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Barioni NO, Beduschi RS, da Silva AV, Martins MG, Almeida-Francia CCD, Rodrigues SA, López DE, Gómez-Nieto R, Horta-Júnior JAC. The role of the Ventral Nucleus of the Trapezoid Body in the auditory prepulse inhibition of the acoustic startle reflex. Hear Res 2024; 450:109070. [PMID: 38972084 DOI: 10.1016/j.heares.2024.109070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/28/2024] [Accepted: 06/13/2024] [Indexed: 07/09/2024]
Abstract
Cholinergic signaling is essential to mediate the auditory prepulse inhibition (PPI), an operational measure of sensorimotor gating, that refers to the reduction of the acoustic startle reflex (ASR) when a low-intensity, non-startling acoustic stimulus (the prepulse) is presented just before the onset of the acoustic startle stimulus. The cochlear root neurons (CRNs) are the first cells of the ASR circuit to receive cholinergic inputs from non-olivocochlear neurons of the ventral nucleus of the trapezoid body (VNTB) and subsequently decrease their neuronal activity in response to auditory prepulses. Yet, the contribution of the VNTB-CRNs pathway to the mediation of PPI has not been fully elucidated. In this study, we used the immunotoxin anti-choline acetyltransferase (ChAT)-saporin as well as electrolytic lesions of the medial olivocochlear bundle to selectively eliminate cholinergic VNTB neurons, and then assessed the ASR and PPI paradigms. Retrograde track-tracing experiments were conducted to precisely determine the site of lesioning VNTB neurons projecting to the CRNs. Additionally, the effects of VNTB lesions and the integrity of the auditory pathway were evaluated via auditory brain responses tests, ChAT- and FOS-immunohistochemistry. Consequently, we established three experimental groups: 1) intact control rats (non-lesioned), 2) rats with bilateral lesions of the olivocochlear bundle (OCB-lesioned), and 3) rats with bilateral immunolesions affecting both the olivocochlear bundle and the VNTB (OCB/VNTB-lesioned). All experimental groups underwent ASR and PPI tests at several interstimulus intervals before the lesion and 7, 14, and 21 days after it. Our results show that the ASR amplitude remained unaffected both before and after the lesion across all experimental groups, suggesting that the VNTB does not contribute to the ASR. The%PPI increased across the time points of evaluation in the control and OCB-lesioned groups but not in the OCB/VNTB-lesioned group. At the ISI of 50 ms, the OCB-lesioned group exhibited a significant increase in%PPI (p < 0.01), which did not occur in the OCB/VNTB-lesioned group. Therefore, the ablation of cholinergic non-olivocochlear neurons in the OCB/VNTB-lesioned group suggests that these neurons contribute to the mediation of auditory PPI at the 50 ms ISI through their cholinergic projections to CRNs. Our study strongly reinforces the notion that auditory PPI encompasses a complex mechanism of top-down cholinergic modulation, effectively attenuating the ASR across different interstimulus intervals within multiple pathways.
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Affiliation(s)
- N O Barioni
- Department of Functional and Structural Biology - Anatomy Division, Institute of Biosciences of Botucatu, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
| | - R S Beduschi
- Department of Functional and Structural Biology - Anatomy Division, Institute of Biosciences of Botucatu, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
| | - A V da Silva
- Medicine School, Federal University of Mato Grosso do Sul, UFMS-CPTL, Três Lagoas, Mato Grosso do Sul, Brazil
| | - M G Martins
- Department of Functional and Structural Biology - Anatomy Division, Institute of Biosciences of Botucatu, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
| | - C C D Almeida-Francia
- Department of Functional and Structural Biology - Anatomy Division, Institute of Biosciences of Botucatu, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
| | - S A Rodrigues
- Department of Bioprocesses and Biotechnology - Faculty of Agricultural Sciences, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
| | - D E López
- Neuroscience Institute of Castilla y León (INCyL), Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain; Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - R Gómez-Nieto
- Neuroscience Institute of Castilla y León (INCyL), Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain; Department of Cell Biology and Pathology, University of Salamanca, Salamanca, Spain.
| | - J A C Horta-Júnior
- Department of Functional and Structural Biology - Anatomy Division, Institute of Biosciences of Botucatu, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil.
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De Vreese S, Orekhova K, Morell M, Gerussi T, Graïc JM. Neuroanatomy of the Cetacean Sensory Systems. Animals (Basel) 2023; 14:66. [PMID: 38200796 PMCID: PMC10778493 DOI: 10.3390/ani14010066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/10/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Cetaceans have undergone profound sensory adaptations in response to their aquatic environment during evolution. These adaptations are characterised by anatomo-functional changes in the classically defined sensory systems, shaping their neuroanatomy accordingly. This review offers a concise and up-to-date overview of our current understanding of the neuroanatomy associated with cetacean sensory systems. It encompasses a wide spectrum, ranging from the peripheral sensory cells responsible for detecting environmental cues, to the intricate structures within the central nervous system that process and interpret sensory information. Despite considerable progress in this field, numerous knowledge gaps persist, impeding a comprehensive and integrated understanding of their sensory adaptations, and through them, of their sensory perspective. By synthesising recent advances in neuroanatomical research, this review aims to shed light on the intricate sensory alterations that differentiate cetaceans from other mammals and allow them to thrive in the marine environment. Furthermore, it highlights pertinent knowledge gaps and invites future investigations to deepen our understanding of the complex processes in cetacean sensory ecology and anatomy, physiology and pathology in the scope of conservation biology.
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Affiliation(s)
- Steffen De Vreese
- Laboratory of Applied Bioacoustics (LAB), Universitat Politècnica de Catalunya-BarcelonaTech (UPC), 08800 Vilanova i la Geltrú, Spain
| | - Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
| | - Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
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Munoz F, Vicencio-Jimenez S, Jorratt P, Delano PH, Terreros G. Corticofugal and Brainstem Functions Associated With Medial Olivocochlear Cholinergic Transmission. Front Neurosci 2022; 16:866161. [PMID: 35573302 PMCID: PMC9094045 DOI: 10.3389/fnins.2022.866161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/24/2022] [Indexed: 11/29/2022] Open
Abstract
Cholinergic transmission is essential for survival and reproduction, as it is involved in several physiological responses. In the auditory system, both ascending and descending auditory pathways are modulated by cholinergic transmission, affecting the perception of sounds. The auditory efferent system is a neuronal network comprised of several feedback loops, including corticofugal and brainstem pathways to the cochlear receptor. The auditory efferent system's -final and mandatory synapses that connect the brain with the cochlear receptor- involve medial olivocochlear neurons and outer hair cells. A unique cholinergic transmission mediates these synapses through α9/α10 nicotinic receptors. To study this receptor, it was generated a strain of mice carrying a null mutation of the Chrna9 gene (α9-KO mice), lacking cholinergic transmission between medial olivocochlear neurons and outer hair cells, providing a unique opportunity to study the role of medial olivocochlear cholinergic transmission in auditory and cognitive functions. In this article, we review behavioral and physiological studies carried out to research auditory efferent function in the context of audition, cognition, and hearing impairments. Auditory studies have shown that hearing thresholds in the α9-KO mice are normal, while more complex auditory functions, such as frequency selectivity and sound localization, are altered. The corticofugal pathways have been studied in α9-KO mice using behavioral tasks, evidencing a reduced capacity to suppress auditory distractors during visual selective attention. Finally, we discuss the evolutionary role of the auditory efferent system detecting vocalizations in noise and its role in auditory disorders, such as the prevention of age-related hearing loss.
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Affiliation(s)
- Felipe Munoz
- Instituto de Ciencias de la Salud, Universidad de O’Higgins, Rancagua, Chile
- Universidad de Valparaíso, Valparaíso, Chile
| | - Sergio Vicencio-Jimenez
- Department of Otolaryngology-Head and Neck Surgery, The Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Pascal Jorratt
- National Institute of Mental Health, Klecany, Czechia
- Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Paul H. Delano
- Facultad de Medicina, Neuroscience Department, Universidad de Chile, Santiago, Chile
- Department of Otolaryngology, Hospital Clínico de la Universidad de Chile, Santiago, Chile
- Centro Avanzado de Ingeniería Eléctrica y Electrónica, AC3E, Universidad Técnica Federico Santa María, Valparaíso, Chile
- Facultad de Medicina, Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
| | - Gonzalo Terreros
- Instituto de Ciencias de la Salud, Universidad de O’Higgins, Rancagua, Chile
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4
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Hernández-Pérez H, Mikiel-Hunter J, McAlpine D, Dhar S, Boothalingam S, Monaghan JJM, McMahon CM. Understanding degraded speech leads to perceptual gating of a brainstem reflex in human listeners. PLoS Biol 2021; 19:e3001439. [PMID: 34669696 PMCID: PMC8559948 DOI: 10.1371/journal.pbio.3001439] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/01/2021] [Accepted: 10/07/2021] [Indexed: 11/19/2022] Open
Abstract
The ability to navigate "cocktail party" situations by focusing on sounds of interest over irrelevant, background sounds is often considered in terms of cortical mechanisms. However, subcortical circuits such as the pathway underlying the medial olivocochlear (MOC) reflex modulate the activity of the inner ear itself, supporting the extraction of salient features from auditory scene prior to any cortical processing. To understand the contribution of auditory subcortical nuclei and the cochlea in complex listening tasks, we made physiological recordings along the auditory pathway while listeners engaged in detecting non(sense) words in lists of words. Both naturally spoken and intrinsically noisy, vocoded speech-filtering that mimics processing by a cochlear implant (CI)-significantly activated the MOC reflex, but this was not the case for speech in background noise, which more engaged midbrain and cortical resources. A model of the initial stages of auditory processing reproduced specific effects of each form of speech degradation, providing a rationale for goal-directed gating of the MOC reflex based on enhancing the representation of the energy envelope of the acoustic waveform. Our data reveal the coexistence of 2 strategies in the auditory system that may facilitate speech understanding in situations where the signal is either intrinsically degraded or masked by extrinsic acoustic energy. Whereas intrinsically degraded streams recruit the MOC reflex to improve representation of speech cues peripherally, extrinsically masked streams rely more on higher auditory centres to denoise signals.
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Affiliation(s)
- Heivet Hernández-Pérez
- Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia
| | - Jason Mikiel-Hunter
- Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia
| | - David McAlpine
- Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia
| | - Sumitrajit Dhar
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois, United States of America
| | - Sriram Boothalingam
- University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jessica J. M. Monaghan
- Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia
- National Acoustic Laboratories, Sydney, Australia
| | - Catherine M. McMahon
- Department of Linguistics, The Australian Hearing Hub, Macquarie University, Sydney, Australia
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Ohata K, Kondo M, Ozono Y, Hanada Y, Sato T, Inohara H, Shimada S. Cochlear protection against noise exposure requires serotonin type 3A receptor via the medial olivocochlear system. FASEB J 2021; 35:e21486. [PMID: 33811700 DOI: 10.1096/fj.202002383r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/27/2021] [Accepted: 02/15/2021] [Indexed: 11/11/2022]
Abstract
The cochlear efferent feedback system plays important roles in auditory processing, including regulation of the dynamic range of hearing, and provides protection against acoustic trauma. These functions are performed through medial olivocochlear (MOC) neurons. However, the underlying cellular and molecular mechanisms are not fully understood. The serotonin type 3A (5-HT3A) receptor is widely expressed throughout the nervous system, which suggests important roles in various neural functions. However, involvement of the 5-HT3A receptor in the MOC system remains unclear. We used mice in this study and found that the 5-HT3A receptor was expressed in MOC neurons that innervated outer hair cells in the cochlea and was involved in the activation of MOC neurons by noise exposure. 5-HT3A receptor knockout impaired MOC functions, potentiated noise-induced hearing loss, and increased loss of ribbon synapses following noise exposure. Furthermore, 5-HT3 receptor agonist treatment alleviated the noise-induced hearing loss and loss of ribbon synapses, which enhanced cochlear protection provided by the MOC system. Our findings demonstrate that the 5-HT3A receptor plays fundamental roles in the MOC system and critically contributes to protection from noise-induced hearing impairment.
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Affiliation(s)
- Kazuya Ohata
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Makoto Kondo
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan.,Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Osaka, Japan
| | - Yoshiyuki Ozono
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yukiko Hanada
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Takashi Sato
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Japan.,Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Osaka, Japan
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6
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Keppler H, Degeest S, Vinck B. Short-Term Test-Retest Reliability of Contralateral Suppression of Click-Evoked Otoacoustic Emissions in Normal-Hearing Subjects. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2021; 64:1062-1072. [PMID: 33719513 DOI: 10.1044/2020_jslhr-20-00393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Purpose The objective of the current study was to investigate the short-term test-retest reliability of contralateral suppression (CS) of click-evoked otoacoustic emissions (CEOAEs) using commercially available otoacoustic emission equipment. Method Twenty-three young normal-hearing subjects were tested. An otoscopic evaluation, admittance measures, pure-tone audiometry, measurements of CEOAEs without and with contralateral acoustic stimulation (CAS) to determine CS were performed at baseline (n = 23), an immediate retest without and with refitting of the probe (only CS of CEOAEs; n = 11), and a retest after 1 week (n = 23) were performed. Test-retest reliability parameters were determined on CEOAE response amplitudes without and with CAS, and on raw and normalized CS indices between baseline and the other test moments. Results Repeated-measures analysis of variance indicated no random or systematic changes in CEOAE response amplitudes without and with CAS, and in raw and normalized CS indices between the test moments. Moderate-to-high intraclass correlation coefficients with mostly high significant between-subjects variability between baseline and each consecutive test moment were found for CEOAE response amplitude without and with CAS, and for the raw and normalized CS indices. Other reliability parameters deteriorated between CEOAE response amplitudes with CAS as compared to without CAS, between baseline and retest with probe refitting, and after 1 week, as well as for frequency-specific raw and normalized CS indices as compared to global CS indices. Conclusions There was considerable variability in raw and normalized CS indices as measured using CEOAEs with CAS using commercially available otoacoustic emission equipment. More research is needed to optimize the measurement of CS of CEOAEs and to reduce influencing factors, as well as to make generalization of test-retest reliability data possible.
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Affiliation(s)
- Hannah Keppler
- Department of Rehabilitation Sciences, Faculty of Medicine and Health Sciences, Ghent University, Belgium
- Department of Otorhinolaryngology, Ghent University Hospital, Belgium
| | - Sofie Degeest
- Department of Rehabilitation Sciences, Faculty of Medicine and Health Sciences, Ghent University, Belgium
| | - Bart Vinck
- Department of Rehabilitation Sciences, Faculty of Medicine and Health Sciences, Ghent University, Belgium
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Marrufo-Pérez MI, Johannesen PT, Lopez-Poveda EA. Correlation and Reliability of Behavioral and Otoacoustic-Emission Estimates of Contralateral Medial Olivocochlear Reflex Strength in Humans. Front Neurosci 2021; 15:640127. [PMID: 33664649 PMCID: PMC7921326 DOI: 10.3389/fnins.2021.640127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/26/2021] [Indexed: 11/18/2022] Open
Abstract
The roles of the medial olivocochlear reflex (MOCR) in human hearing have been widely investigated but remain controversial. We reason that this may be because the effects of MOCR activation on cochlear mechanical responses can be assessed only indirectly in healthy humans, and the different methods used to assess those effects possibly yield different and/or unreliable estimates. One aim of this study was to investigate the correlation between three methods often employed to assess the strength of MOCR activation by contralateral acoustic stimulation (CAS). We measured tone detection thresholds (N = 28), click-evoked otoacoustic emission (CEOAE) input/output (I/O) curves (N = 18), and distortion-product otoacoustic emission (DPOAE) I/O curves (N = 18) for various test frequencies in the presence and the absence of CAS (broadband noise of 60 dB SPL). As expected, CAS worsened tone detection thresholds, suppressed CEOAEs and DPOAEs, and horizontally shifted CEOAE and DPOAE I/O curves to higher levels. However, the CAS effect on tone detection thresholds was not correlated with the horizontal shift of CEOAE or DPOAE I/O curves, and the CAS-induced CEOAE suppression was not correlated with DPOAE suppression. Only the horizontal shifts of CEOAE and DPOAE I/O functions were correlated with each other at 1.5, 2, and 3 kHz. A second aim was to investigate which of the methods is more reliable. The test–retest variability of the CAS effect was high overall but smallest for tone detection thresholds and CEOAEs, suggesting that their use should be prioritized over the use of DPOAEs. Many factors not related with the MOCR, including the limited parametric space studied, the low resolution of the I/O curves, and the reduced numbers of observations due to data exclusion likely contributed to the weak correlations and the large test–retest variability noted. These findings can help us understand the inconsistencies among past studies and improve our understanding of the functional significance of the MOCR.
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Affiliation(s)
- Miriam I Marrufo-Pérez
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Peter T Johannesen
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Enrique A Lopez-Poveda
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain.,Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
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Jovanovic S, Milenkovic I. Purinergic Modulation of Activity in the Developing Auditory Pathway. Neurosci Bull 2020; 36:1285-1298. [PMID: 33040238 DOI: 10.1007/s12264-020-00586-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
Purinergic P2 receptors, activated by endogenous ATP, are prominently expressed on neuronal and non-neuronal cells during development of the auditory periphery and central auditory neurons. In the mature cochlea, extracellular ATP contributes to ion homeostasis, and has a protective function against noise exposure. Here, we focus on the modulation of activity by extracellular ATP during early postnatal development of the lower auditory pathway. In mammals, spontaneous patterned activity is conveyed along afferent auditory pathways before the onset of acoustically evoked signal processing. During this critical developmental period, inner hair cells fire bursts of action potentials that are believed to provide a developmental code for synaptic maturation and refinement of auditory circuits, thereby establishing a precise tonotopic organization. Endogenous ATP-release triggers such patterned activity by raising the extracellular K+ concentration and contributes to firing by increasing the excitability of auditory nerve fibers, spiral ganglion neurons, and specific neuron types within the auditory brainstem, through the activation of diverse P2 receptors. We review recent studies that provide new models on the contribution of purinergic signaling to early development of the afferent auditory pathway. Further, we discuss potential future directions of purinergic research in the auditory system.
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Affiliation(s)
- Sasa Jovanovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany
| | - Ivan Milenkovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany.
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9
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Rao A, Koerner TK, Madsen B, Zhang Y. Investigating Influences of Medial Olivocochlear Efferent System on Central Auditory Processing and Listening in Noise: A Behavioral and Event-Related Potential Study. Brain Sci 2020; 10:brainsci10070428. [PMID: 32635442 PMCID: PMC7408540 DOI: 10.3390/brainsci10070428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/21/2020] [Accepted: 06/30/2020] [Indexed: 11/16/2022] Open
Abstract
This electrophysiological study investigated the role of the medial olivocochlear (MOC) efferents in listening in noise. Both ears of eleven normal-hearing adult participants were tested. The physiological tests consisted of transient-evoked otoacoustic emission (TEOAE) inhibition and the measurement of cortical event-related potentials (ERPs). The mismatch negativity (MMN) and P300 responses were obtained in passive and active listening tasks, respectively. Behavioral responses for the word recognition in noise test were also analyzed. Consistent with previous findings, the TEOAE data showed significant inhibition in the presence of contralateral acoustic stimulation. However, performance in the word recognition in noise test was comparable for the two conditions (i.e., without contralateral stimulation and with contralateral stimulation). Peak latencies and peak amplitudes of MMN and P300 did not show changes with contralateral stimulation. Behavioral performance was also maintained in the P300 task. Together, the results show that the peripheral auditory efferent effects captured via otoacoustic emission (OAE) inhibition might not necessarily be reflected in measures of central cortical processing and behavioral performance. As the MOC effects may not play a role in all listening situations in adults, the functional significance of the cochlear effects of the medial olivocochlear efferents and the optimal conditions conducive to corresponding effects in behavioral and cortical responses remain to be elucidated.
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Affiliation(s)
- Aparna Rao
- Department of Speech and Hearing Science, Arizona State University, Tempe, AZ 85287, USA
- Correspondence: (A.R.); (Y.Z.); Tel.: +1-480-727-2761 (A.R.); +1-612-624-7818 (Y.Z.)
| | - Tess K. Koerner
- VA RR & D National Center for Rehabilitative Auditory Research, Portland, OR 97239, USA; (T.K.K.); (B.M.)
| | - Brandon Madsen
- VA RR & D National Center for Rehabilitative Auditory Research, Portland, OR 97239, USA; (T.K.K.); (B.M.)
| | - Yang Zhang
- Department of Speech-Language-Hearing Sciences & Center for Neurobehavioral Development, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: (A.R.); (Y.Z.); Tel.: +1-480-727-2761 (A.R.); +1-612-624-7818 (Y.Z.)
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10
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Mishra SK. The role of efferents in human auditory development: efferent inhibition predicts frequency discrimination in noise for children. J Neurophysiol 2020; 123:2437-2448. [PMID: 32432503 DOI: 10.1152/jn.00136.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The descending corticofugal fibers originate from the auditory cortex and exert control on the periphery via the olivocochlear efferents. Medial efferents are thought to enhance the discriminability of transient sounds in background noise. In addition, the observation of deleterious long-term effects of efferent sectioning on the response properties of auditory nerve fibers in neonatal cats supports an efferent-mediated control of normal development. However, the role of the efferent system in human hearing remains unclear. The objective of the present study was to test the hypothesis that the medial efferents are involved in the development of frequency discrimination in noise. The hypothesis was examined with a combined behavioral and physiological approach. Frequency discrimination in noise and efferent inhibition were measured in 5- to 12-yr-old children (n = 127) and young adults (n = 37). Medial efferent strength was noninvasively assayed with a rigorous otoacoustic emission protocol. Results revealed an age-mediated relationship between efferent inhibition and frequency discrimination in noise. Efferent inhibition strongly predicted frequency discrimination in noise for younger children (5-9 yr). However, for older children (>9 yr) and adults, efferent inhibition was not related to frequency discrimination in noise. These findings support the role of efferents in the development of hearing-in-noise in humans; specifically, younger children compared with older children and adults are relatively more dependent on efferent inhibition for extracting relevant cues in noise. Additionally, the present findings caution against postulating an oversimplified relationship between efferent inhibition and measures of auditory perception in humans.NEW & NOTEWORTHY Despite several decades of research, the functional role of medial olivocochlear efferents in humans remains controversial and is thought to be insignificant. Here it is shown that medial efferent inhibition strongly predicts frequency discrimination in noise for younger children but not for older children and adults. Young children are relatively more dependent on the efferent system for listening-in-noise. This study highlights the role of the efferent system in hearing-in-noise during childhood development.
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Affiliation(s)
- Srikanta K Mishra
- Department of Communication Sciences and Disorders, The University of Texas Rio Grande Valley, Edinburg, Texas.,Department of Communication Disorders, New Mexico State University, Las Cruces, New Mexico
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11
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Finneran JJ. Conditioned attenuation of dolphin monaural and binaural auditory evoked potentials after preferential stimulation of one ear. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:2302. [PMID: 32359288 DOI: 10.1121/10.0001033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
Previous studies have demonstrated that some species of odontocetes can be conditioned to reduce hearing sensitivity when warned of an impending intense sound; however, the underlying mechanisms remain poorly understood. In the present study, conditioned hearing attenuation was elicited in two bottlenose dolphins by pairing a 10-kHz tone (the conditioned stimulus) with a more intense tone (the unconditioned stimulus) at 28 kHz. Testing was performed in air, with sounds presented via contact transducers. Hearing was assessed via noninvasive measurement of monaural auditory nerve responses (ANR) and binaural auditory brainstem responses (ABR). ABRs/ANRs were measured in response to 40-kHz tone bursts, over 2 to 3-s time intervals before and after the conditioned and unconditioned stimuli. Results showed reductions in ABR/ANR amplitude and increases in latency after pairing the warning and more intense tones. Monaural ANRs from the left and right ears were attenuated by similar amounts when the warning and more intense sounds were preferentially applied to the right ear. The data support a neural mechanism operating at the level of the cochlea and/or auditory nerve and suggest the involvement of neural projections that can affect the contralateral ear.
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Affiliation(s)
- James J Finneran
- U.S. Navy Marine Mammal Program, Naval Information Warfare Center Pacific, Code 56710, 53560 Hull Street, San Diego, California 92152, USA
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12
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Effects of Efferent Activity on Hair Bundle Mechanics. J Neurosci 2020; 40:2390-2402. [PMID: 32086256 DOI: 10.1523/jneurosci.1312-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 01/31/2020] [Accepted: 02/09/2020] [Indexed: 11/21/2022] Open
Abstract
Hair cells in both the auditory and vestibular systems receive efferent innervation. A number of prior studies have indicated that efferent regulation serves to diminish the overall sensitivity of the auditory system. The efferent pathway is believed to affect the sensitivity and frequency selectivity of the hair cell by modulating its membrane potential. However, its effect on the mechanical response of the hair cell has not been established. We explored how stimulation of the efferent neurons affects the mechanical responsiveness of an individual hair bundle. We tested this effect on in vitro preparations of hair cells in the sacculi of American bullfrogs of both genders. Efferent stimulation routinely resulted in an immediate increase of the frequency of hair bundle spontaneous oscillations for the duration of the stimulus. Enlarging the stimulus amplitude and pulse length, or conversely, decreasing the interpulse interval led to oscillation suppression. Additionally, we tested the effects of efference on the hair bundle response to mechanical stimulation. The receptive field maps of hair cells undergoing efferent actuation demonstrated an overall desensitization with respect to those of unstimulated cells.SIGNIFICANCE STATEMENT The efferent system is an important aide for the performance of the auditory system. It has been seen to contribute to sound detection and localization, ototoxicity prevention, and speech comprehension. Although measurements have demonstrated that efference suppresses basilar membrane movement, there is still much unknown about how efferent activity affects hearing mechanics. Here, we explore the mechanical basis for the efferent system's capabilities at the level of the hair bundle. We present optical recordings, receptive field maps, and sensitivity curves that show a hair bundle is desensitized by efferent stimulation. This supports the hypothesis that efferent regulation may be a biological control parameter for tuning the hair bundle's mechanical sensitivity.
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13
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No intermodal interference effects of threatening information during concurrent audiovisual stimulation. Neuropsychologia 2019; 136:107283. [PMID: 31783079 DOI: 10.1016/j.neuropsychologia.2019.107283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/05/2019] [Accepted: 11/24/2019] [Indexed: 11/24/2022]
Abstract
Changes in attention can result in sensory processing trade-off effects, in which sensory cortical responses to attended stimuli are heightened and responses to competing distractors are attenuated. However, it is unclear if competition or facilitation effects will be observed at the level of sensory cortex when attending to competing stimuli in two modalities. The present study used electroencephalogram (EEG) and frequency-tagging to quantitatively assess auditory-visual interactions during sustained multimodal sensory stimulation. The emotional content of a 6.66 Hz rapid serial visual presentation (RSVP) was manipulated to elicit well-established emotional attention effects, while a constant 63 dB tone with a 40.8 Hz modulation served as a concurrent auditory stimulus in two experiments. As a directed attention manipulation, participants were instructed to detect transient sound level events in the auditory stream in Experiment 1. To manipulate attention through threat anticipation, participants were instructed to expect an aversive noise burst after a higher 40.8 Hz modulated tone in Experiment 2. Each stimulus evoked reliable steady-state sensory cortical responses in all participants (n = 30) in both experiments. The visual cortical responses were modulated by the auditory detection task, but not by threat anticipation: Visual responses were smaller during auditory streams with a transient target as compared to uninterrupted auditory streams. Conversely, visual stimulus condition had no significant effects on auditory sensory cortical responses in either experiment. These results indicate that there is neither a competition nor facilitation effect of visual content on concurrent auditory sensory cortical processing. They further indicate that competition effects of auditory stream content on sustained visuocortical responses are limited to auditory target processing.
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14
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Giuliani N, Holte L, Shy M, Grider T. The audiologic profile of patients with Charcot-Marie Tooth neuropathy can be characterised by both cochlear and neural deficits. Int J Audiol 2019; 58:902-912. [PMID: 31318300 DOI: 10.1080/14992027.2019.1633022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: The primary goal of this study was to characterise the cochlear and neural components of hearing loss in a large cohort of people with Charcot-Marie Tooth neuropathy who reported hearing difficulties.Design: A full complement of audiologic measures including behavioral, physiologic and subjective assessments were administered.Study sample: Seventy-nine participants completed the study. Forty-four people had CMT1, 27 had CMT2 and four had CMT-INT.Results: Pure tone average was related to age and the absence of high-frequency DPOAE energy, suggesting a strong cochlear component. Acoustic reflexes were often elevated or absent and many participants exhibited abnormal ABR waveforms, suggesting additional neural hearing loss components. Participants with an abnormal or absent ABR wave V exhibited poorer speech perception abilities. There was an association between a prolonged ABR wave I latency and an abnormal or absent ABR wave V with a higher Charcot-Marie Tooth Neuropathy Score (indicating greater disability).Conclusions: The hearing abilities of people with CMT are highly variable. While there were strong neural hearing loss components, speech perception abilities were not disproportionately affected in most participants. Therefore, a hearing aid trial is recommended. ABR responses may be a useful tool for monitoring the progression of CMT over time.
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Affiliation(s)
- Nicholas Giuliani
- Department of Otolaryngology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Lenore Holte
- Department of Communications Sciences and Disorders, University of Iowa, Iowa City, IA, USA.,Center for Disabilities and Development, University Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Michael Shy
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Tiffany Grider
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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15
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Perelmuter JT, Wilson AB, Sisneros JA, Forlano PM. Forebrain Dopamine System Regulates Inner Ear Auditory Sensitivity to Socially Relevant Acoustic Signals. Curr Biol 2019; 29:2190-2198.e3. [PMID: 31204161 DOI: 10.1016/j.cub.2019.05.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/13/2019] [Accepted: 05/20/2019] [Indexed: 01/11/2023]
Abstract
Dopamine is integral to attentional and motivational processes, but studies are largely restricted to the central nervous system. In mammals [1, 2] and fishes [3, 4], central dopaminergic neurons project to the inner ear and could modulate acoustic signals at the earliest stages of processing. Studies in rodents show dopamine inhibits cochlear afferent neurons and protects against noise-induced acoustic injury [5-10]. However, other functions for inner ear dopamine have not been investigated, and the effect of dopamine on peripheral auditory processing in non-mammalians remains unknown [11, 12]. Insights could be gained by studies conducted in the context of intraspecific acoustic communication. We present evidence from a vocal fish linking reproductive-state-dependent changes in auditory sensitivity with seasonal changes in the dopaminergic efferent system in the saccule, their primary organ of hearing. Plainfin midshipman (Porichthys notatus) migrate from deep-water winter habitats to the intertidal zone in the summer to breed. Nesting males produce nocturnal vocalizations to attract females [13]. Both sexes undergo seasonal enhancement of hearing sensitivity at the level of the hair cell [14-16], increasing the likelihood of detecting conspecific signals [17, 18]. Importantly, reproductive females concurrently have reduced dopaminergic input to the saccule [19]. Here, we show that dopamine decreases saccule auditory sensitivity via a D2-like receptor. Saccule D2a receptor expression is reduced in the summer and correlates with sensitivity within and across seasons. We propose that reproductive-state-dependent changes to the dopaminergic efferent system provide a release of inhibition in the saccule, enhancing peripheral encoding of social-acoustic signals.
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Affiliation(s)
- Jonathan T Perelmuter
- Psychology Subprogram in Behavioral & Cognitive Neuroscience, The Graduate Center, City University of New York, 365 5(th) Avenue, New York, NY 10016, USA; Biology Department, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA.
| | - Anthony B Wilson
- Biology Department, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA; Biology Subprogram in Ecology, Evolutionary Biology and Behavior, The Graduate Center, City University of New York, 365 5(th) Avenue, New York, NY 10016, USA
| | - Joseph A Sisneros
- Psychology Department, University of Washington, Guthrie Hall, Seattle, WA 98195, USA
| | - Paul M Forlano
- Psychology Subprogram in Behavioral & Cognitive Neuroscience, The Graduate Center, City University of New York, 365 5(th) Avenue, New York, NY 10016, USA; Biology Department, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA; Biology Subprogram in Neuroscience, The Graduate Center, City University of New York, 365 5(th) Avenue, New York, NY 10016, USA; Biology Subprogram in Ecology, Evolutionary Biology and Behavior, The Graduate Center, City University of New York, 365 5(th) Avenue, New York, NY 10016, USA.
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16
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Carney LH. Supra-Threshold Hearing and Fluctuation Profiles: Implications for Sensorineural and Hidden Hearing Loss. J Assoc Res Otolaryngol 2018; 19:331-352. [PMID: 29744729 PMCID: PMC6081887 DOI: 10.1007/s10162-018-0669-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 04/19/2018] [Indexed: 12/22/2022] Open
Abstract
An important topic in contemporary auditory science is supra-threshold hearing. Difficulty hearing at conversational speech levels in background noise has long been recognized as a problem of sensorineural hearing loss, including that associated with aging (presbyacusis). Such difficulty in listeners with normal thresholds has received more attention recently, especially associated with descriptions of synaptopathy, the loss of auditory nerve (AN) fibers as a result of noise exposure or aging. Synaptopathy has been reported to cause a disproportionate loss of low- and medium-spontaneous rate (L/MSR) AN fibers. Several studies of synaptopathy have assumed that the wide dynamic ranges of L/MSR AN fiber rates are critical for coding supra-threshold sounds. First, this review will present data from the literature that argues against a direct role for average discharge rates of L/MSR AN fibers in coding sounds at moderate to high sound levels. Second, the encoding of sounds at supra-threshold levels is examined. A key assumption in many studies is that saturation of AN fiber discharge rates limits neural encoding, even though the majority of AN fibers, high-spontaneous rate (HSR) fibers, have saturated average rates at conversational sound levels. It is argued here that the cross-frequency profile of low-frequency neural fluctuation amplitudes, not average rates, encodes complex sounds. As described below, this fluctuation-profile coding mechanism benefits from both saturation of inner hair cell (IHC) transduction and average rate saturation associated with the IHC-AN synapse. Third, the role of the auditory efferent system, which receives inputs from L/MSR fibers, is revisited in the context of fluctuation-profile coding. The auditory efferent system is hypothesized to maintain and enhance neural fluctuation profiles. Lastly, central mechanisms sensitive to neural fluctuations are reviewed. Low-frequency fluctuations in AN responses are accentuated by cochlear nucleus neurons which, either directly or via other brainstem nuclei, relay fluctuation profiles to the inferior colliculus (IC). IC neurons are sensitive to the frequency and amplitude of low-frequency fluctuations and convert fluctuation profiles from the periphery into a phase-locked rate profile that is robust across a wide range of sound levels and in background noise. The descending projection from the midbrain (IC) to the efferent system completes a functional loop that, combined with inputs from the L/MSR pathway, is hypothesized to maintain "sharp" supra-threshold hearing, reminiscent of visual mechanisms that regulate optical accommodation. Examples from speech coding and detection in noise are reviewed. Implications for the effects of synaptopathy on control mechanisms hypothesized to influence supra-threshold hearing are discussed. This framework for understanding neural coding and control mechanisms for supra-threshold hearing suggests strategies for the design of novel hearing aid signal-processing and electrical stimulation patterns for cochlear implants.
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Affiliation(s)
- Laurel H Carney
- Departments of Biomedical Engineering, Neuroscience, and Electrical & Computer Engineering, Del Monte Institute for Neuroscience, University of Rochester, 601 Elmwood Ave., Box 603, Rochester, NY, 14642, USA.
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17
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Lopez-Poveda EA. Olivocochlear Efferents in Animals and Humans: From Anatomy to Clinical Relevance. Front Neurol 2018; 9:197. [PMID: 29632514 PMCID: PMC5879449 DOI: 10.3389/fneur.2018.00197] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/13/2018] [Indexed: 11/13/2022] Open
Abstract
Olivocochlear efferents allow the central auditory system to adjust the functioning of the inner ear during active and passive listening. While many aspects of efferent anatomy, physiology and function are well established, others remain controversial. This article reviews the current knowledge on olivocochlear efferents, with emphasis on human medial efferents. The review covers (1) the anatomy and physiology of olivocochlear efferents in animals; (2) the methods used for investigating this auditory feedback system in humans, their limitations and best practices; (3) the characteristics of medial-olivocochlear efferents in humans, with a critical analysis of some discrepancies across human studies and between animal and human studies; (4) the possible roles of olivocochlear efferents in hearing, discussing the evidence in favor and against their role in facilitating the detection of signals in noise and in protecting the auditory system from excessive acoustic stimulation; and (5) the emerging association between abnormal olivocochlear efferent function and several health conditions. Finally, we summarize some open issues and introduce promising approaches for investigating the roles of efferents in human hearing using cochlear implants.
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Affiliation(s)
- Enrique A Lopez-Poveda
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
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18
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Lee DH, Aronoff JM. Changing stimulation patterns can change the broadness of contralateral masking functions for bilateral cochlear implant users. Hear Res 2018; 363:55-61. [PMID: 29548706 DOI: 10.1016/j.heares.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/19/2018] [Accepted: 03/02/2018] [Indexed: 11/29/2022]
Abstract
Past studies have found that contralateral masking functions are sharper than ipsilateral masking functions for cochlear implant (CI) users. This could suggest that contralateral masking effects are only sensitive to the peak of the masker stimulation for this population. To determine if that is the case, this study investigated whether using broader stimulation patterns affects the broadness of the contralateral masking function. Contralateral masking functions were measured for six bilateral CI users using both a broad and narrow masker. Findings from this study revealed that the broad masker resulted in a broader contralateral masking function. This would suggest that stimulation outside of the peak of the masker affects contralateral masking functions for CI users.
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Affiliation(s)
- Daniel H Lee
- Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, 901 S. 6th St., Champaign, IL 61820, USA.
| | - Justin M Aronoff
- Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, 901 S. 6th St., Champaign, IL 61820, USA.
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19
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Perelmuter JT, Forlano PM. Connectivity and ultrastructure of dopaminergic innervation of the inner ear and auditory efferent system of a vocal fish. J Comp Neurol 2017; 525:2090-2108. [PMID: 28118481 DOI: 10.1002/cne.24177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/23/2022]
Abstract
Dopamine (DA) is a conserved modulator of vertebrate neural circuitry, yet our knowledge of its role in peripheral auditory processing is limited to mammals. The present study combines immunohistochemistry, neural tract tracing, and electron microscopy to investigate the origin and synaptic characteristics of DA fibers innervating the inner ear and the hindbrain auditory efferent nucleus in the plainfin midshipman, a vocal fish that relies upon the detection of mate calls for reproductive success. We identify a DA cell group in the diencephalon as a common source for innervation of both the hindbrain auditory efferent nucleus and saccule, the main hearing endorgan of the inner ear. We show that DA terminals in the saccule contain vesicles but transmitter release appears paracrine in nature, due to the apparent lack of synaptic contacts. In contrast, in the hindbrain, DA terminals form traditional synaptic contacts with auditory efferent neuronal cell bodies and dendrites, as well as unlabeled axon terminals, which, in turn, form inhibitory-like synapses on auditory efferent somata. Our results suggest a distinct functional role for brain-derived DA in the direct and indirect modulation of the peripheral auditory system of a vocal nonmammalian vertebrate.
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Affiliation(s)
- Jonathan T Perelmuter
- Program in Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, New York, New York, 10016.,Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, 11210
| | - Paul M Forlano
- Program in Behavioral and Cognitive Neuroscience, The Graduate Center, City University of New York, New York, New York, 10016.,Program in Ecology, Evolutionary Biology and Behavior, The Graduate Center, City University of New York, New York, New York, 10016.,Program in Neuroscience, The Graduate Center, City University of New York, New York, New York, 10016.,Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, 11210.,Aquatic Research and Environmental Assessment Center, Brooklyn College, Brooklyn NY, New York, 11210
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20
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Micarelli A, Viziano A, Genovesi G, Bruno E, Ottaviani F, Alessandrini M. Lack of contralateral suppression in transient-evoked otoacoustic emissions in multiple chemical sensitivity: a clinical correlation study. Noise Health 2016; 18:143-9. [PMID: 27157687 PMCID: PMC4918670 DOI: 10.4103/1463-1741.181997] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Multiple chemical sensitivity (MCS) is a chronic disorder characterized by a variety of symptoms associated with the exposure to chemicals at a concentration below the toxic level. Previous studies have demonstrated peculiar responses in brain activity in these patients with respect to sensory stimuli while the association between chemical sensitivity and other environmental intolerances such as noise sensitivity has been questioned by researchers. In this study, a cohort of 18 MCS patients underwent transient-evoked otoacoustic emission (TEOAE) testing with and without contralateral suppression to evaluate the functionality of the medial olivocochlear (MOC) reflex involved in speech-in-noise sensitivity. Results were compared with an age- and gender-matched control group (n = 20) and correlation analysis with disease onset and quick environmental exposure sensitivity inventory (qEESI) symptom severity scale was performed. Subjects affected by MCS showed statistically significant impairment of MOC reflex, and the onset of the disease and several symptom subscales showed to be correlated to such reduction in some of the frequencies tested. These data suggest that alterations of MOC reflex could be part of the complex features of this disease although more studies are needed to further explore auditory perception disorders in environmental intolerances.
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Affiliation(s)
- Alessandro Micarelli
- Department of Clinical Sciences and Traslational Medicine; Department of Systems Medicine, Neuroscience Unit, University of Rome 'Tor Vergata', Rome, Italy
| | - Andrea Viziano
- Department of Clinical Sciences and Traslational Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Giuseppe Genovesi
- Department of Experimental Medicine, University of Rome 'La Sapienza', Rome, Italy
| | - Ernesto Bruno
- Department of Clinical Sciences and Traslational Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Fabrizio Ottaviani
- Department of Clinical Sciences and Traslational Medicine, University of Rome 'Tor Vergata', Rome, Italy
| | - Marco Alessandrini
- Department of Clinical Sciences and Traslational Medicine, University of Rome 'Tor Vergata', Rome, Italy
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21
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Park SY, Park JM, Back SA, Yeo SW, Park SN. Functional Significance of Medial Olivocochlear System Morphology in the Mouse Cochlea. Clin Exp Otorhinolaryngol 2016; 10:137-142. [PMID: 27464515 PMCID: PMC5426398 DOI: 10.21053/ceo.2016.00444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/07/2016] [Accepted: 06/19/2016] [Indexed: 11/22/2022] Open
Abstract
Objectives Baso-apical gradients exist in various cochlear structures including medial olivocochlear (MOC) efferent system. This study investigated the cochlear regional differentials in the function and morphology of the MOC system, and addressed the functional implications of regional MOC efferent terminals (ETs) in the mouse cochlea. Methods In CBA/J mice, MOC reflex (MOCR) was assessed based on the distortion product otoacoustic emission in the absence and presence of contralateral acoustic stimulation. High, middle, and low frequencies were grouped according to a mouse place-frequency map. Cochlear whole mounts were immunostained for ETs with anti-α-synuclein and examined using confocal laser scanning microscopy. The diameters of ETs and the number of ETs per outer hair cell were measured from the z-stack images of the basal, middle and apical regions, respectively. Results The middle cochlear region expressed large, clustered MOC ETs with strong MOCR, the base expressed small, less clustered ETs with strong MOCR, and the apex expressed large, but less clustered ETs with weak MOCR. Conclusion The mouse cochlea demonstrated regional differentials in the function and morphology of the MOC system. Strong MOCR along with superior MOC morphology in the middle region may contribute to ‘signal detection in noise,’ the primary efferent function, in the best hearing frequencies. Strong MOCR in spite of inferior MOC morphology in the base may reflect the importance of ‘protection from noise trauma’ in the high frequencies.
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Affiliation(s)
- So Young Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jung Mee Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang A Back
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang Won Yeo
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Shi Nae Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Otsuka S, Tsuzaki M, Sonoda J, Tanaka S, Furukawa S. A Role of Medial Olivocochlear Reflex as a Protection Mechanism from Noise-Induced Hearing Loss Revealed in Short-Practicing Violinists. PLoS One 2016; 11:e0146751. [PMID: 26745634 PMCID: PMC4706422 DOI: 10.1371/journal.pone.0146751] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 12/20/2015] [Indexed: 11/26/2022] Open
Abstract
Previous studies have indicated that extended exposure to a high level of sound might increase the risk of hearing loss among professional symphony orchestra musicians. One of the major problems associated with musicians' hearing loss is difficulty in estimating its risk simply on the basis of the physical amount of exposure, i.e. the exposure level and duration. The aim of this study was to examine whether the measurement of the medial olivocochlear reflex (MOCR), which is assumed to protect the cochlear from acoustic damage, could enable us to assess the risk of hearing loss among musicians. To test this, we compared the MOCR strength and the hearing deterioration caused by one-hour instrument practice. The participants in the study were music university students who are majoring in the violin, whose left ear is exposed to intense violin sounds (broadband sounds containing a significant number of high-frequency components) during their regular instrument practice. Audiogram and click-evoked otoacoustic emissions (CEOAEs) were measured before and after a one-hour violin practice. There was a larger exposure to the left ear than to the right ear, and we observed a left-ear specific temporary threshold shift (TTS) after the violin practice. Left-ear CEOAEs decreased proportionally to the TTS. The exposure level, however, could not entirely explain the inter-individual variation in the TTS and the decrease in CEOAE. On the other hand, the MOCR strength could predict the size of the TTS and CEOAE decrease. Our findings imply that, among other factors, the MOCR is a promising measure for assessing the risk of hearing loss among musicians.
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Affiliation(s)
- Sho Otsuka
- NTT Communication Science Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Minoru Tsuzaki
- Kyoto City University of Arts, 13-6 Kutsukake-cho, Oe, Nishikyo-ku, Kyoto 610-1197, Japan
| | - Junko Sonoda
- Kyoto City University of Arts, 13-6 Kutsukake-cho, Oe, Nishikyo-ku, Kyoto 610-1197, Japan
| | - Satomi Tanaka
- Kyoto City University of Arts, 13-6 Kutsukake-cho, Oe, Nishikyo-ku, Kyoto 610-1197, Japan
| | - Shigeto Furukawa
- NTT Communication Science Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan
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Neuroanatomical Evidence for Catecholamines as Modulators of Audition and Acoustic Behavior in a Vocal Teleost. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 877:439-75. [PMID: 26515325 DOI: 10.1007/978-3-319-21059-9_19] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The plainfin midshipman fish (Porichthys notatus) is a well-studied model to understand the neural and endocrine mechanisms underlying vocal-acoustic communication across vertebrates. It is well established that steroid hormones such as estrogen drive seasonal peripheral auditory plasticity in female Porichthys in order to better encode the male's advertisement call. However, little is known of the neural substrates that underlie the motivation and coordinated behavioral response to auditory social signals. Catecholamines, which include dopamine and noradrenaline, are good candidates for this function, as they are thought to modulate the salience of and reinforce appropriate behavior to socially relevant stimuli. This chapter summarizes our recent studies which aimed to characterize catecholamine innervation in the central and peripheral auditory system of Porichthys as well as test the hypotheses that innervation of the auditory system is seasonally plastic and catecholaminergic neurons are activated in response to conspecific vocalizations. Of particular significance is the discovery of direct dopaminergic innervation of the saccule, the main hearing end organ, by neurons in the diencephalon, which also robustly innervate the cholinergic auditory efferent nucleus in the hindbrain. Seasonal changes in dopamine innervation in both these areas appear dependent on reproductive state in females and may ultimately function to modulate the sensitivity of the peripheral auditory system as an adaptation to the seasonally changing soundscape. Diencephalic dopaminergic neurons are indeed active in response to exposure to midshipman vocalizations and are in a perfect position to integrate the detection and appropriate motor response to conspecific acoustic signals for successful reproduction.
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Fuente A. The olivocochlear system and protection from acoustic trauma: a mini literature review. Front Syst Neurosci 2015; 9:94. [PMID: 26157366 PMCID: PMC4475794 DOI: 10.3389/fnsys.2015.00094] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/02/2015] [Indexed: 11/29/2022] Open
Abstract
Large intersubject variability in the susceptibility to noise-induced hearing loss (NIHL) is known to occur in both humans and animals. It has been suggested that the olivocochlear system (OCS) plays a significant role in protecting the cochlea from exposure to high levels of noise. A mini literature review about the scientific evidence from animal and human studies about the association between the function of the OCS and susceptibility to NIHL was carried out. Animal data consistently show that de-efferented ears exhibit larger temporary threshold shift (TTS) and permanent threshold shift (PTS) than efferented ears. Data from human studies do not consistently show a correlation between the strength of the OCS function and amount of TTS. Further research on human subjects is required to determine how the OCS function could be used to predict susceptibility to NIHL in individual subjects.
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Affiliation(s)
- Adrian Fuente
- Faculté de médecine, École d'orthophonie et d'audiologie, Université de Montréal Montréal, QC, Canada
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