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Janky K, Steyger PS. Mechanisms and Impact of Aminoglycoside-Induced Vestibular Deficits. Am J Audiol 2023; 32:746-760. [PMID: 37319406 PMCID: PMC10721243 DOI: 10.1044/2023_aja-22-00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/26/2023] [Accepted: 03/06/2023] [Indexed: 06/17/2023] Open
Abstract
PURPOSE Acquired vestibulotoxicity from hospital-prescribed medications such as aminoglycoside antibiotics affects as many as 40,000 people each year in North America. However, there are no current federally approved drugs to prevent or treat the debilitating and permanent loss of vestibular function caused by bactericidal aminoglycoside antibiotics. This review will cover our current understanding of the impact of, and mechanisms underlying, aminoglycoside-induced vestibulotoxicity and highlight the gaps in our knowledge that remain. CONCLUSIONS Aminoglycoside-induced vestibular deficits have long-term impacts on patients across the lifespan. Additionally, the prevalence of aminoglycoside-induced vestibulotoxicity appears to be greater than cochleotoxicity. Thus, monitoring for vestibulotoxicity should be independent of auditory monitoring and encompass patients of all ages from young children to older adults before, during, and after aminoglycoside therapy.
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Affiliation(s)
- Kristen Janky
- Department of Audiology, Boys Town National Research Hospital, Omaha, NE
| | - Peter S. Steyger
- Bellucci Translational Hearing Center, Creighton University, Omaha, NE
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2
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Forbes PA, Kwan A, Mitchell DE, Blouin JS, Cullen KE. The Neural Basis for Biased Behavioral Responses Evoked by Galvanic Vestibular Stimulation in Primates. J Neurosci 2023; 43:1905-1919. [PMID: 36732070 PMCID: PMC10027042 DOI: 10.1523/jneurosci.0987-22.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Noninvasive electrical stimulation of the vestibular system in humans has become an increasingly popular tool with a broad range of research and clinical applications. However, common assumptions regarding the neural mechanisms that underlie the activation of central vestibular pathways through such stimulation, known as galvanic vestibular stimulation (GVS), have not been directly tested. Here, we show that GVS is encoded by VIIIth nerve vestibular afferents with nonlinear dynamics that differ markedly from those predicted by current models. GVS produced asymmetric activation of both semicircular canal and otolith afferents to the onset versus offset and cathode versus anode of applied current, that in turn produced asymmetric eye movement responses in three awake-behaving male monkeys. Additionally, using computational methods, we demonstrate that the experimentally observed nonlinear neural response dynamics lead to an unexpected directional bias in the net population response when the information from both vestibular nerves is centrally integrated. Together our findings reveal the neural basis by which GVS activates the vestibular system, establish that neural response dynamics differ markedly from current predictions, and advance our mechanistic understanding of how asymmetric activation of the peripheral vestibular system alters vestibular function. We suggest that such nonlinear encoding is a general feature of neural processing that will be common across different noninvasive electrical stimulation approaches.SIGNIFICANCE STATEMENT Here, we show that the application of noninvasive electrical currents to the vestibular system (GVS) induces more complex responses than commonly assumed. We recorded vestibular afferent activity in macaque monkeys exposed to GVS using a setup analogous to human studies. GVS evoked notable asymmetries in irregular afferent responses to cathodal versus anodal currents. We developed a nonlinear model explaining these GVS-evoked afferent responses. Our model predicts that GVS induces directional biases in centrally integrated head motion signals and establishes electrical stimuli that recreate physiologically plausible sensations of motion. Altogether, our findings provide new insights into how GVS activates the vestibular system, which will be vital to advancing new clinical and biomedical applications.
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Affiliation(s)
- Patrick A Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands
| | | | | | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, British Colombia V6T 1Z1, Canada
| | - Kathleen E Cullen
- Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
- Departments of Biomedical Engineering
- Otolaryngology-Head and Neck Surgery
- Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, Maryland 21205
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3
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Büki B, Migliaccio AA. The vergence-mediated gain increase: Physiology and clinical relevance. J Vestib Res 2023; 33:173-186. [PMID: 37005906 DOI: 10.3233/ves-220133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
BACKGROUND During near-viewing, the vestibulo-ocular reflex (VOR) response/gain increases to compensate for the relatively larger translation of the eyes with respect to the target. OBJECTIVE To review vergence-mediated gain increase (VMGI) testing methods stimuli and responses (latency and amplitude), peripheral/central pathways and clinical relevance. METHODS The authors discuss publications listed in PUBMED since 1980 in the light of their own studies. RESULTS The VMGI can be measured during rotational, linear and combined head accelerations. It has short-latency, non-compensatory amplitude, and relies on irregularly discharging peripheral afferents and their pathways. It is driven by a combination of perception, visual-context and internal modelling. CONCLUSIONS Currently, there are technical barriers that hinder VMGI measurement in the clinic. However, the VMGI may have diagnostic value, especially with regards to measuring otolith function. The VMGI also may have potential value in rehabilitation by providing insight about a patient's lesion and how to best tailor a rehabilitation program for them, that potentially includes VOR adaptation training during near-viewing.
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Affiliation(s)
- Bela Büki
- Department of Otolaryngology, Karl Landsteiner University Hospital Krems, Mitterweg, Austria
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia
- Graduate School of Biomedical Engineering, University of NSW, Sydney, NSW, Australia
- Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, USA
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia
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4
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Cullen KE. Vestibular motor control. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:31-54. [PMID: 37562876 DOI: 10.1016/b978-0-323-98818-6.00022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The vestibular system is an essential sensory system that generates motor reflexes that are crucial for our daily activities, including stabilizing the visual axis of gaze and maintaining head and body posture. In addition, the vestibular system provides us with our sense of movement and orientation relative to space and serves a vital role in ensuring accurate voluntary behaviors. Neurophysiological studies have provided fundamental insights into the functional circuitry of vestibular motor pathways. A unique feature of the vestibular system compared to other sensory systems is that the same central neurons that receive direct input from the afferents of the vestibular component of the 8th nerve can also directly project to motor centers that control vital vestibular motor reflexes. In turn, these reflexes ensure stabilize gaze and the maintenance of posture during everyday activities. For instance, a direct three-neuron pathway mediates the vestibulo-ocular reflex (VOR) pathway to provide stable gaze. Furthermore, recent studies have advanced our understanding of the computations performed by the cerebellum and cortex required for motor learning, compensation, and voluntary movement and navigation. Together, these findings have provided new insights into how the brain ensures accurate self-movement during our everyday activities and have also advanced our knowledge of the neurobiological mechanisms underlying disorders of vestibular processing.
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Affiliation(s)
- Kathleen E Cullen
- Departments of Biomedical Engineering, of Otolaryngology-Head and Neck Surgery, and of Neuroscience; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States.
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Soriano-Reixach MM, Rey-Martínez J, Altuna X, Perez-Fernandez N. Synchronized refixation saccades in enhanced VVOR test. A new application for PR score. J Vestib Res 2022; 32:443-451. [PMID: 35124630 DOI: 10.3233/ves-210127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Main objectives for this study were to develop a quantification method to obtain a Perez-Rey (PR) score adapted to the VVOR test and to evaluate the correlation of the PR score obtained with quantified VVOR with the PR score of the vHIT test. METHODS A new PR score calculation method for quantified VVOR test was developed using the MATLAB computational software based on saccadic response time latency variability between each head oscillation cycle of the VVOR test. Retrospective correlation between PR scores in VVOR and vHIT tests, performed in the same vHIT testing session for patients with vestibular neuritis and vestibular neurectomy, was performed to correlate new PR (VVOR) score with the classic PR (vHIT) score. RESULTS Thirty patients were included: 11 post-neurectomy and 19 subacute vestibular neuritis. Pearson's correlation coefficient (R2) for the overall sample was 0.92 (p < 0.001) and 95% confidence interval was 0.85 -0.96. In the linear mixed-effects statistical model developed, only PRVHIT and PRVVOR scores showed statistical association in Wald X2 test (p = 0.008). CONCLUSION The new developed PR score for synchronization measurement of saccadic responses in VVOR testing is a valid method that outputs synchronization values and highly correlates with PR score in vHIT test.
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Affiliation(s)
- Maria Montserrat Soriano-Reixach
- Neurotology Unit, Department of Otorhinolaryngology Head and Neck Surgery, Hospital Universitario Donostia, Donostia-San Sebastian, Basque Country, Spain.,Biodonostia Health Research Institute, Otorhinolaryngology Area, Osakidetza Basque Health Service, Donostia-San Sebastián, Spain
| | - Jorge Rey-Martínez
- Neurotology Unit, Department of Otorhinolaryngology Head and Neck Surgery, Hospital Universitario Donostia, Donostia-San Sebastian, Basque Country, Spain.,Biodonostia Health Research Institute, Otorhinolaryngology Area, Osakidetza Basque Health Service, Donostia-San Sebastián, Spain
| | - Xabier Altuna
- Neurotology Unit, Department of Otorhinolaryngology Head and Neck Surgery, Hospital Universitario Donostia, Donostia-San Sebastian, Basque Country, Spain.,Biodonostia Health Research Institute, Otorhinolaryngology Area, Osakidetza Basque Health Service, Donostia-San Sebastián, Spain
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Assessing the Clinical Value of Objective and Patient-Reported Audiovestibular Outcome Measures in the Risk Estimation of Systemic Cobalt Toxicity for Patients With a Metal-on-Metal Hip Implant. Ear Hear 2022; 43:1502-1514. [DOI: 10.1097/aud.0000000000001200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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杨 军, 金 玉, 陈 建, 张 青, 段 茂. [To address on the refined and individualized comprehensive evaluation of inner ear function]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2022; 36:651-658;664. [PMID: 36036063 PMCID: PMC10127629 DOI: 10.13201/j.issn.2096-7993.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Auditory and vestibular function detection technology is the premise and key to the diagnosis and management for inner ear diseases. Concurrent damage to the auditory and vestibular system occurs in many inner ear diseases. The general points and issues on hearing and vestibular function tests, as well as the clinical significance of refined and individualized comprehensive evaluation of inner ear function are described in this paper.
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Affiliation(s)
- 军 杨
- 上海交通大学医学院附属新华医院耳鼻咽喉-头颈外科 上海交通大学医学院耳科学研究所 上海耳鼻疾病转化医学重点实验室(上海,200092)Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Jiaotong University School of Medicine Ear Institute; Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, 200092, China
| | - 玉莲 金
- 上海交通大学医学院附属新华医院耳鼻咽喉-头颈外科 上海交通大学医学院耳科学研究所 上海耳鼻疾病转化医学重点实验室(上海,200092)Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Jiaotong University School of Medicine Ear Institute; Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, 200092, China
| | - 建勇 陈
- 上海交通大学医学院附属新华医院耳鼻咽喉-头颈外科 上海交通大学医学院耳科学研究所 上海耳鼻疾病转化医学重点实验室(上海,200092)Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Jiaotong University School of Medicine Ear Institute; Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, 200092, China
| | - 青 张
- 上海交通大学医学院附属新华医院耳鼻咽喉-头颈外科 上海交通大学医学院耳科学研究所 上海耳鼻疾病转化医学重点实验室(上海,200092)Department of Otorhinolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine; Shanghai Jiaotong University School of Medicine Ear Institute; Shanghai Key Laboratory of Translational Medicine on Ear and Nose diseases, Shanghai, 200092, China
| | - 茂利 段
- 瑞典斯德哥尔摩卡罗林斯卡大学医院创伤与修复医学耳鼻咽喉病区Ear Nose and Throat Patient Area, Trauma and Reparative Medicine Theme, Karolinska University Hospital, Stockholm, Sweden
- 瑞典斯德哥尔摩卡罗林斯卡医学院临床科学干预及技术系耳鼻咽喉头颈外科Division of Ear, Nose and Throat Diseases, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
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8
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Contini D, Holstein GR, Art JJ. Simultaneous Dual Recordings From Vestibular Hair Cells and Their Calyx Afferents Demonstrate Multiple Modes of Transmission at These Specialized Endings. Front Neurol 2022; 13:891536. [PMID: 35899268 PMCID: PMC9310783 DOI: 10.3389/fneur.2022.891536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/02/2022] [Indexed: 11/18/2022] Open
Abstract
In the vestibular periphery, transmission via conventional synaptic boutons is supplemented by post-synaptic calyceal endings surrounding Type I hair cells. This review focusses on the multiple modes of communication between these receptors and their enveloping calyces as revealed by simultaneous dual-electrode recordings. Classic orthodromic transmission is accompanied by two forms of bidirectional communication enabled by the extensive cleft between the Type I hair cell and its calyx. The slowest cellular communication low-pass filters the transduction current with a time constant of 10–100 ms: potassium ions accumulate in the synaptic cleft, depolarizing both the hair cell and afferent to potentials greater than necessary for rapid vesicle fusion in the receptor and potentially triggering action potentials in the afferent. On the millisecond timescale, conventional glutamatergic quantal transmission occurs when hair cells are depolarized to potentials sufficient for calcium influx and vesicle fusion. Depolarization also permits a third form of transmission that occurs over tens of microseconds, resulting from the large voltage- and ion-sensitive cleft-facing conductances in both the hair cell and the calyx that are open at their resting potentials. Current flowing out of either the hair cell or the afferent divides into the fraction flowing across the cleft into its cellular partner, and the remainder flowing out of the cleft and into the surrounding fluid compartment. These findings suggest multiple biophysical bases for the extensive repertoire of response dynamics seen in the population of primary vestibular afferent fibers. The results further suggest that evolutionary pressures drive selection for the calyx afferent.
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Affiliation(s)
- Donatella Contini
- Department of Anatomy & Cell Biology, University of Illinois College of Medicine, Chicago, IL, United States
| | - Gay R. Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jonathan J. Art
- Department of Anatomy & Cell Biology, University of Illinois College of Medicine, Chicago, IL, United States
- *Correspondence: Jonathan J. Art
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9
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Mukhopadhyay M, Pangrsic T. Synaptic transmission at the vestibular hair cells of amniotes. Mol Cell Neurosci 2022; 121:103749. [PMID: 35667549 DOI: 10.1016/j.mcn.2022.103749] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 05/09/2022] [Accepted: 06/01/2022] [Indexed: 11/19/2022] Open
Abstract
A harmonized interplay between the central nervous system and the five peripheral end organs is how the vestibular system helps organisms feel a sense of balance and motion in three-dimensional space. The receptor cells of this system, much like their cochlear equivalents, are the specialized hair cells. However, research over the years has shown that the vestibular endorgans and hair cells evolved very differently from their cochlear counterparts. The structurally unique calyceal synapse, which appeared much later in the evolutionary time scale, and continues to intrigue researchers, is now known to support several forms of synaptic neurotransmission. The conventional quantal transmission is believed to employ the ribbon structures, which carry several tethered vesicles filled with neurotransmitters. However, the field of vestibular hair cell synaptic molecular anatomy is still at a nascent stage and needs further work. In this review, we will touch upon the basic structure and function of the peripheral vestibular system, with the focus on the various modes of neurotransmission at the type I vestibular hair cells. We will also shed light on the current knowledge about the molecular anatomy of the vestibular hair cell synapses and vestibular synaptopathy.
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Affiliation(s)
- Mohona Mukhopadhyay
- Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, and Institute for Auditory Neuroscience, 37075 Göttingen, Germany
| | - Tina Pangrsic
- Experimental Otology Group, InnerEarLab, Department of Otolaryngology, University Medical Center Göttingen, and Institute for Auditory Neuroscience, 37075 Göttingen, Germany; Auditory Neuroscience Group, Max Planck Institute for Multidisciplinary Sciences, 37075 Göttingen, Germany; Collaborative Research Center 889, University of Göttingen, Göttingen, Germany; Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany.
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10
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Carriot J, McAllister G, Hooshangnejad H, Mackrous I, Cullen KE, Chacron MJ. Sensory adaptation mediates efficient and unambiguous encoding of natural stimuli by vestibular thalamocortical pathways. Nat Commun 2022; 13:2612. [PMID: 35551186 PMCID: PMC9098492 DOI: 10.1038/s41467-022-30348-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 04/26/2022] [Indexed: 11/09/2022] Open
Abstract
Sensory systems must continuously adapt to optimally encode stimuli encountered within the natural environment. The prevailing view is that such optimal coding comes at the cost of increased ambiguity, yet to date, prior studies have focused on artificial stimuli. Accordingly, here we investigated whether such a trade-off between optimality and ambiguity exists in the encoding of natural stimuli in the vestibular system. We recorded vestibular nuclei and their target vestibular thalamocortical neurons during naturalistic and artificial self-motion stimulation. Surprisingly, we found no trade-off between optimality and ambiguity. Using computational methods, we demonstrate that thalamocortical neural adaptation in the form of contrast gain control actually reduces coding ambiguity without compromising the optimality of coding under naturalistic but not artificial stimulation. Thus, taken together, our results challenge the common wisdom that adaptation leads to ambiguity and instead suggest an essential role in underlying unambiguous optimized encoding of natural stimuli.
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Affiliation(s)
- Jerome Carriot
- Department of Physiology, McGill University, Montréal, Canada
| | | | - Hamed Hooshangnejad
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA
| | | | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, USA
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刘 嘉, 胡 亚, 汪 芹, 丁 艳, 李 娟, 唐 海. [Correlation and difference analysis in parameters between video head impulse test and caloric test in vestibular disease]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2021; 35:802-806. [PMID: 34628832 PMCID: PMC10127836 DOI: 10.13201/j.issn.2096-7993.2021.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Indexed: 06/13/2023]
Abstract
Objective:To investigate interrelationships in parameters between caloric test and video head impulse test(vHIT) in the common peripheral vertigo diseases and healthy people, and to conduct correlation and difference analysis between the results in two tests, so as to evaluate the clinical diagnosis value of peripheral vertigo. Methods:The caloric test and vHIT were fulfilled in 68 patients with vertigo and 17 healthy volunteers. The diagnosis was done according to history inquiring, otology and audiology examination and vestibular tests. The vestibulo-ocular reflex(VOR) gain and gain asymmetry(GA) of a vHIT as well as unilateral weakness(UW) and the sum of the slow-phase velocities(SPVs) of warm and cold irrigation of the same side were compared. A cutoff value of VOR gain of a vHIT was also calculated using a receiver-operating characteristic curve. Results:In all ears(n=170), there was significant correlation in ipsilateral SPVs and VOR gain(r=0.568, P<0.0001); In all ears(n=34) of 17 healthy volunteers, there was no correlation in ipsilateral SPVs and VOR gain(r=-0.05, P=0.778); In all affected ears(n=76), there was statistically positive correlation in ipsilateral SPVs and VOR gain(r=0.571, P<0.0001); In all the unaffected ears(n=94), there was positive correlation in ipsilateral SPVs and VOR gain(r=0.286, P=0.005). In 60 patients with unilateral vestibular disease(n=60), there was statistically significant negative correlation between the VOR gain of affected ears and UW(r=-0.513, P<0.0001); there was statistically significant positive correlation between GA of a vHIT and UW(r=0.713, P<0.0001). There was a statistically significant negative correlation between the VOR gain of affected ears and UW in the fluctuating vertigo group(r=-0.516, P=0.002) as well as a positive correlation between GA and UW(r=0.529, P=0.001); In the non-fluctuating vertigo group, there was a statistically significant negative correlation between the VOR gain of affected ears and UW(r=-0.428, P=0.029); there was a positive correlation between GA of a vHIT and UW(r=0.743, P<0.0001). In the vestibular neuropathy group, there was a negative correlation between the VOR gain of affected ears and UW(r=-0.462, P=0.030); there was a statistically significant positive correlation between GA of a vHIT and UW(r=0.757, P<0.0001). There was a negative correlation between the VOR gain of affected ears and UW in the vestibular peripheral disease group(r=-0.516, P=0.002) as well as a statistically significant positive correlation between GA and UW(r=0.529, P=0.001). The mean value of UW(65.5%) was higher in the overt saccade group than that in the normal VOR group, there was statistically significant difference(P=0.006). According to the UW damage degree grading, there was statistically significant difference in abnormal educe rates(χ²=17.76, P<0.05). Based on the gold standard of caloric response, a cutoff value of 0.865 was determined; the parameters of the two tests were dissociated in 28.3%. Conclusion:There was a statistically significant correlation in parameters between vHIT and caloric test. The patients of overt saccade always accompany with the high UW, which could indicate that the vestibular function severely damaged. vHIT and caloric test can be complementary tools for the comprehensive evaluation of patients' vestibule function, on account of dissociation between the results of vHIT and caloric test and general result of consistent check.
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Affiliation(s)
- 嘉 刘
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - 亚 胡
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - 芹 汪
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - 艳 丁
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - 娟 李
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - 海兰 唐
- 中南大学湘雅二医院耳鼻咽喉头颈外科(长沙,410011)Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, China
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12
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Kirazli G, Hepkarsi S, Kirazli T. Evaluation of high frequency horizontal VOR parameters in patients with chronic bilateral and unilateral peripheral vestibulopathy: a preliminary study. Acta Otolaryngol 2020; 140:1007-1012. [PMID: 32862738 DOI: 10.1080/00016489.2020.1810314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Caloric test is one of the tests which evaluates the low frequency component of vestibular system for both diagnosis of the BPV and UPV. AIMS The main objectives are to determine and increase the diagnostic value of BPV and UPV by evaluating the high frequency horizontal VOR parameters with HIMP, SHIMP and fHIT, to compare test results with healthy controls, and to evaluate correlation of these tests with vertigo dizziness imbalance (VDI) questionnaire results in these patients. MATERIAL AND METHODS Six patients with BPV, ten patients with UPV and fifteen healthy controls were recruited. High frequency hVOR were evaluated with HIMP, SHIMP and fHIT. Vestibular symptoms and quality of life were assessed with VDI Questionnaire. RESULTS Lower percentage of correct answers, and lower VOR gains were obtained in affected sides for BPV and UPV. HIMP elicited compensatory saccades in patients, whereas SHIMP elicited large anticompensatory saccades in controls and unaffected side of UPV, but no saccades in BPV. No correlation was found between VDI outcomes and all tests. CONCLUSIONS The results show that all tests are complementary each other and able to identify the affected labyrinth and to show residual vestibular function. These tests are thought to be important in the vestibular rehabilitation process.
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Affiliation(s)
- Gulce Kirazli
- Audiometry Program, Ataturk Health Services Vocational High School, Ege University, Izmir, Turkey
| | - Sevinc Hepkarsi
- Otorhinolaryngology Department, School of Medicine, Ege University, Izmir, Turkey
| | - Tayfun Kirazli
- Otorhinolaryngology Department, School of Medicine, Ege University, Izmir, Turkey
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13
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Ren P, Li B, Dong S, Lyu B, Gong S, Zhang Q, Qu J, Han P. The head fixation based on skull cap: An improved protocol used in single unit recording in the vestibular system. MethodsX 2020; 7:101109. [PMID: 33145185 PMCID: PMC7596295 DOI: 10.1016/j.mex.2020.101109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/12/2020] [Indexed: 11/24/2022] Open
Abstract
Single unit recording has an important application in neuroscience, especially in the vestibular system such as visual stabilization, posture maintenance, spatial orientation and cognition. However, single unit recording conducted in living animals is a demanding technique and non-ideal mechanical stability between the recording location of nerve tissues and the tip of microelectrode always results in failure to obtain successful recordings in the vestibular system. In order to improve the mechanical stability during single unit recording, we constructed a novel head fixation method based on skull cap. This article describes in detail how to construct this novel head fixation. Following the step-by-step procedure mentioned in this article will provide a high-quality mechanical stability for single unit recording in the vestibular system, allowing us to successfully record the nonlinear neural dynamic response over a big magnitude motion stimulation. This improvement of head fixation contributes to the in-depth understanding of the vestibular system.
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Affiliation(s)
- Pengyu Ren
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China.,Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, United States
| | - Bowen Li
- Division of Health Sciences Informatics, Johns Hopkins University School of Medicine, 2024 E Monument St, Baltimore, MD 21205, United States
| | - Shiyao Dong
- Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, United States
| | - Boqiang Lyu
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Shouping Gong
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Qing Zhang
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital of Shanghai Jiaotong University, 1665 Kongjiang Rd, Shanghai 200093, China
| | - Jianqiang Qu
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Peng Han
- Department of Otolaryngology-Head & Neck Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, 227 Yanta West Roud, Xi'an, Shaanxi 710061, China
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14
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Kaci B, Nooristani M, Mijovic T, Maheu M. Usefulness of Video Head Impulse Test Results in the Identification of Meniere's Disease. Front Neurol 2020; 11:581527. [PMID: 33193038 PMCID: PMC7658335 DOI: 10.3389/fneur.2020.581527] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/28/2020] [Indexed: 01/09/2023] Open
Abstract
Meniere's disease (MD) is an inner ear disorder inducing tinnitus, aural fullness, sensorineural hearing loss, and vertigo episodes. In the past few years, efforts have been made to develop objective measures able to distinguish MD from other pathologies. Indeed, some authors investigated electrophysiological measures, such as electrocochleography and vestibular evoked myogenic potentials or imaging techniques. More recently, the video head impulse test (vHIT) was developed to assess the vestibulo-ocular reflex (VOR). In the last few years, authors aimed at identifying how vHIT may help to identify MD. The objective of this manuscript is to review the different vHIT results in MD patients. We will discuss the usefulness of these findings in the identification of MD, how these results may be explained by pathophysiological mechanisms associated with MD, and finally provide directions for future studies.
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Affiliation(s)
- Brahim Kaci
- Vestibulab, School of Speech Language Pathology and Audiology, University of Montreal, Montreal, QC, Canada.,Centre de Recherche Interdisciplinaire en Réadaptation - Institut Universitaire sur la Réadaptation en Déficience Physique de Montréal (IURDPM), Pavillon Laurier, CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, QC, Canada
| | - Mujda Nooristani
- Vestibulab, School of Speech Language Pathology and Audiology, University of Montreal, Montreal, QC, Canada.,Centre de Recherche Interdisciplinaire en Réadaptation - Institut Universitaire sur la Réadaptation en Déficience Physique de Montréal (IURDPM), Pavillon Laurier, CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, QC, Canada
| | - Tamara Mijovic
- Department of Otolaryngology-Head and Neck Surgery, Royal Victoria Hospital, Montreal, QC, Canada
| | - Maxime Maheu
- Vestibulab, School of Speech Language Pathology and Audiology, University of Montreal, Montreal, QC, Canada.,Centre de Recherche Interdisciplinaire en Réadaptation - Institut Universitaire sur la Réadaptation en Déficience Physique de Montréal (IURDPM), Pavillon Laurier, CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montreal, QC, Canada
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15
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Steinhardt CR, Fridman GY. Predicting Response of Spontaneously Firing Afferents to Prosthetic Pulsatile Stimulation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:2929-2933. [PMID: 33018620 DOI: 10.1109/embc44109.2020.9175282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pulsatile electrical stimulation is used in neural prostheses such as the vestibular prosthesis. In a healthy vestibular system, head motion is encoded by changes in the firing rates of afferents around their spontaneous baseline rate. For people suffering from bilateral vestibular disorder (BVD), head motion no longer modulates firing rate. Vestibular prostheses use a gyroscope to detect head motion and stimulate neurons directly in a way that mimics natural modulation. Proper restoration of vestibular function relies on the ability of stimulation to evoke the same firing patterns as the healthy system. For this reason, it is necessary to understand what firing rates are produced for different stimulation parameters. Two stimulation parameters commonly controlled in pulsatile neuromodulation are pulse rate and pulse amplitude. Previous neural recording experiments in the vestibular nerve contradict widely held assumptions about the relationship between pulse rates and evoked spike activity, and the relationship between pulse amplitude and neural activity has not been explored. Here we use a well-established computational model of the vestibular afferent to simulate responses to different pulse rates and amplitudes. We confirm that our simulated neural results agree with the existing experimental data. Finally, we developed the "Action Potential Collision" (APC) equation that defines induced firing as a function of spontaneous firing rate, pulse rate, and pulse amplitude. We show that this relationship can successfully predict simulated vestibular activity by accounting for interactions between pulses and spontaneous firing.
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16
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Figtree WVC, Schubert MC, Rinaudo CN, Migliaccio AA. The instantaneous training demand drives vestibulo-ocular reflex adaptation. Exp Brain Res 2020; 238:2965-2972. [PMID: 33070228 DOI: 10.1007/s00221-020-05953-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/09/2020] [Indexed: 11/28/2022]
Abstract
The vestibulo-ocular reflex (VOR) maintains stable vision during rapid head rotations by rotating the eyes in the opposite direction to the head. The latency between onset of the head rotation and onset of the eye rotation is 5-8 ms in healthy humans. However, VOR latency can be 3-4 times larger in patients treated with intra-tympanic gentamicin. A prior study showed that latency can be trained with head rotations at 0.2 Hz. We sought to determine how the VOR is affected when a delay between vestibular and visual stimuli is added during adaptation training with high-frequency head rotations (impulses), where the VOR is the main vision-stabilizing system. Using a variant of the incremental VOR adaptation technique, the delay between head rotation onset and movement onset of a visual target was gradually increased. With this training, the instantaneous VOR gain demand (= target/head velocity) varied from less than unity to greater than unity during each head impulse, albeit in a consistent and repeatable way. We measured the active and passive VOR gain and latency before and after VOR adaptation training in healthy normal subjects. There was no significant change in VOR latency across subjects; however, there was a significant decrease in VOR gain of - 6.0 ± 4.5%. These data suggest that during high-frequency head rotations delay/latency is interpreted as a changing instantaneous VOR gain demand. Although the gain demand in this study had a complex trajectory, adaptation was evident with the VOR seeming to use an average of the instantaneous gain demand.
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Affiliation(s)
- William V C Figtree
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, Sydney, NSW, 2031, Australia
| | - Michael C Schubert
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Physical Medicine and Rehabilitation, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Carlo N Rinaudo
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2033, Australia
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Cnr Barker Street & Easy Street, Randwick, Sydney, NSW, 2031, Australia. .,University of New South Wales, Sydney, NSW, 2033, Australia. .,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, 21205, USA. .,School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia.
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17
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Ren P, Li B, Dong S, Lyu B, Qu J, Gong S, Zhang Q, Han P. The real identity and sensory overlap mechanism of special vestibular afferent neurons that sense both rotation and linear force. Life Sci 2020; 259:118144. [PMID: 32755624 DOI: 10.1016/j.lfs.2020.118144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/12/2020] [Accepted: 07/21/2020] [Indexed: 10/23/2022]
Abstract
AIMS Although the vestibular system has been widely investigated over the past 50 years, there is still an unsolved mystery. Some special vestibular afferent (SVA) neurons responding to both rotation and linear force were found through neurophysiological techniques, however, the sensory overlap mechanism of SVA neurons is still unclear, which may be closely related to vestibular-related diseases. MATERIALS AND METHODS To address the above-mentioned problem, a cupula buoyancy theory was established in the present study, where SVA neurons were considered semicircular canal afferent (SCCA) neurons. Then labyrinth anatomy and neural response dynamics of vestibular afferent neurons in chinchilla were investigated through vestibular labyrinth reconstruction and single unit recording technique, respectively. KEY FINDINGS We analyzed the deflections of cupulae under multiple conditions with the help of Amira Software and predicted the neural response law of SCCA neurons to linear force based on the cupula buoyancy theory. Data analysis confirmed that the basic response characteristic of SVA neurons had no significant difference to those of SCCA neurons, but were significantly different from those of otolith afferent neurons. Further, the actual responses of SVA neurons to linear force are completely consistent with our predictions. These results strongly suggest that SVA neurons actually are SCCA neurons, and the cupula buoyancy theory is the key to the sensory overlap mechanism of SCCA neurons. SIGNIFICANCE Our study revealed the real identity of SVA neurons and provided a reasonable mechanism for sensory overlap of rotation and linear force, which improved our understanding about the vestibular system.
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Affiliation(s)
- Pengyu Ren
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China; Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Bowen Li
- Division of Health Sciences Informatics, Johns Hopkins University School of Medicine, 2024 E Monument St, Baltimore, MD 21205, USA
| | - Shiyao Dong
- Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Boqiang Lyu
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Jianqiang Qu
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Shouping Gong
- Department of Neurosurgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 West 5th Road, Xi'an, Shaanxi 710004, China
| | - Qing Zhang
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital of Shanghai Jiaotong University, 1665 Kongjiang Rd, Shanghai 200093, China
| | - Peng Han
- Department of Otolaryngology-Head & Neck Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 227 Yanta West Roud, Xi'an, Shaanxi 710061, China.
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18
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Mackrous I, Carriot J, Cullen KE, Chacron MJ. Neural variability determines coding strategies for natural self-motion in macaque monkeys. eLife 2020; 9:57484. [PMID: 32915134 PMCID: PMC7521927 DOI: 10.7554/elife.57484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/10/2020] [Indexed: 12/12/2022] Open
Abstract
We have previously reported that central neurons mediating vestibulo-spinal reflexes and self-motion perception optimally encode natural self-motion (Mitchell et al., 2018). Importantly however, the vestibular nuclei also comprise other neuronal classes that mediate essential functions such as the vestibulo-ocular reflex (VOR) and its adaptation. Here we show that heterogeneities in resting discharge variability mediate a trade-off between faithful encoding and optimal coding via temporal whitening. Specifically, neurons displaying lower variability did not whiten naturalistic self-motion but instead faithfully represented the stimulus' detailed time course, while neurons displaying higher variability displayed temporal whitening. Using a well-established model of VOR pathways, we demonstrate that faithful stimulus encoding is necessary to generate the compensatory eye movements found experimentally during naturalistic self-motion. Our findings suggest a novel functional role for variability toward establishing different coding strategies: (1) faithful stimulus encoding for generating the VOR; (2) optimized coding via temporal whitening for other vestibular functions.
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Affiliation(s)
| | - Jérome Carriot
- Department of Physiology, McGill University, Montreal, Canada
| | - Kathleen E Cullen
- The Department of Otolaryngology- Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, United States.,The Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, United States.,The Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, United States
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19
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Aplin FP, Singh D, Della Santina CC, Fridman GY. Combined ionic direct current and pulse frequency modulation improves the dynamic range of vestibular canal stimulation. J Vestib Res 2020; 29:89-96. [PMID: 30856136 DOI: 10.3233/ves-190651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Vestibular prostheses emulate normal vestibular function by electrically stimulating the semicircular canals using pulse frequency modulation (PFM). Spontaneous activity at the vestibular nerve may limit the dynamic range elicited by PFM. One proposed solution is the co-application of ionic direct current (iDC) to inhibit this spontaneous activity. OBJECTIVE We aimed to test the hypothesis that a tonic iDC baseline delivered in conjunction with PFM to the vestibular semicircular canals could improve the dynamic range of evoked eye responses. METHODS Gentamicin-treated chinchillas were implanted with microcatheter electrodes in the vestibular semicircular canals through which pulsatile and iDC current was delivered. PFM was used to modulate vestibulo-ocular reflex (VOR) once it was adapted to a preset iDC and pulse-frequency baseline. Responses to stimulation were assessed by recording the evoked VOR eye direction and velocity. RESULTS PFM produced VOR responses aligned to the stimulated canal. Introduction of an iDC baseline lead to a small but statistically significant increase in eye response velocity, without influencing the direction of eye rotation. CONCLUSIONS Tonic iDC baselines increase the dynamic range of encoding head velocity evoked by pulsatile stimulation, potentially via the inhibition of spontaneous activity in the vestibular nerve.
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Affiliation(s)
- F P Aplin
- Departments of Otolaryngology Head and Neck Surgery and Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - D Singh
- Departments of Otolaryngology Head and Neck Surgery and Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - C C Della Santina
- Departments of Otolaryngology Head and Neck Surgery and Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - G Y Fridman
- Departments of Otolaryngology Head and Neck Surgery and Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
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20
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Prins TJ, Myers ZA, Saldate JJ, Hoffman LF. Calbindin expression in adult vestibular epithelia. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:623-637. [PMID: 32350587 DOI: 10.1007/s00359-020-01418-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/28/2020] [Accepted: 04/01/2020] [Indexed: 01/11/2023]
Abstract
The mammalian vestibular epithelia exhibit a remarkably stereotyped organization featuring cellular characteristics under planar cell polarity (PCP) control. PCP mechanisms are responsible for the organization of hair cell morphologic polarization vectors, and are thought to be responsible for the postsynaptic expression of the calcium-binding protein calretinin that defines the utricular striola and cristae central zone. However, recent analyses revealed that subtle differences in the topographic expression of oncomodulin, another calcium-binding protein, reflects heterogeneous factors driving the subtle variations in expression. Calbindin represents a third calcium-binding protein that has been previously described to be expressed in both hair cells and afferent calyces in proximity to the utricular striola and crista central zone. The objective of the present investigation was to determine calbindin's topographic pattern of expression to further elucidate the extent to which PCP mechanisms might exert control over the organization of vestibular neuroepithelia. The findings revealed that calbindin exhibited an expression pattern strikingly similar to oncomodulin. However, within calyces of the central zone calbindin was colocalized with calretinin. These results indicate that organizational features of vestibular epithelia are governed by a suite of factors that include PCP mechanisms as well others yet to be defined.
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Affiliation(s)
- Terry J Prins
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Box 951624, Los Angeles, CA, 90095-1624, USA.,Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA, 90095, USA
| | - Zachary A Myers
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Box 951624, Los Angeles, CA, 90095-1624, USA
| | - Johnny J Saldate
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Box 951624, Los Angeles, CA, 90095-1624, USA
| | - Larry F Hoffman
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Box 951624, Los Angeles, CA, 90095-1624, USA. .,Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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21
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Ono K, Keller J, López Ramírez O, González Garrido A, Zobeiri OA, Chang HHV, Vijayakumar S, Ayiotis A, Duester G, Della Santina CC, Jones SM, Cullen KE, Eatock RA, Wu DK. Retinoic acid degradation shapes zonal development of vestibular organs and sensitivity to transient linear accelerations. Nat Commun 2020; 11:63. [PMID: 31896743 PMCID: PMC6940366 DOI: 10.1038/s41467-019-13710-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 11/21/2019] [Indexed: 01/18/2023] Open
Abstract
Each vestibular sensory epithelium in the inner ear is divided morphologically and physiologically into two zones, called the striola and extrastriola in otolith organ maculae, and the central and peripheral zones in semicircular canal cristae. We found that formation of striolar/central zones during embryogenesis requires Cytochrome P450 26b1 (Cyp26b1)-mediated degradation of retinoic acid (RA). In Cyp26b1 conditional knockout mice, formation of striolar/central zones is compromised, such that they resemble extrastriolar/peripheral zones in multiple features. Mutants have deficient vestibular evoked potential (VsEP) responses to jerk stimuli, head tremor and deficits in balance beam tests that are consistent with abnormal vestibular input, but normal vestibulo-ocular reflexes and apparently normal motor performance during swimming. Thus, degradation of RA during embryogenesis is required for formation of highly specialized regions of the vestibular sensory epithelia with specific functions in detecting head motions.
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Affiliation(s)
- Kazuya Ono
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James Keller
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
- Qiagen Sciences Inc., Germantown, MD, 20874, USA
| | - Omar López Ramírez
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA
| | | | - Omid A Zobeiri
- Department of Physiology McGill University, Montreal, QC, Canada, H3G 1Y6
| | | | - Sarath Vijayakumar
- Department of Special Education and Communication Disorders, 301 Barkley Memorial Center, University of Nebraska-Lincoln, Lincoln, NE, 68583-0738, USA
| | - Andrianna Ayiotis
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Gregg Duester
- Neuroscience and Aging Research Center, Stanford Burnham Prebys Medical Discovery Institutes, Stanford, CA, 92037, USA
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sherri M Jones
- Department of Special Education and Communication Disorders, 301 Barkley Memorial Center, University of Nebraska-Lincoln, Lincoln, NE, 68583-0738, USA
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ruth Anne Eatock
- Department of Neurobiology, University of Chicago, Chicago, IL, 60637, USA
| | - Doris K Wu
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
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22
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The Ototoxic Potential of Cobalt From Metal-on-Metal Hip Implants: Objective Auditory and Vestibular Outcome. Ear Hear 2020; 41:217-230. [DOI: 10.1097/aud.0000000000000747] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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23
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Hageman KN, Chow MR, Roberts D, Boutros PJ, Tooker A, Lee K, Felix S, Pannu SS, Haque R, Della Santina CC. Binocular 3D otolith-ocular reflexes: responses of chinchillas to prosthetic electrical stimulation targeting the utricle and saccule. J Neurophysiol 2019; 123:259-276. [PMID: 31747349 DOI: 10.1152/jn.00883.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
From animal experiments by Cohen and Suzuki et al. in the 1960s to the first-in-human clinical trials now in progress, prosthetic electrical stimulation targeting semicircular canal branches of the vestibular nerve has proven effective at driving directionally appropriate vestibulo-ocular reflex eye movements, postural responses, and perception. That work was considerably facilitated by the fact that all hair cells and primary afferent neurons in each canal have the same directional sensitivity to head rotation, the three canals' ampullary nerves are geometrically distinct from one another, and electrically evoked three-dimensional (3D) canal-ocular reflex responses approximate a simple vector sum of linearly independent components representing relative excitation of each of the three canals. In contrast, selective prosthetic stimulation of the utricle and saccule has been difficult to achieve, because hair cells and afferents with many different directional sensitivities are densely packed in those endorgans and the relationship between 3D otolith-ocular reflex responses and the natural and/or prosthetic stimuli that elicit them is more complex. As a result, controversy exists regarding whether selective, controllable stimulation of electrically evoked otolith-ocular reflexes (eeOOR) is possible. Using micromachined, planar arrays of electrodes implanted in the labyrinth, we quantified 3D, binocular eeOOR responses to prosthetic electrical stimulation targeting the utricle, saccule, and semicircular canals of alert chinchillas. Stimuli delivered via near-bipolar electrode pairs near the maculae elicited sustained ocular countertilt responses that grew reliably with pulse rate and pulse amplitude, varied in direction according to which stimulating electrode was employed, and exhibited temporal dynamics consistent with responses expected for isolated macular stimulation.NEW & NOTEWORTHY As the second in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper describes new planar electrode arrays and vestibular prosthesis architecture designed to target the three semicircular canals and the utricle and saccule. With this technological advancement, electrically evoked otolith-ocular reflexes due to stimulation via utricle- and saccule-targeted electrodes were recorded in chinchillas. Results demonstrate advances toward achieving selective stimulation of the utricle and saccule.
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Affiliation(s)
- Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Dale Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Peter J Boutros
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Angela Tooker
- Lawrence Livermore National Laboratory, Livermore, California
| | - Kye Lee
- Lawrence Livermore National Laboratory, Livermore, California
| | - Sarah Felix
- Lawrence Livermore National Laboratory, Livermore, California
| | | | - Razi Haque
- Lawrence Livermore National Laboratory, Livermore, California
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
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Rinaudo CN, Schubert MC, Figtree WVC, Todd CJ, Migliaccio AA. Human vestibulo-ocular reflex adaptation is frequency selective. J Neurophysiol 2019; 122:984-993. [PMID: 31339801 DOI: 10.1152/jn.00162.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vestibulo-ocular reflex (VOR) is the only system that maintains stable vision during rapid head rotations. The VOR gain (eye/head velocity) can be trained to increase using a vestibular-visual mismatch stimulus. We sought to determine whether low-frequency (sinusoidal) head rotation during training leads to changes in the VOR during high-frequency head rotation testing, where the VOR is more physiologically relevant. We tested eight normal subjects over three sessions. For training protocol 1, subjects performed active sinusoidal head rotations at 1.3 Hz while tracking a laser target, whose velocity incrementally increased relative to head velocity so that the VOR gain required to stabilize the target went from 1.1 to 2 over 15 min. Protocol 2 was the same as protocol 1, except that head rotations were at 0.5 Hz. For protocol 3, head rotation frequency incrementally increased from 0.5 to 2 Hz over 15 min, while the VOR gain required to stabilize the target was kept at 2. We measured the active and passive, sinusoidal (1.3Hz) and head impulse VOR gains before and after each protocol. Sinusoidal and head impulse VOR gains increased in protocols 1 and 3; however, although the sinusoidal VOR gain increase was ~20%, the related head impulse gain increase was only ~10%. Protocol 2 resulted in no-gain adaptation. These data show human VOR adaptation is frequency selective, suggesting that if one seeks to increase the higher-frequency VOR response, i.e., where it is physiologically most relevant, then higher-frequency head movements are required during training, e.g., head impulses.NEW & NOTEWORTHY This study shows that human vestibulo-ocular reflex adaptation is frequency selective at frequencies >0.3 Hz. The VOR in response to mid- (1.3 Hz) and high-frequency (impulse) head rotations were measured before and after mid-frequency sinusoidal VOR adaptation training, revealing that the mid-frequency gain change was higher than high-frequency gain change. Thus, if one seeks to increase the higher-frequency VOR response, where it is physiologically most relevant, then higher-frequency head movements are required during training.
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Affiliation(s)
- Carlo N Rinaudo
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Michael C Schubert
- Laboratory of Vestibular NeuroAdaptation, Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland.,Physical Medicine and Rehabilitation, Johns Hopkins University, Baltimore, Maryland
| | - William V C Figtree
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, Australia
| | - Christopher J Todd
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, Australia
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.,Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland.,School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia
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25
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Covelli E, Talamonti R, Benincasa AT, Filippi C, Marrone V, Tarentini S, Monini S, Barbara M. Video Head Impulse Test in Labyrinthine Fistula due to Middle Ear Cholesteatoma. J Int Adv Otol 2019; 15:283-288. [PMID: 31257189 DOI: 10.5152/iao.2019.5678] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES To assess and monitor lateral semicircular canal (LSC) function over time in patients affected by chronic otitis media with cholesteatoma (CHO) complicated by fistula of LSC (LSC-F) before and after surgery using video Head Impulse Test (vHIT). MATERIALS AND METHODS Eight patients aged 18-67 years affected by CHO with imaging-ascertained LSC-F were included in this preliminary prospective study. The following protocol has been applied: oto-microscopic diagnosis with patient's history; computed tomography scan of the temporal bone; surgery with concomitant resurfacing of LSF-F; audiological and vestibular evaluation before surgery (T0) and at 30 days (T1), 6 months (T2), and 1 year after surgery (T3). vHIT was used to assess vestibulo-ocular reflex (VOR) in LSC. RESULTS None of the patients showed deterioration of bone conduction hearing levels during the different time of evaluation. Three patients showed a reduced VOR gain and catch-up saccades at T0, with VOR gain normalization at T2. This finding remained stable at the 1-year follow-up. The VOR gain in the nonaffected side generally experienced an increase, paralleled by the normalization on the affected side, with statistically significant correlation. The subjects with normal vHIT before surgery did not show any variation following surgery. CONCLUSION vHIT allows the assessment of LSC function in case of fistula. The adopted surgical fistula repair did not induce deterioration of the auditory or LSC function, but indeed, it could prevent worsening and help promoting recovery to the normal function.
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Affiliation(s)
- Edoardo Covelli
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Rita Talamonti
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Anna Teresa Benincasa
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Chiara Filippi
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Vania Marrone
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Silvia Tarentini
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Simonetta Monini
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
| | - Maurizio Barbara
- Department of Department of Neuroscience, Mental Health and Sense Organs NESMOS, Sapienza University, Rome, Italy
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26
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Ren PY, Li BW, Dong SY, Wu M, Han P. Improvement of Mechanical Stability for Single Unit Recording Based on Skull Cap in Living Chinchilla. Curr Med Sci 2019; 39:166-172. [PMID: 30868508 DOI: 10.1007/s11596-019-2015-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/17/2018] [Indexed: 11/29/2022]
Abstract
Three-point head fixation was constructed to provide mechanical stability for single unit recording (SUR) on vestibular sensory system in living chinchilla previously. However, it is no more qualified to this work when the stimulation intensity becomes large because of frequent unit losing and neuron damage, which strongly implies that the mechanical stability has been broken during the stimulation. Here, we constructed a novel head fixation (skull cap assistant head fixation) provided by skull cap on the basis of three-point head fixation in order to improve the mechanical stability for SUR under the stimulation with large magnitude. The large area bone connection is the feature and advantage of this improved method, which directly fixes the tested local nervous tissue and microelectrode in an intact stable system through skull cap except two ear bars and a tube face mask. Our data exhibited that skull cap assistant head fixation could significantly improve the success rate of neural response activity recording in the population of semicircular canal neurons under the stimulation with large intensity (amplitude ≥100 deg/s). Based on the analysis of neural response activity and noise base-line during stimulation, our data further indicated that this method could significantly improve the mechanical stability for SUR during high-speed motion stimulation on vestibular system in living chinchilla. Skull cap assistant head fixation extends the application of SUR on vestibular neuron in linear response range and provides a solid foundation for electrophysiological research on vestibular sensory system in further studies.
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Affiliation(s)
- Peng-Yu Ren
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004, China.,Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, 21205, USA
| | - Bo-Wen Li
- Division of Health Sciences Informatics, Johns Hopkins University School of Medicine, Baltimore, 21205, USA
| | - Shi-Yao Dong
- School of Mathematics and Statistics, Central China Normal University, Wuhan, 430079, China
| | - Ming Wu
- School of Mathematics and Statistics, Central China Normal University, Wuhan, 430079, China.
| | - Peng Han
- Department of Otolaryngology-Head & Neck Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China.
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27
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Rabbitt RD. Semicircular canal biomechanics in health and disease. J Neurophysiol 2019; 121:732-755. [PMID: 30565972 PMCID: PMC6520623 DOI: 10.1152/jn.00708.2018] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
The semicircular canals are responsible for sensing angular head motion in three-dimensional space and for providing neural inputs to the central nervous system (CNS) essential for agile mobility, stable vision, and autonomic control of the cardiovascular and other gravity-sensitive systems. Sensation relies on fluid mechanics within the labyrinth to selectively convert angular head acceleration into sensory hair bundle displacements in each of three inner ear sensory organs. Canal afferent neurons encode the direction and time course of head movements over a broad range of movement frequencies and amplitudes. Disorders altering canal mechanics result in pathological inputs to the CNS, often leading to debilitating symptoms. Vestibular disorders and conditions with mechanical substrates include benign paroxysmal positional nystagmus, direction-changing positional nystagmus, alcohol positional nystagmus, caloric nystagmus, Tullio phenomena, and others. Here, the mechanics of angular motion transduction and how it contributes to neural encoding by the semicircular canals is reviewed in both health and disease.
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Affiliation(s)
- R. D. Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah
- Otolaryngology-Head Neck Surgery, University of Utah, Salt Lake City, Utah
- Neuroscience Program, University of Utah, Salt Lake City, Utah
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28
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Eatock RA. Specializations for Fast Signaling in the Amniote Vestibular Inner Ear. Integr Comp Biol 2019; 58:341-350. [PMID: 29920589 DOI: 10.1093/icb/icy069] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During rapid locomotion, the vestibular inner ear provides head-motion signals that stabilize posture, gaze, and heading. Afferent nerve fibers from central and peripheral zones of vestibular sensory epithelia use temporal and rate encoding, respectively, to emphasize different aspects of head motion: central afferents adapt faster to sustained head position and favor higher stimulus frequencies, reflecting specializations at each stage from motion of the accessory structure to spike propagation to the brain. One specialization in amniotes is an unusual nonquantal synaptic mechanism by which type I hair cells transmit to large calyceal terminals of afferent neurons. The reduced synaptic delay of this mechanism may have evolved to serve reliable and fast input to reflex pathways that ensure stable locomotion on land.
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Affiliation(s)
- Ruth Anne Eatock
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
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29
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Mitchell DE, Kwan A, Carriot J, Chacron MJ, Cullen KE. Neuronal variability and tuning are balanced to optimize naturalistic self-motion coding in primate vestibular pathways. eLife 2018; 7:e43019. [PMID: 30561328 PMCID: PMC6312400 DOI: 10.7554/elife.43019] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 12/17/2018] [Indexed: 12/14/2022] Open
Abstract
It is commonly assumed that the brain's neural coding strategies are adapted to the statistics of natural stimuli. Specifically, to maximize information transmission, a sensory neuron's tuning function should effectively oppose the decaying stimulus spectral power, such that the neural response is temporally decorrelated (i.e. 'whitened'). However, theory predicts that the structure of neuronal variability also plays an essential role in determining how coding is optimized. Here, we provide experimental evidence supporting this view by recording from neurons in early vestibular pathways during naturalistic self-motion. We found that central vestibular neurons displayed temporally whitened responses that could not be explained by their tuning alone. Rather, computational modeling and analysis revealed that neuronal variability and tuning were matched to effectively complement natural stimulus statistics, thereby achieving temporal decorrelation and optimizing information transmission. Taken together, our findings reveal a novel strategy by which neural variability contributes to optimized processing of naturalistic stimuli.
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Affiliation(s)
| | - Annie Kwan
- Department of PhysiologyMcGill UniversityMontrealCanada
| | | | | | - Kathleen E Cullen
- Department of PhysiologyMcGill UniversityMontrealCanada
- Department of Biomedical EngineeringThe Johns Hopkins UniversityBaltimoreUnited States
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30
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Sachgau C, Chung W, Barnett-Cowan M. Perceived timing of active head movement at different speeds. Neurosci Lett 2018; 687:253-258. [PMID: 30287302 DOI: 10.1016/j.neulet.2018.09.065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 09/21/2018] [Accepted: 09/29/2018] [Indexed: 10/28/2022]
Abstract
The central nervous system must determine which sensory events occur at the same time. Actively moving the head corresponds with large changes in the relationship between the observer and the environment, sensorimotor processing, and spatiotemporal perception. Active head movement perception has been shown to be dependent on head movement velocity where participants who move their head fastest require the head to move earlier than comparison stimuli for perceived simultaneity more so than those who move their head slower. Such between-subject results cannot address whether active head movement perception changes with velocity. The present study used a within-subjects design to measure the point of subjective simultaneity (PSS) between active head movement speeds and a comparison sound stimulus to characterize the relationship between the velocity and perception of head movement onset. Our results clearly show that i) head movement perception is faster with faster head movements within-subjects, ii) active head movement onset must still precede the onset of other sensory events (average PSS: -123 ms to -52 ms; median PSS: -42 ms to -100 ms) in order to be perceived as occurring simultaneously even at the fastest speeds (average peak velocity: 76°/s-257°/s; median peak velocity 72 ms-257 ms). We conclude that head movement perception is slow, but that this delay is minimized with increased speed. These within-subject results are contrary to previous and present study between-subject results and are in agreement with literature where perception of auditory, visual and vestibular stimulus onset is less delayed with increased stimulus intensity.
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Affiliation(s)
- Carolin Sachgau
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
| | - William Chung
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Michael Barnett-Cowan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
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31
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Aplin FP, Singh D, Santina CCD, Fridman GY. Ionic Direct Current Modulation for Combined Inhibition/Excitation of the Vestibular System. IEEE Trans Biomed Eng 2018; 66:775-783. [PMID: 30010547 DOI: 10.1109/tbme.2018.2856698] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Prosthetic electrical stimulation delivered to the vestibular nerve could provide therapy for people suffering from bilateral vestibular dysfunction. Common encoding methods use pulse-frequency modulation (PFM) to stimulate the semicircular canals of the vestibular system. We previously showed that delivery of ionic direct current (iDC) can also modulate the vestibular system. In this study, we compare the dynamic range of head velocity encoding from iDC modulation to that of PFM controls. METHODS Gentamicin-treated wild-type chinchillas were implanted with microcatheter tubes that delivered ionic current to the left ear vestibular canals and stimulated with steps of anodic/cathodic iDC or PFM. Evoked vestibulo-ocular reflex eye velocity was used to compare PFM and iDC vestibular modulation. RESULTS Cathodic iDC steps effectively elicited eye rotations consistent with an increased firing rate of the implanted semicircular canal afferents. Anodic iDC current steps elicited eye rotations in the opposite direction that, when paired with an adapted cathodic offset, increased the dynamic range of eye rotation velocities in comparison to PFM controls. CONCLUSION Our results suggest that iDC modulation can effectively modulate the vestibular system across a functional range of rotation vectors and velocities, with a potential benefit over a PFM stimulation paradigm. SIGNIFICANCE In conjunction with a safe dc delivery system, iDC modulation could potentially increase the range of simulated head rotation velocities available to neuroelectric vestibular prostheses.
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32
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Ren P, Li B, Dong S, Chen L, Zhang Y. The reliability of nonlinear least-squares algorithm for data analysis of neural response activity during sinusoidal rotational stimulation in semicircular canal neurons. PLoS One 2018; 13:e0190596. [PMID: 29304173 PMCID: PMC5755832 DOI: 10.1371/journal.pone.0190596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/17/2017] [Indexed: 11/19/2022] Open
Abstract
Although many mathematical methods were used to analyze the neural activity under sinusoidal stimulation within linear response range in vestibular system, the reliabilities of these methods are still not reported, especially in nonlinear response range. Here we chose nonlinear least-squares algorithm (NLSA) with sinusoidal model to analyze the neural response of semicircular canal neurons (SCNs) during sinusoidal rotational stimulation (SRS) over a nonlinear response range. Our aim was to acquire a reliable mathematical method for data analysis under SRS in vestibular system. Our data indicated that the reliability of this method in an entire SCNs population was quite satisfactory. However, the reliability was strongly negatively depended on the neural discharge regularity. In addition, stimulation parameters were the vital impact factors influencing the reliability. The frequency had a significant negative effect but the amplitude had a conspicuous positive effect on the reliability. Thus, NLSA with sinusoidal model resulted a reliable mathematical tool for data analysis of neural response activity under SRS in vestibular system and more suitable for those under the stimulation with low frequency but high amplitude, suggesting that this method can be used in nonlinear response range. This method broke out of the restriction of neural activity analysis under nonlinear response range and provided a solid foundation for future study in nonlinear response range in vestibular system.
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Affiliation(s)
- Pengyu Ren
- Department of Neurosurgery, Xi’an Jiaotong University School of Medicine, Xi’an, People’s Republic of China
- Departments of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - Bowen Li
- Division of Health Sciences Informatics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shiyao Dong
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Lin Chen
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yuelin Zhang
- Department of Neurosurgery, Xi’an Jiaotong University School of Medicine, Xi’an, People’s Republic of China
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33
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Guinand N, Van de Berg R, Cavuscens S, Ranieri M, Schneider E, Lucieer F, Kingma H, Guyot JP, Pérez Fornos A. The Video Head Impulse Test to Assess the Efficacy of Vestibular Implants in Humans. Front Neurol 2017; 8:600. [PMID: 29184530 PMCID: PMC5694451 DOI: 10.3389/fneur.2017.00600] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/27/2017] [Indexed: 11/27/2022] Open
Abstract
The purpose of this study was to evaluate whether it is possible to restore the high-frequency angular vestibulo-ocular reflex (aVOR) in patients suffering from a severe bilateral vestibulopathy (BV) and implanted with a vestibular implant prototype. Three patients (S1–3) participated in the study. They received a prototype vestibular implant with one to three electrode branches implanted in the proximity of the ampullary branches of the vestibular nerve. Five electrodes were available for electrical stimulation: one implanted in proximity of the left posterior ampullary nerve in S1, one in the left lateral and another one in the superior ampullary nerves in S2, and one in the right lateral and another one in the superior ampullary nerves in S3. The high-frequency aVOR was assessed using the video head impulse test (EyeSeeCam; EyeSeeTec, Munich, Germany), while motion-modulated electrical stimulation was delivered via one of the implanted vestibular electrodes at a time. aVOR gains were compared to control measurements obtained in the same patients when the device was not activated. In three out of the five tested electrodes the aVOR gain increased monotonically with increased stimulation strength when head impulses were delivered in the plane of the implanted canal. In these cases, gains ranging from 0.4 to values above 1 were measured. A “reversed” aVOR could also be generated when inversed stimulation paradigms were used. In most cases, the gain for excitatory head impulses was superior to that recorded for inhibitory head impulses, consistent with unilateral vestibular stimulation. Improvements of aVOR gain were generally accompanied by a concomitant decrease of corrective saccades, providing additional evidence of an effective aVOR. High inter-electrode and inter-subject variability were observed. These results, together with previous research, demonstrate that it is possible to restore the aVOR in a broad frequency range using motion-modulated electrical stimulation of the vestibular afferents. This provides additional encouraging evidence of the possibility of achieving a useful rehabilitation alternative for patients with BV in the near future.
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Affiliation(s)
- Nils Guinand
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland.,Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Raymond Van de Berg
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Samuel Cavuscens
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Maurizio Ranieri
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Erich Schneider
- Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Floor Lucieer
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Herman Kingma
- Division of Balance Disorders, Department of ENT, Maastricht University Medical Centre, Maastricht, Netherlands.,Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Jean-Philippe Guyot
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Angélica Pérez Fornos
- Service of Otorhinolaryngology Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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Core Body Temperature Effects on the Mouse Vestibulo-ocular Reflex. J Assoc Res Otolaryngol 2017; 18:827-835. [PMID: 28755310 DOI: 10.1007/s10162-017-0639-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 07/17/2017] [Indexed: 01/12/2023] Open
Abstract
Core body temperature has been shown to affect vestibular end-organ and nerve afferents so that their resting discharge rate and sensitivity increase with temperature. Our aim was to determine whether these changes observed in extracellular nerve recordings of anaesthetized C57BL/6 mice corresponded to changes in the behavioural vestibulo-ocular reflex (VOR) of alert mice. The VOR drives eye rotations to keep images stable on the retina during head movements. We measured the VOR gain (eye velocity/head velocity) and phase (delay between vestibular stimulus and response) during whole-body sinusoidal rotations ranging 0.5-12 Hz with peak velocity 50 or 100 °/s in nine adult C57BL/6 mice. We also measured the VOR during whole-body transient rotations with acceleration 3000 or 6000 °/s2 reaching a plateau of 150 or 300 °/s. These measures were obtained while the mouse's core body temperature was held at either 32 or 37 °C for at least 35 min before recording. The temperature presentation order and timing were pseudo-randomized. We found that a temperature increase from 32 to 37 °C caused a significant increase in sinusoidal VOR gain of 17 % (P < 0.001). Temperature had no other effects on the behavioural VOR. Our data suggest that temperature effects on regularly firing afferents best correspond to the changes that we observed in the VOR gain.
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35
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Dugué GP, Tihy M, Gourévitch B, Léna C. Cerebellar re-encoding of self-generated head movements. eLife 2017; 6:e26179. [PMID: 28608779 PMCID: PMC5489315 DOI: 10.7554/elife.26179] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/09/2017] [Indexed: 02/01/2023] Open
Abstract
Head movements are primarily sensed in a reference frame tied to the head, yet they are used to calculate self-orientation relative to the world. This requires to re-encode head kinematic signals into a reference frame anchored to earth-centered landmarks such as gravity, through computations whose neuronal substrate remains to be determined. Here, we studied the encoding of self-generated head movements in the rat caudal cerebellar vermis, an area essential for graviceptive functions. We found that, contrarily to peripheral vestibular inputs, most Purkinje cells exhibited a mixed sensitivity to head rotational and gravitational information and were differentially modulated by active and passive movements. In a subpopulation of cells, this mixed sensitivity underlay a tuning to rotations about an axis defined relative to gravity. Therefore, we show that the caudal vermis hosts a re-encoded, gravitationally polarized representation of self-generated head kinematics in freely moving rats.
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Affiliation(s)
- Guillaume P Dugué
- Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Matthieu Tihy
- Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
| | - Boris Gourévitch
- Genetics and Physiology of Hearing Laboratory, Inserm UMR1120, University Paris 6, Institut Pasteur, Paris, France
| | - Clément Léna
- Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France
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36
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Burns JC, Stone JS. Development and regeneration of vestibular hair cells in mammals. Semin Cell Dev Biol 2017; 65:96-105. [PMID: 27864084 PMCID: PMC5423856 DOI: 10.1016/j.semcdb.2016.11.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 10/20/2022]
Abstract
Vestibular sensation is essential for gaze stabilization, balance, and perception of gravity. The vestibular receptors in mammals, Type I and Type II hair cells, are located in five small organs in the inner ear. Damage to hair cells and their innervating neurons can cause crippling symptoms such as vertigo, visual field oscillation, and imbalance. In adult rodents, some Type II hair cells are regenerated and become re-innervated after damage, presenting opportunities for restoring vestibular function after hair cell damage. This article reviews features of vestibular sensory cells in mammals, including their basic properties, how they develop, and how they are replaced after damage. We discuss molecules that control vestibular hair cell regeneration and highlight areas in which our understanding of development and regeneration needs to be deepened.
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Affiliation(s)
- Joseph C Burns
- Decibel Therapeutics, 215 First St., Suite 430, Cambridge, MA 02142, USA.
| | - Jennifer S Stone
- Department of Otolaryngology/Head and Neck Surgery and The Virginia Merrill Bloedel Hearing Research Center, University of Washington School of Medicine, Box 357923, Seattle, WA 98195-7923, USA.
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37
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Hübner PP, Khan SI, Migliaccio AA. The mammalian efferent vestibular system plays a crucial role in vestibulo-ocular reflex compensation after unilateral labyrinthectomy. J Neurophysiol 2017; 117:1553-1568. [PMID: 28077670 PMCID: PMC5376604 DOI: 10.1152/jn.01049.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 11/22/2022] Open
Abstract
The α9-nicotinic acetylcholine receptor (α9-nAChR) subunit is expressed in the vestibular and auditory periphery, and its loss of function could compromise peripheral input from the predominantly cholinergic efferent vestibular system (EVS). A recent study has shown that α9-nAChRs play an important role in short-term vestibulo-ocular reflex (VOR) adaptation. We hypothesize that α9-nAChRs could also be important for other forms of vestibular plasticity, such as that needed for VOR recovery after vestibular organ injury. We measured the efficacy of VOR compensation in α9 knockout mice. These mice have deletion of most of the gene (chrna9) encoding the nAChR and thereby lack α9-nAChRs. We measured the VOR gain (eye velocity/head velocity) in 20 α9 knockout mice and 16 cba129 controls. We measured the sinusoidal (0.2-10 Hz, 20-100°/s) and transient (1,500-6,000°/s2) VOR in complete darkness before (baseline) unilateral labyrinthectomy (UL) and then 1, 5, and 28 days after UL. On day 1 after UL, cba129 mice retained ~50% of their initial function for contralesional rotations, whereas α9 knockout mice only retained ~20%. After 28 days, α9 knockout mice had ~50% lower gain for both ipsilesional and contralesional rotations compared with cba129 mice. Cba129 mice regained ~75% of their baseline function for ipsilesional and ~90% for contralesional rotations. In contrast, α9 knockout mice only regained ~30% and ~50% function, respectively, leaving the VOR severely impaired for rotations in both directions. Our results show that loss of α9-nAChRs severely affects VOR compensation, suggesting that complimentary central and peripheral EVS-mediated adaptive mechanisms might be affected by this loss.NEW & NOTEWORTHY Loss of the α9-nicotinic acetylcholine receptor (α9-nAChR) subunit utilized by the efferent vestibular system (EVS) has been shown to significantly affect vestibulo-ocular reflex (VOR) adaptation. In our present study we have shown that loss of α9-nAChRs also affects VOR compensation, suggesting that the mammalian EVS plays an important role in vestibular plasticity, in general, and that VOR compensation is a more distributed process than previously thought, relying on both central and peripheral changes.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/physiology
- Animals
- Efferent Pathways/physiology
- Female
- Functional Laterality/genetics
- Functional Laterality/physiology
- Linear Models
- Male
- Mice
- Mice, Inbred CBA
- Mice, Knockout
- Nystagmus, Physiologic
- Reaction Time
- Receptors, Nicotinic/deficiency
- Receptors, Nicotinic/genetics
- Reflex, Vestibulo-Ocular/physiology
- Rotation
- Time Factors
- Vestibule, Labyrinth/physiology
- Vestibule, Labyrinth/surgery
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Affiliation(s)
- Patrick P Hübner
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia; and
| | - Serajul I Khan
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia; and
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia;
- University of New South Wales, Sydney, New South Wales, Australia; and
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland
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Curthoys IS, MacDougall HG, Vidal PP, de Waele C. Sustained and Transient Vestibular Systems: A Physiological Basis for Interpreting Vestibular Function. Front Neurol 2017; 8:117. [PMID: 28424655 PMCID: PMC5371610 DOI: 10.3389/fneur.2017.00117] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/14/2017] [Indexed: 01/17/2023] Open
Abstract
Otolithic afferents with regular resting discharge respond to gravity or low-frequency linear accelerations, and we term these the static or sustained otolithic system. However, in the otolithic sense organs, there is anatomical differentiation across the maculae and corresponding physiological differentiation. A specialized band of receptors called the striola consists of mainly type I receptors whose hair bundles are weakly tethered to the overlying otolithic membrane. The afferent neurons, which form calyx synapses on type I striolar receptors, have irregular resting discharge and have low thresholds to high frequency (e.g., 500 Hz) bone-conducted vibration and air-conducted sound. High-frequency sound and vibration likely causes fluid displacement which deflects the weakly tethered hair bundles of the very fast type I receptors. Irregular vestibular afferents show phase locking, similar to cochlear afferents, up to stimulus frequencies of kilohertz. We term these irregular afferents the transient system signaling dynamic otolithic stimulation. A 500-Hz vibration preferentially activates the otolith irregular afferents, since regular afferents are not activated at intensities used in clinical testing, whereas irregular afferents have low thresholds. We show how this sustained and transient distinction applies at the vestibular nuclei. The two systems have differential responses to vibration and sound, to ototoxic antibiotics, to galvanic stimulation, and to natural linear acceleration, and such differential sensitivity allows probing of the two systems. A 500-Hz vibration that selectively activates irregular otolithic afferents results in stimulus-locked eye movements in animals and humans. The preparatory myogenic potentials for these eye movements are measured in the new clinical test of otolith function—ocular vestibular-evoked myogenic potentials. We suggest 500-Hz vibration may identify the contribution of the transient system to vestibular controlled responses, such as vestibulo-ocular, vestibulo-spinal, and vestibulo-sympathetic responses. The prospect of particular treatments targeting one or the other of the transient or sustained systems is now being realized in the clinic by the use of intratympanic gentamicin which preferentially attacks type I receptors. We suggest that it is valuable to view vestibular responses by this sustained-transient distinction.
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Affiliation(s)
- Ian S Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW, Australia
| | - Hamish G MacDougall
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW, Australia
| | - Pierre-Paul Vidal
- Cognition and Action Group, CNRS UMR8257, Centre Universitaire des Saints-Pères, University Paris Descartes, Paris, France
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Takimoto Y, Imai T, Kondo M, Hanada Y, Uno A, Ishida Y, Kamakura T, Kitahara T, Inohara H, Shimada S. Cisplatin-induced toxicity decreases the mouse vestibulo-ocular reflex. Toxicol Lett 2016; 262:49-54. [PMID: 27659732 DOI: 10.1016/j.toxlet.2016.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/05/2016] [Accepted: 09/17/2016] [Indexed: 10/21/2022]
Abstract
Cisplatin is a chemotherapeutic agent commonly used for the treatment of solid tumors, and its side-effects include vestibulotoxicity. Previous studies have reported cisplatin-induced vestibulotoxicity in various animal models, but no study has investigated in vivo mouse vestibular dysfunction after cisplatin. The aim of this study was to investigate cisplatin-induced vestibulotoxicity in C57BL/6J mice. Vestibular function was assessed by recording the vestibulo-ocular reflex (VOR). This was done during sinusoidal rotations in the horizontal plane at three frequencies (0.5, 1.0 and 2.5Hz). A high-resolution, high-frequency digital infra-red camera was used with eye-tracking algorithms. Cisplatin at 16mg/kg, but not 8mg/kg, decreased the VOR gain at 2.5Hz compared with the vehicle control. Following 16mg/kg cisplatin treatment, the animals showed no change in the optokinetic nystagmus response, suggesting that no major changes in visual or oculomotor functions had occurred. This mouse model may be useful for studying cisplatin-induced vestibulotoxicity and its treatment.
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Affiliation(s)
- Yasumitsu Takimoto
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Otorhinolaryngology, Suita Municipal Hospital, 2-13-20 Katayama-cho, Suita City, Osaka 564-0082, Japan.
| | - Takao Imai
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Makoto Kondo
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yukiko Hanada
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuhiko Uno
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yusuke Ishida
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takefumi Kamakura
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tadashi Kitahara
- Department of Otorhinolaryngology-Head and Neck Surgery, Nara Medical University School of Medicine, 480 Shijocho, Kashihara, Nara 634-8522, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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40
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Video head impulse test: a review of the literature. Eur Arch Otorhinolaryngol 2016; 274:1215-1222. [DOI: 10.1007/s00405-016-4157-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/15/2016] [Indexed: 10/21/2022]
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41
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Rabbitt RD, Brichta AM, Tabatabaee H, Boutros PJ, Ahn J, Della Santina CC, Poppi LA, Lim R. Heat pulse excitability of vestibular hair cells and afferent neurons. J Neurophysiol 2016; 116:825-43. [PMID: 27226448 DOI: 10.1152/jn.00110.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022] Open
Abstract
In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at -68 mV and in 67% of hair cells at -60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability.
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Affiliation(s)
- Richard D Rabbitt
- Departments of Bioengineering and Otolaryngology, University of Utah, Salt Lake City, Utah;
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Hessam Tabatabaee
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Peter J Boutros
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - JoongHo Ahn
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Lauren A Poppi
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
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42
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DiGiovanna J, Nguyen TAK, Guinand N, Pérez-Fornos A, Micera S. Neural Network Model of Vestibular Nuclei Reaction to Onset of Vestibular Prosthetic Stimulation. Front Bioeng Biotechnol 2016; 4:34. [PMID: 27148528 PMCID: PMC4837148 DOI: 10.3389/fbioe.2016.00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/30/2016] [Indexed: 11/24/2022] Open
Abstract
The vestibular system incorporates multiple sensory pathways to provide crucial information about head and body motion. Damage to the semicircular canals, the peripheral vestibular organs that sense rotational velocities of the head, can severely degrade the ability to perform activities of daily life. Vestibular prosthetics address this problem by using stimulating electrodes that can trigger primary vestibular afferents to modulate their firing rates, thus encoding head movement. These prostheses have been demonstrated chronically in multiple animal models and acutely tested in short-duration trials within the clinic in humans. However, mainly, due to limited opportunities to fully characterize stimulation parameters, there is a lack of understanding of “optimal” stimulation configurations for humans. Here, we model possible adaptive plasticity in the vestibular pathway. Specifically, this model highlights the influence of adaptation of synaptic strengths and offsets in the vestibular nuclei to compensate for the initial activation of the prosthetic. By changing the synaptic strengths, the model is able to replicate the clinical observation that erroneous eye movements are attenuated within 30 minutes without any change to the prosthetic stimulation rate. Although our model was only built to match this time point, we further examined how it affected subsequent pulse rate modulation (PRM) and pulse amplitude modulation (PAM). PAM was more effective than PRM for nearly all stimulation configurations during these acute tests. Two non-intuitive relationships highlighted by our model explain this performance discrepancy. Specifically, the attenuation of synaptic strengths for afferents stimulated during baseline adaptation and the discontinuity between baseline and residual firing rates both disproportionally boost PAM. Comodulation of pulse rate and amplitude has been experimentally shown to induce both excitatory and inhibitory eye movements even at high baseline stimulation rates. We also modeled comodulation and found synergistic combinations of stimulation parameters to achieve equivalent output to only amplitude modulation. This may be an important strategy to reduce current spread and misalignment. The model outputs reflected observed trends in clinical testing and aspects of existing vestibular prosthetic literature. Importantly, the model provided insight to efficiently explore the stimulation parameter space, which was helpful, given limited available patient time.
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Affiliation(s)
- Jack DiGiovanna
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - T A K Nguyen
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
| | - Nils Guinand
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Angelica Pérez-Fornos
- Cochlear Implant Center for French Speaking Switzerland, Service of Otorhinolaryngology - Head and Neck Surgery, Geneva University Hospitals , Geneva , Switzerland
| | - Silvestro Micera
- Center for Neuroprosthetics, Bertarelli Foundation Chair in Translational Neuroengineering, École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
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43
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Straka H, Zwergal A, Cullen KE. Vestibular animal models: contributions to understanding physiology and disease. J Neurol 2016; 263 Suppl 1:S10-23. [PMID: 27083880 PMCID: PMC4833800 DOI: 10.1007/s00415-015-7909-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 12/20/2022]
Abstract
Our knowledge of the vestibular sensory system, its functional significance for gaze and posture stabilization, and its capability to ensure accurate spatial orientation perception and spatial navigation has greatly benefitted from experimental approaches using a variety of vertebrate species. This review summarizes the attempts to establish the roles of semicircular canal and otolith endorgans in these functions followed by an overview of the most relevant fields of vestibular research including major findings that have advanced our understanding of how this system exerts its influence on reflexive and cognitive challenges encountered during daily life. In particular, we highlight the contributions of different animal models and the advantage of using a comparative research approach. Cross-species comparisons have established that the morpho-physiological properties underlying vestibular signal processing are evolutionarily inherent, thereby disclosing general principles. Based on the documented success of this approach, we suggest that future research employing a balanced spectrum of standard animal models such as fish/frog, mouse and primate will optimize our progress in understanding vestibular processing in health and disease. Moreover, we propose that this should be further supplemented by research employing more “exotic” species that offer unique experimental access and/or have specific vestibular adaptations due to unusual locomotor capabilities or lifestyles. Taken together this strategy will expedite our understanding of the basic principles underlying vestibular computations to reveal relevant translational aspects. Accordingly, studies employing animal models are indispensible and even mandatory for the development of new treatments, medication and technical aids (implants) for patients with vestibular pathologies.
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Affiliation(s)
- Hans Straka
- Department Biology II, Ludwig-Maximilians-University Munich, Grosshaderner Str. 2, 82152, Planegg, Germany. .,German Center for Vertigo and Balance Disorders, DSGZ, Ludwig-Maximilians-University of Munich, Munich, Germany.
| | - Andreas Zwergal
- German Center for Vertigo and Balance Disorders, DSGZ, Ludwig-Maximilians-University of Munich, Munich, Germany.,Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Kathleen E Cullen
- Department of Physiology, McGill University, Montreal, QC, H3A 0G4, Canada
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44
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Francis HW, Papel I, Lina I, Koch W, Tunkel D, Fuchs P, Lin S, Kennedy D, Ruben R, Linthicum F, Marsh B, Best S, Carey J, Lane A, Byrne P, Flint P, Eisele DW. Otolaryngology-head and neck surgery at Johns Hopkins: The first 100 years (1914-2014). Laryngoscope 2015; 125 Suppl 9:S1-35. [PMID: 26297867 PMCID: PMC4696071 DOI: 10.1002/lary.25490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Howard W Francis
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ira Papel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ioan Lina
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Wayne Koch
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Tunkel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Fuchs
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Sandra Lin
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Kennedy
- the Department of Otolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert Ruben
- the Departments ofOtorhinolaryngology-Head and Neck Surgery and Pediatrics, Albert Einstein College of Medicine Montefiore Medical Center, New York, New York
| | - Fred Linthicum
- the Department of Otolaryngology-Head and Neck Surgery, University of California at Los Angeles, Los Angeles, California
| | - Bernard Marsh
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Simon Best
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - John Carey
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Andrew Lane
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Patrick Byrne
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Flint
- Department of Otolaryngology-Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon, U.S.A
| | - David W Eisele
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
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45
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Hübner PP, Khan SI, Migliaccio AA. The mammalian efferent vestibular system plays a crucial role in the high-frequency response and short-term adaptation of the vestibuloocular reflex. J Neurophysiol 2015; 114:3154-65. [PMID: 26424577 DOI: 10.1152/jn.00307.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 09/28/2015] [Indexed: 11/22/2022] Open
Abstract
Although anatomically well described, the functional role of the mammalian efferent vestibular system (EVS) remains unclear. Unlike in fish and reptiles, the mammalian EVS does not seem to play a role in modulation of primary afferent activity in anticipation of active head movements. However, it could play a role in modulating long-term mechanisms requiring plasticity such as vestibular adaptation. We measured the efficacy of vestibuloocular reflex (VOR) adaptation in α9-knockout mice. These mice carry a missense mutation of the gene encoding the α9 nicotinic acetylcholine receptor (nAChR) subunit. The α9 nAChR subunit is expressed in the vestibular and auditory periphery, and its loss of function could compromise peripheral input from the predominantly cholinergic EVS. We measured the VOR gain (eye velocity/head velocity) in 26 α9-knockout mice and 27 cba129 control mice. Mice were randomly assigned to one of three groups: gain-increase adaptation (1.5×), gain-decrease adaptation (0.5×), or no adaptation (baseline, 1×). After adaptation training (horizontal rotations at 0.5 Hz with peak velocity 20°/s), we measured the sinusoidal (0.2-10 Hz, 20-100°/s) and transient (1,500-6,000°/s(2)) VOR in complete darkness. α9-Knockout mice had significantly lower baseline gains compared with control mice. This difference increased with stimulus frequency (∼ 5% <1 Hz to ∼ 25% >1 Hz). Moreover, vestibular adaptation (difference in VOR gain of gain-increase and gain-decrease adaptation groups as % of gain increase) was significantly reduced in α9-knockout mice (17%) compared with control mice (53%), a reduction of ∼ 70%. Our results show that the loss of α9 nAChRs moderately affects the VOR but severely affects VOR adaptation, suggesting that the EVS plays a crucial role in vestibular plasticity.
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Affiliation(s)
- Patrick P Hübner
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia; and
| | - Serajul I Khan
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia; and
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia; and Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland
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46
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The increased sensitivity of irregular peripheral canal and otolith vestibular afferents optimizes their encoding of natural stimuli. J Neurosci 2015; 35:5522-36. [PMID: 25855169 DOI: 10.1523/jneurosci.3841-14.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Efficient processing of incoming sensory input is essential for an organism's survival. A growing body of evidence suggests that sensory systems have developed coding strategies that are constrained by the statistics of the natural environment. Consequently, it is necessary to first characterize neural responses to natural stimuli to uncover the coding strategies used by a given sensory system. Here we report for the first time the statistics of vestibular rotational and translational stimuli experienced by rhesus monkeys during natural (e.g., walking, grooming) behaviors. We find that these stimuli can reach intensities as high as 1500 deg/s and 8 G. Recordings from afferents during naturalistic rotational and linear motion further revealed strongly nonlinear responses in the form of rectification and saturation, which could not be accurately predicted by traditional linear models of vestibular processing. Accordingly, we used linear-nonlinear cascade models and found that these could accurately predict responses to naturalistic stimuli. Finally, we tested whether the statistics of natural vestibular signals constrain the neural coding strategies used by peripheral afferents. We found that both irregular otolith and semicircular canal afferents, because of their higher sensitivities, were more optimized for processing natural vestibular stimuli as compared with their regular counterparts. Our results therefore provide the first evidence supporting the hypothesis that the neural coding strategies used by the vestibular system are matched to the statistics of natural stimuli.
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47
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Abstract
OBJECTIVES Quantification of the perceptual thresholds to vestibular stimuli may offer valuable complementary information to that provided by measures of the vestibulo-ocular reflex (VOR). Perceptual thresholds could be particularly important in evaluating some subjects, such as the elderly, who might have a greater potential of central as well as peripheral vestibular dysfunction. The authors hypothesized that perceptual detection and discrimination thresholds would worsen with aging, and that there would be a poor relation between thresholds and traditional measures of the angular VOR represented by gain and phase on rotational chair testing. DESIGN The authors compared the detection and discrimination thresholds of 19 younger and 16 older adults in response to earth-vertical, 0.5 Hz rotations. Perceptual results of the older subjects were then compared with the gain and phase of their VOR in response to earth-vertical rotations over the frequency range from 0.025 to 0.5 Hz. RESULTS Detection thresholds were found to be 0.69 ± 0.29 degree/sec (mean ± standard deviation) for the younger participants and 0.81 ± 0.42 degree/sec for older participants. Discrimination thresholds in younger and older adults were 4.83 ± 1.80 degree/sec and 4.33 ± 1.57 degree/sec, respectively. There was no difference in either measure between age groups. Perceptual thresholds were independent of the gain and phase of the VOR. CONCLUSIONS These results indicate that there is no inevitable loss of vestibular perception with aging. Elevated thresholds among the elderly are therefore suggestive of pathology rather than normal consequences of aging. Furthermore, perceptual thresholds offer additional insight, beyond that supplied by the VOR alone, into vestibular function.
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48
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McCaslin DL, Rivas A, Jacobson GP, Bennett ML. The dissociation of video head impulse test (vHIT) and bithermal caloric test results provide topological localization of vestibular system impairment in patients with "definite" Ménière's disease. Am J Audiol 2015; 24:1-10. [PMID: 25381440 DOI: 10.1044/2014_aja-14-0040] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 10/12/2014] [Indexed: 11/09/2022] Open
Abstract
PURPOSE We report 3 patients with Ménière's disease and describe how the combination of audiometry, video head impulse testing, and caloric results may prove helpful in the diagnosis of Ménière's disease. METHOD Three patients with "definite" Ménière's disease were evaluated in a tertiary care medical center. Each patient underwent videonystagmography, horizontal canal video head impulse testing, and audiometry. RESULTS All 3 patients demonstrated moderate, flat, sensorineural hearing losses; significant caloric asymmetries; and bilaterally normal video head impulse testing. This pattern of findings suggests differential preservation of high-frequency function (video head impulse testing) with impairment of low-frequency function (unilaterally abnormal caloric test results) in these patients. CONCLUSION Ipsilesional abnormal caloric testing in the presence of normal video head impulse testing is a pattern of findings observed in a cohort of patients who have "definite" Ménière's disease.
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Meredith FL, Rennie KJ. Zonal variations in K+ currents in vestibular crista calyx terminals. J Neurophysiol 2014; 113:264-76. [PMID: 25343781 DOI: 10.1152/jn.00399.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We developed a rodent crista slice to investigate regional variations in electrophysiological properties of vestibular afferent terminals. Thin transverse slices of the gerbil crista ampullaris were made and electrical properties of calyx terminals in central zones (CZ) and peripheral zones (PZ) compared with whole cell patch clamp. Spontaneous action potential firing was observed in 25% of current-clamp recordings and was either regular or irregular in both zones. Firing was abolished when extracellular choline replaced Na(+) but persisted when hair cell mechanotransduction channels or calyx AMPA receptors were blocked. This suggests that ion channels intrinsic to the calyx can generate spontaneous firing. In response to depolarizing voltage steps, outward K(+) currents were observed at potentials above -60 mV. K(+) currents in PZ calyces showed significantly more inactivation than currents in CZ calyces. Underlying K(+) channel populations contributing to these differences were investigated. The KCNQ channel blocker XE991 dihydrochloride blocked a slowly activating, sustained outward current in both PZ and CZ calyces, indicating the presence of KCNQ channels. Mean reduction was greatest in PZ calyces. XE991 also reduced action potential firing frequency in CZ and PZ calyces and broadened mean action potential width. The K(+) channel blocker 4-aminopyridine (10-50 μM) blocked rapidly activating, moderately inactivating currents that were more prevalent in PZ calyces. α-Dendrotoxin, a selective blocker of KV1 channels, reduced outward currents in CZ calyces but not in PZ calyces. Regional variations in K(+) conductances may contribute to different firing responses in calyx afferents.
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Affiliation(s)
- Frances L Meredith
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Katherine J Rennie
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, Colorado; and Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado
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Statistics of the vestibular input experienced during natural self-motion: implications for neural processing. J Neurosci 2014; 34:8347-57. [PMID: 24920638 DOI: 10.1523/jneurosci.0692-14.2014] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/f(α)), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life.
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