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Mafi AM, Tokar N, Russ MG, Barat O, Mellott JG. Age-related ultrastructural changes in the lateral cortex of the inferior colliculus. Neurobiol Aging 2022; 120:43-59. [PMID: 36116395 PMCID: PMC10276896 DOI: 10.1016/j.neurobiolaging.2022.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/15/2022] [Accepted: 08/15/2022] [Indexed: 10/15/2022]
Abstract
Temporal precision, a key component of sound and speech processing in the inferior colliculus (IC), depends on a balance of inhibition and excitation, and this balance degrades during aging. The cause of disrupted excitatory-inhibitory balance in aging is unknown, however changes at the synapse are a likely candidate. We sought to determine whether synaptic changes occur in the lateral cortex of the IC (IClc), a multimodal nucleus that processes lemniscal, intrinsic, somatosensory, and descending auditory input. Using electron microscopic techniques across young, middle age and old Fisher Brown Norway rats, our results demonstrate minimal loss of synapses in middle age, but significant (∼28%) loss during old age. However, in middle age, targeting of GABAergic dendrites by GABAergic synapses is increased and the active zones of excitatory synapses (that predominantly target GABA-negative dendrites) are lengthened. These synaptic changes likely result in a net increase of excitation in the IClc during middle age. Thus, disruption of excitatory-inhibitory balance in the aging IClc may be due to synaptic changes that begin in middle age.
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Affiliation(s)
- Amir M Mafi
- The Ohio State College of Medicine, The Ohio State, Columbus, OH, USA
| | - Nick Tokar
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Matthew G Russ
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Oren Barat
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Jeffrey G Mellott
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA.
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2
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Chen GD, Li L, McCall A, Ding D, Xing Z, Yu YE, Salvi R. Hearing impairment in murine model of Down syndrome. Front Genet 2022; 13:936128. [PMID: 35991545 PMCID: PMC9385999 DOI: 10.3389/fgene.2022.936128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
Hearing impairment is a cardinal feature of Down syndrome (DS), but its clinical manifestations have been attributed to multiple factors. Murine models could provide mechanistic insights on various causes of hearing loss in DS. To investigate mechanisms of hearing loss in DS in the absence of the cadherin 23 mutation, we backcrossed our DS mice, Dp(16)1Yey, onto normal-hearing CBA/J mice and evaluated their auditory function. Body weights of wild type (WT) and DS mice were similar at 3-months of age, but at 9-months, WT weighed 30% more than DS mice. Distortion product otoacoustic emissions (DPOAE), a test of sensory outer hair cell (OHC) function negatively impacted by conductive hearing loss, were reduced in amplitude and sensitivity across all frequencies in DS mice. The middle ear space in DS mice appeared normal with no evidence of infection. MicroCT structural imaging of DS temporal bones revealed a smaller tympanic membrane diameter, oval window, and middle ear space and localized thickening of the bony otic capsule, but no gross abnormalities of the middle ear ossicles. Histological analysis of the cochlear and vestibular sensory epithelium revealed a normal density of cochlear and vestibular hair cells; however, the cochlear basal membrane was approximately 0.6 mm shorter in DS than WT mice so that the total number of hair cells was greater in WT than DS mice. In DS mice, the early and late peaks in the auditory brainstem response (ABR), reflecting neural responses from the cochlear auditory nerve followed by subsequent neural centers in the brainstem, were reduced in amplitude and ABR thresholds were elevated to a similar degree across all frequencies, consistent with a conductive hearing impairment. The latency of the peaks in the ABR waveform were longer in DS than WT mice when compared at the same intensity; however, the latency delays disappeared when the data were compared at the same intensity above thresholds to compensate for the conductive hearing loss. Future studies using wideband tympanometry and absorbance together with detailed histological analysis of the middle ear could illuminate the nature of the conductive hearing impairment in DS mice.
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Affiliation(s)
- Guang-Di Chen
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, United States
| | - Li Li
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, United States
| | - Andrew McCall
- Optical Imaging and Analysis Facility, School of Dental Medicine, University at Buffalo, Buffalo, NY, United States
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, United States
| | - Zhuo Xing
- The Children’s Guild Foundation Down Syndrome Research Program, Genetics and Genomics Program and Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
- Genetics, Genomics and Bioinformatics Program, University of New York at Buffalo, Buffalo, NY, United States
| | - Y. Eugene Yu
- The Children’s Guild Foundation Down Syndrome Research Program, Genetics and Genomics Program and Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
- Genetics, Genomics and Bioinformatics Program, University of New York at Buffalo, Buffalo, NY, United States
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, United States
- *Correspondence: Richard Salvi,
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Guan B, Xu Y, Chen YC, Xing C, Xu L, Shang S, Xu JJ, Wu Y, Yan Q. Reorganized Brain Functional Network Topology in Presbycusis. Front Aging Neurosci 2022; 14:905487. [PMID: 35693344 PMCID: PMC9177949 DOI: 10.3389/fnagi.2022.905487] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 04/27/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose Presbycusis is characterized by bilateral sensorineural hearing loss at high frequencies and is often accompanied by cognitive decline. This study aimed to identify the topological reorganization of brain functional network in presbycusis with/without cognitive decline by using graph theory analysis approaches based on resting-state functional magnetic resonance imaging (rs-fMRI). Methods Resting-state fMRI scans were obtained from 30 presbycusis patients with cognitive decline, 30 presbycusis patients without cognitive decline, and 50 age-, sex-, and education-matched healthy controls. Graph theory was applied to analyze the topological properties of brain functional networks including global and nodal metrics, modularity, and rich-club organization. Results At the global level, the brain functional networks of all participants were found to possess small-world properties. Also, significant group differences in global network metrics were observed among the three groups such as clustering coefficient, characteristic path length, normalized characteristic path length, and small-worldness. At the nodal level, several nodes with abnormal betweenness centrality, degree centrality, nodal efficiency, and nodal local efficiency were detected in presbycusis patients with/without cognitive decline. Changes in intra-modular connections in frontal lobe module and inter-modular connections in prefrontal subcortical lobe module were found in presbycusis patients exposed to modularity analysis. Rich-club nodes were reorganized in presbycusis patients, while the connections among them had no significant group differences. Conclusion Presbycusis patients exhibited topological reorganization of the whole-brain functional network, and presbycusis patients with cognitive decline showed more obvious changes in these topological properties than those without cognitive decline. Abnormal changes of these properties in presbycusis patients may compensate for cognitive impairment by mobilizing additional neural resources.
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Affiliation(s)
- Bing Guan
- Department of Otolaryngology, Head and Neck Surgery, Clinical Medical College, Yangzhou University, Yangzhou, China
| | - Yixi Xu
- Department of Otolaryngology, Head and Neck Surgery, Clinical Medical College, Yangzhou University, Yangzhou, China
| | - Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Chunhua Xing
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Li Xu
- Department of Otolaryngology, Head and Neck Surgery, Clinical Medical College, Yangzhou University, Yangzhou, China
| | - Song'an Shang
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jin-Jing Xu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yuanqing Wu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
- *Correspondence: Yuanqing Wu
| | - Qi Yan
- Department of Otolaryngology, Head and Neck Surgery, Clinical Medical College, Yangzhou University, Yangzhou, China
- Qi Yan
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Yong W, Song J, Xing C, Xu JJ, Xue Y, Yin X, Wu Y, Chen YC. Disrupted Topological Organization of Resting-State Functional Brain Networks in Age-Related Hearing Loss. Front Aging Neurosci 2022; 14:907070. [PMID: 35669463 PMCID: PMC9163682 DOI: 10.3389/fnagi.2022.907070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 04/25/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose Age-related hearing loss (ARHL), associated with the function of speech perception decreases characterized by bilateral sensorineural hearing loss at high frequencies, has become an increasingly critical public health problem. This study aimed to investigate the topological features of the brain functional network and structural dysfunction of the central nervous system in ARHL using graph theory. Methods Forty-six patients with ARHL and forty-five age, sex, and education-matched healthy controls were recruited to undergo a resting-state functional magnetic resonance imaging (fMRI) scan in this study. Graph theory was applied to analyze the topological properties of the functional connectomes by studying the local and global organization of neural networks. Results Compared with healthy controls, the patient group showed increased local efficiency (Eloc) and clustering coefficient (Cp) of the small-world network. Besides, the degree centrality (Dc) and nodal efficiency (Ne) values of the left inferior occipital gyrus (IOG) in the patient group showed a decrease in contrast with the healthy control group. In addition, the intra-modular interaction of the occipital lobe module and the inter-modular interaction of the parietal occipital module decreased in the patient group, which was positively correlated with Dc and Ne. The intra-modular interaction of the occipital lobe module decreased in the patient group, which was negatively correlated with the Eloc. Conclusion Based on fMRI and graph theory, we indicate the aberrant small-world network topology in ARHL and dysfunctional interaction of the occipital lobe and parietal lobe, emphasizing the importance of dysfunctional left IOG. These results suggest that early diagnosis and treatment of patients with ARHL is necessary, which can avoid the transformation of brain topology and decreased brain function.
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Affiliation(s)
- Wei Yong
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jiajie Song
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
- Department of Radiology, Nanjing Pukou Central Hospital, Pukou Branch Hospital of Jiangsu Province Hospital, Nanjing, China
| | - Chunhua Xing
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jin-Jing Xu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yuan Xue
- Department of Otolaryngology, Nanjing Pukou Central Hospital, Pukou Branch Hospital of Jiangsu Province Hospital, Nanjing, China
| | - Xindao Yin
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yuanqing Wu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
- *Correspondence: Yuanqing Wu
| | - Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
- Yu-Chen Chen
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Chen YC, Yong W, Xing C, Feng Y, Haidari NA, Xu JJ, Gu JP, Yin X, Wu Y. Directed functional connectivity of the hippocampus in patients with presbycusis. Brain Imaging Behav 2021; 14:917-926. [PMID: 31270776 DOI: 10.1007/s11682-019-00162-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Presbycusis, associated with a diminished quality of life characterized by bilateral sensorineural hearing loss at high frequencies, has become an increasingly critical public health problem. This study aimed to identify directed functional connectivity (FC) of the hippocampus in patients with presbycusis and to explore the causes if the directed functional connections of the hippocampus were disrupted. Presbycusis patients (n = 32) and age-, sex-, and education-matched healthy controls (n = 40) were included in this study. The seed regions of bilateral hippocampus were selected to identify directed FC in patients with presbycusis using Granger causality analysis (GCA) approach. Correlation analyses were conducted to detect the associations of disrupted directed FC of hippocampus with clinical measures of presbycusis. Compared to healthy controls, decreased directed FC between inferior parietal lobule, insula, right supplementary motor area, middle temporal gyrus and hippocampus were detected in presbycusis patients. Furthermore, a negative correlation between TMB score and the decline of directed FC from left inferior parietal lobule to left hippocampus (r = -0.423, p = 0.025) and from right inferior parietal lobule to right hippocampus (r = -0.516, p = 0.005) were also observed. The decreased directed functional connections of the hippocampus were detected in patients with presbycusis, which was associated with specific cognitive performance. This study mainly emphasizes the crucial role of hippocampus in presbycusis and will enhance our understanding of the neuropathological mechanisms of presbycusis.
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Affiliation(s)
- Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Wei Yong
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Chunhua Xing
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Yuan Feng
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Nasir Ahmad Haidari
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Jin-Jing Xu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Jian-Ping Gu
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China
| | - Xindao Yin
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China.
| | - Yuanqing Wu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, No.68, Changle Road, Nanjing, 210006, China.
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6
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Rai V, Wood MB, Feng H, Schabla NM, Tu S, Zuo J. The immune response after noise damage in the cochlea is characterized by a heterogeneous mix of adaptive and innate immune cells. Sci Rep 2020; 10:15167. [PMID: 32938973 PMCID: PMC7495466 DOI: 10.1038/s41598-020-72181-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/24/2020] [Indexed: 02/08/2023] Open
Abstract
Cells of the immune system are present in the adult cochlea and respond to damage caused by noise exposure. However, the types of immune cells involved and their locations within the cochlea are unclear. We used flow cytometry and immunostaining to reveal the heterogeneity of the immune cells in the cochlea and validated the presence of immune cell gene expression by analyzing existing single-cell RNA-sequencing (scRNAseq) data. We demonstrate that cell types of both the innate and adaptive immune system are present in the cochlea. In response to noise damage, immune cells increase in number. B, T, NK, and myeloid cells (macrophages and neutrophils) are the predominant immune cells present. Interestingly, immune cells appear to respond to noise damage by infiltrating the organ of Corti. Our studies highlight the need to further understand the role of these immune cells within the cochlea after noise exposure.
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MESH Headings
- Adaptive Immunity
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/pathology
- Cochlea/immunology
- Cochlea/injuries
- Cochlea/pathology
- Disease Models, Animal
- Evoked Potentials, Auditory, Brain Stem/immunology
- Female
- Hearing Loss, Noise-Induced/immunology
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Immunity, Innate
- Killer Cells, Natural/immunology
- Killer Cells, Natural/pathology
- Leukocyte Common Antigens/metabolism
- Macrophages/immunology
- Macrophages/pathology
- Male
- Mice
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Transgenic
- Neutrophils/immunology
- Neutrophils/pathology
- Organ of Corti/immunology
- Organ of Corti/injuries
- Organ of Corti/pathology
- RNA-Seq
- T-Lymphocytes/immunology
- T-Lymphocytes/pathology
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Affiliation(s)
- Vikrant Rai
- Department of Biomedical Science, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA
| | - Megan B Wood
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD, 21205, USA
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Hao Feng
- Department of Biomedical Science, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA
| | - Nathan M Schabla
- Department of Medical Microbiology and Immunology and Flow Cytometry Core, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA
| | - Shu Tu
- Department of Biomedical Science, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA
| | - Jian Zuo
- Department of Biomedical Science, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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7
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Beckmann D, Feldmann M, Shchyglo O, Manahan-Vaughan D. Hippocampal Synaptic Plasticity, Spatial Memory, and Neurotransmitter Receptor Expression Are Profoundly Altered by Gradual Loss of Hearing Ability. Cereb Cortex 2020; 30:4581-4596. [PMID: 32202614 PMCID: PMC7325716 DOI: 10.1093/cercor/bhaa061] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/20/2020] [Accepted: 02/12/2020] [Indexed: 12/27/2022] Open
Abstract
Sensory information comprises the substrate from which memories are created. Memories of spatial sensory experience are encoded by means of synaptic plasticity in the hippocampus. Hippocampal dependency on sensory information is highlighted by the fact that sudden and complete loss of a sensory modality results in an impairment of hippocampal function that persists for months. Effects are accompanied by extensive changes in the expression of neurotransmitter receptors in cortex and hippocampus, consistent with a substantial adaptive reorganization of cortical function. Whether gradual sensory loss affects hippocampal function is unclear. Progressive age-dependent hearing loss (presbycusis) is a risk factor for cognitive decline. Here, we scrutinized C57BL/6 mice that experience hereditary and cumulative deafness starting in young adulthood. We observed that 2–4 months postnatally, increases in the cortical and hippocampal expression of GluN2A and GluN2B subunits of the N-methyl-D-aspartate receptor occurred compared to control mice that lack sensory deficits. Furthermore, GABA and metabotropic glutamate receptor expression were significantly altered. Hippocampal synaptic plasticity was profoundly impaired and mice exhibited significant deficits in spatial memory. These data show that during cortical adaptation to cumulative loss of hearing, plasticity-related neurotransmitter expression is extensively altered in the cortex and hippocampus. Furthermore, cumulative sensory loss compromises hippocampal function.
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Affiliation(s)
- Daniela Beckmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Mirko Feldmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
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8
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McClannahan KS, Backer KC, Tremblay KL. Auditory Evoked Responses in Older Adults With Normal Hearing, Untreated, and Treated Age-Related Hearing Loss. Ear Hear 2020; 40:1106-1116. [PMID: 30762601 PMCID: PMC6689468 DOI: 10.1097/aud.0000000000000698] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The goal of this study was to identify the effects of auditory deprivation (age-related hearing loss) and auditory stimulation (history of hearing aid use) on the neural registration of sound across two stimulus presentation conditions: (1) equal sound pressure level and (2) equal sensation level. DESIGN We used a between-groups design, involving three groups of 14 older adults (n = 42; 62 to 84 years): (1) clinically defined normal hearing (≤25 dB from 250 to 8000 Hz, bilaterally), (2) bilateral mild-moderate/moderately severe sensorineural hearing loss who have never used hearing aids, and (3) bilateral mild-moderate/moderately severe sensorineural hearing loss who have worn bilateral hearing aids for at least the past 2 years. RESULTS There were significant delays in the auditory P1-N1-P2 complex in older adults with hearing loss compared with their normal hearing peers when using equal sound pressure levels for all participants. However, when the degree and configuration of hearing loss were accounted for through the presentation of equal sensation level stimuli, no latency delays were observed. These results suggest that stimulus audibility modulates P1-N1-P2 morphology and should be controlled for when defining deprivation and stimulus-related neuroplasticity in people with hearing loss. Moreover, a history of auditory stimulation, in the form of hearing aid use, does not appreciably alter the neural registration of unaided auditory evoked brain activity when quantified by the P1-N1-P2. CONCLUSIONS When comparing auditory cortical responses in older adults with and without hearing loss, stimulus audibility, and not hearing loss-related neurophysiological changes, results in delayed response latency for those with age-related hearing loss. Future studies should carefully consider stimulus presentation levels when drawing conclusions about deprivation- and stimulation-related neuroplasticity. Additionally, auditory stimulation, in the form of a history of hearing aid use, does not significantly affect the neural registration of sound when quantified using the P1-N1-P2-evoked response.
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Affiliation(s)
- Katrina S McClannahan
- Department of Psychological and Brain Sciences, Washington University, St Louis, Washington, USA
- Department of Speech and Hearing Sciences, University of Washington, Washington, USA
| | - Kristina C Backer
- Department of Cognitive and Information Sciences, University of California, Merced, California, USA
| | - Kelly L Tremblay
- Department of Speech and Hearing Sciences, University of Washington, Washington, USA
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9
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Chen YC, Chen H, Jiang L, Bo F, Xu JJ, Mao CN, Salvi R, Yin X, Lu G, Gu JP. Presbycusis Disrupts Spontaneous Activity Revealed by Resting-State Functional MRI. Front Behav Neurosci 2018; 12:44. [PMID: 29593512 PMCID: PMC5859072 DOI: 10.3389/fnbeh.2018.00044] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/26/2018] [Indexed: 12/03/2022] Open
Abstract
Purpose: Presbycusis, age-related hearing loss, is believed to involve neural changes in the central nervous system, which is associated with an increased risk of cognitive impairment. The goal of this study was to determine if presbycusis disrupted spontaneous neural activity in specific brain areas involved in auditory processing, attention and cognitive function using resting-state functional magnetic resonance imaging (fMRI) approach. Methods: Hearing and resting-state fMRI measurements were obtained from 22 presbycusis patients and 23 age-, sex- and education-matched healthy controls. To identify changes in spontaneous neural activity associated with age-related hearing loss, we compared the amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) of fMRI signals in presbycusis patients vs. controls and then determined if these changes were linked to clinical measures of presbycusis. Results: Compared with healthy controls, presbycusis patients manifested decreased spontaneous activity mainly in the superior temporal gyrus (STG), parahippocampal gyrus (PHG), precuneus and inferior parietal lobule (IPL) as well as increased neural activity in the middle frontal gyrus (MFG), cuneus and postcentral gyrus (PoCG). A significant negative correlation was observed between ALFF/ReHo activity in the STG and average hearing thresholds in presbycusis patients. Increased ALFF/ReHo activity in the MFG was positively correlated with impaired Trail-Making Test B (TMT-B) scores, indicative of impaired cognitive function involving the frontal lobe. Conclusions: Presbycusis patients have disrupted spontaneous neural activity reflected by ALFF and ReHo measurements in several brain regions; these changes are associated with specific cognitive performance and speech/language processing. These findings mainly emphasize the crucial role of aberrant resting-state ALFF/ReHo patterns in presbycusis patients and will lead to a better understanding of the neuropathological mechanisms underlying presbycusis.
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Affiliation(s)
- Yu-Chen Chen
- Department of Medical Imaging, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.,Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Huiyou Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Liang Jiang
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Fan Bo
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jin-Jing Xu
- Department of Otolaryngology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Cun-Nan Mao
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Xindao Yin
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Guangming Lu
- Department of Medical Imaging, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Jian-Ping Gu
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
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10
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Masana M, Jukic M, Kretzschmar A, Wagner K, Westerholz S, Schmidt M, Rein T, Brodski C, Müller M. Deciphering the spatio-temporal expression and stress regulation of Fam107B, the paralog of the resilience-promoting protein DRR1 in the mouse brain. Neuroscience 2015; 290:147-58. [DOI: 10.1016/j.neuroscience.2015.01.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/12/2015] [Accepted: 01/16/2015] [Indexed: 11/26/2022]
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11
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Watanabe KI, Bloch W. Histone methylation and acetylation indicates epigenetic change in the aged cochlea of mice. Eur Arch Otorhinolaryngol 2012; 270:1823-30. [PMID: 23081671 DOI: 10.1007/s00405-012-2222-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 10/04/2012] [Indexed: 10/27/2022]
Abstract
It is currently accepted that epigenetics plays an important role in normal genetics and differentiation, and its failure triggers various diseases such as cancer, aging, metabolic diseases, and abnormal differentiations. The typical mechanism involves the modification of histones and the methylation of DNA. In this study, we investigated the modification of histones in the aged cochlea of mice using immunohistochemistry. Eight mice [C57BL/6(B6)] at the age of 8 weeks (young group) and 132 weeks (aged group) were used. Cochleas were fixed with paraformaldehyde and then decalcified. Hematoxylin-eosin staining was performed for the morphological study using a light microscope. After removing paraffin, the sections were incubated with the primary antibody to acetyl-histone H3 Lys9 or dimethyl-histone H3 Lys9. Confocal scanning microscopy was performed for observation. The degeneration was severest in the spiral ganglion cells and the organ of Corti of the basal turn as determined by light microscopy. Acetylated histone H3 was detected in the spiral ganglion cells and the organ of Corti of the young group, but not in those of the aged group. Dimethylated histone H3 was detected in the spiral ganglion cells and the organ of Corti of the aged group, but not in those of the young group. Acetylation was switched to methylation during ageing. Histone modification is known to have a critical role in neuro-degeneration. Our findings suggest that epigenetic change participates in the process of presbycusis.
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Affiliation(s)
- Ken-Ichi Watanabe
- Department of Otorhinolaryngology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.
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12
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Baizer JS, Manohar S, Paolone NA, Weinstock N, Salvi RJ. Understanding tinnitus: the dorsal cochlear nucleus, organization and plasticity. Brain Res 2012; 1485:40-53. [PMID: 22513100 DOI: 10.1016/j.brainres.2012.03.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 03/16/2012] [Accepted: 03/19/2012] [Indexed: 02/07/2023]
Abstract
Tinnitus, the perception of a phantom sound, is a common consequence of damage to the auditory periphery. A major goal of tinnitus research is to find the loci of the neural changes that underlie the disorder. Crucial to this endeavor has been the development of an animal behavioral model of tinnitus, so that neural changes can be correlated with behavioral evidence of tinnitus. Three major lines of evidence implicate the dorsal cochlear nucleus (DCN) in tinnitus. First, elevated spontaneous activity in the DCN is correlated with peripheral damage and tinnitus. Second, there are somatosensory inputs to the DCN that can modulate spontaneous activity and might mediate the somatic-auditory interactions seen in tinnitus patients. Third, we have found a subpopulation of DCN neurons in the adult rat that express doublecortin, a plasticity-related protein. The expression of this protein may reflect a role of these neurons in the neural reorganization causing tinnitus. However, there is a problem in extending the findings in the rodent DCN to humans. Classic studies state that the structure of the primate DCN is quite different from that of rodents, with primates lacking granule cells, the recipients of somatosensory input. To address the possibility of major species differences in DCN organization, we compared Nissl-stained sections of the DCN in five different species. In contrast to earlier reports, our data suggest that the organization of the primate DCN is not dramatically different from that of the rodents, and validate the use of animal data in the study of tinnitus. This article is part of a Special Issue entitled: Tinnitus Neuroscience.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, Buffalo, NY 14214, USA.
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13
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Osumi Y, Shibata SB, Kanda S, Yagi M, Ooka H, Shimano T, Asako M, Kawamoto K, Kuriyama H, Inoue T, Nishiyama T, Yamashita T, Tomoda K. Downregulation of N-methyl-D-aspartate receptor ζ1 subunit (GluN1) gene in inferior colliculus with aging. Brain Res 2012; 1454:23-32. [PMID: 22483791 DOI: 10.1016/j.brainres.2012.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 02/17/2012] [Accepted: 03/06/2012] [Indexed: 11/15/2022]
Abstract
Presbycusis is the impairment of auditory function associated with aging, which stems from peripheral cochlear lesions and degeneration of the central auditory process. The effect of age-induced peripheral hearing loss on the central auditory process is not fully understood. C57Bl/6 (C57) mice present accelerated peripheral hearing loss, which is well developed by middle-age and mimics the human presbycusis pattern. The aim of this study was to elucidate the molecular effects of peripheral hearing loss in the inferior colliculus (IC) with age between young and middle-aged C57 mice using cDNA microarray. Glutamate receptor ionotropic NMDA ζ1 (GluN1) exhibited the greatest decrease in the middle-aged group as determined using cDNA microarray and by further assessment using real-time PCR (qPCR). Histological assessment with in situ hybridization of GluN1 showed significantly decreased expression in all IC subdivisions of the middle-aged group. GluN1 is a receptor for excitatory neurotransmission, and significant downregulation of this gene may be subsequent to the decline of afferent input from the cochlea in aging C57 mice. Consequently, using the combination of microarray, qPCR, and in situ hybridization, we showed that the decline of GluN1 in the IC of aging animals might have a key role in the pathogenesis of presbycusis.
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Affiliation(s)
- Yasunori Osumi
- Department of Otolaryngology, Kansai Medical University, Takii Hospital, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8506, Japan
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14
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Lubka-Pathak M, Shah AA, Gallozzi M, Müller M, Zimmermann U, Löwenheim H, Pfister M, Knipper M, Blin N, Schimmang T. Altered expression of securin (Pttg1) and serpina3n in the auditory system of hearing-impaired Tff3-deficient mice. Cell Mol Life Sci 2011; 68:2739-49. [PMID: 21076990 PMCID: PMC11114927 DOI: 10.1007/s00018-010-0586-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 10/22/2010] [Accepted: 10/26/2010] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Tff3 peptide exerts important functions in cytoprotection and restitution of the gastrointestinal (GI) tract epithelia. Moreover, its presence in the rodent inner ear and involvement in the hearing process was demonstrated recently. However, its role in the auditory system still remains elusive. Our previous results showed a deterioration of hearing with age in Tff3-deficient animals. RESULTS Present detailed analysis of auditory brain stem response (ABR) measurements and immunohistochemical study of selected functional proteins indicated a normal function and phenotype of the cochlea in Tff3 mutants. However, a microarray-based screening of tissue derived from the auditory central nervous system revealed an alteration of securin (Pttg1) and serpina3n expression between wild-type and Tff3 knock-out animals. This was confirmed by qRT-PCR, immunostaining and western blots. CONCLUSIONS We found highly down-regulated Pttg1 and up-regulated serpina3n expression as a consequence of genetically deleting Tff3 in mice, indicating a potential role of these factors during the development of presbyacusis.
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Affiliation(s)
- M. Lubka-Pathak
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - A. A. Shah
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - M. Gallozzi
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
| | - M. Müller
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - U. Zimmermann
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - H. Löwenheim
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Pfister
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Knipper
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - N. Blin
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - T. Schimmang
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
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Yu YF, Zhai F, Dai CF, Hu JJ. The relationship between age-related hearing loss and synaptic changes in the hippocampus of C57BL/6J mice. Exp Gerontol 2011; 46:716-22. [PMID: 21586320 DOI: 10.1016/j.exger.2011.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/20/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
To explore the relationship between age-related hearing loss (presbycusis) and synaptic degeneration in the hippocampal CA3 region of C57BL/6J mice, we investigated both cognitive performance and synaptic changes within the hippocampus of C57BL/6J mice from three age groups of 6-8, 24-26, and 42-44 weeks; CBA/CaJ mice served as controls. The auditory brainstem response was used as a measure of hearing threshold, and cognitive behavior was evaluated using the Morris water maze. The ultrastructure of synapses was observed with transmission electron microscopy, and the quantity and distribution of the synaptic markers synaptophysin and PSD-95 were observed with immunohistochemistry. The hearing threshold of C57BL/6J mice was significantly higher at 24-26 weeks than at 6-8 weeks, and hearing loss was profound at 42-44 weeks. This was accompanied by progressive degeneration of synapses within the auditory cortex. In contrast, the hearing threshold of CBA/CaJ mice was relatively unchanged at 24-26 weeks of age, and these mice developed only mild hearing loss at 42-44 weeks of age. Interestingly, C57BL/6J, but not CBA/CaJ mice clearly exhibited both decreased performance in the Morris water maze and degeneration of synapses within the hippocampus. We therefore conclude that age-related hearing loss is accompanied by the degeneration of synapses in the hippocampal CA3 region of C57BL/6J mice.
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Affiliation(s)
- Ya-Feng Yu
- Department of Otology & Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China
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16
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Frisina RD, Zhu X. Auditory sensitivity and the outer hair cell system in the CBA mouse model of age-related hearing loss. ACTA ACUST UNITED AC 2010; 2:9-16. [PMID: 21866215 DOI: 10.2147/oaap.s7202] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Age-related hearing loss is a highly prevalent sensory disorder, from both the clinical and animal model perspectives. Understanding of the neurophysiologic, structural, and molecular biologic bases of age-related hearing loss will facilitate development of biomedical therapeutic interventions to prevent, slow, or reverse its progression. Thus, increased understanding of relationships between aging of the cochlear (auditory portion of the inner ear) hair cell system and decline in overall hearing ability is necessary. The goal of the present investigation was to test the hypothesis that there would be correlations between physiologic measures of outer hair cell function (otoacoustic emission levels) and hearing sensitivity (auditory brainstem response thresholds), starting in middle age. For the CBA mouse, a useful animal model of age-related hearing loss, it was found that correlations between these two hearing measures occurred only for high sound frequencies in middle age. However, in old age, a correlation was observed across the entire mouse range of hearing. These findings have implications for improved early detection of progression of age-related hearing loss in middle-aged mammals, including mice and humans, and distinguishing peripheral etiologies from central auditory system decline.
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Affiliation(s)
- Robert D Frisina
- Otolaryngology, Biomedical Engineering, Neurobiology, and Anatomy Departments, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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17
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How Many Ways Can Mouse Behavioral Experiments Go Wrong? Confounding Variables in Mouse Models of Neurodegenerative Diseases and How to Control Them. ADVANCES IN THE STUDY OF BEHAVIOR 2010. [DOI: 10.1016/s0065-3454(10)41007-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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18
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Cell Biology and Physiology of the Aging Central Auditory Pathway. THE AGING AUDITORY SYSTEM 2010. [DOI: 10.1007/978-1-4419-0993-0_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Bartolome MV, Zuluaga P, Carricondo F, Gil-Loyzaga P. Immunocytochemical detection of synaptophysin in C57BL/6 mice cochlea during aging process. ACTA ACUST UNITED AC 2009; 60:341-8. [PMID: 19565669 DOI: 10.1016/j.brainresrev.2009.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Aged mammals frequently exhibit a bilateral, progressive, and symmetric deafness related to the degeneration of auditory receptor. However, little is still known about aging effects on synapses in this receptor. Synaptophysin (Syp) is a 38 kDa Ca2+ binding glycoprotein widely found in presynaptic membrane and vesicles. The Syp has been found in presynaptic buttons of efferent auditory fibers, within the developing and adult auditory receptor. The detection of Syp in aged cochleae could provide relevant information about synaptic changes and receptor degeneration process observed in old animals. This paper focuses on aging linked changes related to the presence of Syp in cochleae of C57BL/6J mice (from 1 to 24 months old). Results showed that during the first months of age, no significant changes were observed in the Syp distribution under the basal pole of inner (IHCs) neither the outer (OHCs) hair cells. At six months of age, a significant decrease of Syp immunocytochemical detection appeared in fibers under the most external row of OHCs, but restricted to the cochlear basal coil. Only a very scarce reduction of Syp was noted under the IHC and the other OHC rows, also at the basal coil. From mice 9 months old on, a progressive decrease of the presence of Syp was found under IHC and all OHC rows starting at the basal coil and reaching the apical coil in the oldest mice. All these data could indicate that the cochlea aging process early affects to presynaptic membrane proteins of efferent endings fibers. This early alteration of cochleae efferent synapses could be involved in the whole degeneration of the Corti's organ.
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Affiliation(s)
- Maria Visitación Bartolome
- Department of Ophthalmology and Oto-Rhino-Laringology, Complutense University of Madrid, Apartado de Correos 60.075, 28080 Madrid, Spain
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20
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Zhu X, Vasilyeva ON, Kim S, Jacobson M, Romney J, Waterman MS, Tuttle D, Frisina RD. Auditory efferent feedback system deficits precede age-related hearing loss: contralateral suppression of otoacoustic emissions in mice. J Comp Neurol 2007; 503:593-604. [PMID: 17559088 DOI: 10.1002/cne.21402] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The C57BL/6J mouse has been a useful model of presbycusis, as it displays an accelerated age-related peripheral hearing loss. The medial olivocochlear efferent feedback (MOC) system plays a role in suppressing cochlear outer hair cell (OHC) responses, particularly for background noise. Neurons of the MOC system are located in the superior olivary complex, particularly in the dorsomedial periolivary nucleus (DMPO) and in the ventral nucleus of the trapezoid body (VNTB). We previously discovered that the function of the MOC system declines with age prior to OHC degeneration, as measured by contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) in humans and CBA mice. The present study aimed to determine the time course of age changes in MOC function in C57s. DPOAE amplitudes and CS of DPOAEs were collected for C57s from 6 to 40 weeks of age. MOC responses were observed at 6 weeks but were gone at middle (15-30 kHz) and high (30-45 kHz) frequencies by 8 weeks. Quantitative stereological analyses of Nissl sections revealed smaller neurons in the DMPO and VNTB of young adult C57s compared with CBAs. These findings suggest that reduced neuron size may underlie part of the noteworthy rapid decline of the C57 efferent system. In conclusion, the C57 mouse has MOC function at 6 weeks, but it declines quickly, preceding the progression of peripheral age-related sensitivity deficits and hearing loss in this mouse strain.
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Affiliation(s)
- Xiaoxia Zhu
- Department of Otolaryngology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642-8629, USA
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21
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Tadros SF, D’Souza M, Zettel ML, Zhu X, Frisina RD. Glutamate-related gene expression changes with age in the mouse auditory midbrain. Brain Res 2006; 1127:1-9. [PMID: 17113045 PMCID: PMC2423939 DOI: 10.1016/j.brainres.2006.09.081] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 09/18/2006] [Accepted: 09/25/2006] [Indexed: 01/01/2023]
Abstract
Glutamate is the main excitatory neurotransmitter in both the peripheral and central auditory systems. Changes of glutamate and glutamate-related genes with age may be an important factor in the pathogenesis of age-related hearing loss-presbycusis. In this study, changes in glutamate-related mRNA gene expression in the CBA mouse inferior colliculus with age and hearing loss were examined and correlations were sought between these changes and functional hearing measures, such as the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs). Gene expression of 68 glutamate-related genes was investigated using both genechip microarray and real-time PCR (qPCR) molecular techniques for four different age/hearing loss CBA mouse subject groups. Two genes showed consistent differences between groups for both the genechip and qPCR. Pyrroline-5-carboxylate synthetase enzyme (Pycs) showed down-regulation with age and a high-affinity glutamate transporter (Slc1a3) showed up-regulation with age and hearing loss. Since Pycs plays a role in converting glutamate to proline, its deficiency in old age may lead to both glutamate increases and proline deficiencies in the auditory midbrain, playing a role in the subsequent inducement of glutamate toxicity and loss of proline neuroprotective effects. The up-regulation of Slc1a3 gene expression may reflect a cellular compensatory mechanism to protect against age-related glutamate or calcium excitoxicity.
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Affiliation(s)
- Sherif F. Tadros
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Mary D’Souza
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Martha L. Zettel
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - XiaoXia Zhu
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
| | - Robert D. Frisina
- Department of Otolaryngology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester NY, 14642-8629, USA
- International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, 52 Lomb Memorial Drive, Rochester NY, 14623, USA
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22
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Holt AG, Asako M, Lomax CA, MacDonald JW, Tong L, Lomax MI, Altschuler RA. Deafness-related plasticity in the inferior colliculus: gene expression profiling following removal of peripheral activity. J Neurochem 2005; 93:1069-86. [PMID: 15934929 DOI: 10.1111/j.1471-4159.2005.03090.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The inferior colliculus (IC) is a major center of integration in the ascending as well as descending auditory pathways, where both excitatory and inhibitory amino acid neurotransmitters play a key role. When normal input to the auditory system is decreased, the balance between excitation and inhibition in the IC is disturbed. We examined global changes in gene expression in the rat IC 3 and 21 days following bilateral deafening, using Affymetrix GeneChip arrays and focused our analysis on changes in expression of neurotransmission-related genes. Over 1400 probe sets in the Affymetrix Rat Genome U34A Array were identified as genes that were differentially expressed. These genes encoded proteins previously reported to change as a consequence of deafness, such as calbindin, as well as proteins not previously reported to be modulated by deafness, such as clathrin. A subset of 19 differentially expressed genes was further examined using quantitative RT-PCR at 3, 21 and 90 days following deafness. These included several GABA, glycine, glutamate receptor and neuropeptide-related genes. Expression of genes for GABA-A receptor subunits beta2, beta3, and gamma2, plus ionotropic glutamate receptor subunits AMPA 2, AMPA 3, and kainate 2, increased at all three times. Expression of glycine receptor alpha1 initially declined and then later increased, while alpha2 increased sharply at 21 days. Glycine receptor alpha3 increased between 3 and 21 days, but decreased at 90 days. Of the neuropeptide-related genes tested with qRT-PCR, tyrosine hydroxylase decreased approximately 50% at all times tested. Serotonin receptor 2C increased at 3, 21, and 90 days. The 5B serotonin receptor decreased at 3 and 21 days and returned to normal by 90 days. Of the genes tested with qRT-PCR, only glycine receptor alpha2 and serotonin receptor 5B returned to normal levels of expression at 90 days. Changes in GABA receptor beta3, GABA receptor gamma2, glutamate receptor 2/3, enkephalin, and tyrosine hydroxylase were further confirmed using immunocytochemistry.
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Affiliation(s)
- Avril Genene Holt
- Kresge Hearing Research Institute, Department of Otolaryngology/Head Neck Surgery, University of Michigan, Ann Arbor, Michigan, USA.
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Plappert CF, Pilz PKD. Long-term habituation of the startle response in mice evoked by acoustic and tactile stimuli. Behav Brain Res 2005; 162:307-10. [PMID: 15970224 DOI: 10.1016/j.bbr.2005.03.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 03/22/2005] [Accepted: 03/24/2005] [Indexed: 10/25/2022]
Abstract
The present study shows that repetitive presentation of tactile and acoustic stimuli evoke long-term habituation (LTH) of the startle response in C57BL/6J mice. This was indicated by a decrease in response strength over several days. For the LTH of the acoustic startle response two controls were included: first, developing hearing loss during the time of testing did not account for the startle decrease--only 7 days of acoustic stimulation but not 7 days of adaptation led to a decrease in the startle. Second, repetitive presentation of loud acoustic startle stimuli did not raise the auditory threshold, which might otherwise have accounted for the startle decrease: prepulse inhibition (used here as a hearing test) was identical after both 7 days of acoustic startle stimulation and 7 days without stimulation. This proves that LTH to tactile and acoustic stimuli is present and fully functional in mice.
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Affiliation(s)
- Claudia F Plappert
- Tierphysiologie, Zoologisches Institut, Fakultaet fuer Biologie, Universitaet Tuebingen.
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Ison JR, Allen PD. Low-frequency tone pips elicit exaggerated startle reflexes in C57BL/6J mice with hearing loss. J Assoc Res Otolaryngol 2003; 4:495-504. [PMID: 12784135 PMCID: PMC3202743 DOI: 10.1007/s10162-002-3046-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2002] [Accepted: 04/01/2003] [Indexed: 11/28/2022] Open
Abstract
The strength of the acoustic startle reflex (ASR) as a function of age was studied in adult C57BL/6J and CBA/CaJ mice, because altered ASR levels are a potential behavioral consequence of the neural reorganization that accompanies the early-onset hearing loss of the C57BL, in contrast to the normal-hearing CBA. For C57BL mice at 14-36 weeks of age, compared with 7-week-old mice, high-frequency thresholds measured with the auditory brainstem response (ABR) were less sensitive by about 25-30 dB while the hearing loss at low frequencies was 10-15 dB, but by 60 weeks losses of 45-50 dB were present across the entire spectrum. Their ASR amplitudes for 16 kHz tone pips were highest at 7 weeks and then declined with age, but, for 4 kHz tones the ASR increased in strength at 18 weeks and beyond to levels above that of the younger mice. This hyperreactivity persisted even in 60-week-old mice. The ASR for 16 kHz stimuli was positively correlated with hearing sensitivity, but the ASR for 4 kHz stimuli was positively correlated with hearing loss for mice that were 18-36 weeks of age. Furthermore, ASR amplitudes for 4 kHz stimuli were positively correlated with the 16 kHz ASR in young C57BL mice but negatively correlated in older mice. There were no similar ASR or ABR changes in adult CBA mice through 19 weeks of age. Correlations between ASR and ABR scores were always weakly positive, and correlations between 4 kHz and 16 kHz ASR amplitudes were always strongly positive. The ASR data in older C57BL mice with hearing loss are consistent with reports describing their increased neural representation of low-frequency sounds and reinforce the value of this strain for studying the functional consequences that accompany age-related cochlear degeneration.
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Affiliation(s)
- James R Ison
- Department of Brain and Cognitive Sciences, Meliora Hall, University of Rochester, Rochester, NY 14627, USA.
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25
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Lorke DE, Wong LY, Lai HWL, Poon PWF, Zhang A, Chan WY, Yew DTW. Early postnatal sound exposure induces lasting neuronal changes in the inferior colliculus of senescence accelerated mice (SAMP8): a morphometric study on GABAergic neurons and NMDA expression. Cell Mol Neurobiol 2003; 23:143-64. [PMID: 12735628 DOI: 10.1023/a:1022993704617] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Senescence-acceleration-prone mice (SAMP8) provide a model to study the influence of early postnatal sound exposure upon the aging auditory midbrain. SAMP8 were exposed to a 9-kHz monotone of either 53- or 65-dB sound pressure level during the first 30 postnatal days, the neurons in the auditory midbrain responding selectively to 9 kHz were localized by c-fos immunohistochemistry and the following parameters were compared to control SAMP8 not exposed to sound: mortality after sound exposure, dendritic spine density, and quantitative neurochemical alterations in this 9-kHz isofrequency lamina. For morphometric analysis, animals were examined at 1, 4, and 8 months of age. Serial sections of the inferior colliculus were Golgi impregnated or stained immunohistochemically for the expression of epsilon1 subunit of NMDA receptor or GABA. Mortality after exposure to 53 dB was the same as in controls, but was markedly increased from 7 months of age onward after postnatal exposure to 65 dB. No gross morphological alterations were observed in the auditory midbrain after sound exposure. However, sound exposure to 53 or 65 dB significantly reduced dendritic spine density by 11% at 4 months or by 11-17% both at 1 and 4 months of age, respectively. The effect of sound exposure upon neurons expressing the NMDAepsilon1 subunit was dose-dependent. Increasing with age until 4 months in control mice and remaining essentially stable thereafter, the percentage of NMDAepsilon1-immunoreactive neurons was significantly elevated by 40-66% in 1- and 8-month-old SAMP8 exposed to 53 dB, whereas no significant effect of 65 dB was apparent. The proportion of GABAergic cells declined with age in controls. It was significantly decreased at 1 month after 53 and 65 dB sound exposure. In contrast, it was elevated at later stages, being significantly increased at 4 months after exposure to 53 dB and at 8 months after exposure to 65 dB. The total cell number in the 9-kHz isofrequency lamina of SAMP8 decreased with age, but was not affected by exposure to either 53 or 65 dB. The present results indicate that early postnatal exposure to a monotone of mild intensity has long-term effects upon the aging auditory brain stem. Some of the changes induced by sound exposure, e.g., decline in spine density, are interpreted as accelerations of the normal aging process, whereas other effects, e.g., increased NMDAepsilon1 expression after 53 dB and elevated GABA expression after both 53 and 65 dB, are not merely explicable by accelerated aging.
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Affiliation(s)
- Dietrich Ernst Lorke
- Institute of Neuroanatomy, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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26
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Abstract
The C57BL6 mouse (B6) is homozygous for the gene for age-related hearing loss (ahl/ahl) and shows normal adult-like hearing before subtle changes in hearing begin at about 30 days of age. The B6Cast mouse is congenic to B6, having the wild type allele for normal hearing from Castaneous Ei on a B6 background. It has normal hearing throughout most of its lifespan. This study characterized the morphology of octopus cell (OC) somata in the posterior-ventral cochlear nucleus and of synaptic terminals on the OC somata in 8-week-old B6 and B6Cast mice, and the immunolocalization of antibodies to GluR1 (glutamate receptor subunit 1) and GRIP-C (glutamate receptor interacting protein-C terminus). By 8 weeks of age there are significant changes in the morphology of OCs and synaptic terminals around their somata in B6 mice compared to B6Cast mice. The distribution of immunoreactivity for the proteins GluR1 and GRIP is also significantly different in B6 mice from that in B6Cast mice. The modest degenerative changes reported in some B6 outer hair cells of the basal turn at this age do not seem adequate to explain the major changes observed in most OCs at a time when physiological studies show that many measures of the animals' hearing are still near normal. The findings suggest that changes in the alpha-amino-3-hydroxy-5-methyl-4-isoxazole glutamate receptor subunits and/or their binding proteins are part of the phenotype of ahl, and may reflect a role of the glutamate receptor pathway in the mechanism of ahl.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Age Factors
- Animals
- Animals, Congenic
- Carrier Proteins/chemistry
- Carrier Proteins/metabolism
- Cochlear Nucleus/cytology
- Cochlear Nucleus/metabolism
- Cochlear Nucleus/pathology
- Disease Models, Animal
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/pathology
- Immunohistochemistry
- Mice
- Mice, Inbred C57BL
- Microscopy, Immunoelectron
- Nerve Tissue Proteins/chemistry
- Nerve Tissue Proteins/metabolism
- Neuroglia/metabolism
- Phenotype
- Presbycusis/genetics
- Presbycusis/metabolism
- Presbycusis/pathology
- Presynaptic Terminals/metabolism
- Presynaptic Terminals/ultrastructure
- Receptors, AMPA/metabolism
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Affiliation(s)
- Ilsa R Schwartz
- Department of Surgery/Otolaryngology, Yale School of Medicine, P.O. Box 208041, 333 Cedar Street, New Haven, CT 06520-8041, USA.
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27
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Syka J. Plastic changes in the central auditory system after hearing loss, restoration of function, and during learning. Physiol Rev 2002; 82:601-36. [PMID: 12087130 DOI: 10.1152/physrev.00002.2002] [Citation(s) in RCA: 271] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Traditionally the auditory system was considered a hard-wired sensory system; this view has been challenged in recent years in light of the plasticity of other sensory systems, particularly the visual and somatosensory systems. Practical experience in clinical audiology together with the use of prosthetic devices, such as cochlear implants, contributed significantly to the present view on the plasticity of the central auditory system, which was originally based on data obtained in animal experiments. The loss of auditory receptors, the hair cells, results in profound changes in the structure and function of the central auditory system, typically demonstrated by a reorganization of the projection maps in the auditory cortex. These plastic changes occur not only as a consequence of mechanical lesions of the cochlea or biochemical lesions of the hair cells by ototoxic drugs, but also as a consequence of the loss of hair cells in connection with aging or noise exposure. In light of the aging world population and the increasing amount of noise in the modern world, understanding the plasticity of the central auditory system has its practical consequences and urgency. In most of these situations, a common denominator of central plastic changes is a deterioration of inhibition in the subcortical auditory nuclei and the auditory cortex. In addition to the processes that are elicited by decreased or lost receptor function, the function of nerve cells in the adult central auditory system may dynamically change in the process of learning. A better understanding of the plastic changes in the central auditory system after sensory deafferentation, sensory stimulation, and learning may contribute significantly to improvement in the rehabilitation of damaged or lost auditory function and consequently to improved speech processing and production.
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Affiliation(s)
- Josef Syka
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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28
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Zettel ML, O'Neill WE, Trang TT, Frisina RD. Early bilateral deafening prevents calretinin up-regulation in the dorsal cortex of the inferior colliculus of aged CBA/CaJ mice. Hear Res 2001; 158:131-8. [PMID: 11506945 DOI: 10.1016/s0378-5955(01)00305-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study was conducted to test the hypothesis that age-related calretinin (CR) up-regulation seen in the dorsal cortex of the inferior colliculus (ICdc) of old hearing CBA mice is dependent upon neural activity within the auditory pathway. We tested this hypothesis by bilaterally deafening young CBA/CaJ mice with kanamycin, and then aging them until 24 months. This manipulation mimics the lack of sound-evoked auditory activity experienced by old C57BL/6J mice, who are deaf and do not show CR up-regulation with age. Cell counts revealed that the density of CR+ cells in the ICdc of old hearing CBA mice was statistically different from old deafened CBA mice raised under identical conditions. Old hearing CBAs possessed an average of 27.54 more CR+ cells/100 microm2 than old deafened CBAs. When old deafened CBAs were compared to young hearing CBAs, young hearing C57s, and old deaf C57s, there was no significant difference in mean CR+ cell density in ICdc. Thus, only the old normal hearing CBAs showed an increase in CR+ cells with age, supporting the hypothesis that CR up-regulation depends upon sound-evoked activity. Moreover, these results demonstrate that up-regulation of CR expression was not simply due to a mouse strain difference.
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Affiliation(s)
- M L Zettel
- Department of Surggery, University of Rochester School of Medicine and Dentistry, NY 14642-8629, USA.
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29
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McFadden SL, Ding D, Salvi R. Anatomical, Metabolic and Genetic Aspects of Age-related Hearing Loss in Mice: Aspectos anatómicos, metabólicos y genéticos de la hipoacusia relacionada con la edad en ratones. Int J Audiol 2001. [DOI: 10.3109/00206090109073128] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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30
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Kazee AM, West NR. Preservation of synapses on principal cells of the central nucleus of the inferior colliculus with aging in the CBA mouse. Hear Res 1999; 133:98-106. [PMID: 10416868 DOI: 10.1016/s0378-5955(99)00058-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The light and electron microscopic features of principal neurons of the central nucleus of the inferior colliculus were quantitated in the CBA mouse. Three age groups of mice were examined, including young (3 months), middle-aged (8 months) and old (25 months). No changes were noted in the size of the principal neurons over the age range examined. At the ultrastructural level, synapses on the somata of the principal neurons showed no change in the number or type of synapses, the length of synaptic apposition nor the size of synaptic terminal area. These results are in contrast with the moderately severe synapse loss which we previously reported in the C57BL/6 mouse strain, a strain which has a genetic deficit producing progressive sensorineural hearing loss starting in young adulthood (Kazee et al., 1995). In contrast, hearing is quite well-preserved across the lifespan in the CBA mouse strain, making this a useful animal to study the intrinsic effects of aging in the auditory system versus the effects of sensorineural hearing loss. The preservation of synapses on principal neurons in this strain suggests that synaptic loss is not an inevitable event in aging, but may be related to the preservation of peripheral auditory function and input to the neurons.
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Affiliation(s)
- A M Kazee
- Department of Pathology, SUNY Health Science Center at Syracuse, NY 13210, USA.
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31
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32
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Carlson S, Willott JF. Caudal pontine reticular formation of C57BL/6J mice: responses to startle stimuli, inhibition by tones, and plasticity. J Neurophysiol 1998; 79:2603-14. [PMID: 9582232 DOI: 10.1152/jn.1998.79.5.2603] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
C57BL/6J (C57) mice were used to examine relationships between the behavioral acoustic startle response (ASR) and the responses of neurons in the caudal pontine reticular formation (PnC) in three contexts: 1) responses evoked by basic startle stimuli; 2) the prepulse inhibition (PPI) paradigm; and 3) the effects of high-frequency hearing loss and concomitant neural plasticity that occurs in middle-aged C57 mice. 1) Responses (evoked action potentials) of PnC neurons closely paralleled the ASR with respect to latency, threshold, and responses to rapidly presented stimuli. 2) "Neural PPI" (inhibition of responses evoked by a startle stimulus when preceded by a tone prepulse) was observed in all PnC neurons studied. 3) In PnC neurons of 6-mo-old mice with high-frequency (>20 kHz) hearing loss, neural PPI was enhanced with 12- and 4-kHz prepulses, as it is behaviorally. These are frequencies that have become "overrepresented" in the central auditory system of 6-mo-old C57 mice. Thus neural plasticity in the auditory system, induced by high-frequency hearing loss, is correlated with increased salience of the inhibiting tones in both behavioral and neural PPI paradigms.
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Affiliation(s)
- S Carlson
- Department of Psychology, Northern Illinois University, DeKalb, Illinois 60115, USA
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33
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Age-related alteration in processing of temporal sound features in the auditory midbrain of the CBA mouse. J Neurosci 1998. [PMID: 9502833 DOI: 10.1523/jneurosci.18-07-02764.1998] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The perception of complex sounds, such as speech and animal vocalizations, requires the central auditory system to analyze rapid, ongoing fluctuations in sound frequency and intensity. A decline in temporal acuity has been identified as one component of age-related hearing loss. The detection of short, silent gaps is thought to reflect an important fundamental dimension of temporal resolution. In this study we compared the neural response elicited by silent gaps imbedded in noise of single neurons in the inferior colliculus (IC) of young and old CBA mice. IC neurons were classified by their temporal discharge patterns. Phasic units, which accounted for the majority of response types encountered, tended to have the shortest minimal gap thresholds (MGTs), regardless of age. We report three age-related changes in neural processing of silent gaps. First, although the shortest MGTs (1-2 msec) were observed in phasic units from both young and old animals, the number of neurons exhibiting the shortest MGTs was much lower in old mice, regardless of the presentation level. Second, in the majority of phasic units, recovery of response to the stimulus after the silent gap was of a lower magnitude and much slower in units from old mice. Finally, the neuronal map representing response latency versus best frequency was found to be altered in the old IC. These results demonstrate a central auditory system correlate for age-related decline in temporal processing at the level of the auditory midbrain.
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34
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Frisina RD, Walton JP, Lynch-Armour MA, Byrd JD. Inputs to a physiologically characterized region of the inferior colliculus of the young adult CBA mouse. Hear Res 1998; 115:61-81. [PMID: 9472736 DOI: 10.1016/s0378-5955(97)00176-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Presbycusis is a sensory perceptual disorder involving loss of high-pitch hearing and reduced ability to process biologically relevant acoustic signals in noisy environments. The present investigation is part of an ongoing series of studies aimed at discerning the neural bases of presbycusis. The purpose of the present experiment was to delineate the inputs to a functionally characterized region of the dorsomedial inferior colliculus (IC, auditory midbrain) in young, adult CBA mice. Focal, iontophoretic injections of horseradish peroxidase were made in the 18-24 kHz region of dorsomedial IC of the CBA strain following physiological mapping experiments. Serial sections were reacted with diaminobenzidine or tetramethylbenzidine, counterstained and examined for retrogradely labeled cell bodies. Input projections were observed contralaterally from: all three divisions of cochlear nucleus; intermediate and dorsal nuclei of the lateral lemniscus (LL); and the central nucleus, external nucleus and dorsal cortex of the IC. Input projections were observed ipsilaterally from: the medial and lateral superior olivary nuclei; the superior paraolivary nucleus; the dorsolateral and anterolateral periolivary nuclei; the dorsal and ventral divisions of the ventral nucleus of LL; the dorsal and intermediate nuclei of LL; the central nucleus, external nucleus and dorsal cortex of the IC outside the injection site; and small projections from central gray and the medial geniculate body. These findings in young, adult mice with normal hearing can now serve as a baseline for similar experiments being conducted in mice of older ages and with varying degrees of hearing loss to discover neural changes that may cause age-related hearing disorders.
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Affiliation(s)
- R D Frisina
- Department of Surgery, University of Rochester School of Medicine and Dentistry, NY 14642-8629, USA.
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35
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O'Neill WE, Zettel ML, Whittemore KR, Frisina RD. Calbindin D-28k immunoreactivity in the medial nucleus of the trapezoid body declines with age in C57BL/6, but not CBA/CaJ, mice. Hear Res 1997; 112:158-66. [PMID: 9367238 DOI: 10.1016/s0378-5955(97)00116-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study compared calbindin D-28k immunoreactivity in the medial nucleus of the trapezoid body (MNTB) in young (3-4 month old) and old (24-26 month old) CBA/CaJ mice, and young (3-4 month old), middle-aged (6.5-8.5 month old), and old (24-29 month old) C57BL/6 mice. C57BL/6 mice exhibit progressively more severe peripheral (sensorineural) hearing loss between 4 and 12 months of age, whereas CBA/CaJ mice show little change in peripheral sensitivity until very late in life. We obtained auditory brainstem response audiograms on all subject mice. Old CBA mice were selected for study whose audiograms matched those of young CBA and C57 controls. Middle-aged C57 mice showed elevated thresholds indicative of peripheral degeneration. Brain sections were reacted with anti-calbindin D-28k (CB). Staining patterns in Nissl and anti-CB material were characterized and cells were counted. We found no significant change in the number of CB+ cells or the total number of cells in the MNTB of old CBA mice compared to young controls. However, the mean number of CB+ cells decreased by 11% in middle-aged, and by 14.8% in old C57 mice. Since the decline in C57 mice was significant by 6.5-8.5 months of age, the decrease could be the consequence of a loss of input from the cochlear nucleus where cell numbers are known to decline by this age in this strain. The total number of neurons in MNTB assessed from Nissl material showed a more modest 7.1% decline with age in C57 mice, implying that the greater loss of CB immunoreactive cells with age cannot be completely attributed to a reduction in the total number of cells.
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Affiliation(s)
- W E O'Neill
- Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, NY 14642-8603, USA.
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36
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Zettel ML, Frisina RD, Haider SE, O'Neill WE. Age-related changes in calbindin D-28k and calretinin immunoreactivity in the inferior colliculus of CBA/CaJ and C57Bl/6 mice. J Comp Neurol 1997; 386:92-110. [PMID: 9303527 DOI: 10.1002/(sici)1096-9861(19970915)386:1<92::aid-cne9>3.0.co;2-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study examines calbindin D-28k and calretinin immunoreactivity in the inferior colliculus (IC) of young and old mice of two strains. The CBA/CaJ mouse maintains good hearing until very late in life, whereas the C57Bl/6 strain exhibits severe sensorineural hearing loss at an early age. Young and old mice of both strains were selected with matching auditory brainstem response audiograms and gap detection thresholds. Brain sections were reacted with anti-calbindin D-28k (CB) and anti-calretinin (CR). Staining patterns were characterized and cell counts performed. CB immunoreactivity was high only in the nucleus of the commissure (NCO); counts revealed a 22.3% decrease in the number of CB+ cells in old CBA mice and a 25.1% decrease in old C57 mice. Calretinin immunoreactivity was high in the pericentral regions of the IC, but the central nucleus was devoid of CR+ cells. The dorsal cortex, lateral nucleus, and NCO showed increases of 42.3, 49.0, and 61%, respectively, in the number of CR+ cells, but only in the old CBA mice. No significant change was observed in the old C57 mice. Whereas decreases in CB immunoreactivity are common with age, this study is the first to report an age-related increase in CR immunoreactivity in the auditory system. The increase in CR+ cells is a possible compensatory adaptation to the decrease in CB+ cells. That the number of CR+ cells remains constant with age in C57 mice suggests this compensation may depend upon stimulus-driven activity, but this requires further study.
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Affiliation(s)
- M L Zettel
- Department of Surgery, University of Rochester School of Medicine and Dentistry, New York 14642, USA
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37
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Spongr VP, Flood DG, Frisina RD, Salvi RJ. Quantitative measures of hair cell loss in CBA and C57BL/6 mice throughout their life spans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1997; 101:3546-3553. [PMID: 9193043 DOI: 10.1121/1.418315] [Citation(s) in RCA: 226] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The CBA mouse shows little evidence of hearing loss until late in life, whereas the C57BL/6 strain develops a severe and progressive, high-frequency sensorineural hearing loss beginning around 3-6 months of age. These functional differences have been linked to genetic differences in the amount of hair cell loss as a function of age; however, a precise quantitative description of the sensory cell loss is unavailable. The present study provides mean values of inner hair cell (IHC) and outer hair cell (OHC) loss for CBA and C57BL/6 mice at 1, 3, 8, 18, and 26 months of age. CBA mice showed little evidence of hair cell loss until 18 months of age. At 26 months of age, OHC losses in the apex and base of the cochlea were approximately 65% and 50%, respectively, and IHC losses were approximately 25% and 35%. By contrast, C57BL/6 mice showed approximately a 75% OHC and a 55% IHC loss in the base of the cochlea at 3 months of age. OHC and IHC losses increased rapidly with age along a base-to-apex gradient. By 26 months of age, more than 80% of the OHCs were missing throughout the entire cochlea; however, IHC losses ranged from 100% near the base of the cochlea to approximately 20% in the apex.
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Affiliation(s)
- V P Spongr
- Department of Commmunicative Disorders and Sciences, SUNY at Buffalo 14214, USA
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38
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Frisina RD, Walton JP, Lynch-Armour MA, Klotz DA. Efferent projections of a physiologically characterized region of the inferior colliculus of the young adult CBA mouse. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1997; 101:2741-2753. [PMID: 9165729 DOI: 10.1121/1.418562] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The present investigation is part of an ongoing series of studies aimed at discerning the neural bases of presbycusis. Presbycusis is a sensory perceptual disorder involving loss of high-pitch hearing and reduced ability to process biologically relevant acoustic signals in noisy environments. The purpose of the present experiment was to delineate the efferent projections of a functionally characterized region of the dorsomedial inferior colliculus (IC, auditory midbrain) in young, adult CBA mice. The CBA strain's progressive loss of hearing over its lifespan approximates many aspects of the mild-to-moderate hearing loss experienced by a significant number of humans suffering from presbycusis. Focal, iontophoretic injections of HRP were made in the 18-24 kHz region of dorsomedial IC of the CBA strain following physiological mapping experiments. Serial sections were reacted with a chromagen, counterstained and examined for anterogradely labeled fibers and boutons. Efferent projections were observed ipsilaterally in: medial and ventral divisions of the medial geniculate body (MGB); middle layers of the superior colliculus; central gray; and external nucleus (E), dorsal cortex (DC) and central nucleus of IC. Contralaterally, labeled fibers and boutons were seen in the IC at a location homologous to the injection site, as well as in E and DC. A small projection was noted in contralateral MGB. These findings in young, adult mice with normal hearing can now serve as a baseline for similar experiments being conducted in mice and animals of other species of older ages and with varying degrees of hearing loss.
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Affiliation(s)
- R D Frisina
- Department of Surgery, University of Rochester School of Medicine and Dentistry, New York 14642-8629, USA.
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39
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Suzuki H, Ikeda K, Takasaka T. Age-related changes of the globular substance in the otoconial membrane of mice. Laryngoscope 1997; 107:378-81. [PMID: 9121317 DOI: 10.1097/00005537-199703000-00019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The globular substance, which occurs in the vestibular macula as a precursor of otoconia, was examined in aged mice in comparison with young adult mice. Dissected otoconial membrane from the utricular macula of C57BL/6J mice was loaded with fluo-3-AM, and directly observed under a confocal laser scanning microscope. Internal free Ca2+ concentration ([Ca2+]i) of the globular substance was determined through in situ calibration performed by superfusion with ionomycin and Mn2+. Total area of the otoconial membrane, average diameter of the globular substance, and [Ca2+]i showed no significant differences between young adult and aged groups. However, the number of globular substances in young adult mice was significantly larger than those of aged mice. These results suggest a reduced rate of otoconial formation in the aged vestibule, which would result in the sparseness of otoconia in the aged vestibule and lead to balance disorders commonly seen in elderly persons.
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Affiliation(s)
- H Suzuki
- Department of Otolaryngology, Tohoku University School of Medicine, Aoba-ku, Sendai, Japan
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40
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Gummer AW, Preyer S. Cochlear Amplification and its Pathology: Emphasis on the Role of the Tectorial Membrane. EAR, NOSE & THROAT JOURNAL 1997. [DOI: 10.1177/014556139707600309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Anthony W. Gummer
- University of Tubingen, Dept. of Otolaryngology, Section of Physiological Acoustics and Communication, Tübingen, Germany
| | - Serena Preyer
- University of Tubingen, Dept. of Otolaryngology, Section of Physiological Acoustics and Communication, Tübingen, Germany
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41
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Walton JP, Frisina RD, Meierhans LR. Sensorineural hearing loss alters recovery from short-term adaptation in the C57BL/6 mouse. Hear Res 1995; 88:19-26. [PMID: 8575994 DOI: 10.1016/0378-5955(95)00093-j] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several strains of laboratory mouse (Mus musculus) have a pattern of hearing loss which resembles that found in humans. The C57BL/6 strain of mouse has a genetic defect that results in degeneration of the organ of Corti, originating in the basal, high-frequency region and then proceeding apically over time. The end result is a severe-to-profound sensorineural hearing loss (SNHL) by 14 months of age. In contrast, auditory function of the CBA strain remains normal through its early life span then slowly declines later in life, much like that typified by human presbycusis. The purpose of the present study was to compare ABR (peak 5) forward masking recovery functions in young, normal-hearing CBA and C57BL/6 mice to hearing-impaired C57BL/6 mice. ABR audiograms were obtained prior to collecting the tone-on-tone forward masking data. Masking was defined as a 50% reduction in the P5 component of the ABR, elicited and masked by 12 kHz tone bursts, using masker/probe time delays from 0 to 100 ms. Time constants were computed from an exponential model fit to the recovery functions (masker level vs. time delay). In hearing-impaired animals there was a significant increase in recovery from short-term adaptation as measured by the time constants, as well as a significant latency shift in the P5 component. The effects of SNHL on the recovery of the P5 component from short-term adaptation was comparable to that reported behaviorally for human hearing-impaired listeners and physiologically from the inferior colliculus (IC) of chinchillas suffering permanent threshold shifts.
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Affiliation(s)
- J P Walton
- Department of Surgery, University of Rochester School of Medicine and Dentistry, NY 14642-8629, USA
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