envelope following responses (EFRs) provide a non-invasive method to assess the encoding of the fundamental frequency (f0) of voice that is important for speech understanding. It is well-known that EFRs are influenced by voice f0. However, this effect of f0 has not been examined independent of concomitant changes in spectra or neural generators. We evaluated the effect of voice f0 on EFRs while controlling for vowel formant characteristics and potentially avoiding significant changes in dominant neural generators using a small f0 range. EFRs were elicited by a male-spoken vowel /u/ (average f0 = 100.4 Hz) and its lowered f0 version (average f0 = 91.9 Hz) with closely matched formant characteristics. Vowels were presented to each ear of 17 young adults with normal hearing. EFRs were simultaneously recorded between the vertex and the nape, and the vertex and the ipsilateral mastoid-the two most common electrode montages used for EFRs. Our results indicate that when vowel formant characteristics are matched, an increase in f0 by 8.5 Hz reduces EFR amplitude by 25 nV, phase coherence by 0.05 and signal-to-noise ratio by 3.5 dB, on average. The reduction in EFR characteristics was similar across ears of stimulation and the two montages used. These findings will help parse the influence of f0 or stimulus spectra on EFRs when both co-vary.
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Affiliation(s)
- Vijayalakshmi Easwar
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States; Waisman Center, University of Wisconsin-Madison, United States
| | - Sriram Boothalingam
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States; Waisman Center, University of Wisconsin-Madison, United States
| | - Regan Flaherty
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States; Waisman Center, University of Wisconsin-Madison, United States
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14
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Fallah E, Strimbu CE, Olson ES. Nonlinearity of intracochlear motion and local cochlear microphonic: Comparison between guinea pig and gerbil. Hear Res 2021; 405:108234. [PMID: 33930834 DOI: 10.1016/j.heares.2021.108234] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/08/2021] [Accepted: 03/26/2021] [Indexed: 12/19/2022]
Abstract
Studying the in-vivo mechanical and electrophysiological cochlear responses in several species helps us to have a comprehensive view of the sensitivity and frequency selectivity of the cochlea. Different species might use different mechanisms to achieve the sharp frequency-place map. The outer hair cells (OHC) play an important role in mediating frequency tuning. In the present work, we measured the OHC-generated local cochlear microphonic (LCM) and the motion of different layers in the organ of Corti using optical coherence tomography (OCT) in the first turn of the cochlea in guinea pig. In the best frequency (BF) band, our observations were similar to our previous measurements in gerbil: a nonlinear peak in LCM responses and in the basilar membrane (BM) and OHC-region displacements, and higher motion in the OHC region than the BM. Sub-BF the responses in the two species were different. In both species the sub-BF displacement of the BM was linear and LCM was nonlinear. Sub-BF in the OHC-region, nonlinearity was only observed in a subset of healthy guinea pig cochleae while in gerbil, robust nonlinearity was observed in all healthy cochleae. The differences suggest that gerbils and guinea pigs employ different mechanisms for filtering sub-BF OHC activity from BM responses. However, it cannot be ruled out that the differences are due to technical measurement differences across the species.
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Affiliation(s)
- Elika Fallah
- Department of Biomedical Engineering, Columbia University, New York City, NY, United States
| | - C Elliott Strimbu
- Department of Otolaryngology-Head and Neck Surgery, Columbia University, New York City, NY, United States
| | - Elizabeth S Olson
- Department of Biomedical Engineering, Columbia University, New York City, NY, United States; Department of Otolaryngology-Head and Neck Surgery, Columbia University, New York City, NY, United States.
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15
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Tani T, Koike-Tani M, Tran MT, Shribak M, Levic S. Postnatal structural development of mammalian Basilar Membrane provides anatomical basis for the maturation of tonotopic maps and frequency tuning. Sci Rep 2021; 11:7581. [PMID: 33828185 PMCID: PMC8027603 DOI: 10.1038/s41598-021-87150-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/16/2021] [Indexed: 02/01/2023] Open
Abstract
The basilar membrane (BM) of the mammalian cochlea constitutes a spiraling acellular ribbon that is intimately attached to the organ of Corti. Its graded stiffness, increasing from apex to the base of the cochlea provides the mechanical basis for sound frequency analysis. Despite its central role in auditory signal transduction, virtually nothing is known about the BM's structural development. Using polarized light microscopy, the present study characterized the architectural transformations of freshly dissected BM at time points during postnatal development and maturation. The results indicate that the BM structural elements increase progressively in size, becoming radially aligned and more tightly packed with maturation and reach the adult structural signature by postnatal day 20 (P20). The findings provide insight into structural details and developmental changes of the mammalian BM, suggesting that BM is a dynamic structure that changes throughout the life of an animal.
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Affiliation(s)
- Tomomi Tani
- Marine Biological Laboratory, Eugene Bell Center, Woods Hole, MA, USA
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan
| | - Maki Koike-Tani
- Marine Biological Laboratory, Eugene Bell Center, Woods Hole, MA, USA
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan
| | - Mai Thi Tran
- Marine Biological Laboratory, Eugene Bell Center, Woods Hole, MA, USA
- College of Engineering and Computer Science, VinUniversity, Gia Lam District, Hanoi, Vietnam
| | - Michael Shribak
- Marine Biological Laboratory, Eugene Bell Center, Woods Hole, MA, USA
| | - Snezana Levic
- Marine Biological Laboratory, Eugene Bell Center, Woods Hole, MA, USA.
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK.
- Brighton and Sussex Medical School, University of Sussex, Brighton, BN1 9PX, UK.
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16
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Lucchetti F, Nonclercq A, Avan P, Giraudet F, Fan X, Deltenre P. Subcortical neural generators of the envelope-following response in sleeping children: A transfer function analysis. Hear Res 2020; 401:108157. [PMID: 33360182 DOI: 10.1016/j.heares.2020.108157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 01/23/2023]
Abstract
Multiple auditory structures, from cochlea to cortex, phase-lock to the envelope of complex stimuli. The relative contributions of these structures to the human surface-recorded envelope-following response (EFR) are still uncertain. Identification of the active contributor(s) is complicated by the fact that even the simplest two-tone (f1&f2) stimulus, targeting its (f2-f1) envelope, evokes additional linear (f1&f2) and non-linear (2f1-f2) phase-locked components as well as a transient auditory brainstem response (ABR). Here, we took advantage of the generalized primary tone phase variation method to isolate each predictable component in the time domain, allowing direct measurements of onset latency, duration and phase discontinuity values from which the involved generators were inferred. Targeting several envelope frequencies (0.22-1 kHz), we derived the EFR transfer functions along a vertical vertex-to-neck and a horizontal earlobe-to-earlobe recording channels, yielding respectively EFR-V and EFR-H waveforms. Subjects (N= 30) were sleeping children with normal electrophysiological thresholds and normal oto-acoustic emissions. Both EFR-H and EFR-V phase-locking values (PLV) transfer functions had a low-pass profile, EFR-V showing a lower cut-off frequency than EFR-H. We also computed the frequency-latency relationships of both EFRs onset latencies. EFR-H data fitted a power-law function incorporating a frequency-dependent traveling wave delay and a fixed one amounting to 1.2 ms. The fitted function nicely fell within five published estimations of the latency-frequency function of the ABR wave-I, thus pointing to a cochlear nerve origin. The absence of phase discontinuity and overall response durations that were equal to that of the stimulus indicated no contribution from a later generator. The recording of an entirely similar EFR-H response in a patient who had severe brainstem encephalitis with a normal, isolated, ABR wave-I but complete absence of later waves, further substantiated a cochlear nerve origin. Modeling of the EFR-V latency-frequency functions indicated a fixed transport time of 2 ms with respect to EFR-H onset, suggesting a cochlear nucleus (CN) origin, here also, without indication for multiple generators. Other features of the EFR-V response pointing to the CN were, at least for the EFR frequency below the cut-off values of the transfer functions, higher PLVs coupled with increased harmonic distortion. Such a behavior has been described in the so-called highly-synchronized neurons of the ventral cochlear nucleus (VCN). The present study compellingly demonstrated the advantage of isolating the EFR in the temporal domain so as to extract detailed spectro-temporal parameters that, combined with orthogonal recording channels, shed new light on the involved neural generators.
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Affiliation(s)
- Federico Lucchetti
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium; Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium.
| | - Antoine Nonclercq
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium; Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium; Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Paul Avan
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Fabrice Giraudet
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Xiaoya Fan
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium.
| | - Paul Deltenre
- Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium.
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17
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Lentz JJ, Pan B, Ponnath A, Tran CM, Nist-Lund C, Galvin A, Goldberg H, Robillard KN, Jodelka FM, Farris HE, Huang J, Chen T, Zhu H, Zhou W, Rigo F, Hastings ML, Géléoc GSG. Direct Delivery of Antisense Oligonucleotides to the Middle and Inner Ear Improves Hearing and Balance in Usher Mice. Mol Ther 2020; 28:2662-2676. [PMID: 32818431 PMCID: PMC7704764 DOI: 10.1016/j.ymthe.2020.08.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/05/2020] [Accepted: 08/02/2020] [Indexed: 12/16/2022] Open
Abstract
Usher syndrome is a syndromic form of hereditary hearing impairment that includes sensorineural hearing loss and delayed-onset retinitis pigmentosa (RP). Type 1 Usher syndrome (USH1) is characterized by congenital profound sensorineural hearing impairment and vestibular areflexia, with adolescent-onset RP. Systemic treatment with antisense oligonucleotides (ASOs) targeting the human USH1C c.216G>A splicing mutation in a knockin mouse model of USH1 restores hearing and balance. Herein, we explore the effect of delivering ASOs locally to the ear to treat hearing and vestibular dysfunction associated with Usher syndrome. Three localized delivery strategies were investigated in USH1C mice: inner ear injection, trans-tympanic membrane injection, and topical tympanic membrane application. We demonstrate, for the first time, that ASOs delivered directly to the ear correct Ush1c expression in inner ear tissue, improve cochlear hair cell transduction currents, restore vestibular afferent irregularity, spontaneous firing rate, and sensitivity to head rotation, and successfully recover hearing thresholds and balance behaviors in USH1C mice. We conclude that local delivery of ASOs to the middle and inner ear reach hair cells and can rescue both hearing and balance. These results also demonstrate the therapeutic potential of ASOs to treat hearing and balance deficits associated with Usher syndrome and other ear diseases.
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Affiliation(s)
- Jennifer J Lentz
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
| | - Bifeng Pan
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Abhilash Ponnath
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Christopher M Tran
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Carl Nist-Lund
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alice Galvin
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hannah Goldberg
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Katelyn N Robillard
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Francine M Jodelka
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Hamilton E Farris
- Department of Otorhinolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA; Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Jun Huang
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Tianwen Chen
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Hong Zhu
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Wu Zhou
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Inc., Carlsbad, CA 92008, USA
| | - Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Gwenaëlle S G Géléoc
- Department of Otolaryngology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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18
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Ota T, Nin F, Choi S, Muramatsu S, Sawamura S, Ogata G, Sato MP, Doi K, Doi K, Tsuji T, Kawano S, Reichenbach T, Hibino H. Characterisation of the static offset in the travelling wave in the cochlear basal turn. Pflugers Arch 2020; 472:625-635. [PMID: 32318797 PMCID: PMC7239825 DOI: 10.1007/s00424-020-02373-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/18/2020] [Accepted: 03/23/2020] [Indexed: 02/07/2023]
Abstract
In mammals, audition is triggered by travelling waves that are evoked by acoustic stimuli in the cochlear partition, a structure containing sensory hair cells and a basilar membrane. When the cochlea is stimulated by a pure tone of low frequency, a static offset occurs in the vibration in the apical turn. In the high-frequency region at the cochlear base, multi-tone stimuli induce a quadratic distortion product in the vibrations that suggests the presence of an offset. However, vibrations below 100 Hz, including a static offset, have not been directly measured there. We therefore constructed an interferometer for detecting motion at low frequencies including 0 Hz. We applied the interferometer to record vibrations from the cochlear base of guinea pigs in response to pure tones. When the animals were exposed to sound at an intensity of 70 dB or higher, we recorded a static offset of the sinusoidally vibrating cochlear partition by more than 1 nm towards the scala vestibuli. The offset’s magnitude grew monotonically as the stimuli intensified. When stimulus frequency was varied, the response peaked around the best frequency, the frequency that maximised the vibration amplitude at threshold sound pressure. These characteristics are consistent with those found in the low-frequency region and are therefore likely common across the cochlea. The offset diminished markedly when the somatic motility of mechanosensitive outer hair cells, the force-generating machinery that amplifies the sinusoidal vibrations, was pharmacologically blocked. Therefore, the partition offset appears to be linked to the electromotile contraction of outer hair cells.
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Affiliation(s)
- Takeru Ota
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan.
| | - Samuel Choi
- AMED-CREST, AMED, Niigata, 951-8510, Japan.,Department of Electrical and Electronics Engineering, Niigata University, Niigata, 950-2181, Japan
| | - Shogo Muramatsu
- Department of Electrical and Electronics Engineering, Niigata University, Niigata, 950-2181, Japan
| | - Seishiro Sawamura
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| | - Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| | - Mitsuo P Sato
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, 589-8511, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, 589-8511, Japan
| | - Kentaro Doi
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, 560-8531, Japan
| | - Tetsuro Tsuji
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, 560-8531, Japan.,Department of Advanced Mathematical Sciences, Graduate School of Informatics, Kyoto University, Kyoto, 606-8501, Japan
| | - Satoyuki Kawano
- AMED-CREST, AMED, Niigata, 951-8510, Japan.,Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, 560-8531, Japan
| | - Tobias Reichenbach
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan. .,AMED-CREST, AMED, Niigata, 951-8510, Japan.
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19
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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: 1.7] [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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20
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Sadreev II, Burwood GWS, Flaherty SM, Kim J, Russell IJ, Abdullin TI, Lukashkin AN. Drug Diffusion Along an Intact Mammalian Cochlea. Front Cell Neurosci 2019; 13:161. [PMID: 31080407 PMCID: PMC6497751 DOI: 10.3389/fncel.2019.00161] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/08/2019] [Indexed: 12/29/2022] Open
Abstract
Intratympanic drug administration depends on the ability of drugs to pass through the round window membrane (RW) at the base of the cochlea and diffuse from this location to the apex. While the RW permeability for many different drugs can be promoted, passive diffusion along the narrowing spiral of the cochlea is limited. Earlier measurements of the distribution of marker ions, corticosteroids, and antibiotics demonstrated that the concentration of substances applied to the RW was two to three orders of magnitude higher in the base compared to the apex. The measurements, however, involved perforating the cochlear bony wall and, in some cases, sampling perilymph. These manipulations can change the flow rate of perilymph and lead to intake of perilymph through the cochlear aqueduct, thereby disguising concentration gradients of the delivered substances. In this study, the suppressive effect of salicylate on cochlear amplification via block of the outer hair cell (OHC) somatic motility was utilized to assess salicylate diffusion along an intact guinea pig cochlea in vivo. Salicylate solution was applied to the RW and threshold elevation of auditory nerve responses was measured at different times and frequencies after application. Resultant concentrations of salicylate along the cochlea were calculated by fitting the experimental data using a mathematical model of the diffusion and clearing of salicylate in a tube of variable diameter combined with a model describing salicylate action on cochlear amplification. Concentrations reach a steady-state at different times for different cochlear locations and it takes longer to reach the steady-state at more apical locations. Even at the steady-state, the predicted concentration at the apex is negligible. Model predictions for the geometry of the longer human cochlea show even higher differences in the steady-state concentrations of the drugs between cochlear base and apex. Our findings confirm conclusions that achieving therapeutic drug concentrations throughout the entire cochlear duct is hardly possible when the drugs are applied to the RW and are distributed via passive diffusion. Assisted methods of drug delivery are needed to reach a more uniform distribution of drugs along the cochlea.
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Affiliation(s)
- Ildar I Sadreev
- Department of Medicine, Faculty of Medicine, Imperial College, London, United Kingdom
| | - George W S Burwood
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Samuel M Flaherty
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Jongrae Kim
- School of Mechanical Engineering, Institute of Design, Robotics and Optimisation, Aerospace Systems Engineering, University of Leeds, Leeds, United Kingdom
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Timur I Abdullin
- Department of Biochemistry, Biotechnology and Pharmacology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom.,Centre for Regenerative Medicine and Devices, University of Brighton, Brighton, United Kingdom
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