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Singh A, Smith PF, Zheng Y. Targeting the Limbic System: Insights into Its Involvement in Tinnitus. Int J Mol Sci 2023; 24:9889. [PMID: 37373034 DOI: 10.3390/ijms24129889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Tinnitus is originally derived from the Latin verb tinnire, which means "to ring". Tinnitus, a complex disorder, is a result of sentient cognizance of a sound in the absence of an external auditory stimulus. It is reported in children, adults, and older populations. Patients suffering from tinnitus often present with hearing loss, anxiety, depression, and sleep disruption in addition to a hissing and ringing in the ear. Surgical interventions and many other forms of treatment have been only partially effective due to heterogeneity in tinnitus patients and a lack of understanding of the mechanisms of tinnitus. Although researchers across the globe have made significant progress in understanding the underlying mechanisms of tinnitus over the past few decades, tinnitus is still deemed to be a scientific enigma. This review summarises the role of the limbic system in tinnitus development and provides insight into the development of potential target-specific tinnitus therapies.
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Affiliation(s)
- Anurag Singh
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
| | - Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- The Eisdell Moore Centre for Research in Hearing and Balance Disorders, University of Auckland, Auckland 1023, New Zealand
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Billig AJ, Lad M, Sedley W, Griffiths TD. The hearing hippocampus. Prog Neurobiol 2022; 218:102326. [PMID: 35870677 PMCID: PMC10510040 DOI: 10.1016/j.pneurobio.2022.102326] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/08/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022]
Abstract
The hippocampus has a well-established role in spatial and episodic memory but a broader function has been proposed including aspects of perception and relational processing. Neural bases of sound analysis have been described in the pathway to auditory cortex, but wider networks supporting auditory cognition are still being established. We review what is known about the role of the hippocampus in processing auditory information, and how the hippocampus itself is shaped by sound. In examining imaging, recording, and lesion studies in species from rodents to humans, we uncover a hierarchy of hippocampal responses to sound including during passive exposure, active listening, and the learning of associations between sounds and other stimuli. We describe how the hippocampus' connectivity and computational architecture allow it to track and manipulate auditory information - whether in the form of speech, music, or environmental, emotional, or phantom sounds. Functional and structural correlates of auditory experience are also identified. The extent of auditory-hippocampal interactions is consistent with the view that the hippocampus makes broad contributions to perception and cognition, beyond spatial and episodic memory. More deeply understanding these interactions may unlock applications including entraining hippocampal rhythms to support cognition, and intervening in links between hearing loss and dementia.
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Affiliation(s)
| | - Meher Lad
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - William Sedley
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - Timothy D Griffiths
- Biosciences Institute, Newcastle University Medical School, Newcastle upon Tyne, UK; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, UK; Human Brain Research Laboratory, Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, USA
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Zhang L, Wang J, Sun H, Feng G, Gao Z. Interactions between the hippocampus and the auditory pathway. Neurobiol Learn Mem 2022; 189:107589. [DOI: 10.1016/j.nlm.2022.107589] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 01/12/2022] [Accepted: 01/29/2022] [Indexed: 12/22/2022]
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de Deus JL, Amorim MR, Ribeiro AB, Barcellos-Filho PCG, Ceballos CC, Branco LGS, Cunha AOS, Leão RM. Loss of Brain-Derived Neurotrophic Factor Mediates Inhibition of Hippocampal Long-Term Potentiation by High-Intensity Sound. Cell Mol Neurobiol 2021; 41:751-763. [PMID: 32445041 DOI: 10.1007/s10571-020-00881-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 05/16/2020] [Indexed: 01/15/2023]
Abstract
Exposure to noise produces cognitive and emotional disorders, and recent studies have shown that auditory stimulation or deprivation affects hippocampal function. Previously, we showed that exposure to high-intensity sound (110 dB, 1 min) strongly inhibits Schaffer-CA1 long-term potentiation (LTP). Here we investigated possible mechanisms involved in this effect. We found that exposure to 110 dB sound activates c-fos expression in hippocampal CA1 and CA3 neurons. Although sound stimulation did not affect glutamatergic or GABAergic neurotransmission in CA1, it did depress the level of brain-derived neurotrophic factor (BDNF), which is involved in promoting hippocampal synaptic plasticity. Moreover, perfusion of slices with BDNF rescued LTP in animals exposed to sound stimulation, whereas BDNF did not affect LTP in sham-stimulated rats. Furthermore, LM22A4, a TrkB receptor agonist, also rescued LTP from sound-stimulated animals. Our results indicate that depression of hippocampal BDNF mediates the inhibition of LTP produced by high-intensity sound stimulation.
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Affiliation(s)
- Júnia L de Deus
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
- Department of Basic and Oral Biology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil
| | - Mateus R Amorim
- Department of Basic and Oral Biology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil
| | - Aline B Ribeiro
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Procópio C G Barcellos-Filho
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - César C Ceballos
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Luiz Guilherme S Branco
- Department of Basic and Oral Biology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil
| | - Alexandra O S Cunha
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Ricardo M Leão
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil.
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Lazarini-Lopes W, Do Val-da Silva RA, da Silva-Júnior RMP, Cunha AOS, Garcia-Cairasco N. Cannabinoids in Audiogenic Seizures: From Neuronal Networks to Future Perspectives for Epilepsy Treatment. Front Behav Neurosci 2021; 15:611902. [PMID: 33643007 PMCID: PMC7904685 DOI: 10.3389/fnbeh.2021.611902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/06/2021] [Indexed: 12/17/2022] Open
Abstract
Cannabinoids and Cannabis-derived compounds have been receiving especial attention in the epilepsy research scenario. Pharmacological modulation of endocannabinoid system's components, like cannabinoid type 1 receptors (CB1R) and their bindings, are associated with seizures in preclinical models. CB1R expression and functionality were altered in humans and preclinical models of seizures. Additionally, Cannabis-derived compounds, like cannabidiol (CBD), present anticonvulsant activity in humans and in a great variety of animal models. Audiogenic seizures (AS) are induced in genetically susceptible animals by high-intensity sound stimulation. Audiogenic strains, like the Genetically Epilepsy Prone Rats, Wistar Audiogenic Rats, and Krushinsky-Molodkina, are useful tools to study epilepsy. In audiogenic susceptible animals, acute acoustic stimulation induces brainstem-dependent wild running and tonic-clonic seizures. However, during the chronic protocol of AS, the audiogenic kindling (AuK), limbic and cortical structures are recruited, and the initially brainstem-dependent seizures give rise to limbic seizures. The present study reviewed the effects of pharmacological modulation of the endocannabinoid system in audiogenic seizure susceptibility and expression. The effects of Cannabis-derived compounds in audiogenic seizures were also reviewed, with especial attention to CBD. CB1R activation, as well Cannabis-derived compounds, induced anticonvulsant effects against audiogenic seizures, but the effects of cannabinoids modulation and Cannabis-derived compounds still need to be verified in chronic audiogenic seizures. The effects of cannabinoids and Cannabis-derived compounds should be further investigated not only in audiogenic seizures, but also in epilepsy related comorbidities present in audiogenic strains, like anxiety, and depression.
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Affiliation(s)
- Willian Lazarini-Lopes
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.,Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Raquel A Do Val-da Silva
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Rui M P da Silva-Júnior
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Alexandra O S Cunha
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Norberto Garcia-Cairasco
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.,Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.,Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil
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Hitier M, Zhang YF, Sato G, Besnard S, Zheng Y, Smith PF. The effects of selective electrical stimulation of the rat cochlea on hippocampal field potentials. Hear Res 2020; 395:108023. [DOI: 10.1016/j.heares.2020.108023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/09/2020] [Accepted: 06/17/2020] [Indexed: 10/23/2022]
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Kapolowicz MR, Thompson LT. Plasticity in Limbic Regions at Early Time Points in Experimental Models of Tinnitus. Front Syst Neurosci 2020; 13:88. [PMID: 32038184 PMCID: PMC6992603 DOI: 10.3389/fnsys.2019.00088] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/23/2019] [Indexed: 01/09/2023] Open
Abstract
Tinnitus is one of the most prevalent auditory disorders worldwide, manifesting in both chronic and acute forms. The pathology of tinnitus has been mechanistically linked to induction of harmful neural plasticity stemming from traumatic noise exposure, exposure to ototoxic medications, input deprivation from age-related hearing loss, and in response to injuries or disorders damaging the conductive apparatus of the ears, the cochlear hair cells, the ganglionic cells of the VIIIth cranial nerve, or neurons of the classical auditory pathway which link the cochlear nuclei through the inferior colliculi and medial geniculate nuclei to auditory cortices. Research attempting to more specifically characterize the neural plasticity occurring in tinnitus have used a wide range of techniques, experimental paradigms, and sampled at different windows of time to reach different conclusions about why and which specific brain regions are crucial in the induction or ongoing maintenance of tinnitus-related plasticity. Despite differences in experimental methodologies, evidence reveals similar findings that strongly suggest that immediate and prolonged activation of non-classical auditory structures (i.e., amygdala, hippocampus, and cingulate cortex) may contribute to the initiation and development of tinnitus in addition to the ongoing maintenance of this devastating condition. The overarching focus of this review, therefore, is to highlight findings from the field supporting the hypothesis that abnormal early activation of non-classical sensory limbic regions are involved in tinnitus induction, with activation of these regions continuing to occur at different temporal stages. Since initial/early stages of tinnitus are difficult to control and to quantify in human clinical populations, a number of different animal paradigms have been developed and assessed in experimental investigations. Reviews of traumatic noise exposure and ototoxic doses of sodium salicylate, the most prevalently used animal models to induce experimental tinnitus, indicate early limbic system plasticity (within hours, minutes, or days after initial insult), supports subsequent plasticity in other auditory regions, and contributes to the pathophysiology of tinnitus. Understanding this early plasticity presents additional opportunities for intervention to reduce or eliminate tinnitus from the human condition.
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Affiliation(s)
- Michelle R. Kapolowicz
- Center for Hearing Research, University of California, Irvine, Irvine, CA, United States
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Lucien T. Thompson
- Department of Neurobiology, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX, United States
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Cunha AOS, de Deus JL, Ceballos CC, Leão RM. Increased hippocampal GABAergic inhibition after long-term high-intensity sound exposure. PLoS One 2019; 14:e0210451. [PMID: 31067215 PMCID: PMC6505933 DOI: 10.1371/journal.pone.0210451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/24/2019] [Indexed: 12/17/2022] Open
Abstract
Exposure to loud sounds is related to harmful mental and systemic effects. The hippocampal function can be affected to either high-intensity sound exposure or long-term sound deprivation. We previously showed that hippocampal long-term potentiation (LTP) is inhibited after ten days of daily exposure to 2 minutes of high-intensity noise (110 dB), in the hippocampi of Wistar rats. Here we investigated how the glutamatergic and GABAergic neurotransmission mediated by ionotropic receptors is affected by the same protocol of high-intensity sound exposure. We found that while the glutamatergic transmission both by AMPA/kainate and NMDA receptors in the Schaffer-CA1 synapses is unaffected by long-term exposure to high-intensity sound, the amplitude of the inhibitory GABAergic currents is potentiated, but not the frequency of both spontaneous and miniature currents. We conclude that after prolonged exposure to short periods of high-intensity sound, GABAergic transmission is potentiated in the hippocampal CA1 pyramidal neurons. This effect could be an essential factor for the reduced LTP in the hippocampi of these animals after high-intensity sound exposure. We conclude that prolonged exposure to high- intensity sound could affect hippocampal inhibitory transmission and consequently, its function.
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Affiliation(s)
| | - Junia L. de Deus
- Department of Physiology, FMRP, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Cesar C. Ceballos
- Department of Physiology, FMRP, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ricardo M. Leão
- Department of Physiology, FMRP, University of São Paulo, Ribeirão Preto, SP, Brazil
- * E-mail:
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