1
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Kersbergen CJ, Bergles DE. Priming central sound processing circuits through induction of spontaneous activity in the cochlea before hearing onset. Trends Neurosci 2024; 47:522-537. [PMID: 38782701 PMCID: PMC11236524 DOI: 10.1016/j.tins.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/02/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024]
Abstract
Sensory systems experience a period of intrinsically generated neural activity before maturation is complete and sensory transduction occurs. Here we review evidence describing the mechanisms and functions of this 'spontaneous' activity in the auditory system. Both ex vivo and in vivo studies indicate that this correlated activity is initiated by non-sensory supporting cells within the developing cochlea, which induce depolarization and burst firing of groups of nearby hair cells in the sensory epithelium, activity that is conveyed to auditory neurons that will later process similar sound features. This stereotyped neural burst firing promotes cellular maturation, synaptic refinement, acoustic sensitivity, and establishment of sound-responsive domains in the brain. While sensitive to perturbation, the developing auditory system exhibits remarkable homeostatic mechanisms to preserve periodic burst firing in deaf mice. Preservation of this early spontaneous activity in the context of deafness may enhance the efficacy of later interventions to restore hearing.
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Affiliation(s)
- Calvin J Kersbergen
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
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2
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Ortiz EA, Campbell PD, Nelson JC, Granato M. A single base pair substitution in zebrafish distinguishes between innate and acute startle behavior regulation. PLoS One 2024; 19:e0300529. [PMID: 38498506 PMCID: PMC10947677 DOI: 10.1371/journal.pone.0300529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/26/2024] [Indexed: 03/20/2024] Open
Abstract
Behavioral thresholds define the lowest stimulus intensities sufficient to elicit a behavioral response. Establishment of baseline behavioral thresholds during development is critical for proper responses throughout the animal's life. Despite the relevance of such innate thresholds, the molecular mechanisms critical to establishing behavioral thresholds during development are not well understood. The acoustic startle response is a conserved behavior whose threshold is established during development yet is subsequently acutely regulated. We have previously identified a zebrafish mutant line (escapist) that displays a decreased baseline or innate acoustic startle threshold. Here, we identify a single base pair substitution on Chromosome 25 located within the coding sequence of the synaptotagmin 7a (syt7a) gene that is tightly linked to the escapist acoustic hypersensitivity phenotype. By generating animals in which we deleted the syt7a open reading frame, and subsequent complementation testing with the escapist line, we demonstrate that loss of syt7a function is not the cause of the escapist behavioral phenotype. Nonetheless, escapist mutants provide a powerful tool to decipher the overlap between acute and developmental regulation of behavioral thresholds. Extensive behavioral analyses reveal that in escapist mutants the establishment of the innate acoustic startle threshold is impaired, while regulation of its acute threshold remains intact. Moreover, our behavioral analyses reveal a deficit in baseline responses to visual stimuli, but not in the acute regulation of responses to visual stimuli. Together, this work eliminates loss of syt7a as causative for the escapist phenotype and suggests that mechanisms that regulate the establishment of behavioral thresholds in escapist larvae can operate independently from those regulating acute threshold regulation.
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Affiliation(s)
- Elelbin A. Ortiz
- Department of Neuroscience, University of Pennsylvania, Pennsylvania, PA, United States of America
- Department of Cell and Developmental Biology, University of Pennsylvania, Pennsylvania, PA, United States of America
| | - Philip D. Campbell
- Department of Cell and Developmental Biology, University of Pennsylvania, Pennsylvania, PA, United States of America
- Department of Psychiatry, University of Pennsylvania, Pennsylvania, PA, United States of America
| | - Jessica C. Nelson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Michael Granato
- Department of Cell and Developmental Biology, University of Pennsylvania, Pennsylvania, PA, United States of America
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3
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Bakay WMH, Cervantes B, Lao-Rodríguez AB, Johannesen PT, Lopez-Poveda EA, Furness DN, Malmierca MS. How 'hidden hearing loss' noise exposure affects neural coding in the inferior colliculus of rats. Hear Res 2024; 443:108963. [PMID: 38308936 DOI: 10.1016/j.heares.2024.108963] [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: 10/29/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 02/05/2024]
Abstract
Exposure to brief, intense sound can produce profound changes in the auditory system, from the internal structure of inner hair cells to reduced synaptic connections between the auditory nerves and the inner hair cells. Moreover, noisy environments can also lead to alterations in the auditory nerve or to processing changes in the auditory midbrain, all without affecting hearing thresholds. This so-called hidden hearing loss (HHL) has been shown in tinnitus patients and has been posited to account for hearing difficulties in noisy environments. However, much of the neuronal research thus far has investigated how HHL affects the response characteristics of individual fibres in the auditory nerve, as opposed to higher stations in the auditory pathway. Human models show that the auditory nerve encodes sound stochastically. Therefore, a sufficient reduction in nerve fibres could result in lowering the sampling of the acoustic scene below the minimum rate necessary to fully encode the scene, thus reducing the efficacy of sound encoding. Here, we examine how HHL affects the responses to frequency and intensity of neurons in the inferior colliculus of rats, and the duration and firing rate of those responses. Finally, we examined how shorter stimuli are encoded less effectively by the auditory midbrain than longer stimuli, and how this could lead to a clinical test for HHL.
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Affiliation(s)
- Warren M H Bakay
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Blanca Cervantes
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; School of Medicine, University Anáhuac Puebla, Mexico
| | - Ana B Lao-Rodríguez
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Peter T Johannesen
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain
| | - Enrique A Lopez-Poveda
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain; Department of Surgery, Faculty of Medicine, University of Salamanca, Spain
| | - David N Furness
- School of Life Sciences, Keele University, Keele, United Kingdom
| | - Manuel S Malmierca
- Cognitive and Auditory Neuroscience Laboratory, Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Spain; Institute for Biomedical Research of Salamanca, Salamanca, Spain; Department of Biology and Pathology, Faculty of Medicine, University of Salamanca, Spain.
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4
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Ortiz EA, Campbell PD, Nelson JC, Granato M. A single base pair substitution on Chromosome 25 in zebrafish distinguishes between development and acute regulation of behavioral thresholds. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.25.554673. [PMID: 37662318 PMCID: PMC10473726 DOI: 10.1101/2023.08.25.554673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Behavioral thresholds define the lowest stimulus intensities sufficient to elicit a behavioral response. Establishment of baseline behavioral thresholds during development is critical for proper responses throughout the animal's life. Despite the relevance of such innate thresholds, the molecular mechanisms critical to establishing behavioral thresholds during development are not well understood. The acoustic startle response is a conserved behavior whose threshold is established during development yet is subsequently acutely regulated. We have previously identified a zebrafish mutant line ( escapist ) that displays a decreased baseline or innate acoustic startle threshold. Here, we identify a single base pair substitution on Chromosome 25 located within the coding sequence of the synaptotagmin 7a ( syt7a ) gene that is tightly linked to the escapist acoustic hypersensitivity phenotype. By generating animals in which we deleted the syt7a open reading frame, and subsequent complementation testing with the escapist line, we demonstrate that loss of syt7a function is not the cause of the escapist behavioral phenotype. Nonetheless, escapist mutants provide a powerful tool to decipher the overlap between acute and developmental regulation of behavioral thresholds. Extensive behavioral analyses reveal that in escapist mutants the establishment of the innate acoustic startle threshold is impaired, while regulation of its acute threshold remains intact. Moreover, our behavioral analyses reveal a deficit in baseline responses to visual stimuli, but not in the acute regulation of responses to visual stimuli. Together, this work eliminates loss of syt7a as causative for the escapist phenotype and suggests that mechanisms that regulate the establishment of behavioral thresholds in escapist larvae can operate largely independently from those regulating acute threshold regulation.
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5
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McGill M, Hight AE, Watanabe YL, Parthasarathy A, Cai D, Clayton K, Hancock KE, Takesian A, Kujawa SG, Polley DB. Neural signatures of auditory hypersensitivity following acoustic trauma. eLife 2022; 11:e80015. [PMID: 36111669 PMCID: PMC9555866 DOI: 10.7554/elife.80015] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/14/2022] [Indexed: 11/25/2022] Open
Abstract
Neurons in sensory cortex exhibit a remarkable capacity to maintain stable firing rates despite large fluctuations in afferent activity levels. However, sudden peripheral deafferentation in adulthood can trigger an excessive, non-homeostatic cortical compensatory response that may underlie perceptual disorders including sensory hypersensitivity, phantom limb pain, and tinnitus. Here, we show that mice with noise-induced damage of the high-frequency cochlear base were behaviorally hypersensitive to spared mid-frequency tones and to direct optogenetic stimulation of auditory thalamocortical neurons. Chronic two-photon calcium imaging from ACtx pyramidal neurons (PyrNs) revealed an initial stage of spatially diffuse hyperactivity, hyper-correlation, and auditory hyperresponsivity that consolidated around deafferented map regions three or more days after acoustic trauma. Deafferented PyrN ensembles also displayed hypersensitive decoding of spared mid-frequency tones that mirrored behavioral hypersensitivity, suggesting that non-homeostatic regulation of cortical sound intensity coding following sensorineural loss may be an underlying source of auditory hypersensitivity. Excess cortical response gain after acoustic trauma was expressed heterogeneously among individual PyrNs, yet 40% of this variability could be accounted for by each cell's baseline response properties prior to acoustic trauma. PyrNs with initially high spontaneous activity and gradual monotonic intensity growth functions were more likely to exhibit non-homeostatic excess gain after acoustic trauma. This suggests that while cortical gain changes are triggered by reduced bottom-up afferent input, their subsequent stabilization is also shaped by their local circuit milieu, where indicators of reduced inhibition can presage pathological hyperactivity following sensorineural hearing loss.
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Affiliation(s)
- Matthew McGill
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Ariel E Hight
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Yurika L Watanabe
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
| | - Aravindakshan Parthasarathy
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Dongqin Cai
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Kameron Clayton
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Kenneth E Hancock
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Anne Takesian
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Sharon G Kujawa
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
| | - Daniel B Polley
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear InfirmaryBostonUnited States
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical SchoolBostonUnited States
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6
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Bone conducted responses in the neonatal rat auditory cortex. Sci Rep 2021; 11:16777. [PMID: 34408208 PMCID: PMC8373948 DOI: 10.1038/s41598-021-96188-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/22/2021] [Indexed: 12/14/2022] Open
Abstract
Rats are born deaf and start hearing at the end of the second postnatal week, when the ear canals open and low-intensity sounds start to evoke responses in the auditory cortex. Here, using μECoG electrode arrays and intracortical silicon probe recordings, we found that bone-conducted (BC) sounds evoked biphasic responses in the auditory cortex starting from postnatal day (P) 8. The initial phase of these responses, generated by thalamocortical input, was followed by intracortical propagation within supragranular layers. BC-evoked responses co-localized with the responses evoked by electrical stimulation of the cochlea and the deepest layers of the inferior colliculus prior to onset of low-threshold hearing (P13), as well as with the responses evoked by high-frequency (30 kHz) low-intensity (70 dB) air-conducted sounds after that. Thus, BC signals reach high-frequency processing regions of the auditory cortex well before the onset of low-threshold hearing, reflecting early integrity of the auditory system.
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7
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Bures Z, Pysanenko K, Syka J. The influence of developmental noise exposure on the temporal processing of acoustical signals in the auditory cortex of rats. Hear Res 2021; 409:108306. [PMID: 34311267 DOI: 10.1016/j.heares.2021.108306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022]
Abstract
Previous experiments have acknowledged that inappropriate or missing auditory inputs during the critical period of development cause permanent changes of the structure and function of the auditory system (Bures et al., 2017). We explore in this study how developmental noise exposure influences the coding of temporally structured stimuli in the neurons of the primary auditory cortex (AC) in Long Evans rats. The animals were exposed on postnatal day 14 (P14) for 12 minutes to a loud (125 dB SPL) broad-band noise. The responses to an amplitude-modulated (AM) noise, frequency-modulated (FM) tones, and click trains, were recorded from the right AC of rats of two age groups: young-adult (ca. 6 months old) and adult (ca. 2 years old), both in the exposed animals and in control unexposed rats. The neonatal exposure resulted in a higher synchronization ability (phase-locking) of the AC neurons for all three stimuli; furthermore, the similarity of neuronal response patterns to repetitive stimulation was higher in the exposed rats. On the other hand, the exposed animals showed a steeper decline of modulation-transfer functions towards higher modulation frequencies/repetition rates. Differences between the two age groups were also apparent; in general, aging had qualitatively the same effect as the developmental exposure. The current results demonstrate that brief noise exposure during the maturation of the auditory system influences both the temporal and the rate coding of periodically modulated sounds in the AC of rats; the changes are permanent and observable up to late adulthood.
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Affiliation(s)
- Zbynek Bures
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic; Department of Cognitive Systems and Neurosciences, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University, Jugoslávských partyzánů 1580/3, 160 00 Prague 6, Czech Republic.
| | - Kateryna Pysanenko
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Vídeňská 1083, 14220 Prague 4, Czech Republic
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8
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Acoustically Enriched Environment during the Critical Period of Postnatal Development Positively Modulates Gap Detection and Frequency Discrimination Abilities in Adult Rats. Neural Plast 2021; 2021:6611922. [PMID: 33777134 PMCID: PMC7979287 DOI: 10.1155/2021/6611922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/05/2021] [Accepted: 02/23/2021] [Indexed: 11/18/2022] Open
Abstract
Throughout life, sensory systems adapt to the sensory environment to provide optimal responses to relevant tasks. In the case of a developing system, sensory inputs induce changes that are permanent and detectable up to adulthood. Previously, we have shown that rearing rat pups in a complex acoustic environment (spectrally and temporally modulated sound) from postnatal day 14 (P14) to P28 permanently improves the response characteristics of neurons in the inferior colliculus and auditory cortex, influencing tonotopical arrangement, response thresholds and strength, and frequency selectivity, along with stochasticity and the reproducibility of neuronal spiking patterns. In this study, we used a set of behavioral tests based on a recording of the acoustic startle response (ASR) and its prepulse inhibition (PPI), with the aim to extend the evidence of the persistent beneficial effects of the developmental acoustical enrichment. The enriched animals were generally not more sensitive to startling sounds, and also, their PPI of ASR, induced by noise or pure tone pulses, was comparable to the controls. They did, however, exhibit a more pronounced PPI when the prepulse stimulus was represented either by a change in the frequency of a background tone or by a silent gap in background noise. The differences in the PPI of ASR between the enriched and control animals were significant at lower (55 dB SPL), but not at higher (65-75 dB SPL), intensities of background sound. Thus, rearing pups in the acoustically enriched environment led to an improvement of the frequency resolution and gap detection ability under more difficult testing conditions, i.e., with a worsened stimulus clarity. We confirmed, using behavioral tests, that an acoustically enriched environment during the critical period of development influences the frequency and temporal processing in the auditory system, and these changes persist until adulthood.
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9
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Escabi CD, Frye MD, Trevino M, Lobarinas E. The rat animal model for noise-induced hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3692. [PMID: 31795685 PMCID: PMC7480078 DOI: 10.1121/1.5132553] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rats make excellent models for the study of medical, biological, genetic, and behavioral phenomena given their adaptability, robustness, survivability, and intelligence. The rat's general anatomy and physiology of the auditory system is similar to that observed in humans, and this has led to their use for investigating the effect of noise overexposure on the mammalian auditory system. The current paper provides a review of the rat model for studying noise-induced hearing loss and highlights advancements that have been made using the rat, particularly as these pertain to noise dose and the hazardous effects of different experimental noise types. In addition to the traditional loss of auditory function following acoustic trauma, recent findings have indicated the rat as a useful model in observing alterations in neuronal processing within the central nervous system following noise injury. Furthermore, the rat provides a second animal model when investigating noise-induced cochlear synaptopathy, as studies examining this in the rat model resemble the general patterns observed in mice. Together, these findings demonstrate the relevance of this animal model for furthering the authors' understanding of the effects of noise on structural, anatomical, physiological, and perceptual aspects of hearing.
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Affiliation(s)
- Celia D Escabi
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Mitchell D Frye
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Monica Trevino
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Edward Lobarinas
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Texas 75080, USA
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10
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Rybalko N, Mitrovic D, Šuta D, Bureš Z, Popelář J, Syka J. Behavioral evaluation of auditory function abnormalities in adult rats with normal hearing thresholds that were exposed to noise during early development. Physiol Behav 2019; 210:112620. [DOI: 10.1016/j.physbeh.2019.112620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 06/07/2019] [Accepted: 07/15/2019] [Indexed: 11/25/2022]
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11
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Bureš Z, Profant O, Svobodová V, Tóthová D, Vencovský V, Syka J. Speech Comprehension and Its Relation to Other Auditory Parameters in Elderly Patients With Tinnitus. Front Aging Neurosci 2019; 11:219. [PMID: 31496946 PMCID: PMC6713070 DOI: 10.3389/fnagi.2019.00219] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/02/2019] [Indexed: 11/13/2022] Open
Abstract
Deteriorated speech comprehension is a common manifestation of the age-related decline of auditory functions (presbycusis). It could be assumed that when presbycusis is accompanied by tinnitus, general hearing functions, and particularly comprehension of speech in quiet and speech in noise (SIN), will be significantly affected. In this study, speech comprehension ability and other parameters of auditory function were assessed in elderly subjects with (T, n = 25) and without (NT, n = 26) tinnitus, aiming for examination of both peripheral and central auditory processing. Apart from high-frequency audiograms in quiet and in background noise, speech recognition thresholds in silence or in competitive babble noise, and the ability to understand temporally gated speech (GS), we measured also sensitivity to frequency modulation (FM) and interaural delay, gap detection thresholds (GDT), or the difference limens of intensity. The results show that in elderly participants matched by age (mean ages around 68 years), cognitive status (median MoCA scores around 27), and hearing thresholds [median pure-tone averages (PTA) around 16 dB hearing loss (HL)], tinnitus per se has little influence on speech comprehension. The tinnitus patients also show similar GDT, sensitivity to interaural intensity difference, and sensitivity to FM as the NT subjects. Despite these similarities, nevertheless, significant differences in auditory processing have been found in the tinnitus participants: a worse ability to detect tones in noise, a higher sensitivity to intensity changes, and a higher sensitivity to interaural time differences. Additional correlation analyses further revealed that speech comprehension in the T subjects is dependent on the sensitivity to temporal modulation and interaural time delay (ITD), while these correlations are weak and non-significant in the NT subjects. Therefore, despite similarities in average speech comprehension and several other parameters of auditory function, elderly people with tinnitus exhibit different auditory processing, particularly at a suprathreshold level. The results also suggest that speech comprehension ability of elderly tinnitus patients relies more on temporal features of the sound stimuli, especially under difficult conditions, compared to elderly people without tinnitus.
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Affiliation(s)
- Zbyněk Bureš
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Technical Studies, College of Polytechnics, Jihlava, Czechia
| | - Oliver Profant
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology of Faculty Hospital Královské Vinohrady and 3rd Faculty of Medicine, Charles University, Prague, Czechia
| | - Veronika Svobodová
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University in Prague, University Hospital Motol, Prague, Czechia
| | - Diana Tóthová
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University in Prague, University Hospital Motol, Prague, Czechia
| | - Václav Vencovský
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia.,Department of Radioelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
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12
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Xia C, Yin M, Pan P, Fang F, Zhou Y, Ji Y. Long-term exposure to moderate noise induces neural plasticity in the infant rat primary auditory cortex. Anim Cells Syst (Seoul) 2019; 23:260-269. [PMID: 31489247 PMCID: PMC6711034 DOI: 10.1080/19768354.2019.1643782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 11/17/2022] Open
Abstract
Previous studies have reported that rearing infant rat pups in continuous moderate-level noise delayed the formation of topographic representational order and the refinement of response selectivity in the primary auditory (A1) cortex. The present study further verified that exposure to long-term moderate-intensity white noise (70 dB sound pressure level) from postnatal day (P) 12 to P30 elevated the hearing thresholds of infant rats. Compared with age-matched control rats, noise exposure (NE) rats had elevated hearing thresholds ranging from low to high frequencies, accompanied by decreased amplitudes and increased latencies of the two initial auditory brainstem response waves. The power of raw local field potential oscillations and high-frequency β oscillation in the A1 cortex of NE rats were larger, whereas the power of high-frequency γ oscillation was smaller than that of control rats. In addition, the expression levels of five glutamate receptor (GluR) subunits in the A1 cortex of NE rats were decreased with laminar specificity. These results suggest that the altered neural excitability and decreased GluR expression may underlie the delay of functional maturation in the A1 cortex, and may have implications for the treatment of hearing impairment induced by environmental noise.
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Affiliation(s)
- Chenchen Xia
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Manli Yin
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Ping Pan
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - Fanghao Fang
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
| | - You Zhou
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China.,Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, People's Republic of China
| | - Yonghua Ji
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai, People's Republic of China
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13
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Yu F, Xu X, Ren Z, Yang J, Kong F. Maternal high-decibel acoustic exposure elevates prenatal stress, impairing postnatal hearing thresholds associated with decreasing ribbon synapses in young rats. Reprod Toxicol 2019; 89:21-27. [PMID: 31238098 DOI: 10.1016/j.reprotox.2019.05.067] [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: 11/19/2018] [Revised: 05/16/2019] [Accepted: 05/30/2019] [Indexed: 10/26/2022]
Abstract
Maternal stress may affect the fetal auditory system than direct sound exposure. The objective of this study was to evaluate the role of prenatal stress due to high-decibel (dB) sound exposure on postnatal hearing and cochlear structure. Pregnant rats were exposed to 95 or 65 dB noise or music for 2 h once a day from gestational day 15 until delivery. The serum corticosterone was measured in the pregnant dams and pups. On postnatal day 22, pups underwent auditory brainstem response (ABR) testing. Then, the cochleae were immediately harvested for biochemical and molecular investigations. Prenatal stress impaired reproductive parameters, increased serum corticosterone and ABR thresholds with the decrease in wave I peak amplitude and the number of pre-synaptic ribbon. Thus, prenatal stress induces postnatal hearing loss in young rats, which are related to the reduction of ribbon synapses.
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Affiliation(s)
- Fei Yu
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China.
| | - Xueying Xu
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China
| | - Zhongjuan Ren
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China
| | - Jun Yang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, China
| | - Fanxue Kong
- Department of Orthopaedics, First Affiliated Hospital of Dalian Medical University, No.222 Zhongshan Road, Xigang District, Dalian, China.
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14
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Mazarati A, Jones NC, Galanopoulou AS, Harte‐Hargrove LC, Kalynchuk LE, Lenck‐Santini P, Medel‐Matus J, Nehlig A, de la Prida LM, Sarkisova K, Veliskova J. A companion to the preclinical common data elements on neurobehavioral comorbidities of epilepsy: a report of the TASK3 behavior working group of the ILAE/AES Joint Translational Task Force. Epilepsia Open 2018; 3:24-52. [PMID: 30450484 PMCID: PMC6210046 DOI: 10.1002/epi4.12236] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
The provided companion has been developed by the Behavioral Working Group of the Joint Translational Task Force of the International League Against Epilepsy (ILAE) and the American Epilepsy Society (AES) with the purpose of assisting the implementation of Preclinical Common Data Elements (CDE) for studying and for reporting neurobehavioral comorbidities in rodent models of epilepsy. Case Report Forms (CRFs) are provided, which should be completed on a per animal/per test basis, whereas the CDEs are a compiled list of the elements that should be reported. This companion is not designed as a list of recommendations, or guidelines for how the tests should be run-rather, it describes the different types of assessments, and highlights the importance of rigorous data collection and transparency in this regard. The tests are divided into 7 categories for examining behavioral dysfunction on the syndrome level: deficits in learning and memory; depression; anxiety; autism; attention deficit/hyperactivity disorder; psychosis; and aggression. Correspondence and integration of these categories into the National Institute of Mental Health (NIMH) Research Domain Criteria (RDoC) is introduced. Developmental aspects are addressed through the introduction of developmental milestones. Discussion includes complexities, limitations, and biases associated with neurobehavioral testing, especially when performed in animals with epilepsy, as well as the importance of rigorous data collection and of transparent reporting. This represents, to our knowledge, the first such resource dedicated to preclinical CDEs for behavioral testing of rodents.
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Affiliation(s)
- Andrey Mazarati
- Department of PediatricsDavid Geffen School of Medicine at UCLALos AngelesCaliforniaU.S.A.
- UCLA Children's Discovery and Innovation InstituteLos AngelesCaliforniaU.S.A.
| | - Nigel C. Jones
- Department of NeuroscienceCentral Clinical SchoolMonash University MelbourneMelbourneVictoriaAustralia
| | - Aristea S. Galanopoulou
- Saul R. Korey Department of Neurology and Dominick P. Purpura Department of NeuroscienceLaboratory of Developmental EpilepsyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Lauren C. Harte‐Hargrove
- Joint Translational Task Force of the International League Against Epilepsy (ILAE) and American Epilepsy Society (AES)
| | - Lisa E. Kalynchuk
- Division of Medical SciencesUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | - Pierre‐Pascal Lenck‐Santini
- INMEDAix‐Marseille University, INSERMMarseille France
- Department of Neurological SciencesUniversity of VermontBurlingtonVermontU.S.A.
| | | | - Astrid Nehlig
- Pediatric NeurologyNecker‐Enfants Malades HospitalUniversity of Paris Descartes, INSERM U1129ParisFrance
| | | | - Karine Sarkisova
- Institute of Higher Nervous Activity and NeurophysiologyRussian Academy of SciencesMoscowRussia
| | - Jana Veliskova
- Departments of Cell Biology & AnatomyNew York Medical CollegeValhallaNew YorkU.S.A.
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15
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Acoustical Enrichment during Early Development Improves Response Reliability in the Adult Auditory Cortex of the Rat. Neural Plast 2018; 2018:5903720. [PMID: 30002673 PMCID: PMC5998158 DOI: 10.1155/2018/5903720] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/16/2018] [Accepted: 04/29/2018] [Indexed: 11/18/2022] Open
Abstract
It is well known that auditory experience during early development shapes response properties of auditory cortex (AC) neurons, influencing, for example, tonotopical arrangement, response thresholds and strength, or frequency selectivity. Here, we show that rearing rat pups in a complex acoustically enriched environment leads to an increased reliability of responses of AC neurons, affecting both the rate and the temporal codes. For a repetitive stimulus, the neurons exhibit a lower spike count variance, indicating a more stable rate coding. At the level of individual spikes, the discharge patterns of individual neurons show a higher degree of similarity across stimulus repetitions. Furthermore, the neurons follow more precisely the temporal course of the stimulus, as manifested by improved phase-locking to temporally modulated sounds. The changes are persistent and present up to adulthood. The results document that besides basic alterations of receptive fields presented in our previous study, the acoustic environment during the critical period of postnatal development also leads to a decreased stochasticity and a higher reproducibility of neuronal spiking patterns.
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16
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Specific Influences of Early Acoustic Environments on Cochlear Hair Cells in Postnatal Mice. Neural Plast 2018; 2018:5616930. [PMID: 29849558 PMCID: PMC5926484 DOI: 10.1155/2018/5616930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/05/2018] [Accepted: 03/21/2018] [Indexed: 01/24/2023] Open
Abstract
The auditory function develops and matures after birth in many mammalian species. After hearing onset, environmental sounds exert profound and long-term effects on auditory functions. However, the effects of the acoustic environment on the functional development of the peripheral auditory system, especially the cochlear sensory hair cells, are still unclear. In the present study, we exposed mouse pups to frequency-enriched acoustic environments in postnatal days 0–14. The results indicated that the acoustic environment significantly decreased the threshold of the auditory brainstem response in a frequency-specific manner. Compared with controls, no difference was found in the number and alignment of inner and outer hair cells or in the length of hair bundles after acoustic overstimulation. The expression and function of prestin, the motor protein of outer hair cells (OHCs), were specifically increased in OHCs activated by acoustic stimulation at postnatal days 7–11. We analyzed the postnatal maturation of ribbon synapses in the hair cell areas. After acoustic stimulation, the number of ribbon synapses was closer to the mature stage than to the controls. Taken together, these data indicate that early acoustic exposure could promote the functional maturation of cochlear hair cells and the development of hearing.
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17
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Popelář J, Díaz Gómez M, Lindovský J, Rybalko N, Burianová J, Oohashi T, Syka J. The absence of brain-specific link protein Bral2 in perineuronal nets hampers auditory temporal resolution and neural adaptation in mice. Physiol Res 2017; 66:867-880. [PMID: 29020454 DOI: 10.33549/physiolres.933605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Brain-specific link protein Bral2 represents a substantial component of perineuronal nets (PNNs) enwrapping neurons in the central nervous system. To elucidate the role of Bral2 in auditory signal processing, the hearing function in knockout Bral2(-/-) (KO) mice was investigated using behavioral and electrophysiological methods and compared with wild type Bral2(+/+) (WT) mice. The amplitudes of the acoustic startle reflex (ASR) and the efficiency of the prepulse inhibition of ASR (PPI of ASR), produced by prepulse noise stimulus or gap in continuous noise, was similar in 2-week-old WT and KO mice. Over the 2-month postnatal period the increase of ASR amplitudes was significantly more evident in WT mice than in KO mice. The efficiency of the PPI of ASR significantly increased in the 2-month postnatal period in WT mice, whereas in KO mice the PPI efficiency did not change. Hearing thresholds in 2-month-old WT mice, based on the auditory brainstem response (ABR) recordings, were significantly lower at high frequencies than in KO mice. However, amplitudes and peak latencies of individual waves of click-evoked ABR did not differ significantly between WT and KO mice. Temporal resolution and neural adaptation were significantly better in 2-month-old WT mice than in age-matched KO mice. These results support a hypothesis that the absence of perineuronal net formation at the end of the developmental period in the KO mice results in higher hearing threshold at high frequencies and weaker temporal resolution ability in adult KO animals compared to WT mice.
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Affiliation(s)
- J Popelář
- Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czech Republic.
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18
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The effect of noise exposure during the developmental period on the function of the auditory system. Hear Res 2017; 352:1-11. [DOI: 10.1016/j.heares.2016.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 03/14/2016] [Indexed: 12/12/2022]
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19
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Liberman MC, Kujawa SG. Cochlear synaptopathy in acquired sensorineural hearing loss: Manifestations and mechanisms. Hear Res 2017; 349:138-147. [PMID: 28087419 PMCID: PMC5438769 DOI: 10.1016/j.heares.2017.01.003] [Citation(s) in RCA: 430] [Impact Index Per Article: 61.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
Common causes of hearing loss in humans - exposure to loud noise or ototoxic drugs and aging - often damage sensory hair cells, reflected as elevated thresholds on the clinical audiogram. Recent studies in animal models suggest, however, that well before this overt hearing loss can be seen, a more insidious, but likely more common, process is taking place that permanently interrupts synaptic communication between sensory inner hair cells and subsets of cochlear nerve fibers. The silencing of affected neurons alters auditory information processing, whether accompanied by threshold elevations or not, and is a likely contributor to a variety of perceptual abnormalities, including speech-in-noise difficulties, tinnitus and hyperacusis. Work described here will review structural and functional manifestations of this cochlear synaptopathy and will consider possible mechanisms underlying its appearance and progression in ears with and without traditional 'hearing loss' arising from several common causes in humans.
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MESH Headings
- Animals
- Auditory Perception
- Auditory Threshold
- Cochlear Nerve/metabolism
- Cochlear Nerve/pathology
- Cochlear Nerve/physiopathology
- Glutamic Acid/metabolism
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hearing
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Hearing Loss, Noise-Induced/psychology
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/pathology
- Hearing Loss, Sensorineural/physiopathology
- Hearing Loss, Sensorineural/psychology
- Humans
- Nerve Degeneration
- Noise/adverse effects
- Risk Factors
- Synapses/metabolism
- Synapses/pathology
- Synaptic Transmission
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Affiliation(s)
- M Charles Liberman
- Department of Otology and Laryngology, Harvard Medical School, Boston MA, USA; Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston MA, USA
| | - Sharon G Kujawa
- Department of Otology and Laryngology, Harvard Medical School, Boston MA, USA; Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston MA, USA.
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20
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Hickox AE, Larsen E, Heinz MG, Shinobu L, Whitton JP. Translational issues in cochlear synaptopathy. Hear Res 2017; 349:164-171. [PMID: 28069376 DOI: 10.1016/j.heares.2016.12.010] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/15/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
Understanding the biology of the previously underappreciated sensitivity of cochlear synapses to noise insult, and its clinical consequences, is becoming a mission for a growing number of auditory researchers. In addition, several research groups have become interested in developing therapeutic approaches that can reverse synaptopathy and restore hearing function. One of the major challenges to realizing the potential of synaptopathy rodent models is that current clinical audiometric approaches cannot yet reveal the presence of this subtle cochlear pathology in humans. This has catalyzed efforts, both from basic and clinical perspectives, to investigate novel means for diagnosing synaptopathy and to determine the main functional consequences for auditory perception and hearing abilities. Such means, and a strong concordance between findings in pre-clinical animal models and clinical studies in humans, are important for developing and realizing therapeutics. This paper frames the key outstanding translational questions that need to be addressed to realize this ambitious goal.
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Affiliation(s)
- Ann E Hickox
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
| | - Erik Larsen
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
| | - Michael G Heinz
- Speech, Language, and Hearing Sciences and Biomedical Engineering, Purdue University, 715 Clinic Drive, West Lafayette, IN, 47907, USA.
| | - Leslie Shinobu
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
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21
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Goepfrich AA, Friemel CM, Pauen S, Schneider M. Ontogeny of sensorimotor gating and short-term memory processing throughout the adolescent period in rats. Dev Cogn Neurosci 2016; 25:167-175. [PMID: 27908562 PMCID: PMC6987840 DOI: 10.1016/j.dcn.2016.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 11/02/2016] [Accepted: 11/15/2016] [Indexed: 11/17/2022] Open
Abstract
Adolescence and puberty are highly susceptible developmental periods during which the neuronal organization and maturation of the brain is completed. The endocannabinoid (eCB) system, which is well known to modulate cognitive processing, undergoes profound and transient developmental changes during adolescence. With the present study we were aiming to examine the ontogeny of cognitive skills throughout adolescence in male rats and clarify the potential modulatory role of CB1 receptor signalling. Cognitive skills were assessed repeatedly every 10th day in rats throughout adolescence. All animals were tested for object recognition memory and prepulse inhibition of the acoustic startle reflex. Although cognitive performance in short-term memory as well as sensorimotor gating abilities were decreased during puberty compared to adulthood, both tasks were found to show different developmental trajectories throughout adolescence. A low dose of the CB1 receptor antagonist/inverse agonist SR141716 was found to improve recognition memory specifically in pubertal animals while not affecting behavioral performance at other ages tested. The present findings demonstrate that the developmental trajectory of cognitive abilities does not occur linearly for all cognitive processes and is strongly influenced by pubertal maturation. Developmental alterations within the eCB system at puberty onset may be involved in these changes in cognitive processing.
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Affiliation(s)
- Anja A Goepfrich
- Research Group Developmental Neuropsychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Chris M Friemel
- Research Group Developmental Neuropsychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Sabina Pauen
- Department of Psychology, University of Heidelberg, Germany
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22
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Shi L, Guo X, Shen P, Liu L, Tao S, Li X, Song Q, Yu Z, Yin S, Wang J. Noise-induced damage to ribbon synapses without permanent threshold shifts in neonatal mice. Neuroscience 2015; 304:368-77. [PMID: 26232715 DOI: 10.1016/j.neuroscience.2015.07.066] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 11/29/2022]
Abstract
Recently, ribbon synapses to the hair cells (HCs) in the cochlea have become a novel site of interest in the investigation of noise-induced cochlear lesions in adult rodents (Kujawa and Liberman, 2009; Lin et al., 2011; Liu et al., 2012; Shi et al., 2013). Permanent noise-induced damage to this type of synapse can result in subsequent degeneration of spiral ganglion neurons (SGNs) in the absence of permanent changes to hearing sensitivity. To verify whether noise exposure during an early developmental period produces a similar impact on ribbon synapses, the present study examined the damaging effects of noise exposure in neonatal Kunming mice. The animals received exposure to broadband noise at 105-decibel (dB) sound pressure level (SPL) for 2h on either postnatal day 10 (P10d) or postnatal day 14 (P14d), and then hearing function (based on the auditory brainstem response (ABR)) and cochlear morphology were evaluated during either postnatal weeks 3-4 (P4w) or postnatal weeks 7-8 (P8w). There were no significant differences in the hearing threshold between noise-exposed and control animals, which suggests that noise did not cause permanent loss of hearing sensitivity. However, noise exposure did produce a significant loss of ribbon synapses, particularly in P14d mice, which continued to increase from P4w to P8w. Additionally, a corresponding reduction in the amplitude of compound action potential (CAP) was observed in the noise-exposed groups at P4w and P8w, and the CAP latency was elongated, indicating a change in synaptic function.
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Affiliation(s)
- L Shi
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China.
| | - X Guo
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China; Children's Medical Center, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan Road North, Nanjing 210003, China.
| | - P Shen
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China.
| | - L Liu
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China.
| | - S Tao
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China.
| | - X Li
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China.
| | - Q Song
- Department of Otolaryngology, 6th Affiliated Hospital, Jiaotong University, 600 Yishan Road, Shanghai 200233, China.
| | - Z Yu
- School of Human Communication Disorders, Dalhousie University, 1256 Barrington Street, Halifax, NS B3J1Y6, Canada.
| | - S Yin
- Department of Otolaryngology, 6th Affiliated Hospital, Jiaotong University, 600 Yishan Road, Shanghai 200233, China.
| | - J Wang
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China; School of Human Communication Disorders, Dalhousie University, 1256 Barrington Street, Halifax, NS B3J1Y6, Canada.
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23
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Frequency discrimination in rats exposed to noise as juveniles. Physiol Behav 2015; 144:60-5. [DOI: 10.1016/j.physbeh.2015.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 11/18/2022]
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