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Scherberich J, Stange-Marten A, Schöneich S, Merdan-Desik M, Nowotny M. Multielectrode array use in insect auditory neuroscience to unravel the spatio-temporal response pattern in the prothoracic ganglion of Mecopoda elongata. J Exp Biol 2024; 227:jeb245497. [PMID: 38197244 DOI: 10.1242/jeb.245497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 12/27/2023] [Indexed: 01/11/2024]
Abstract
Mechanoreceptors in hearing organs transduce sound-induced mechanical responses into neuronal signals, which are further processed and forwarded to the brain along a chain of neurons in the auditory pathway. Bushcrickets (katydids) have their ears in the front leg tibia, and the first synaptic integration of sound-induced neuronal signals takes place in the primary auditory neuropil of the prothoracic ganglion. By combining intracellular recordings of the receptor activity in the ear, extracellular multichannel array recordings on top of the prothoracic ganglion and hook electrode recordings at the neck connective, we mapped the timing of neuronal responses to tonal sound stimuli along the auditory pathway from the ears towards the brain. The use of the multielectrode array allows the observation of spatio-temporal patterns of neuronal responses within the prothoracic ganglion. By eliminating the sensory input from one ear, we investigated the impact of contralateral projecting interneurons in the prothoracic ganglion and added to previous research on the functional importance of contralateral inhibition for binaural processing. Furthermore, our data analysis demonstrates changes in the signal integration processes at the synaptic level indicated by a long-lasting increase in the local field potential amplitude. We hypothesize that this persistent increase of the local field potential amplitude is important for the processing of complex signals, such as the conspecific song.
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Affiliation(s)
- Jan Scherberich
- Animal Physiology Group, Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, 07743 Jena, Germany
| | - Annette Stange-Marten
- Animal Physiology Group, Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, 07743 Jena, Germany
| | - Stefan Schöneich
- Animal Physiology Group, Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, 07743 Jena, Germany
| | - Melisa Merdan-Desik
- Animal Physiology Group, Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, 07743 Jena, Germany
- Neurobiology and Biosensors Group, Institute of Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
| | - Manuela Nowotny
- Animal Physiology Group, Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, 07743 Jena, Germany
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Gokdogan O, Gokdogan C, Yalcinkaya F, Cengiz B, Bolay H. Evaluation of Auditory Temporal Discrimination Thresholds in Migraine Patients. Audiol Neurootol 2023; 28:420-426. [PMID: 37231786 DOI: 10.1159/000529593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 01/30/2023] [Indexed: 05/27/2023] Open
Abstract
INTRODUCTION Although vestibular migraine is well defined, the effects of migraine on the auditory system have not been clearly identified yet. The aim of this study was to determine the effect of migraine on the auditory system. METHODS Migraine patients without hearing loss were included in the study. Group 1 consisted of patients with migraine pain, group 2 consisted of patients with migraine in the interictal period, and group 3 consisted of healthy volunteers with similar demographic characteristics to groups 1 and 2. Random gap detection test was applied to all 3 groups. Additionally, group 2 and group 3 patients were evaluated with the auditory cortical potentials and the mismatch negativity test. RESULTS There was a statistically significant difference between the 3 groups in the random gap detection test. There was no statistically significant difference in auditory cortical potentials between group 2 and group 3; however, a statistically significant difference was found between the groups in terms of mismatch negativity test latency. CONCLUSION An auditory pathway may be affected in migraine patients, although hearing tests are normal. This interaction continues between attacks, being more evident during the pain period. Therefore, disorders of hearing or speech perception in migraine patients should be evaluated by further audiological tests.
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Affiliation(s)
- Ozan Gokdogan
- Mugla Sitki Kocman University Medicine Faculty Department of Otorhinolaryngology, Mugla, Turkey
| | - Cagil Gokdogan
- Mugla Sitki Kocman University Medicine Faculty Department of Otorhinolaryngology, Mugla, Turkey
| | - Fulya Yalcinkaya
- Atlas University Health Sciences Faculty Department of Speech and Language Therapy, Istanbul, Turkey
| | - Bulent Cengiz
- Gazi University Medicine Faculty Department of Neurology, Ankara, Turkey
| | - Hayrunnisa Bolay
- Gazi University Medicine Faculty Department of Neurology, Ankara, Turkey
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Varshney S, Angral S, Aggarwal P, Sharma S, Kumar N, Sasanka KSBS, Aanand P. Effect of Electromagnetic Radiation from Mobile Phones on Auditory Brainstem Response. Indian J Otolaryngol Head Neck Surg 2023; 75:380-392. [PMID: 37206726 PMCID: PMC10188679 DOI: 10.1007/s12070-022-03384-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/08/2022] [Indexed: 01/30/2023] Open
Abstract
Mobile phones are being used by around 70% of the global population. A simple non-invasive procedure to detect early impairment of the acoustic nerve and auditory pathway is by auditory brainstem response (ABR). It's a response to the sound stimulus generated from the brainstem in the form of electrical impulses. To determine the effect of long-term usage of mobile phones on auditory brainstem responses (ABRs). This Epidemiological, cross-sectional study was undertaken at a tertiary care hospital and includes 865 individuals aged between 18 to 45 years using mobile phone for > 2 years. Users were categorized into various groups according to the minutes of mobile usage per day, years of mobile usage and total duration of mobile phone use in dominant (mobile using) and non-Dominant (non-mobile using) ears. The changes in ABR were studied in each ear to ascertain the effect of EMF exposure due to chronic mobile phone use. Mean age of subjects was 27.01 years. (M: F = 1.57:1.0). Range of mobile phone usage was from 4 to 900 min/day, with mean as 85.94 min/day. No significant differences were seen between dominant and non-dominant ears in regard to amplitudes of wave I, III and V, latencies of wave I and V and Inter peak latency (IPL) of wave I-III, III-V and I-V. No statistically significant difference for I-III, III-V and I-V IPL were found b/w two groups/ears except for usage of mobile phone for > 180 min/day in wave I-V, usage for 0-4 years in wave I-III and I-V and net hours usage for > 1500 h in wave I-V. The mean IPL in all the waves increases with the increase in years of mobile usage and is maximum in all waves in > 12 years mobile users. The long-term exposure to EMF does induce measurable changes in ABRs. Amplitude and IPLs of ABR were found comparable between the dominant and non-dominant ears using mobile phones, except for those using mobile usage for > 180 min/day and with increasing years of usage of mobile phone. Therefore, prudent use of mobile phone should be encouraged for a shorter period of time and for essential purpose only.
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Affiliation(s)
- Saurabh Varshney
- Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Deoghar, Jharkhand 814142 India
- Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Rishikesh, Uttarakhand 249203 India
| | - Sumeet Angral
- Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Deoghar, Jharkhand 814142 India
| | - Pradeep Aggarwal
- Department of Community and Family Medicine, All India Institute of Medical Sciences, Rishikesh, Uttarakhand 249203 India
| | - Suresh Sharma
- College of Nursing, All India Institute of Medical Sciences, Jodhpur, 342001 India
| | - Narendra Kumar
- All India Institute of Medical Sciences, Rishikesh, Rishikesh, Uttarakhand 249203 India
| | - K. S. B. S. Sasanka
- Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Deoghar, Jharkhand 814142 India
| | - Prem Aanand
- Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Deoghar, Jharkhand 814142 India
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Dubey K. Tinnitus: Summary of Current Understanding of the Pathophysiology Mechanisms in different Ear Diseases. Int Tinnitus J 2022; 26:63-67. [PMID: 35861460 DOI: 10.5935/0946-5448.20220009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
INTRODUCTION Tinnitus is well known since ancient time with wide prevalence in our community everywhere. Despite advancement in technology, we are far from knowing confirmed Pathomechanism and one treatment of choice for tinnitus. Present review article is an attempt to investigate various pathophysiology mechanisms available, in literature to explain the generation of tinnitus with respect to known diagnoses in which tinnitus is a significant complaint. METHOD Author performed detailed online data search for publications on PubMed, Medline, Google Search, Scopus between 1990-2020. Author's focus during search was, on the tinnitus and pathophysiology behind the diagnoses involving external ear, middle ear, and inner ear as site of pathology. RESULT Few studies are available explaining likely pathophysiology and mechanism of tinnitus development in diseases involving different subsites of ear. CONCLUSION We still do not know with surety the likely cause behind the generation of tinnitus in various diseases except for objective which are treatable. While rest of subjective type there is no curative treatment available.
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Affiliation(s)
- Kamlesh Dubey
- Assistant Professor, Manipal University College Malaysia (MUCM), Melaka, Malaysia
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Zhu HY, Chen L, Hou XY, Tang ZQ, Sun JQ, Sun JW, Guo XT. Electrically evoked auditory brainstem responses in deaf patients with Mondini malformation during cochlear implantation. Eur Arch Otorhinolaryngol 2022; 279:4847-4852. [PMID: 35247096 DOI: 10.1007/s00405-022-07307-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/08/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the auditory pathway functions in deaf patients with Mondini malformation using the electrically evoked auditory brainstem response (EABR) during cochlear implantation (CI). METHODS A total of 58 patients with severe to profound sensorineural hearing loss (SNHL) were included in this study. Of these patients, 27 cases had Mondini malformation and 31 control cases had no inner ear malformations (IEMs). Intraoperative EABRs evoked by electrical stimulation at the round window niche (RWN) and round window membrane (RWM) were recorded. RESULTS Patients with Mondini malformation showed significantly lower EABR extraction rates than those with no IEMs did. However, for patients who showed EABRs, no significant difference in EABR thresholds, wave III (eIII) latencies, wave V (eV) latencies or eIII-eV latency intervals was found between two groups. CONCLUSION The physiological functions of the peripheral auditory system in patients with Mondini malformation may divide into opposite extremes, as revealed by a robust EABR and the absence of the EABR, respectively. The auditory conduction function should be objectively and individually evaluated for patients with Mondini malformation by the EABR.
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Affiliation(s)
- Han-Yu Zhu
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Li Chen
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Xiao-Yan Hou
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Zheng-Quan Tang
- School of Life Sciences, Anhui University, Hefei, 230601, Anhui, China.,Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei, 230601, Anhui, China
| | - Jia-Qiang Sun
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China.
| | - Jing-Wu Sun
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China.
| | - Xiao-Tao Guo
- Department of Otolaryngology-Head and Neck Surgery, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230001, Anhui, China. .,CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China.
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Dzulkarnain AAA, Salamat S, Shahrudin FA, Jamal FN, Zakaria MN. Influence of Stimulus Polarity on the Auditory Brainstem Response From Level-Specific Chirp. J Audiol Otol 2021; 25:199-208. [PMID: 34425654 PMCID: PMC8524115 DOI: 10.7874/jao.2021.00248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/14/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND OBJECTIVES No known studies have investigated the influence of stimulus polarity on the Auditory Brainstem Response (ABR) elicited from level-specific (LS) chirp. This study is important as it provides a better understanding of the stimulus polarity selection for ABR elicited from LS chirp stimulus. We explored the influence of stimulus polarity on the ABR from LS chirp compared to the ABR from click at 80 dBnHL in normal-hearing adults. SUBJECTS AND PURPOSE Nineteen adults with normal hearing participated. The ABRs were acquired using click and LS chirp stimuli using three stimulus polarities (rarefaction, condensation, and alternating) at 80 dBnHL. The ABRs were tested only on the right ear at a stimulus rate of 33.33 Hz. The ABR test was stopped when the recording reached the residual noise level of 0.04 µV. The ABRs amplitudes, absolute latencies, inter-peak latencies (IPLs), and the recorded number of averages were statistically compared among ABRs at different stimulus polarities and stimuli combinations. RESULTS Rarefaction polarity had the largest ABR amplitudes and SNRs compared with other stimulus polarities in both stimuli. There were marginal differences in the absolute latencies and IPLs among stimulus polarities. No significant difference in the number of averages required to reach the stopping criteria was found. CONCLUSIONS Stimulus polarities have a significant influence on the ABR to LS chirp. Rarefaction polarity is recommended for clinical use because of its larger ABR peak I, III, and V amplitudes than those of the other stimulus polarities.
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Affiliation(s)
- Ahmad Aidil Arafat Dzulkarnain
- Department of Audiology and Speech-Language Pathology, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Kuantan, Malaysia
- Address for correspondence Ahmad Aidil Arafat Dzulkarnain, PhD Department of Audiology and Speech-Language Pathology, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, 25200 Kuantan, Pahang, Malaysia Tel +609-570-5402 Fax +609-571-6776 E-mail
| | - Sabrina Salamat
- Department of Audiology and Speech-Language Pathology, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Kuantan, Malaysia
| | - Fatin Amira Shahrudin
- Department of Audiology and Speech-Language Pathology, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Kuantan, Malaysia
| | - Fatin Nabilah Jamal
- Department of Audiology and Speech-Language Pathology, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Kuantan, Malaysia
| | - Mohd Normani Zakaria
- Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kubarg Kerian, Malaysia
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Chen L, Zhang JG, Sun JW, Guo XT, Sun JQ. Electrically evoked auditory brainstem responses to electrical stimulation at round window membrane in congenitally deaf children at different ages. Int J Pediatr Otorhinolaryngol 2021; 148:110821. [PMID: 34225082 DOI: 10.1016/j.ijporl.2021.110821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To investigate the usefulness of measuring the electrically evoked auditory brainstem responses (eABRs) to electrical stimulation at the round window niche (RWN) and round window membrane (RWM) and the effect of deafness duration on functions of the auditory pathway to the level of the brainstem. METHODS According to the age at cochlear implantation (CI), 99 children with profound sensorineural hearing loss were divided into four groups: ≤12 months (group A), 13-36 months (group B), 37-60 months (group C) and >60 months (group D). The eABRs were evoked by electrical stimulation at RWN and RWM during the operation of CI. RESULTS The higher eABR extraction rate and lower threshold for RWM stimulation was found than those for RWN stimulation. The eⅢ latencies and eⅢ-eⅤ latency intervals for RWM stimulation were similar among four groups. However, children with earlier CI (group A) showed a significantly shorter eⅤ latency than others. CONCLUSION The eABR evoked by the electrical stimulation at RWM is more stable and sensitive compared with that at RWN for evaluating functions of the auditory conduction pathway. Development in the upper brainstem pathway may be more vulnerable to long-term deafness as revealed by the eⅤ latency.
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Sengul Y, Bal N, Louis ED. Evidence of central involvement in essential tremor: a detailed study of auditory pathway physiology. J Neural Transm (Vienna) 2020; 127:1153-1159. [PMID: 32507996 DOI: 10.1007/s00702-020-02215-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 05/28/2020] [Indexed: 10/24/2022]
Abstract
Essential tremor (ET) is a common tremor disorder that is likely neurodegenerative. The pathophysiology of ET involves the cerebellum and its connections in the brainstem and thalamus. Hearing dysfunction has been shown to be a non-motor finding in ET patients. A limited number of studies have suggested that cochlear pathology is the cause, but studies have not evaluated the integrity of the primary auditory pathway in ET. The main aim of this study is to investigate the integrity of the auditory pathway via auditory brainstem response (ABR) and auditory middle latency response (AMLR), thereby allowing us to evaluate the auditory pathway from the 8th cranial nerve to the cerebral cortex. Sixteen ET patients and sixteen age- and gender-matched controls (64 ears) were evaluated. In the ABR study, we detected prolongation of wave V peak latencies (ms) in ET (p = 0.02). In the AMLR study, P0 (p = 0.03), Pa (p = 0.008), Na (p = 0.03), and Nb (p = 0.01) waves differed between the two groups. Eleven ET patients and four control subjects had abnormal electrophysiological findings (ABR or AMLR or both) (68.8% vs. 25%, p = 0.01). Tremor duration was greater in ET patients with abnormal electrophysiological findings (p = 0.01). Finally, we observed prolongation of latencies after the ABR III wave, indicating that abnormalities exist within the superior olivary complex. For the first time, our research provides evidence that ET-related pathology is present at the subcortical and cortical levels of the auditory pathway.
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Affiliation(s)
- Yildizhan Sengul
- Department of Neurology, Faculty of Medicine, Bezmialem Foundation University, Fatih, Istanbul, Turkey. .,Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Nilufer Bal
- Department of Audiology, Faculty of Medical Sciences, Bezmialem Foundation University, Fatih, Istanbul, Turkey
| | - Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.,Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
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Berlot E, Arts R, Smit J, George E, Gulban OF, Moerel M, Stokroos R, Formisano E, De Martino F. A 7 Tesla fMRI investigation of human tinnitus percept in cortical and subcortical auditory areas. Neuroimage Clin 2020; 25:102166. [PMID: 31958686 PMCID: PMC6970183 DOI: 10.1016/j.nicl.2020.102166] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/12/2019] [Accepted: 01/09/2020] [Indexed: 01/13/2023]
Abstract
Tinnitus is a clinical condition defined by hearing a sound in the absence of an objective source. Early experiments in animal models have suggested that tinnitus stems from an alteration of processing in the auditory system. However, translating these results to humans has proven challenging. One limiting factor has been the insufficient spatial resolution of non-invasive measurement techniques to investigate responses in subcortical auditory nuclei, like the inferior colliculus and the medial geniculate body (MGB). Here we employed ultra-high field functional magnetic resonance imaging (UHF-fMRI) at 7 Tesla to investigate the frequency-specific processing in sub-cortical and cortical regions in a cohort of six tinnitus patients and six hearing loss matched controls. We used task-based fMRI to perform tonotopic mapping and compared the magnitude and tuning of frequency-specific responses between the two groups. Additionally, we used resting-state fMRI to investigate the functional connectivity. Our results indicate frequency-unspecific reductions in the selectivity of frequency tuning that start at the level of the MGB and continue in the auditory cortex, as well as reduced thalamocortical and cortico-cortical connectivity with tinnitus. These findings suggest that tinnitus may be associated with reduced inhibition in the auditory pathway, potentially leading to increased neural noise and reduced functional connectivity. Moreover, these results indicate the relevance of high spatial resolution UHF-fMRI for the investigation of the role of sub-cortical auditory regions in tinnitus.
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Affiliation(s)
- Eva Berlot
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, the Netherlands; The Brain and Mind Institute, University of Western Ontario, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Remo Arts
- Cochlear Benelux NV, Mechelen Campus - Industrie Noord, Schaliënhoevedreef 20, Building I, Mechelen B-2800, Belgium
| | - Jasper Smit
- Department of Ear Nose and Throat/Head and Neck Surgery, Maastricht University Medical Center, Maastricht, the Netherlands; Department of Ear Nose and Throat/Head and Neck Surgery, Zuyderland Medical Center, Sittard/Heerlen, the Netherlands
| | - Erwin George
- Department of Ear Nose and Throat /Audiology, School for Mental Health and Neuroscience (MHENS), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Omer Faruk Gulban
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Michelle Moerel
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, the Netherlands; Maastricht Centre for Systems Biology, Maastricht University, Maastricht, the Netherlands
| | - Robert Stokroos
- UMC Utrecht, department of Otolaryngology- Head and Neck Surgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Elia Formisano
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, the Netherlands; Maastricht Centre for Systems Biology, Maastricht University, Maastricht, the Netherlands
| | - Federico De Martino
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, the Netherlands; Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States.
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Cakir Z, Yildirim C, Buran I, Önalan EE, Bal R. Acid-sensing ion channels (ASICs) influence excitability of stellate neurons in the mouse cochlear nucleus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:769-781. [PMID: 31451914 DOI: 10.1007/s00359-019-01365-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 08/08/2019] [Accepted: 08/13/2019] [Indexed: 02/06/2023]
Abstract
Acid-sensing ion channels (ASICs) are voltage-independent and proton-gated channels. In this study, we aimed to test the hypothesis whether ASICs might be involved in modifying the excitability of stellate cells in the cochlear nucleus (CN). We determined gene expressions of ASIC1, ASIC2 and ASIC3 in the CN of BALB/mice. ASIC currents in stellate cells were characterized by using whole-cell patch-clamp technique. In the voltage-clamp experiments, inward currents were recorded upon application of 2-[N-Morpholino ethanesulfonic acid]-normal artificial cerebrospinal fluid (MES-aCSF), whose pH 50 was 5.84. Amiloride inhibited the acid-induced currents in a dose-dependent manner. Inhibition of the ASIC currents by extracellular Ca2+ and Pb2+ (10 μM) was significant evidence for the existence of homomeric ASIC1a subunits. ASIC currents were increased by 20% upon extracellular application of Zn2+ (300 μM) (p < 0.05, n = 13). In current-clamp experiments, application of MES-aCSF resulted in the depolarization of stellate cells. The results show that the ASIC currents in stellate cells of the cochlear nucleus are carried largely by the ASIC1a and ASIC2a channels. ASIC channels affect the excitability of the stellate cells and therefore they appear to have a role in the processing of auditory information.
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Affiliation(s)
- Ziya Cakir
- Department of Physiology, Faculty of Medicine, Tokat Gaziosmanpasa University, 60250, Tokat, Turkey
| | - Caner Yildirim
- Department of Physiology, Faculty of Medicine, Kafkas University, 36100, Kars, Turkey
| | - Ilay Buran
- Department of Medical Biology, Faculty of Medicine, Firat University, 23100, Elazig, Turkey
| | - Ebru Etem Önalan
- Department of Medical Biology, Faculty of Medicine, Firat University, 23100, Elazig, Turkey
| | - Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey.
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McCormick CA. Immunocytochemical Evidence for Electrical Synapses in the Dorsal Descending and Dorsal Anterior Octaval Nuclei in the Goldfish, Carassius auratus. Brain Behav Evol 2019; 93:34-50. [PMID: 31189161 DOI: 10.1159/000499687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/13/2019] [Indexed: 11/19/2022]
Abstract
The dorsal portion of the descending octaval nucleus (dDO), the main first-order auditory nucleus in jawed fish, includes four lateral and three medial neuronal populations that project to the auditory midbrain. One medial population and one lateral population contain neurons that receive a remarkably large axon terminal from the utricular branch of the octaval nerve. Immunocytochemistry for connexin 35 (Cx35) was used to determine whether this connection includes electrical synapses. Although Cx35 was not localized to these large contacts, it was observed in the three other lateral dDO populations. Another first-order nucleus, the dorsal portion of the anterior octaval nucleus (dAO), primitively projects to the auditory midbrain in jawed fishes and contains neurons positive for Cx35. Utricular branch terminals were coincident with some Cx35 puncta in dDO and dAO. The results are discussed in light of what is known about the occurrence of electrical synapses in first-order auditory and vestibular nuclei in fish and tetrapods.
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Affiliation(s)
- Catherine A McCormick
- Department of Biology and Department of Neuroscience, Oberlin College, Oberlin, Ohio, USA,
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Kusaba M, Takagi T, Tomogane Y, Iida T, Sakamoto D, Ishikura R, Yoshimura S. Relationship between auditory pathway fractional anisotropy and audibility in patients with cerebellopontine angle tumors on diffusion tensor imaging. Clin Neurol Neurosurg 2019; 179:42-46. [PMID: 30822748 DOI: 10.1016/j.clineuro.2019.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/17/2018] [Accepted: 02/17/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Recent reports demonstrated that acoustic nerve disorders affect the auditory pathway on diffusion tensor imaging (DTI). The aim was to investigate whether auditory pathway fractional anisotropy (FA) values are associated with audibility in patients with cerebellopontine angle tumors. PATIENTS AND METHODS Patients with cerebellopontine angle tumors were included in this retrospective study. Preoperatively, all patients underwent magnetic resonance imaging (MRI) including DTI. Two regions of interest on the lateral lemniscus (LL) and inferior colliculus (IC) were set bilaterally on DTI. FA values were calculated using software. Correlations between FA values and audibility were evaluated using Spearman's rank correlation coefficient. Statistical significance was defined as p < 0.05. RESULTS Seventeen patients with cerebellopontine angle tumors were included in this study. FA values in the bilateral LL showed a significant negative correlation with hearing impairment severity (r = -0.758, -0.600, p < 0.05). FA values on the ipsilateral side of the IC showed a significant negative correlation with hearing impairment severity (r = -0.477, p < 0.05). FA values on the contralateral side of the IC did not correlate with hearing impairment severity (r = -0.201, p > 0.05). One patient with a low FA value on the contralateral side of the IC had postoperative hearing impairment despite good preoperative hearing ability. CONCLUSIONS FA values in the bilateral LL and on the ipsilateral side of the IC reflected hearing impairment severity. Decreased FA values on the contralateral side of the IC might predict hearing impairment postoperatively.
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Affiliation(s)
- Masahiko Kusaba
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Toshinori Takagi
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Yusuke Tomogane
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Tomoko Iida
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Daisuke Sakamoto
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Reiichi Ishikura
- Department of Radiology, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan
| | - Shinichi Yoshimura
- Department of Neurosurgery, Hyogo College of Medicine, 1-1 Mukogawa, Nishinomiya, Hyogo, 663-8501, Japan.
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Abstract
The auditory midbrain is the critical integration center in the auditory pathway of vertebrates. Synaptic inhibition plays a key role during information processing in the auditory midbrain, and these inhibitory neural circuits are seen in all vertebrates and are likely essential for hearing. Here, we review the structure and function of the inhibitory neural circuits of the auditory midbrain. First, we provide an overview on how these inhibitory circuits are organized within different clades of vertebrates. Next, we focus on recent findings in the mammalian auditory midbrain, the most studied of the vertebrates, and discuss how the mammalian auditory midbrain is functionally coordinated.
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Affiliation(s)
- Munenori Ono
- Department of Physiology, School of Medicine, Kanazawa Medical University, Uchinada, Japan
| | - Tetsufumi Ito
- Department of Anatomy, School of Medicine, Kanazawa Medical University, Uchinada, Japan
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James AL, Dixon PR, Harrison RV. Cochlear Nerve Aplasia with Detectable Olivocochlear Efferent Function: A Distinct Presentation of Auditory Neuropathy Spectrum Disorder. Audiol Neurootol 2018; 23:39-47. [PMID: 29936500 DOI: 10.1159/000487584] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/09/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cochlear nerve aplasia (CNA) may present with features of auditory neuropathy spectrum disorder (ANSD), having detectable otoacoustic emissions (OAE) but profound hearing loss. We propose that some children with CNA have a distinct form of afferent ANSD in which efferent cochlear nerve function can be detected using contralateral suppression of OAE. METHODS Children were prospectively enrolled with MRI and auditory brainstem response evidence of unilateral CNA, a normal contralateral ear, and detectable OAE bilaterally. Distortion product OAE (DPOAE) levels were recorded in real time with default primary tone settings: frequency (f)2 = 4.5 kHz and f2/f1 = 1.22 kHz, with level (L)1 = 65 dB SPL and L2 = 55 dB SPL. Recordings were made over 2 min with simultaneous application of an intermittent contralateral broadband noise (CBBN) stimulus at 60 dB SPL. RESULTS Three girls, aged 4.5, 7, and 8 years, participated. Suppression of DPOAE of 0.15-1.3 dB was detected in all 3 ears with CNA in response to CBBN stimulation. No response was detected in the normal ears. CONCLUSIONS Children with unilateral ANSD can have normal efferent cochlear nerve function despite MRI evidence of ipsilateral CNA. The importance of these findings for newborn hearing screening and cochlear implantation is discussed.
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Affiliation(s)
- Adrian L James
- Department of Otolaryngology-HNS, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Peter R Dixon
- Department of Otolaryngology-HNS, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Robert V Harrison
- Department of Otolaryngology-HNS, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada.,Program in Neuroscience and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
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15
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Toth PG, Marsalek P, Pokora O. Ergodicity and parameter estimates in auditory neural circuits. Biol Cybern 2018; 112:41-55. [PMID: 29082437 PMCID: PMC5908860 DOI: 10.1007/s00422-017-0739-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 10/12/2017] [Indexed: 06/07/2023]
Abstract
This paper discusses ergodic properties and circular statistical characteristics in neuronal spike trains. Ergodicity means that the average taken over a long time period and over smaller population should equal the average in less time and larger population. The objectives are to show simple examples of design and validation of a neuronal model, where the ergodicity assumption helps find correspondence between variables and parameters. The methods used are analytical and numerical computations, numerical models of phenomenological spiking neurons and neuronal circuits. Results obtained using these methods are the following. They are: a formula to calculate vector strength of neural spike timing dependent on the spike train parameters, description of parameters of spike train variability and model of output spiking density based on assumption of the computation realized by sound localization neural circuit. Theoretical results are illustrated by references to experimental data. Examples of neurons where spike trains have and do not have the ergodic property are then discussed.
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Affiliation(s)
- Peter G. Toth
- Institute of Pathological Physiology, First Medical Faculty, Charles University, U Nemocnice 5, 12853 Prague 2, Czech Republic
| | - Petr Marsalek
- Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden, Germany
- Czech Technical University in Prague, Zikova 1903/4, 16636 Prague 6, Czech Republic
| | - Ondrej Pokora
- Department of Mathematics and Statistics, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
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Li Q, Liu G, Wei D, Guo J, Yuan G, Wu S. The spatiotemporal pattern of pure tone processing: A single-trial EEG-fMRI study. Neuroimage 2017; 187:184-191. [PMID: 29191479 DOI: 10.1016/j.neuroimage.2017.11.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 11/23/2017] [Accepted: 11/26/2017] [Indexed: 12/12/2022] Open
Abstract
Although considerable research has been published on pure tone processing, its spatiotemporal pattern is not well understood. Specifically, the link between neural activity in the auditory pathway measured by functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) markers of pure tone processing in the P1, N1, P2, and N4 components is not well established. In this study, we used single-trial EEG-fMRI as a multi-modal fusion approach to integrate concurrently acquired EEG and fMRI data, in order to understand the spatial and temporal aspects of the pure tone processing pathway. Data were recorded from 33 subjects who were presented with stochastically alternating pure tone sequences with two different frequencies: 200 and 6400 Hz. Brain network correlated with trial-to-trial variability of the task-discriminating EEG amplitude was identified. We found that neural responses responding to pure tone perception are spatially along the auditory pathway and temporally divided into three stages: (1) the early stage (P1), wherein activation occurs in the midbrain, which constitutes a part of the low level auditory pathway; (2) the middle stage (N1, P2), wherein correlates were found in areas associated with the posterodorsal auditory pathway, including the primary auditory cortex and the motor cortex; (3) the late stage (N4), wherein correlation was found in the motor cortex. This indicates that trial-by-trial variation in neural activity in the P1, N1, P2, and N4 components reflects the sequential engagement of low- and high-level parts of the auditory pathway for pure tone processing. Our results demonstrate that during simple pure tone listening tasks, regions associated with the auditory pathway transiently correlate with trial-to-trial variability of the EEG amplitude, and they do so on a millisecond timescale with a distinct temporal ordering.
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Affiliation(s)
- Qiang Li
- College of Electronic and Information Engineering, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China
| | - Guangyuan Liu
- College of Electronic and Information Engineering, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China.
| | - Dongtao Wei
- Department of Psychology, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China
| | - Jing Guo
- College of Electronic and Information Engineering, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China
| | - Guangjie Yuan
- College of Electronic and Information Engineering, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China
| | - Shifu Wu
- College of Electronic and Information Engineering, Southwest University, No. 2, TianSheng Street, Beibei, Chongqing 400715, China
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Stuermer KJ, Foerst A, Sandmann P, Fuerstenberg D, Lang-Roth R, Walger M. Maturation of auditory brainstem responses in young children with congenital monaural atresia. Int J Pediatr Otorhinolaryngol 2017; 95:39-44. [PMID: 28576530 DOI: 10.1016/j.ijporl.2017.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/22/2017] [Accepted: 01/26/2017] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To date, the impact of conductive hearing loss on the auditory pathway at brainstem level has only been investigated in animal studies, which showed a species-specific delay of maturation. In this study, the functional maturation of auditory brainstem response (ABR) parameters in humans with unilateral atresia of the external auditory canal was investigated. METHODS 42 newborns and toddlers ranging in age from 13 days to 11 months were included. The click-evoked ABR interpeak latencies (IPL) of the atretic ears and the contralateral ears with normal hearing were evaluated. The children had no comorbidities and had never been fitted with any kind of hearing aid. The absolute latencies (AL) and IPL of a matched control group were compared to the contralateral normally hearing ears of the children with unilateral atresia. RESULTS The mean air-bone gap in the ears with atresia was 44 dB HL. Despite this partial acoustic deprivation, no significant difference between the IPLs of normal ears and ears with atresia could be detected. Both for AL and IPL, the differences between the normal ears and the control group were all within 1 standard deviation to the mean. CONCLUSION The data showed that the monaural acoustic deprivation by a block of sound conduction does not produce any delay of functional maturation at brainstem level in this group of patients. With regard to the AL and IPL on brainstem level, no differences between the normal ears of children with unilateral atresia and children with bilateral normal hearing could be detected.
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18
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Kurtcan S, Hatiboglu MA, Alkan A, Toprak H, Seyithanoglu MH, Aralasmak A, Atasoy B, Uysal O. Evaluation of Auditory Pathways Using DTI in Patients Treated with Gamma Knife Radiosurgery for Acoustic Neuroma: A Preliminary Report. Clin Neuroradiol 2017; 28:377-383. [PMID: 28258282 DOI: 10.1007/s00062-017-0572-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 02/21/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE We aimed to evaluate the change in bilateral auditory pathways using diffusion tensor imaging (DTI) after gamma knife radiosurgery (GKR) and to determine the relationship between the radiosurgical treatment variables and DTI findings. METHODS In this study 13 patients with unilateral acoustic neuroma and 11 controls underwent routine magnetic resonance imaging (MRI) and DTI. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured from the bilateral auditory pathways in all individuals before and after GKR. RESULTS Before GKR, subjects' ADC values obtained from the contralateral side were higher at the lateral lemniscus, medial geniculate body and Heschl's gyrus compared to those of the controls. No statistical differences were found in ADC and FA obtained at bilateral auditory pathways before and after GKR. The ADCs measured at the lateral lemniscus were positively correlated with the maximum radiation dose delivered to the brainstem (BS) and the brainstem volume receiving a radiation dose of 10 Gy (BS V10). A negative correlation was found between the FA measured from the inferior colliculus and the maximum radiation dose to the cochlea. The ADCs at the inferior colliculus were positively correlated with the mean radiation dose to the cochlea. CONCLUSION There were no significant differences in the degree of involvement before and after GKR, revealing that GKR did not significantly affect the auditory pathways at 4 months. The major factors that may lead to microstructural injury to auditory pathways at the brainstem level are associated with maximum brainstem radiation dose, BS V10, and cochlear dose. These findings may suggest that more attention should be paid to anatomical structures including the cochlea and brainstem during treatment planning of GKR.
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Affiliation(s)
- Serpil Kurtcan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey.
| | - Mustafa Aziz Hatiboglu
- Department of Neurosurgery, Faculty of Medicine, BezmialemVakif University, Istanbul, Turkey
| | - Alpay Alkan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - Huseyin Toprak
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | | | - Ayse Aralasmak
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - Bahar Atasoy
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - Omer Uysal
- Department of Biostatistics, Faculty of Medicine, BezmialemVakif University, Istanbul, Turkey
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Hasegawa H, Hatano M, Sugimoto H, Ito M, Kawasaki H, Yoshizaki T. The effects of unilateral cochlear ablation on the expression of vesicular glutamate transporter 1 in the lower auditory pathway of neonatal rats. Auris Nasus Larynx 2017; 44:690-699. [PMID: 28238468 DOI: 10.1016/j.anl.2017.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/27/2016] [Accepted: 01/26/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Unilateral cochlear damage has profound effects on the central auditory pathways in the brain. METHODS We examined the effects of unilateral cochlear ablation on VGLUT1 expression in the cochlear nucleus (CN) and the superior olivary complex (SOC) in neonatal rats. RESULTS VGLUT1 expression in the CN subdivisions (the AVCN, the PVCN and the DCN-deep layers) and the SOC (the MnTB, the LSO and the MSO) ipsilateral to the ablated side was significantly suppressed by unilateral cochlear ablation. Interestingly, VGLUT1 expression in the PVCN and the DCN-deep layers contralateral to the ablated side was also reduced. CONCLUSION Our findings indicate that unilateral cochlear ablation affects VGLUT1 expression in the central auditory pathways not only ipsilateral but also contralateral to the ablated side.
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Affiliation(s)
- Hiroki Hasegawa
- Department of Medical Neuroscience, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan; Brain/Liver Interface Medicine Research Center, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan; Department of Otolaryngology-Head and Neck Surgery, Kanazawa University, Graduate School of Medical Science, Kanazawa, Ishikawa 920-8640, Japan
| | - Miyako Hatano
- Department of Otolaryngology-Head and Neck Surgery, Kanazawa University, Graduate School of Medical Science, Kanazawa, Ishikawa 920-8640, Japan
| | - Hisashi Sugimoto
- Department of Otolaryngology-Head and Neck Surgery, Kanazawa University, Graduate School of Medical Science, Kanazawa, Ishikawa 920-8640, Japan
| | - Makoto Ito
- Pediatric Otolaryngology, Jichi Children's Medical Center Tochigi, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
| | - Hiroshi Kawasaki
- Department of Medical Neuroscience, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan; Brain/Liver Interface Medicine Research Center, Kanazawa University, Kanazawa, Ishikawa 920-8640, Japan.
| | - Tomokazu Yoshizaki
- Department of Otolaryngology-Head and Neck Surgery, Kanazawa University, Graduate School of Medical Science, Kanazawa, Ishikawa 920-8640, Japan.
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Behler O, Uppenkamp S. The representation of level and loudness in the central auditory system for unilateral stimulation. Neuroimage 2016; 139:176-188. [PMID: 27318216 DOI: 10.1016/j.neuroimage.2016.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 05/24/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022] Open
Abstract
Loudness is the perceptual correlate of the physical intensity of a sound. However, loudness judgments depend on a variety of other variables and can vary considerably between individual listeners. While functional magnetic resonance imaging (fMRI) has been extensively used to characterize the neural representation of physical sound intensity in the human auditory system, only few studies have also investigated brain activity in relation to individual loudness. The physiological correlate of loudness perception is not yet fully understood. The present study systematically explored the interrelation of sound pressure level, ear of entry, individual loudness judgments, and fMRI activation along different stages of the central auditory system and across hemispheres for a group of normal hearing listeners. 4-kHz-bandpass filtered noise stimuli were presented monaurally to each ear at levels from 37 to 97dB SPL. One diotic condition and a silence condition were included as control conditions. The participants completed a categorical loudness scaling procedure with similar stimuli before auditory fMRI was performed. The relationship between brain activity, as inferred from blood oxygenation level dependent (BOLD) contrasts, and both sound level and loudness estimates were analyzed by means of functional activation maps and linear mixed effects models for various anatomically defined regions of interest in the ascending auditory pathway and in the cortex. Our findings are overall in line with the notion that fMRI activation in several regions within auditory cortex as well as in certain stages of the ascending auditory pathway might be more a direct linear reflection of perceived loudness rather than of sound pressure level. The results indicate distinct functional differences between midbrain and cortical areas as well as between specific regions within auditory cortex, suggesting a systematic hierarchy in terms of lateralization and the representation of level and loudness.1.
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Affiliation(s)
- Oliver Behler
- Medizinische Physik, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany.
| | - Stefan Uppenkamp
- Medizinische Physik, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany; Cluster of Excellence Hearing4All, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany.
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Gransier R, Deprez H, Hofmann M, Moonen M, van Wieringen A, Wouters J. Auditory steady-state responses in cochlear implant users: Effect of modulation frequency and stimulation artifacts. Hear Res 2016; 335:149-160. [PMID: 26994660 DOI: 10.1016/j.heares.2016.03.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/04/2016] [Accepted: 03/14/2016] [Indexed: 11/29/2022]
Abstract
Previous studies have shown that objective measures based on stimulation with low-rate pulse trains fail to predict the threshold levels of cochlear implant (CI) users for high-rate pulse trains, as used in clinical devices. Electrically evoked auditory steady-state responses (EASSRs) can be elicited by modulated high-rate pulse trains, and can potentially be used to objectively determine threshold levels of CI users. The responsiveness of the auditory pathway of profoundly hearing-impaired CI users to modulation frequencies is, however, not known. In the present study we investigated the responsiveness of the auditory pathway of CI users to a monopolar 500 pulses per second (pps) pulse train modulated between 1 and 100 Hz. EASSRs to forty-three modulation frequencies, elicited at the subject's maximum comfort level, were recorded by means of electroencephalography. Stimulation artifacts were removed by a linear interpolation between a pre- and post-stimulus sample (i.e., blanking). The phase delay across modulation frequencies was used to differentiate between the neural response and a possible residual stimulation artifact after blanking. Stimulation artifacts were longer than the inter-pulse interval of the 500pps pulse train for recording electrodes ipsilateral to the CI. As a result the stimulation artifacts could not be removed by artifact removal on the bases of linear interpolation for recording electrodes ipsilateral to the CI. However, artifact-free responses could be obtained in all subjects from recording electrodes contralateral to the CI, when subject specific reference electrodes (Cz or Fpz) were used. EASSRs to modulation frequencies within the 30-50 Hz range resulted in significant responses in all subjects. Only a small number of significant responses could be obtained, during a measurement period of 5 min, that originate from the brain stem (i.e., modulation frequencies in the 80-100 Hz range). This reduced synchronized activity of brain stem responses in long-term severely-hearing impaired CI users could be an attribute of processes associated with long-term hearing impairment and/or electrical stimulation.
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Affiliation(s)
- Robin Gransier
- ExpORL, Dept. of Neurosciences, KU Leuven, Herestraat 49 bus 721, 3000 Leuven, Belgium.
| | - Hanne Deprez
- ExpORL, Dept. of Neurosciences, KU Leuven, Herestraat 49 bus 721, 3000 Leuven, Belgium; STADIUS, Dept. of Electrical Engineering (ESAT), KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Michael Hofmann
- ExpORL, Dept. of Neurosciences, KU Leuven, Herestraat 49 bus 721, 3000 Leuven, Belgium
| | - Marc Moonen
- STADIUS, Dept. of Electrical Engineering (ESAT), KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Astrid van Wieringen
- ExpORL, Dept. of Neurosciences, KU Leuven, Herestraat 49 bus 721, 3000 Leuven, Belgium
| | - Jan Wouters
- ExpORL, Dept. of Neurosciences, KU Leuven, Herestraat 49 bus 721, 3000 Leuven, Belgium
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Toth PG, Marsalek P. Analytical description of coincidence detection synaptic mechanisms in the auditory pathway. Biosystems 2015; 136:90-8. [PMID: 26190796 DOI: 10.1016/j.biosystems.2015.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/16/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
Abstract
Localization of sound source azimuth within horizontal plane uses interaural time differences (ITDs) between sounds arriving through the left and right ear. In mammals, ITDs are processed primarily in the medial superior olive (MSO) neurons. These are the first binaural neurons in the auditory pathway. The MSO neurons are notable because they possess high time precision in the range of tens of microseconds. Several theories and experimental studies explain how neurons are able to achieve such precision. In most theories, neuronal coincidence detection processes the ITDs and encodes azimuth in ascending neurons of the auditory pathway using modalities that are more tractable than the ITD. These modalities have been described as firing rate codes, place codes (labeled line codes) and similarly. In this theoretical model it is described how the ITD is processed by coincidence detection and converted into spikes by summing the postsynaptic potentials. Particular postsynaptic conductance functions are used in order to obtain an analytical solution in a closed form. Specifically, postsynaptic response functions are derived from the exponential decay of postsynaptic conductances and the MSO neuron is modeled as a simplified version of the Spike Response Model (SRM0) which uses linear summations of the membrane responses to synaptic inputs. For plausible ratios of time constants, an analytical solution used to describe properties of coincidence detection window is obtained. The parameter space is then explored in the vicinity of the analytical solution. The variation of parameters does not change the solution qualitatively.
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Affiliation(s)
- Peter G Toth
- Charles University in Prague, First Medical Faculty, Institute of Pathological Physiology, U Nemocnice 5, 128 53 Prague, Czech Republic
| | - Petr Marsalek
- Czech Technical University in Prague, Faculty of Biomedical Engineering, Nam. Sitna 3105, 272 01 Kladno, Czech Republic.
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23
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Wichmann C. Molecularly and structurally distinct synapses mediate reliable encoding and processing of auditory information. Hear Res 2015; 330:178-90. [PMID: 26188105 DOI: 10.1016/j.heares.2015.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/21/2015] [Accepted: 07/10/2015] [Indexed: 01/20/2023]
Abstract
Hearing impairment is the most common human sensory deficit. Considering the sophisticated anatomy and physiology of the auditory system, disease-related failures frequently occur. To meet the demands of the neuronal circuits responsible for processing auditory information, the synapses of the lower auditory pathway are anatomically and functionally specialized to process acoustic information indefatigably with utmost temporal precision. Despite sharing some functional properties, the afferent synapses of the cochlea and of auditory brainstem differ greatly in their morphology and employ distinct molecular mechanisms for regulating synaptic vesicle release. Calyceal synapses of the endbulb of Held and the calyx of Held profit from a large number of release sites that project onto one principal cell. Cochlear inner hair cell ribbon synapses exhibit a unique one-to-one relation of the presynaptic active zone to the postsynaptic cell and use hair-cell-specific proteins such as otoferlin for vesicle release. The understanding of the molecular physiology of the hair cell ribbon synapse has been advanced by human genetics studies of sensorineural hearing impairment, revealing human auditory synaptopathy as a new nosological entity.
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Affiliation(s)
- Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience & InnerEarLab, University Medical Center, Göttingen, Germany.
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24
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Kurtcan S, Alkan A, Kilicarslan R, Bakan AA, Toprak H, Aralasmak A, Aksoy F, Kocer A. Auditory Pathway Features Determined by DTI in Subjects with Unilateral Acoustic Neuroma. Clin Neuroradiol 2015; 26:439-444. [PMID: 25813527 DOI: 10.1007/s00062-015-0385-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/04/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE In the studies concerning the pathology of the auditory pathway in the vestibulocochlear system, few use advanced neuroimaging applications of magnetic resonance imaging (MRI) such as diffusion tensor imaging (DTI). Those who did use reported DTI changes only at the lateral lemniscus and inferior colliculus level. The aim of our study was to determine diffusion changes in the bilateral auditory pathways of subjects with unilateral acoustic neuroma (AN) and compare them with healthy controls. MATERIAL AND METHODS A total of 15 subjects with unilateral AN along with 11 controls underwent routine MRI and DTI. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values obtained from the lateral lemniscus, inferior colliculus, corpus geniculatum mediale, and Heschl's gyrus of the auditory pathway were then compared. RESULTS The subjects' ADC values measured from the contralateral side were significantly higher at the lateral lemniscus, inferior colliculus, and corpus geniculatum mediale compared with those of the controls. Also, decreased FA values were noted at the inferior colliculus for both the contralateral and ipsilateral sides. The highest ADC values were detected in the inferior colliculus of the auditory pathway. CONCLUSIONS In the auditory pathway of subjects with AN, the contralateral side is more affected than the ipsilateral side, the most affected region being the inferior colliculus. DTI is an advanced neuroimaging technique that can be used to determine the presence of microstructural damage to the auditory pathway in subjects with AN, whereas conventional MRI is not sensitive enough to detect damage.
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Affiliation(s)
- S Kurtcan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey.
| | - A Alkan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - R Kilicarslan
- Department of Radiology, Faculty of Medicine, Medipol University, Istanbul, Turkey
| | - A A Bakan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - H Toprak
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - A Aralasmak
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, 34093, Istanbul, Turkey
| | - F Aksoy
- Department of Otorhinolaryngology, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
| | - A Kocer
- Department of Neurology, Faculty of Medicine, Medeniyet University, Istanbul, Turkey
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Jung DJ, Han M, Jin SU, Lee SH, Park I, Cho HJ, Kwon TJ, Lee HJ, Cho JH, Lee KY, Chang Y. Functional mapping of the auditory tract in rodent tinnitus model using manganese-enhanced magnetic resonance imaging. Neuroimage 2014; 100:642-9. [PMID: 24983712 DOI: 10.1016/j.neuroimage.2014.06.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 10/25/2022] Open
Abstract
Animal models of salicylate-induced tinnitus have demonstrated that salicylate modulates neuronal activity in several brain structures leading to neuronal hyperactivity in auditory and non-auditory brain areas. In addition, these animal tinnitus models indicate that tinnitus can be a perceptual consequence of altered spontaneous neural activity along the auditory pathway. Peripheral and/or central effects of salicylate can account for neuronal activity changes in salicylate-induced tinnitus. Because of this ambiguity, an in vivo imaging study would be able to address the peripheral and/or central involvement of salicylate-induced tinnitus. Therefore, in the present study, we developed a novel manganese-enhanced magnetic resonance imaging (MEMRI) method to map the in vivo functional auditory tract in a salicylate-induced tinnitus animal model by administrating manganese through the round window. We found that acute salicylate-induced tinnitus resulted in higher manganese uptake in the cochlea and in the central auditory structures. Furthermore, serial MRI scans demonstrated that the manganese signal increased in an anterograde fashion from the cochlea to the cochlear nucleus. Therefore, our in vivo MEMRI data suggest that acute salicylate-induced tinnitus is associated with higher spontaneous neural activity both in peripheral and central auditory pathways.
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Affiliation(s)
- Da Jung Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Mun Han
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Seong-Uk Jin
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Sang Heun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Daegu Veterans Hospital, Daegu, Republic of Korea
| | - Ilyong Park
- Department of Biomedical Engineering, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Hyun-Ju Cho
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Jun Kwon
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Hui Joong Lee
- Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Jin Ho Cho
- Department of Electronic Engineering, College of IT Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea.
| | - Yongmin Chang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Molecular Medicine, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
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Uran SL, Gómez-Casati ME, Guelman LR. Long-term recovery from hippocampal-related behavioral and biochemical abnormalities induced by noise exposure during brain development. Evaluation of auditory pathway integrity. Int J Dev Neurosci 2014; 37:41-51. [PMID: 24911434 DOI: 10.1016/j.ijdevneu.2014.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/30/2014] [Accepted: 06/01/2014] [Indexed: 11/24/2022] Open
Abstract
Sound is an important part of man's contact with the environment and has served as critical means for survival throughout his evolution. As a result of exposure to noise, physiological functions such as those involving structures of the auditory and non-auditory systems might be damaged. We have previously reported that noise-exposed developing rats elicited hippocampal-related histological, biochemical and behavioral changes. However, no data about the time lapse of these changes were reported. Moreover, measurements of auditory pathway function were not performed in exposed animals. Therefore, with the present work, we aim to test the onset and the persistence of the different extra-auditory abnormalities observed in noise-exposed rats and to evaluate auditory pathway integrity. Male Wistar rats of 15 days were exposed to moderate noise levels (95-97 dB SPL, 2 h a day) during one day (acute noise exposure, ANE) or during 15 days (sub-acute noise exposure, SANE). Hippocampal biochemical determinations as well as short (ST) and long term (LT) behavioral assessments were performed. In addition, histological and functional evaluations of the auditory pathway were carried out in exposed animals. Our results show that hippocampal-related behavioral and biochemical changes (impairments in habituation, recognition and associative memories as well as distortion of anxiety-related behavior, decreases in reactive oxygen species (ROS) levels and increases in antioxidant enzymes activities) induced by noise exposure were almost completely restored by PND 90. In addition, auditory evaluation shows that increased cochlear thresholds observed in exposed rats were re-established at PND 90, although with a remarkable supra-threshold amplitude reduction. These data suggest that noise-induced hippocampal and auditory-related alterations are mostly transient and that the effects of noise on the hippocampus might be, at least in part, mediated by the damage on the auditory pathway. However, we cannot exclude that a different mechanism might be responsible for the observed hippocampal-related changes.
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Zhemchuzhnikov MK, Pfuhl G, Berg BG. Tracing and 3-dimensional representation of the primary afferents from the moth ear. Arthropod Struct Dev 2014; 43:231-241. [PMID: 24732046 DOI: 10.1016/j.asd.2014.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/19/2014] [Accepted: 04/03/2014] [Indexed: 06/03/2023]
Abstract
Heliothine moths perceive acoustic information via two auditory sensory neurons only. Previous cobalt staining experiments have described the projection pattern of the two auditory neurons, called the A1 and the A2 cell, plus one additional neuron, the so-called B cell, up to the prothorax. We have obtained new and improved data about the projection pattern of the three sensory afferents by means of fluorescent staining experiments combined with scanning confocal microscopy. The present data show the fine structure of each sensory axon that arises from the moth ear and its ascending pathway relative to that of the others. In accordance with the previous data, the A2 auditory cell was found to extend projections in the pterothorax only. A novel finding is that terminal branches of the A2 cell cross the midline. The staining pattern of the two remaining neurons, the A1 and B cell, which project tightly together in the thoracic ganglia, differ somewhat from that previously described. As demonstrated here, one of these two neurons, the A1 cell, terminates in the prothoracic ganglion whereas the other, the B cell, projects further on via the cervical connectives to the subesophageal ganglion. The current data, therefore, indicate that none of the auditory afferents in the heliothine moth projects to the brain.
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Affiliation(s)
- Mikhail K Zhemchuzhnikov
- Norwegian University of Science and Technology, Department of Psychology, Neuroscience Unit, 7491 Trondheim, Norway; Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Pr. Torez 44, 194223 Saint-Petersburg, Russia.
| | - Gerit Pfuhl
- Norwegian University of Science and Technology, Department of Psychology, Neuroscience Unit, 7491 Trondheim, Norway.
| | - Bente G Berg
- Norwegian University of Science and Technology, Department of Psychology, Neuroscience Unit, 7491 Trondheim, Norway.
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Jin SU, Lee JJ, Hong KS, Han M, Park JW, Lee HJ, Lee S, Lee KY, Shin KM, Cho JH, Cheong C, Chang Y. Intratympanic manganese administration revealed sound intensity and frequency dependent functional activity in rat auditory pathway. Magn Reson Imaging 2013; 31:1143-9. [PMID: 23659767 DOI: 10.1016/j.mri.2013.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/24/2013] [Accepted: 03/08/2013] [Indexed: 11/28/2022]
Abstract
The cochlear plays a vital role in the sense and sensitivity of hearing; however, there is currently a lack of knowledge regarding the relationships between mechanical transduction of sound at different intensities and frequencies in the cochlear and the neurochemical processes that lead to neuronal responses in the central auditory system. In the current study, we introduced manganese-enhanced MRI (MEMRI), a convenient in vivo imaging method, for investigation of how sound, at different intensities and frequencies, is propagated from the cochlear to the central auditory system. Using MEMRI with intratympanic administration, we demonstrated differential manganese signal enhancements according to sound intensity and frequencies in the ascending auditory pathway of the rat after administration of intratympanic MnCl2.Compared to signal enhancement without explicit sound stimuli, auditory structures in the ascending auditory pathway showed stronger signal enhancement in rats who received sound stimuli of 10 and 40 kHz. In addition, signal enhancement with a stimulation frequency of 40 kHz was stronger than that with 10 kHz. Therefore, the results of this study seem to suggest that, in order to achieve an effective response to high sound intensity or frequency, more firing of auditory neurons, or firing of many auditory neurons together for the pooled neural activity is needed.
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Affiliation(s)
- Seong-Uk Jin
- Department of Medical & Biological Engineering, Kyungpook National University, Dongduk-Ro, Jung-Gu, Daegu, Korea
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Hong SM, Chung SY, Park MS, Huh YB, Park MS, Yeo SG. Immunoreactivity of calcium-binding proteins in the central auditory nervous system of aged rats. J Korean Neurosurg Soc 2009; 45:231-5. [PMID: 19444349 DOI: 10.3340/jkns.2009.45.4.231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 04/05/2009] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE While many factors contribute to aging, changes in calcium homeostasis and calcium related neuronal processes are likely to be important. High intracellular calcium is toxic to cells and alterations in calcium homeostasis are associated with changes in calcium-binding proteins, which confine free Ca(2+). We therefore assayed the expression of the calcium binding proteins calretinin and calbindin in the central auditory nervous system of rats. METHODS Using antibodies to calretinin and calbindin, we assayed their expression in the cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate body and auditory cortex of young (4 months old) and aged (24 months old) rats. RESULTS Calretinin and calbindin staining intensity in neurons of the cochlear nucleus was significantly higher in aged than in young rats (p<0.05) The number and staining intensity of calretinin-positive neurons in the inferior colliculus, and of calbindin-positive neurons in the superior olivary nucleus were greater in aged than in young rats (p<0.05). CONCLUSION These results suggest that auditory processing is altered during aging, which may be due to increased intracellular Ca(2+) concentration, consequently leading to increased immunoreactivity toward calcium-binding proteins.
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Affiliation(s)
- Seok Min Hong
- Department of Otorhinolaryngology and Head and Neck Surgery, College of Medicine, KyungHee University, Seoul, Korea
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