1
|
Colak H, Sendesen E, Turkyilmaz MD. Subcortical auditory system in tinnitus with normal hearing: insights from electrophysiological perspective. Eur Arch Otorhinolaryngol 2024; 281:4133-4142. [PMID: 38555317 PMCID: PMC11266230 DOI: 10.1007/s00405-024-08583-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/26/2024] [Indexed: 04/02/2024]
Abstract
PURPOSE The mechanism of tinnitus remains poorly understood; however, studies have underscored the significance of the subcortical auditory system in tinnitus perception. In this study, our aim was to investigate the subcortical auditory system using electrophysiological measurements in individuals with tinnitus and normal hearing. Additionally, we aimed to assess speech-in-noise (SiN) perception to determine whether individuals with tinnitus exhibit SiN deficits despite having normal-hearing thresholds. METHODS A total 42 normal-hearing participants, including 22 individuals with chronic subjective tinnitus and 20 normal individuals, participated in the study. We recorded auditory brainstem response (ABR) and speech-evoked frequency following response (sFFR) from the participants. SiN perception was also assessed using the Matrix test. RESULTS Our results revealed a significant prolongation of the O peak, which encodes sound offset in sFFR, for the tinnitus group (p < 0.01). The greater non-stimulus-evoked activity was also found in individuals with tinnitus (p < 0.01). In ABR, the tinnitus group showed reduced wave I amplitude and prolonged absolute wave I, III, and V latencies (p ≤ 0.02). Our findings suggested that individuals with tinnitus had poorer SiN perception compared to normal participants (p < 0.05). CONCLUSION The deficit in encoding sound offset may indicate an impaired inhibitory mechanism in tinnitus. The greater non-stimulus-evoked activity observed in the tinnitus group suggests increased neural noise at the subcortical level. Additionally, individuals with tinnitus may experience speech-in-noise deficits despite having a normal audiogram. Taken together, these findings suggest that the lack of inhibition and increased neural noise may be associated with tinnitus perception.
Collapse
Affiliation(s)
- Hasan Colak
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK.
| | - Eser Sendesen
- Department of Audiology, Hacettepe University, Ankara, Turkey
| | | |
Collapse
|
2
|
van den Berg MM, Wong AB, Houtak G, Williamson RS, Borst JGG. Sodium salicylate improves detection of amplitude-modulated sound in mice. iScience 2024; 27:109691. [PMID: 38736549 PMCID: PMC11088340 DOI: 10.1016/j.isci.2024.109691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/14/2024] [Accepted: 04/05/2024] [Indexed: 05/14/2024] Open
Abstract
Salicylate is commonly used to induce tinnitus in animals, but its underlying mechanism of action is still debated. We therefore tested its effects on the firing properties of neurons in the mouse inferior colliculus (IC). Salicylate induced a large decrease in the spontaneous activity and an increase of ∼20 dB SPL in the minimum threshold of single units. In response to sinusoidally modulated noise (SAM noise) single units showed both an increase in phase locking and improved rate coding. Mice also became better at detecting amplitude modulations, and a simple threshold model based on the IC population response could reproduce this improvement. The responses to dynamic random chords (DRCs) suggested that the improved AM encoding was due to a linearization of the cochlear output, resulting in larger contrasts during SAM noise. These effects of salicylate are not consistent with the presence of tinnitus, but should be taken into account when studying hyperacusis.
Collapse
Affiliation(s)
- Maurits M. van den Berg
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Aaron B. Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ghais Houtak
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ross S. Williamson
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - J. Gerard G. Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| |
Collapse
|
3
|
Tureček R, Melichar A, Králíková M, Hrušková B. The role of GABA B receptors in the subcortical pathways of the mammalian auditory system. Front Endocrinol (Lausanne) 2023; 14:1195038. [PMID: 37635966 PMCID: PMC10456889 DOI: 10.3389/fendo.2023.1195038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023] Open
Abstract
GABAB receptors are G-protein coupled receptors for the inhibitory neurotransmitter GABA. Functional GABAB receptors are formed as heteromers of GABAB1 and GABAB2 subunits, which further associate with various regulatory and signaling proteins to provide receptor complexes with distinct pharmacological and physiological properties. GABAB receptors are widely distributed in nervous tissue, where they are involved in a number of processes and in turn are subject to a number of regulatory mechanisms. In this review, we summarize current knowledge of the cellular distribution and function of the receptors in the inner ear and auditory pathway of the mammalian brainstem and midbrain. The findings suggest that in these regions, GABAB receptors are involved in processes essential for proper auditory function, such as cochlear amplifier modulation, regulation of spontaneous activity, binaural and temporal information processing, and predictive coding. Since impaired GABAergic inhibition has been found to be associated with various forms of hearing loss, GABAB dysfunction could also play a role in some pathologies of the auditory system.
Collapse
Affiliation(s)
- Rostislav Tureček
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Adolf Melichar
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Michaela Králíková
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Bohdana Hrušková
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
| |
Collapse
|
4
|
Can GABAkines Quiet the Noise? The GABAA Receptor Neurobiology and Pharmacology of Tinnitus. Biochem Pharmacol 2022; 201:115067. [DOI: 10.1016/j.bcp.2022.115067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 11/20/2022]
|
5
|
Tang HP, Gong HR, Zhang XL, Huang YN, Wu CY, Tang ZQ, Chen L, Wang M. Sodium salicylate enhances neural excitation via reducing GABAergic transmission in the dentate gyrus area of rat hippocampus in vivo. Hippocampus 2021; 31:512-521. [PMID: 33580728 DOI: 10.1002/hipo.23312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 12/31/2020] [Accepted: 01/23/2021] [Indexed: 11/10/2022]
Abstract
Sodium salicylate, one of the non-steroidal anti-inflammatory drugs, is widely prescribed in the clinic, but a high dose of usage can cause hyperactivity in the central nervous system, including the hippocampus. At present, the neural mechanism underlying the induced hyperactivity is not fully understood, in particular, in the hippocampus under an in vivo condition. In this study, we found that systemic administration of sodium salicylate increased the field excitatory postsynaptic potential slope and the population spike amplitude in a dose-dependent manner in the hippocampal dentate gyrus area of rats with in vivo field potential extracellular recordings, which indicates that sodium salicylate enhances basal synaptic transmission and neural excitation. In the presence of picrotoxin, a GABA-A receptor antagonist, sodium salicylate failed to increase the initial slope of the field excitatory postsynaptic potential and the amplitude of the population spike in vivo. To further explore how sodium salicylate enhances the neural excitation, we made whole-cell patch-clamp recordings from hippocampal slices. We found that perfusion of the slice with sodium salicylate decreased electrically evoked GABA receptor-mediated currents, increased paired-pulse ratio, and lowered frequency and amplitude of miniature inhibitory postsynaptic currents. Together, these results demonstrate that sodium salicylate enhances the neural excitation through suppressing GABAergic synaptic transmission in presynaptic and postsynaptic mechanisms in the hippocampal dentate gyrus area. Our findings may help understand the side effects caused by sodium salicylate in the central nervous system.
Collapse
Affiliation(s)
- Hui-Ping Tang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.,Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Hua-Rui Gong
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.,Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xu-Lai Zhang
- Department of Geriatrics, Anhui Mental Health Center, Hefei, China
| | - Yi-Na Huang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.,Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chuan-Yun Wu
- College of Traditional Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Zheng-Quan Tang
- School of Life Sciences, Anhui University, Hefei, China.,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, China
| | - Lin Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.,Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ming Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.,Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| |
Collapse
|
6
|
Salvi R, Auerbach BD, Lau C, Chen YC, Manohar S, Liu X, Ding D, Chen GD. Functional Neuroanatomy of Salicylate- and Noise-Induced Tinnitus and Hyperacusis. Curr Top Behav Neurosci 2020; 51:133-160. [PMID: 32653998 DOI: 10.1007/7854_2020_156] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tinnitus and hyperacusis are debilitating conditions often associated with aging or exposure to intense noise or ototoxic drugs. One of the most reliable methods of inducing tinnitus is with high doses of sodium salicylate, the active ingredient in aspirin. High doses of salicylate have been widely used to investigate the functional neuroanatomy of tinnitus and hyperacusis. High doses of salicylate have been used to develop novel behavioral methods to detect the presence of tinnitus and hyperacusis in animal models. Salicylate typically induces a hearing loss of approximately 20 dB which greatly reduces the neural output of the cochlea. As this weak neural signal emerging from the cochlea is sequentially relayed to the cochlear nucleus, inferior colliculus, medial geniculate, and auditory cortex, the neural response to suprathreshold sounds is progressively amplified by a factor of 2-3 by the time the signal reaches the auditory cortex, a phenomenon referred to as enhanced central gain. Sound-evoked hyperactivity also occurred in the amygdala, a region that assigns emotional significance to sensory stimuli. Resting state functional magnetic imaging of the BOLD signal revealed salicylate-induced increases in spontaneous neural activity in the inferior colliculus, medial geniculate body, and auditory cortex as well as in non-auditory areas such as the amygdala, reticular formation, cerebellum, and other sensory areas. Functional connectivity of the BOLD signal revealed increased neural coupling between several auditory areas and non-auditory areas such as the amygdala, cerebellum, reticular formation, hippocampus, and caudate/putamen; these strengthened connections likely contribute to the multifaceted dimensions of tinnitus. Taken together, these results suggest that salicylate-induced tinnitus disrupts a complex neural network involving many auditory centers as well as brain regions involved with emotion, arousal, memory, and motor planning. These extra-auditory centers embellish the basic auditory percepts that results in tinnitus and which may also contribute to hyperacusis.
Collapse
Affiliation(s)
- Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA.
| | | | - Condon Lau
- Department of Physics, City University of Hong Kong, Hong Kong, China
| | - Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | | | - Xiaopeng Liu
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
| | - Guang-Di Chen
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
| |
Collapse
|
7
|
Zheng Y, McTavish J, Smith PF. Pharmacological Evaluation of Drugs in Animal Models of Tinnitus. Curr Top Behav Neurosci 2020; 51:51-82. [PMID: 33590458 DOI: 10.1007/7854_2020_212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Despite the pressing need for effective drug treatments for tinnitus, currently, there is no single drug that is approved by the FDA for this purpose. Instead, a wide range of unproven over-the-counter tinnitus remedies are available on the market with little or no benefit for tinnitus but with potential harm and adverse effects. Animal models of tinnitus have played a critical role in exploring the pathophysiology of tinnitus, identifying therapeutic targets and evaluating novel and existing drugs for tinnitus treatment. This review summarises and compares the studies on pharmacological evaluation of tinnitus treatment in different animal models based on the pharmacological properties of the drug and provides insights into future directions for tinnitus drug discovery.
Collapse
Affiliation(s)
- Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand. .,Brain Research New Zealand, Auckland, New Zealand. .,Brain Health Research Centre, University of Otago, Dunedin, New Zealand. .,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand.
| | - Jessica McTavish
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Research New Zealand, Auckland, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand.,Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
| |
Collapse
|
8
|
Wu C, Bao W, Yi B, Wang Q, Wu X, Qian M, Zuo C, Huang Z. Increased metabolic activity and hysteretic enhanced GABA A receptor binding in a rat model of salicylate-induced tinnitus. Behav Brain Res 2019; 364:348-355. [PMID: 30797852 DOI: 10.1016/j.bbr.2019.02.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/16/2022]
Abstract
Tinnitus is relevant to neural hyperactivity in the central nervous system (CNS). Normal quantity and functioning of the γ-aminobutyric acid (GABA) receptor are crucial for maintaining the balance between excitation and inhibition in the brain. In this study, we applied a rat model of tinnitus via long-term salicylate administration. The combination of the gap pre-pulse inhibition of acoustic startle (GPIAS) and pre-pulse inhibition (PPI) tests were used to detect tinnitus-like behavior, and rats receiving 7 or 14 consecutive days of salicylate administration showed evidence of tinnitus. After positron emission tomography (PET) scan, we found that the metabolic activity was increased after salicylate treatment followed by enhanced GABAA receptor binding with cessation of salicylate administration in the auditory cortex (AC), medial prefrontal cortex (mPFC), hippocampus (HP), cingulate cortex (CiC) and insular (InC). The inferior colliculus (IC) showed an elevated metabolic activity with no change in the GABAA receptor binding. All the alterations returned to baseline several days after cessation of salicylate treatment despite a mismatch between the time-course of them. By contrast, we found alterations in neither the metabolic activity nor the GABAA receptor binding in the amygdala (AMY) and cerebellum (CRB). These findings indicate that enhanced neural activity in the auditory and limbic system may contribute to the development of tinnitus, while the hysteretic increase of GABAA receptor binding in specific areas of the CNS may be a compensation for hyperactivity, which may be involved in tinnitus relieving.
Collapse
Affiliation(s)
- Cong Wu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Weiqi Bao
- PET Center, Huashan Hospital, Fudan University, Shanghai, China.
| | - Bin Yi
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Qixuan Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Xu Wu
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Minfei Qian
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Chuantao Zuo
- PET Center, Huashan Hospital, Fudan University, Shanghai, China.
| | - Zhiwu Huang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Laboratoryof Auditory Neuroscience, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| |
Collapse
|
9
|
Exploring pathogenesis in subjects with subjective Tinnitus having kidney deficiency pattern in terms of Traditional Chinese Medicine based on serum metabolic profiles. J TRADIT CHIN MED 2018. [DOI: 10.1016/s0254-6272(18)30918-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
10
|
Caspary DM, Llano DA. Auditory thalamic circuits and GABA A receptor function: Putative mechanisms in tinnitus pathology. Hear Res 2017; 349:197-207. [PMID: 27553899 PMCID: PMC5319923 DOI: 10.1016/j.heares.2016.08.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/28/2016] [Accepted: 08/17/2016] [Indexed: 01/02/2023]
Abstract
Tinnitus is defined as a phantom sound (ringing in the ears), and can significantly reduce the quality of life for those who suffer its effects. Ten to fifteen percent of the general adult population report symptoms of tinnitus with 1-2% reporting that tinnitus negatively impacts their quality of life. Noise exposure is the most common cause of tinnitus and the military environment presents many challenging high-noise situations. Military noise levels can be so intense that standard hearing protection is not adequate. Recent studies suggest a role for inhibitory neurotransmitter dysfunction in response to noise-induced peripheral deafferentation as a key element in the pathology of tinnitus. The auditory thalamus, or medial geniculate body (MGB), is an obligate auditory brain center in a unique position to gate the percept of sound as it projects to auditory cortex and to limbic structures. Both areas are thought to be involved in those individuals most impacted by tinnitus. For MGB, opposing hypotheses have posited either a tinnitus-related pathologic decrease or pathologic increase in GABAergic inhibition. In sensory thalamus, GABA mediates fast synaptic inhibition via synaptic GABAA receptors (GABAARs) as well as a persistent tonic inhibition via high-affinity extrasynaptic GABAARs and slow synaptic inhibition via GABABRs. Down-regulation of inhibitory neurotransmission, related to partial peripheral deafferentation, is consistently presented as partially underpinning neuronal hyperactivity seen in animal models of tinnitus. This maladaptive plasticity/Gain Control Theory of tinnitus pathology (see Auerbach et al., 2014; Richardson et al., 2012) is characterized by reduced inhibition associated with increased spontaneous and abnormal neuronal activity, including bursting and increased synchrony throughout much of the central auditory pathway. A competing hypothesis suggests that maladaptive oscillations between the MGB and auditory cortex, thalamocortical dysrhythmia, predict tinnitus pathology (De Ridder et al., 2015). These unusual oscillations/rhythms reflect net increased tonic inhibition in a subset of thalamocortical projection neurons resulting in abnormal bursting. Hyperpolarizing de-inactivation of T-type Ca2+ channels switches thalamocortical projection neurons into burst mode. Thalamocortical dysrhythmia originating in sensory thalamus has been postulated to underpin neuropathies including tinnitus and chronic pain. Here we review the relationship between noise-induced tinnitus and altered inhibition in the MGB.
Collapse
Affiliation(s)
- Donald M Caspary
- Department of Pharmacology and Neuroscience, Southern Illinois University School of Medicine, Springfield, IL, USA.
| | - Daniel A Llano
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| |
Collapse
|
11
|
Eggermont JJ. Can Animal Models Contribute to Understanding Tinnitus Heterogeneity in Humans? Front Aging Neurosci 2016; 8:265. [PMID: 27895575 PMCID: PMC5107573 DOI: 10.3389/fnagi.2016.00265] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/24/2016] [Indexed: 12/30/2022] Open
Abstract
The brain activity of humans with tinnitus of various etiologies is typically studied with electro- and magneto-encephalography and functional magnetic resonance imaging-based imaging techniques. Consequently, they measure population responses and mostly from the neocortex. The latter also underlies changes in neural networks that may be attributed to tinnitus. However, factors not strictly related to tinnitus such as hearing loss and hyperacusis, as well as other co-occurring disorders play a prominent role in these changes. Different types of tinnitus can often not be resolved with these brain-imaging techniques. In animal models of putative behavioral signs of tinnitus, neural activity ranging from auditory nerve to auditory cortex, is studied largely by single unit recordings, augmented by local field potentials (LFPs), and the neural correlates of tinnitus are mainly based on spontaneous neural activity, such as spontaneous firing rates and pair-wise spontaneous spike-firing correlations. Neural correlates of hyperacusis rely on measurement of stimulus-evoked activity and are measured as increased driven firing rates and LFP amplitudes. Connectivity studies would rely on correlated neural activity between pairs of neurons or LFP amplitudes, but are only recently explored. In animal models of tinnitus, only two etiologies are extensively studied; tinnitus evoked by salicylate application and by noise exposure. It appears that they have quite different neural biomarkers. The unanswered question then is: does this different etiology also result in different tinnitus?
Collapse
Affiliation(s)
- Jos J Eggermont
- Department of Physiology and Pharmacology, University of Calgary, CalgaryAB, Canada; Department of Psychology, University of Calgary, CalgaryAB, Canada
| |
Collapse
|