1
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Siminski C, Benson JC, Carlson ML, Lane JI. Prevalence of Scarpa's ganglion enhancement on high-resolution MRI imaging. Neuroradiol J 2024; 37:332-335. [PMID: 38226489 PMCID: PMC11138325 DOI: 10.1177/19714009231224415] [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: 01/17/2024] Open
Abstract
BACKGROUND AND PURPOSE The vestibular ganglion, or Scarpa's ganglion, is a cluster of afferent vestibular neurons within the internal auditory canal (IAC). There is minimal literature describing enhancement of this region on magnetic resonance imaging (MRI) and its correlation to clinical symptoms. Here, we sought to find the prevalence of enhancement at Scarpa's ganglion, and determine whether such enhancement correlates with demographics or clinical symptoms. MATERIALS AND METHODS A retrospective review was performed of consecutive patients with an MRI of the IAC between 3/1/2021 and 5/20/2021. Two neuroradiologists independently reviewed for T1 and FLAIR enhancement of the Scarpa's ganglion on post-contrast fat-saturated T1 and post-contrast FLAIR images. Discrepancies were agreed upon by consensus. Clinical variables (hearing loss, vestibular symptoms, tinnitus, and MRI indication) were gathered from a retrospective chart review. RESULTS Eighty-nine patients were included (51 female); the mean age was 58 (range 19-85). The most common MRI indication was hearing loss (n = 53). FLAIR enhancement was present on the right in 7 patients, on the left in 7 patients, and bilaterally in 6 patients. No enhancement was seen on post-contrast T1 images. There was no statistically significant correlation between consensus FLAIR on at least one side and age (p = .74), gender (p = .29), hearing loss (p = .32), hearing loss side (p = .39), type of hearing loss (p = .87), vestibular symptoms (p = .71), or tinnitus (p = .81). CONCLUSIONS Enhancement is present in the minority of patients on post-contrast FLAIR images. If seen, it should be considered an uncommon but not unexpected finding with no clinical significance.
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Affiliation(s)
| | - John C Benson
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Matthew L Carlson
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, USA
| | - John I Lane
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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2
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Fritzsch B. Evolution and development of extraocular motor neurons, nerves and muscles in vertebrates. Ann Anat 2024; 253:152225. [PMID: 38346566 DOI: 10.1016/j.aanat.2024.152225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/16/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
The purpose of this review is to analyze the origin of ocular motor neurons, define the pattern of innervation of nerve fibers that project to the extraocular eye muscles (EOMs), describe congenital disorders that alter the development of ocular motor neurons, and provide an overview of vestibular pathway inputs to ocular motor nuclei. Six eye muscles are innervated by axons of three ocular motor neurons, the oculomotor (CNIII), trochlear (CNIV), and abducens (CNVI) neurons. Ocular motor neurons (CNIII) originate in the midbrain and innervate the ipsilateral orbit, except for the superior rectus and the levator palpebrae, which are contralaterally innervated. Trochlear motor neurons (CNIV) originate at the midbrain-hindbrain junction and innervate the contralateral superior oblique muscle. Abducens motor neurons (CNVI) originate variously in the hindbrain of rhombomeres r4-6 that innervate the posterior (or lateral) rectus muscle and innervate the retractor bulbi. Genes allow a distinction between special somatic (CNIII, IV) and somatic (CNVI) ocular motor neurons. Development of ocular motor neurons and their axonal projections to the EOMs may be derailed by various genetic causes, resulting in the congenital cranial dysinnervation disorders. The ocular motor neurons innervate EOMs while the vestibular nuclei connect with the midbrain-brainstem motor neurons.
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Affiliation(s)
- Bernd Fritzsch
- Department of Neurological Sciences, University of Nebraska Medical Center, NE, USA.
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3
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Machuca-Márquez P, Sánchez-Benito L, Menardy F, Urpi A, Girona M, Puighermanal E, Appiah I, Palmiter RD, Sanz E, Quintana A. Vestibular CCK signaling drives motion sickness-like behavior in mice. Proc Natl Acad Sci U S A 2023; 120:e2304933120. [PMID: 37847729 PMCID: PMC10622874 DOI: 10.1073/pnas.2304933120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/23/2023] [Indexed: 10/19/2023] Open
Abstract
Travel can induce motion sickness (MS) in susceptible individuals. MS is an evolutionary conserved mechanism caused by mismatches between motion-related sensory information and past visual and motion memory, triggering a malaise accompanied by hypolocomotion, hypothermia, hypophagia, and nausea. Vestibular nuclei (VN) are critical for the processing of movement input from the inner ear. Motion-induced activation of VN neurons recapitulates MS-related signs. However, the genetic identity of VN neurons mediating MS-related autonomic and aversive responses remains unknown. Here, we identify a central role of cholecystokinin (CCK)-expressing VN neurons in motion-induced malaise. Moreover, we show that CCK VN inputs onto the parabrachial nucleus activate Calca-expressing neurons and are sufficient to establish avoidance to novel food, which is prevented by CCK-A receptor antagonism. These observations provide greater insight into the neurobiological regulation of MS by identifying the neural substrates of MS and providing potential targets for treatment.
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Affiliation(s)
| | - Laura Sánchez-Benito
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Fabien Menardy
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Andrea Urpi
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Mònica Girona
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Emma Puighermanal
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Isabella Appiah
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Richard D. Palmiter
- HHMI, University of Washington, Seattle, WA98195
- Department of Biochemistry, University of Washington, Seattle, WA98195
| | - Elisenda Sanz
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona08193, Spain
| | - Albert Quintana
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona08193, Spain
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona08193, Spain
- Focus Area for Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University, Potchefstroom2520, South Africa
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4
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Nham B, Akdal G, Young AS, Özçelik P, Tanrıverdizade T, Ala RT, Bradshaw AP, Wang C, Men S, Giarola BF, Black DA, Thompson EO, Halmagyi GM, Welgampola MS. Capturing nystagmus in the emergency room: posterior circulation stroke versus acute vestibular neuritis. J Neurol 2023; 270:632-641. [PMID: 35849153 PMCID: PMC9886594 DOI: 10.1007/s00415-022-11202-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/30/2022] [Accepted: 02/05/2022] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To compare acute nystagmus characteristics of posterior circulation stroke (PCS) and acute vestibular neuritis (AVN) in the emergency room (ER) within 24 h of presentation. METHODS ER-based video-nystagmography (VNG) was conducted, recording ictal nystagmus in 101 patients with PCS (on imaging) and 104 patients with AVN, diagnosed on accepted clinical and vestibular test criteria. RESULTS Patients with stroke in the brainstem (38/101, affecting midbrain (n = 7), pons (n = 19), and medulla (n = 12)), cerebellum (31/101), both (15/101) or other locations (17/101) were recruited. Common PCS territories included posterior-inferior-cerebellar-artery (41/101), pontine perforators (18/101), multiple-territories (17/101) and anterior-inferior-cerebellar-artery (7/101). In PCS, 44/101 patients had no spontaneous nystagmus. Remaining PCS patients had primary position horizontal (44/101), vertical (8/101) and torsional (5/101) nystagmus. Horizontal nystagmus was 50% ipsiversive and 50% contraversive in lateralised PCS. Most PCS patients with horizontal nystagmus (28/44) had unidirectional "peripheral-appearing" nystagmus. 32/101 of PCS patients had gaze-evoked nystagmus. AVN affected the superior, inferior or both divisions of the vestibular nerve in 55/104, 4/104 and 45/104. Most (102/104) had primary position horizontal nystagmus; none had gaze-evoked nystagmus. Two inferior VN patients had contraversive torsional-downbeat nystagmus. Horizontal nystagmus with SPV ≥ 5.8 °/s separated AVN from PCS with sensitivity and specificity of 91.2% and 83.0%. Absent nystagmus, gaze-evoked nystagmus, and vertical-torsional nystagmus were highly specific for PCS (100%, 100% and 98.1%). CONCLUSION Nystagmus is often absent in PCS and always present in AVN. Unidirectional 'peripheral-appearing' horizontal nystagmus can be seen in PCS. ER-based VNG nystagmus assessment could provide useful diagnostic information when separating PCS from AVN.
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Affiliation(s)
- B Nham
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia.,Faculty of Medicine and Health, Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - G Akdal
- Faculty of Medicine, Department of Neurology, Dokuz Eylül University, İzmir, Turkey.,Department of Neuroscience, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - A S Young
- Faculty of Medicine and Health, Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - P Özçelik
- Department of Neuroscience, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - T Tanrıverdizade
- Department of Neuroscience, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - R T Ala
- Faculty of Medicine, Department of Neurology, Dokuz Eylül University, İzmir, Turkey
| | - A P Bradshaw
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia
| | - C Wang
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia.,Faculty of Medicine and Health, Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - S Men
- Faculty of Medicine, Department of Radiology, Dokuz Eylül University, İzmir, Turkey
| | - B F Giarola
- Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - D A Black
- Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - E O Thompson
- Department of Radiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - G M Halmagyi
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia.,Faculty of Medicine and Health, Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia
| | - M S Welgampola
- Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia. .,Faculty of Medicine and Health, Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, Australia.
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5
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Expression of a Form of Cerebellar Motor Memory Requires Learned Alterations to the Activity of Inhibitory Molecular Layer Interneurons. J Neurosci 2023; 43:601-612. [PMID: 36639897 PMCID: PMC9888511 DOI: 10.1523/jneurosci.0731-22.2022] [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: 03/23/2022] [Revised: 11/30/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
Procedural memories formed in the cerebellum in response to motor errors depend on changes to Purkinje cell (PC) spiking patterns that correct movement when the erroneous context is repeated. Because molecular layer interneurons (MLIs) inhibit PCs, learning-induced changes to MLI output may participate in reshaping PC spiking patterns. However, it remains unclear whether error-driven learning alters MLI activity and whether such changes are necessary for the memory engram. We addressed this knowledge gap by measuring and manipulating MLI activity in the flocculus of both sexes of mice before and after vestibulo-ocular reflex (VOR) adaptation. We found that MLIs are activated during vestibular stimuli and that their population response exhibits a phase shift after the instantiation of gain-increase VOR adaptation, a type of error-driven learning thought to require climbing-fiber-mediated instructive signaling. Although acute optogenetic suppression of MLI activity did not affect baseline VOR performance, it negated the expression of gain-increase learning, demonstrating a specific role of MLI activity changes in motor memory expression. This effect was transitory; after a multiday consolidation period, the expression of VOR gain-increase learning was no longer sensitive to MLI activity suppression. Together, our results indicate that error-driven alteration of MLI activity is necessary for labile, climbing-fiber-induced motor memory expression.SIGNIFICANCE STATEMENT In the cerebellum, motor learning induces an associative memory of the sensorimotor context of an erroneous movement that, when recalled, results in a new pattern of output that improves subsequent trials of performance. Our study shows that error-driven motor learning induces changes to the activity pattern of cerebellar molecular layer interneurons (MLIs) and that this new pattern of activity is required to express the corrective motor memory.
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6
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Shi XB, Wang J, Li FT, Zhang YB, Qu WM, Dai CF, Huang ZL. Whole-brain monosynaptic outputs and presynaptic inputs of GABAergic neurons in the vestibular nuclei complex of mice. Front Neurosci 2022; 16:982596. [PMID: 36090271 PMCID: PMC9459096 DOI: 10.3389/fnins.2022.982596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
GABAergic neurons in the vestibular nuclei (VN) participate in multiple vital vestibular sensory processing allowing for the maintenance and rehabilitation of vestibular functions. However, although the important role of GABA in the central vestibular system has been widely reported, the underlying neural circuits between VN GABAergic neurons and other brain functional regions remain elusive, which limits the further study of the underlying mechanism. Hence, it is necessary to elucidate neural connectivity based on outputs and inputs of GABAergic neurons in the VN. This study employed a modified rabies virus retrograde tracing vector and cre-dependent adeno-associated viruses (AAVs) anterograde tracing vector, combined with a transgenic VGAT-IRES-Cre mice, to map the inputs and outputs of VN GABAergic neurons in the whole brain. We found that 51 discrete brain regions received projections from VN GABAergic neurons in the whole brain, and there were 77 upstream nuclei innervating GABAergic neurons in the VN. These nuclei were mainly located in four brain regions, including the medulla, pons, midbrain, and cerebellum. Among them, VN GABAergic neurons established neural circuits with some functional nuclei in the whole brain, especially regulating balance maintenance, emotion control, pain processing, sleep and circadian rhythm regulation, and fluid homeostasis. Therefore, this study deepens a comprehensive understanding of the whole-brain neural connectivity of VN, providing the neuroanatomical information for further research on the neural mechanism of the co-morbidities with vestibular dysfunction.
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Affiliation(s)
- Xun-Bei Shi
- Department of Otology and Skull Base Surgery, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- Key Laboratory of Hearing Medicine, Ministry of Health, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Jing Wang
- Department of Otology and Skull Base Surgery, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Key Laboratory of Hearing Medicine, Ministry of Health, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Fei-Tian Li
- Department of Otology and Skull Base Surgery, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Key Laboratory of Hearing Medicine, Ministry of Health, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Yi-Bo Zhang
- Department of Otology and Skull Base Surgery, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Key Laboratory of Hearing Medicine, Ministry of Health, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Chun-Fu Dai
- Department of Otology and Skull Base Surgery, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Key Laboratory of Hearing Medicine, Ministry of Health, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
- Chun-Fu Dai
| | - Zhi-Li Huang
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Zhi-Li Huang
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7
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Stitt IM, Wellings TP, Drury HR, Jobling P, Callister RJ, Brichta AM, Lim R. Properties of Deiters' neurons and inhibitory synaptic transmission in the mouse lateral vestibular nucleus. J Neurophysiol 2022; 128:131-147. [PMID: 35730750 DOI: 10.1152/jn.00016.2022] [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: 11/22/2022] Open
Abstract
Deiters' neurons, located exclusively in the lateral vestibular nucleus (LVN), are involved in vestibulospinal reflexes, innervate extensor motoneurons that drive anti-gravity muscles, and receive inhibitory inputs from the cerebellum. We investigated intrinsic membrane properties, short-term plasticity, and inhibitory synaptic inputs of mouse Deiters' and non-Deiters' neurons within the LVN. Deiters' neurons are distinguished from non-Deiters' neurons by their very low input resistance (105.8 vs 521.8 MOhms) respectively, long axons that project as far as the ipsilateral lumbar spinal cord, and expression of the cytostructural protein, non-phosphorylated neurofilament protein (NPNFP). Whole-cell patch clamp recordings in brainstem slices show most Deiters' and non-Deiters' neurons were tonically active (>92%). Short-term plasticity was studied by examining discharge rate modulation following release from hyperpolarization (post-inhibitory rebound firing; PRF) and depolarization (firing rate adaptation; FRA). PRF and FRA gain were similar in Deiters' and non-Deiters' neurons (PRF: 24.9 vs. 20.2 Hz and FRA gain: 231.5 vs. 287.8 spikes/sec/nA respectively). Inhibitory synaptic input to both populations showed GABAergic rather than glycinergic inhibition dominated in Deiters' neurons and GABAA miniature inhibitory postsynaptic current (mIPSC) frequency was much higher in Deiters' neurons compared to non-Deiters' neurons (~15.9 vs. 1.4 Hz respectively). Our data suggest Deiters' neurons can be reliably identified by their intrinsic membrane and synaptic properties. They are tonically active, glutamatergic, have low sensitivity or 'gain', exhibit little adaptation, and receive strong GABAergic input. Together, these features suggest, since Deiters' neurons have minimal short-term plasticity they are well-suited to a role encoding tonic signals for the vestibulospinal reflex.
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Affiliation(s)
- Iain M Stitt
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Thomas P Wellings
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Hannah Rose Drury
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Phillip Jobling
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Robert J Callister
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Alan Martin Brichta
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
| | - Rebecca Lim
- The School of Biomedical Sciences and Pharmacy, The University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, Australia
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8
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Reeves KC, Shah N, Muñoz B, Atwood BK. Opioid Receptor-Mediated Regulation of Neurotransmission in the Brain. Front Mol Neurosci 2022; 15:919773. [PMID: 35782382 PMCID: PMC9242007 DOI: 10.3389/fnmol.2022.919773] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/26/2022] [Indexed: 12/15/2022] Open
Abstract
Opioids mediate their effects via opioid receptors: mu, delta, and kappa. At the neuronal level, opioid receptors are generally inhibitory, presynaptically reducing neurotransmitter release and postsynaptically hyperpolarizing neurons. However, opioid receptor-mediated regulation of neuronal function and synaptic transmission is not uniform in expression pattern and mechanism across the brain. The localization of receptors within specific cell types and neurocircuits determine the effects that endogenous and exogenous opioids have on brain function. In this review we will explore the similarities and differences in opioid receptor-mediated regulation of neurotransmission across different brain regions. We discuss how future studies can consider potential cell-type, regional, and neural pathway-specific effects of opioid receptors in order to better understand how opioid receptors modulate brain function.
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Affiliation(s)
- Kaitlin C. Reeves
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, United States
| | - Nikhil Shah
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
- Medical Scientist Training Program, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Braulio Muñoz
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Brady K. Atwood
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
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9
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Diaz C, Glover JC. The Vestibular Column in the Mouse: A Rhombomeric Perspective. Front Neuroanat 2022; 15:806815. [PMID: 35173589 PMCID: PMC8842660 DOI: 10.3389/fnana.2021.806815] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/20/2021] [Indexed: 11/30/2022] Open
Abstract
The vestibular column is located in the hindbrain between the sensory auditory (dorsal) and trigeminal (ventral) columns, spanning rhombomeres r1 (or r2) to r9. It contains the vestibular nuclear complex that receives sensory innervation from the labyrinthine end organs in the inner ear. Gene expression studies and experimental manipulations of developmental genes, particularly Hox genes and other developmental patterning genes, are providing insight into the morphological and functional organization of the vestibular nuclear complex, particularly from a segmental standpoint. Here, we will review studies of the classical vestibular nuclei and of vestibular projection neurons that innervate distinct targets in relation to individual rhombomeres and the expression of specific genes. Studies in different species have demonstrated that the vestibular complex is organized into a hodological mosaic that relates axon trajectory and target to specific hindbrain rhombomeres and intrarhombomeric domains, with a molecular underpinning in the form of transcription factor signatures, which has been highly conserved during the evolution of the vertebrate lineage.
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Affiliation(s)
- Carmen Diaz
- Department of Medical Sciences, School of Medicine and Institute for Research in Neurological Disabilities, University of Castilla-La Mancha, Albacete, Spain
- *Correspondence: Carmen Diaz,
| | - Joel C. Glover
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Joel C. Glover,
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10
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Pastor AM, Blumer R, de la Cruz RR. Extraocular Motoneurons and Neurotrophism. ADVANCES IN NEUROBIOLOGY 2022; 28:281-319. [PMID: 36066830 DOI: 10.1007/978-3-031-07167-6_12] [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: 06/15/2023]
Abstract
Extraocular motoneurons are located in three brainstem nuclei: the abducens, trochlear and oculomotor. They control all types of eye movements by innervating three pairs of agonistic/antagonistic extraocular muscles. They exhibit a tonic-phasic discharge pattern, demonstrating sensitivity to eye position and sensitivity to eye velocity. According to their innervation pattern, extraocular muscle fibers can be classified as singly innervated muscle fiber (SIF), or the peculiar multiply innervated muscle fiber (MIF). SIF motoneurons show anatomical and physiological differences with MIF motoneurons. The latter are smaller and display lower eye position and velocity sensitivities as compared with SIF motoneurons.
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Affiliation(s)
- Angel M Pastor
- Departamento de Fisiología, Universidad de Sevilla, Seville, Spain.
| | - Roland Blumer
- Center of Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
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11
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Marouane E, El Mahmoudi N, Rastoldo G, Péricat D, Watabe I, Lapôtre A, Tonetto A, Xavier F, Dumas O, Chabbert C, Artzner V, Tighilet B. Sensorimotor Rehabilitation Promotes Vestibular Compensation in a Rodent Model of Acute Peripheral Vestibulopathy by Promoting Microgliogenesis in the Deafferented Vestibular Nuclei. Cells 2021; 10:3377. [PMID: 34943885 PMCID: PMC8699190 DOI: 10.3390/cells10123377] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 12/16/2022] Open
Abstract
Acute peripheral vestibulopathy leads to a cascade of symptoms involving balance and gait disorders that are particularly disabling for vestibular patients. Vestibular rehabilitation protocols have proven to be effective in improving vestibular compensation in clinical practice. Yet, the underlying neurobiological correlates remain unknown. The aim of this study was to highlight the behavioural and cellular consequences of a vestibular rehabilitation protocol adapted to a rat model of unilateral vestibular neurectomy. We developed a progressive sensory-motor rehabilitation task, and the behavioural consequences were quantified using a weight-distribution device. This analysis method provides a precise and ecological analysis of posturolocomotor vestibular deficits. At the cellular level, we focused on the analysis of plasticity mechanisms expressed in the vestibular nuclei. The results obtained show that vestibular rehabilitation induces a faster recovery of posturolocomotor deficits during vestibular compensation associated with a decrease in neurogenesis and an increase in microgliogenesis in the deafferented medial vestibular nucleus. This study reveals for the first time a part of the underlying adaptative neuroplasticity mechanisms of vestibular rehabilitation. These original data incite further investigation of the impact of rehabilitation on animal models of vestibulopathy. This new line of research should improve the management of vestibular patients.
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Affiliation(s)
- Emna Marouane
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- BIOSEB ALLCAT Instruments, Couperigne, 13127 Vitrolles, France;
| | - Nada El Mahmoudi
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Guillaume Rastoldo
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - David Péricat
- Institute of Pharmacology and Structural Biology (IPBS), University of Toulouse, CNRS, 31400 Toulouse, France;
| | - Isabelle Watabe
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Agnès Lapôtre
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
| | - Alain Tonetto
- Fédération de Recherche Sciences Chimiques Marseille FR 1739, Pôle 18 PRATIM, CEDEX 03, 13331 Marseille, France;
| | - Frédéric Xavier
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Olivier Dumas
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Christian Chabbert
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
| | - Vincent Artzner
- BIOSEB ALLCAT Instruments, Couperigne, 13127 Vitrolles, France;
| | - Brahim Tighilet
- Aix-Marseille Université-CNRS, Laboratoire de Neurosciences Cognitives, LNC UMR 7291, Centre Saint-Charles Case C, 3 Place Victor Hugo, CEDEX 03, 13331 Marseille, France; (E.M.); (N.E.M.); (G.R.); (I.W.); (A.L.); (F.X.); (C.C.)
- GDR Physiopathologie Vestibulaire—Unité GDR2074, CNRS, 13003 Marseille, France;
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12
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Feil K, Adrion C, Boesch S, Doss S, Giordano I, Hengel H, Jacobi H, Klockgether T, Klopstock T, Nachbauer W, Schöls L, Steiner KM, Stendel C, Timmann D, Naumann I, Mansmann U, Strupp M. Safety and Efficacy of Acetyl-DL-Leucine in Certain Types of Cerebellar Ataxia: The ALCAT Randomized Clinical Crossover Trial. JAMA Netw Open 2021; 4:e2135841. [PMID: 34905009 PMCID: PMC8672236 DOI: 10.1001/jamanetworkopen.2021.35841] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
IMPORTANCE Cerebellar ataxia is a neurodegenerative disease impairing motor function characterized by ataxia of stance, gait, speech, and fine motor disturbances. OBJECTIVE To investigate the efficacy, safety, and tolerability of the modified essential amino acid acetyl-DL-leucine in treating patients who have cerebellar ataxia. DESIGN, SETTING, AND PARTICIPANTS The Acetyl-DL-leucine on Cerebellar Ataxia (ALCAT) trial was an investigator-initiated, multicenter, double-blind, randomized, placebo-controlled, clinical crossover trial. The study was conducted at 7 university hospitals in Germany and Austria between January 25, 2016, and February 17, 2017. Patients were aged at least 18 years and diagnosed with cerebellar ataxia of hereditary (suspected or genetically confirmed) or nonhereditary or unknown type presenting with a total score of at least 3 points on the Scale for the Assessment and Rating of Ataxia (SARA). Statistical analysis was performed from April 2018 to June 2018 and January 2020 to March 2020. INTERVENTIONS Patients were randomly assigned (1:1) to receive acetyl-DL-leucine orally (5 g per day after 2 weeks up-titration) followed by a matched placebo, each for 6 weeks, separated by a 4-week washout, or vice versa. The randomization was done via a web-based, permuted block-wise randomization list (block size, 2) that was stratified by disease subtype (hereditary vs nonhereditary or unknown) and site. MAIN OUTCOMES AND MEASURES Primary efficacy outcome was the absolute change of SARA total score from (period-dependent) baseline to week 6. RESULTS Among 108 patients who were randomly assigned to sequence groups (54 patients each), 55 (50.9%) were female; the mean (SD) age was 54.8 (14.4) years; and the mean (SD) SARA total score was 13.33 (5.57) points. The full analysis set included 105 patients (80 patients with hereditary, 25 with nonhereditary or unknown cerebellar ataxia). There was no evidence of a difference in the mean absolute change from baseline to week 6 in SARA total scores between both treatments (mean treatment difference: 0.23 points [95% CI, -0.40 to 0.85 points]). CONCLUSIONS AND RELEVANCE In this large multicenter, double-blind, randomized, placebo-controlled clinical crossover trial, acetyl-DL-leucine in the investigated dosage and treatment duration was not superior to placebo for the symptomatic treatment of certain types of ataxia. The drug was well tolerated; and ALCAT yielded valuable information about the duration of treatment periods and the role of placebo response in cerebellar ataxia. These findings suggest that further symptom-oriented trials are needed for evaluating the long-term effects of acetyl-DL-leucine for well-defined subgroups of cerebellar ataxia. TRIAL REGISTRATION EudraCT 2015-000460-34.
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Affiliation(s)
- Katharina Feil
- Department of Neurology with Friedrich-Baur-Institute, Ludwig Maximilians University, University Hospital, Munich, Germany
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig Maximilians University, University Hospital, Campus Grosshadern, Munich, Germany
- Department of Neurology and Stroke, University Hospital Tübingen, Tübingen, Germany
| | - Christine Adrion
- Institute for Medical Informatics, Biometry and Epidemiology (IBE), Ludwig Maximilians University, Munich, Germany
| | - Sylvia Boesch
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Sarah Doss
- Department of Neurology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Neurological Sciences, University of Nebraska Medical Center (UNMC), Omaha
| | - Ilaria Giordano
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
| | - Holger Hengel
- Department of Neurology and Hertie-Institute for Clinical Brain Research, University Hospital Tübingen, Tübingen, Germany
| | - Heike Jacobi
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
- Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Thomas Klockgether
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
| | - Thomas Klopstock
- Department of Neurology with Friedrich-Baur-Institute, Ludwig Maximilians University, University Hospital, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Wolfgang Nachbauer
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Ludger Schöls
- Department of Neurology and Hertie-Institute for Clinical Brain Research, University Hospital Tübingen, Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Katharina Marie Steiner
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Claudia Stendel
- Department of Neurology with Friedrich-Baur-Institute, Ludwig Maximilians University, University Hospital, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Dagmar Timmann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences, University Hospital Essen, Essen, Germany
| | - Ivonne Naumann
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig Maximilians University, University Hospital, Campus Grosshadern, Munich, Germany
| | - Ulrich Mansmann
- Institute for Medical Informatics, Biometry and Epidemiology (IBE), Ludwig Maximilians University, Munich, Germany
| | - Michael Strupp
- Department of Neurology with Friedrich-Baur-Institute, Ludwig Maximilians University, University Hospital, Munich, Germany
- German Center for Vertigo and Balance Disorders (DSGZ), Ludwig Maximilians University, University Hospital, Campus Grosshadern, Munich, Germany
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Abstract
Eye movements are indispensable for visual image stabilization during self-generated and passive head and body motion and for visual orientation. Eye muscles and neuronal control elements are evolutionarily conserved, with novel behavioral repertoires emerging during the evolution of frontal eyes and foveae. The precise execution of eye movements with different dynamics is ensured by morphologically diverse yet complementary sets of extraocular muscle fibers and associated motoneurons. Singly and multiply innervated muscle fibers are controlled by motoneuronal subpopulations with largely selective premotor inputs from task-specific ocular motor control centers. The morphological duality of the neuromuscular interface is matched by complementary biochemical and molecular features that collectively assign different physiological properties to the motor entities. In contrast, the functionality represents a continuum where most motor elements contribute to any type of eye movement, although within preferential dynamic ranges, suggesting that signal transmission and muscle contractions occur within bands of frequency-selective pathways.
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Affiliation(s)
- Anja K E Horn
- Institute of Anatomy and Cell Biology I, Ludwig-Maximilians-University Munich, 80336 Munich, Germany;
| | - Hans Straka
- Department Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg, Germany
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14
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Montardy Q, Wei M, Liu X, Yi T, Zhou Z, Lai J, Zhao B, Besnard S, Tighilet B, Chabbert C, Wang L. Selective optogenetic stimulation of glutamatergic, but not GABAergic, vestibular nuclei neurons induces immediate and reversible postural imbalance in mice. Prog Neurobiol 2021; 204:102085. [PMID: 34171443 DOI: 10.1016/j.pneurobio.2021.102085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 04/21/2021] [Accepted: 05/25/2021] [Indexed: 11/24/2022]
Abstract
Glutamatergic and GABAergic neurons represent the neural components of the medial vestibular nuclei. We assessed the functional role of glutamatergic and GABAergic neuronal pathways arising from the vestibular nuclei (VN) in the maintenance of gait and balance by optogenetically stimulating the VN in VGluT2-cre and GAD2-cre mice. We demonstrate that glutamatergic, but not GABAergic VN neuronal subpopulation is responsible for immediate and strong posturo-locomotor deficits, comparable to unilateral vestibular deafferentation models. During optogenetic stimulation, the support surface dramatically increased in VNVGluT2+ mice, and rapidly fell back to baseline after stimulation, whilst it remained unchanged during similar stimulation of VNGAD2+ mice. This effect persisted when vestibular tactilo kinesthesic plantar inputs were removed. Posturo-locomotor alterations evoked in VNVGluT2+ animals were still present immediately after stimulation, while they disappeared 1 h later. Overall, these results indicate a fundamental role for VNVGluT2+ neurons in balance and posturo-locomotor functions, but not for VNGAD2+ neurons, in this specific context. This new optogenetic approach will be useful to characterize the role of the different VN neuronal populations involved in vestibular physiology and pathophysiology.
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Affiliation(s)
- Q Montardy
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; GDR Physiopathologie Vestibulaire - unité GDR2074 CNRS, France
| | - M Wei
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - X Liu
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - T Yi
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - Z Zhou
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China; McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - J Lai
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - B Zhao
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China
| | - S Besnard
- Aix Marseille University-CNRS, Laboratory of Sensory and Cognitive Neurosciences, UMR 7260, Team Pathophysiology and Therapy of Vestibular Disorders, Marseille, France; Université de Caen Normandie, CHU de Caen, Caen, France; GDR Physiopathologie Vestibulaire - unité GDR2074 CNRS, France
| | - B Tighilet
- Aix Marseille University-CNRS, Laboratory of Sensory and Cognitive Neurosciences, UMR 7260, Team Pathophysiology and Therapy of Vestibular Disorders, Marseille, France; GDR Physiopathologie Vestibulaire - unité GDR2074 CNRS, France.
| | - C Chabbert
- Aix Marseille University-CNRS, Laboratory of Sensory and Cognitive Neurosciences, UMR 7260, Team Pathophysiology and Therapy of Vestibular Disorders, Marseille, France; GDR Physiopathologie Vestibulaire - unité GDR2074 CNRS, France.
| | - L Wang
- Shenzhen Key Lab of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
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15
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Effects of Several Therapeutic Agents on Mammalian Vestibular Function: Meclizine, Diazepam, and JNJ7777120. J Assoc Res Otolaryngol 2021; 22:527-549. [PMID: 34009490 DOI: 10.1007/s10162-021-00803-5] [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: 10/10/2020] [Accepted: 04/27/2021] [Indexed: 10/21/2022] Open
Abstract
Management of vestibular dysfunction may include treatment with medications that are thought to act to suppress vestibular function and reduce or eliminate abnormal sensitivity to head motions. The extent to which vestibular medications act centrally or peripherally is still debated. In this study, two commonly prescribed medications, meclizine and diazepam, and a candidate for future clinical use, JNJ7777120, were evaluated for their effects on short latency compound action potentials generated by the peripheral vestibular system and corresponding central neural relays (i.e., vestibular sensory-evoked potentials, VsEPs). The effects of the selected drugs developed slowly over the course of two hours in the mouse. Findings indicate that meclizine (600 mg/kg) and diazepam (> 60 mg/kg) can act on peripheral elements of the vestibular maculae whereas diazepam also acts most effectively on central gravity receptor circuits to exert its suppressive effects. The novel pharmacological agent JNJ7777120 (160 mg/kg) acts in the vestibular periphery to enhance macular responses to transient stimuli (VsEPs) while, hypothetically, suppressing macular responses to sustained or slowly changing stimuli.
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16
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Yang AHX, Khwaounjoo P, Cakmak YO. Directional effects of whole-body spinning and visual flow in virtual reality on vagal neuromodulation. J Vestib Res 2021; 31:479-494. [PMID: 34024797 DOI: 10.3233/ves-201574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Neural circuits allow whole-body yaw rotation to modulate vagal parasympathetic activity, which alters beat-to-beat variation in heart rate. The overall output of spinning direction, as well as vestibular-visual interactions on vagal activity still needs to be investigated. OBJECTIVE This study investigated direction-dependent effects of visual and natural vestibular stimulation on two autonomic responses: heart rate variability (HRV) and pupil diameter. METHODS Healthy human male subjects (n = 27) underwent constant whole-body yaw rotation with eyes open and closed in the clockwise (CW) and anticlockwise (ACW) directions, at 90°/s for two minutes. Subjects also viewed the same spinning environments on video in a VR headset. RESULTS CW spinning significantly decreased parasympathetic vagal activity in all conditions (CW open p = 0.0048, CW closed p = 0.0151, CW VR p = 0.0019,), but not ACW spinning (ACW open p = 0.2068, ACW closed p = 0.7755, ACW VR p = 0.1775,) as indicated by an HRV metric, the root mean square of successive RR interval differences (RMSSD). There were no direction-dependent effects of constant spinning on sympathetic activity inferred through the HRV metrics, stress index (SI), sympathetic nervous system index (SNS index) and pupil diameter. Neuroplasticity in the CW eyes closed and CW VR conditions post stimulation was observed. CONCLUSIONS Only one direction of yaw spinning, and visual flow caused vagal nerve neuromodulation and neuroplasticity, resulting in an inhibition of parasympathetic activity on the heart, to the same extent in either vestibular or visual stimulation. These results indicate that visual flow in VR can be used as a non-electrical method for vagus nerve inhibition without the need for body motion in the treatment of disorders with vagal overactivity. The findings are also important for VR and spinning chair based autonomic nervous system modulation protocols, and the effects of motion integrated VR.
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Affiliation(s)
| | - Prashanna Khwaounjoo
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Medtech Core NZ, Auckland, New Zealand
| | - Yusuf Ozgur Cakmak
- Department of Anatomy, University of Otago, Dunedin, New Zealand.,Medtech Core NZ, Auckland, New Zealand.,Brain Health Research Centre, Dunedin, New Zealand.,Centre for Health Systems and Technology, Dunedin, New Zealand
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17
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Plescia F, Salvago P, Dispenza F, Messina G, Cannizzaro E, Martines F. Efficacy and Pharmacological Appropriateness of Cinnarizine and Dimenhydrinate in the Treatment of Vertigo and Related Symptoms. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:4787. [PMID: 33946152 PMCID: PMC8125582 DOI: 10.3390/ijerph18094787] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 02/02/2023]
Abstract
Vertigo is not itself a disease, but rather a symptom of various syndromes and disorders that jeopardize balance function, which is essential for daily activities. It is an abnormal sensation of motion that usually occurs in the absence of motion, or when a motion is sensed inaccurately. Due to the complexity of the etiopathogenesis of vertigo, many pharmacological treatments have been tested for efficacy on vertigo. Among these drugs, cinnarizine, usually given together with dimenhydrinate, appears to be the first-line pharmacotherapy for the management of vertigo and inner ear disorders. Based on these considerations, the present non-interventional study aimed to investigate the clinical efficacy and tolerability of a fixed combination of cinnarizine (20 mg) and dimenhydrinate (40 mg) in patients suffering from vertigo-related symptoms. To this end, we enrolled 120 adults-70 males, and 50 females-with an average age of 64 years. Before beginning pharmacological treatment, all patients were screened for the intensity of vertigo, dizziness, and concomitant symptoms through the Visual Scale of Dizziness Disorders and Dizziness Handicap Inventory scales. At the end of the anamnestic evaluation, patients received the fixed-dose combination of cinnarizine (20 mg) plus dimenhydrinate (40 mg) 3 times daily, for 60 days. The results of this study provide further insight regarding the efficacy of the fixed combination when used to reduce symptoms of vestibular vertigo of central and/or peripheral origin, after both the 15- and 60-day therapies. Independent of the type of vertigo, the fixed combination was able to reduce dizziness- and vertigo-associated symptoms in more than 75% of all patients treated, starting from 15 days of therapy, and improving 60 days after starting the therapy. Interestingly, we also found differences between male and female patients in the framework of the pharmacological effects of therapy. This study provides further details concerning the therapeutic efficacy of the fixed combination of cinnarizine and dimenhydrinate, and also focuses attention on the possibility that these drugs could act in a gender-specific manner, paving the way for further research.
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Affiliation(s)
- Fulvio Plescia
- Department of Health Promotion Sciences Maternal and Infantile Care, Internal Medicine and Medical Specialities “Giuseppe D’Alessandro”, University of Palermo, Via del Vespro 133, 90127 Palermo, Italy; (F.P.); (E.C.)
| | - Pietro Salvago
- Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata (BiND), Sezione di Audiologia, Università Degli Studi di Palermo, Via del Vespro 129, 90127 Palermo, Italy;
| | - Francesco Dispenza
- UOC Otorinolaringoiatria, A.O.U.P. “Paolo Giaccone”, Via del Vespro 129, 90127 Palermo, Italy;
| | - Giuseppe Messina
- Department of Psychological, Pedagogical and Human Movement Sciences, University of Palermo, Via Giovanni Pascoli 6, Palermo 90144, Italy;
- PosturaLab Center, 90127 Palermo, Italy
| | - Emanuele Cannizzaro
- Department of Health Promotion Sciences Maternal and Infantile Care, Internal Medicine and Medical Specialities “Giuseppe D’Alessandro”, University of Palermo, Via del Vespro 133, 90127 Palermo, Italy; (F.P.); (E.C.)
| | - Francesco Martines
- Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata (BiND), Sezione di Audiologia, Università Degli Studi di Palermo, Via del Vespro 129, 90127 Palermo, Italy;
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18
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Melatonin Exerts Anti-Inflammatory, Antioxidant, and Neuromodulatory Effects That Could Potentially Be Useful in the Treatment of Vertigo. Int J Otolaryngol 2021; 2021:6641055. [PMID: 33859698 PMCID: PMC8009714 DOI: 10.1155/2021/6641055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022] Open
Abstract
The acute phase of vertigo involves multiple neurotransmitters, inflammatory mediators, and products of oxidative stress. The vestibular pathway has multiple melatonin receptors distributed along its path, both centrally and peripherally. In addition, melatonin has been shown to be a powerful antioxidant and anti-inflammatory agent against factors related to vertigo, such as Bax/caspases, interleukins, and chemokines. Likewise, it exerts central GABAergic, antidopaminergic, and anti-migraine functions and regulates sympathetic activity in a similar way to the drugs classically used in acute vestibular crisis. In this review, the role of melatonin as a potential treatment of the acute phase of vertigo is discussed.
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Ishai R, Seyyedi M, Chancellor AM, McLean CA, Rodriguez ML, Halmagyi GM, Nadol JB, Szmulewicz DJ, Quesnel AM. The Pathology of the Vestibular System in CANVAS. Otol Neurotol 2021; 42:e332-e340. [PMID: 33492056 PMCID: PMC9234914 DOI: 10.1097/mao.0000000000002985] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To describe the site of lesion responsible for the severe, bilateral, symmetrical, selective loss of vestibular function in Cerebellar Ataxia with Neuronopathy and Vestibular Areflexia Syndrome (CANVAS), an adult-onset recessively-inherited ataxia, characterized by progressive imbalance due to a combination of cerebellar, somatosensory, and selective vestibular impairment with normal hearing. METHODS Histologic examination of five temporal bones and the brainstems from four CANVAS patients and the brainstem only from one more, each diagnosed and followed from diagnosis to death by one of the clinician authors. RESULTS All five temporal bones showed severe loss of vestibular ganglion cells (cell counts 3-16% of normal), and atrophy of the vestibular nerves, whereas vestibular receptor hair cells and the vestibular nuclei were preserved. In contrast, auditory receptor hair cells, the auditory ganglia (cell counts 51-100% of normal), and the auditory nerves were relatively preserved. In addition, the cranial sensory ganglia (geniculate and trigeminal), present in two temporal bones, also showed severe degeneration. CONCLUSIONS In CANVAS there is a severe cranial sensory ganglionopathy neuronopathy (ganglionopathy) involving the vestibular, facial, and trigeminal ganglia but sparing the auditory ganglia. These observations, when coupled with the known spinal dorsal root ganglionopathy in CANVAS, indicate a shared pathogenesis of its somatosensory and cranial nerve manifestations. This is the first published account of both the otopathology and neuropathology of CANVAS, a disease that involves the central as well as the peripheral nervous system.
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Affiliation(s)
- Reuven Ishai
- Otopathology Laboratory, Department of Otolaryngology—Head and Neck Surgery, Massachusetts Eye and Ear
- Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Mohammad Seyyedi
- Otopathology Laboratory, Department of Otolaryngology—Head and Neck Surgery, Massachusetts Eye and Ear
- Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | - Joseph B. Nadol
- Otopathology Laboratory, Department of Otolaryngology—Head and Neck Surgery, Massachusetts Eye and Ear
- Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - David J. Szmulewicz
- Balance Disorders and Ataxia Service, Royal Victoria Eye and Ear Hospital, Melbourne, Australia
| | - Alicia M. Quesnel
- Otopathology Laboratory, Department of Otolaryngology—Head and Neck Surgery, Massachusetts Eye and Ear
- Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
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Maruta J. The Scientific Contributions of Bernard Cohen (1929-2019). Front Neurol 2021; 11:624243. [PMID: 33510708 PMCID: PMC7835511 DOI: 10.3389/fneur.2020.624243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/11/2020] [Indexed: 11/13/2022] Open
Abstract
Throughout Bernard Cohen's active career at Mount Sinai that lasted over a half century, he was involved in research on vestibular control of the oculomotor, body postural, and autonomic systems in animals and humans, contributing to our understanding of such maladies as motion sickness, mal de débarquement syndrome, and orthostatic syncope. This review is an attempt to trace and connect Cohen's varied research interests and his approaches to them. His influence was vast. His scientific contributions will continue to drive research directions for many years to come.
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Affiliation(s)
- Jun Maruta
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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21
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Kaya E, Smith DA, Smith C, Morris L, Bremova-Ertl T, Cortina-Borja M, Fineran P, Morten KJ, Poulton J, Boland B, Spencer J, Strupp M, Platt FM. Acetyl-leucine slows disease progression in lysosomal storage disorders. Brain Commun 2020; 3:fcaa148. [PMID: 33738443 PMCID: PMC7954382 DOI: 10.1093/braincomms/fcaa148] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/15/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
Acetyl-dl-leucine is a derivative of the branched chain amino acid leucine. In observational clinical studies, acetyl-dl-leucine improved symptoms of ataxia, in particular in patients with the lysosomal storage disorder, Niemann-Pick disease type C1. Here, we investigated acetyl-dl-leucine and its enantiomers acetyl-l-leucine and acetyl-d-leucine in symptomatic Npc1-/- mice and observed improvement in ataxia with both individual enantiomers and acetyl-dl-leucine. When acetyl-dl-leucine and acetyl-l-leucine were administered pre-symptomatically to Npc1-/- mice, both treatments delayed disease progression and extended life span, whereas acetyl-d-leucine did not. These data are consistent with acetyl-l-leucine being the neuroprotective enantiomer. Altered glucose and antioxidant metabolism were implicated as one of the potential mechanisms of action of the l-enantiomer in Npc1-/- mice. When the standard of care drug miglustat and acetyl-dl-leucine were used in combination significant synergy resulted. In agreement with these pre-clinical data, when Niemann-Pick disease type C1 patients were evaluated after 12 months of acetyl-dl-leucine treatment, rates of disease progression were slowed, with stabilization or improvement in multiple neurological domains. A beneficial effect of acetyl-dl-leucine on gait was also observed in this study in a mouse model of GM2 gangliosidosis (Sandhoff disease) and in Tay-Sachs and Sandhoff disease patients in individual-cases of off-label-use. Taken together, we have identified an unanticipated neuroprotective effect of acetyl-l-leucine and underlying mechanisms of action in lysosomal storage diseases, supporting its further evaluation in clinical trials in lysosomal disorders.
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Affiliation(s)
- Ecem Kaya
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - David A Smith
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Claire Smith
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Lauren Morris
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Tatiana Bremova-Ertl
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.,Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, 81377 München, Germany
| | - Mario Cortina-Borja
- Population, Policy and Practice Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Paul Fineran
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Karl J Morten
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital OX3 9DU, Oxford, UK
| | - Joanna Poulton
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital OX3 9DU, Oxford, UK
| | - Barry Boland
- Department of Pharmacology and Therapeutics, Western Gateway Building, College of Medicine and Health, University College Cork, Cork, T12XF62, Ireland
| | - John Spencer
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9RH UK
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Ludwig Maximilians University, Munich, 81377 München, Germany
| | - Frances M Platt
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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Histochemical Characterization of the Vestibular Y-Group in Monkey. THE CEREBELLUM 2020; 20:701-716. [PMID: 33083961 PMCID: PMC8629908 DOI: 10.1007/s12311-020-01200-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/04/2020] [Indexed: 12/18/2022]
Abstract
The Y-group plays an important role in the generation of upward smooth pursuit eye movements and contributes to the adaptive properties of the vertical vestibulo-ocular reflex. Malfunction of this circuitry may cause eye movement disorders, such as downbeat nystagmus. To characterize the neuron populations in the Y-group, we performed immunostainings for cellular proteins related to firing characteristics and transmitters (calretinin, GABA-related proteins and ion channels) in brainstem sections of macaque monkeys that had received tracer injections into the oculomotor nucleus. Two histochemically different populations of premotor neurons were identified: The calretinin-positive population represents the excitatory projection to contralateral upgaze motoneurons, whereas the GABAergic population represents the inhibitory projection to ipsilateral downgaze motoneurons. Both populations receive a strong supply by GABAergic nerve endings most likely originating from floccular Purkinje cells. All premotor neurons express nonphosphorylated neurofilaments and are ensheathed by strong perineuronal nets. In addition, they contain the voltage-gated potassium channels Kv1.1 and Kv3.1b which suggests biophysical similarities to high-activity premotor neurons of vestibular and oculomotor systems. The premotor neurons of Y-group form a homogenous population with histochemical characteristics compatible with fast-firing projection neurons that can also undergo plasticity and contribute to motor learning as found for the adaptation of the vestibulo-ocular reflex in response to visual-vestibular mismatch stimulation. The histochemical characterization of premotor neurons in the Y-group allows the identification of the homologue cell groups in human, including their transmitter inputs and will serve as basis for correlated anatomical-neuropathological studies of clinical cases with downbeat nystagmus.
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Abstract
OBJECTIVE To identify differences in the vestibulo-ocular reflex (VOR) gain value and the peak saccade velocity in the suppression video head impulse test paradigms according to the age of the subject and the direction of the impulse. STUDY DESIGN Retrospective chart analysis. SETTING Tertiary referral hospital. PATIENTS/INTERVENTIONS Between October 2017 and May 2019, we enrolled subjects who had previous histories of dizziness but no dizziness over the last 1 month. MAIN OUTCOME MEASURE We conducted cervical vestibular-evoked myogenic potential and caloric tests, as well as video head impulse tests. We excluded the subjects who had abnormal cervical vestibular-evoked myogenic potential results (asymmetry ratio of greater than 30%) and abnormal caloric test results (caloric paresis of greater than 25%). RESULTS We included 647 subjects aged 10 to 87 years. The mean VOR gain and peak saccade velocity were maintained in subjects less than 70 years old (VOR gain, 0.991 ± 0.08, peak saccade velocity, 348.47 ± 142.32). However, the decreases in VOR gain and peak saccade velocity were significant in subjects over 70 years old (VOR gain, 0.928 ± 0.09, peak saccade velocity, 315.51 ± 0.09; p < 0.001). The mean VOR gain of the rightward impulse (1.00 ± 0.09) was higher than the leftward impulse (0.96 ± 0.08, p < 0.001). CONCLUSIONS Both the VOR gain and peak saccade velocity of suppression video head impulse test paradigms declined with increasing age over 70 years. In addition, the VOR gain of the rightward impulse was higher than the leftward impulse in the right-eye recordings.
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Abe C, Yamaoka Y, Maejima Y, Mikami T, Yokota S, Yamanaka A, Morita H. VGLUT2-expressing neurons in the vestibular nuclear complex mediate gravitational stress-induced hypothermia in mice. Commun Biol 2020; 3:227. [PMID: 32385401 PMCID: PMC7210111 DOI: 10.1038/s42003-020-0950-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 04/17/2020] [Indexed: 11/17/2022] Open
Abstract
The vestibular system, which is essential for maintaining balance, contributes to the sympathetic response. Although this response is involved in hypergravity load-induced hypothermia in mice, the underlying mechanism remains unknown. This study showed that hypergravity (2g) decreased plasma catecholamines, which resulted in hypoactivity of the interscapular brown adipose tissue (iBAT). Hypothermia induced by 2g load was significantly suppressed by administration of beta-adrenergic receptor agonists, suggesting the involvement of decrease in iBAT activity through sympathoinhibition. Bilateral chemogenetic activation of vesicular glutamate transporter 2 (VGLUT2)-expressing neurons in the vestibular nuclear complex (VNC) induced hypothermia. The VGLUT2-expressing neurons contributed to 2g load-induced hypothermia, since their deletion suppressed hypothermia. Although activation of vesicular gamma-aminobutyric acid transporter-expressing neurons in the VNC induced slight hypothermia instead of hyperthermia, their deletion did not affect 2g load-induced hypothermia. Thus, we concluded that 2g load-induced hypothermia resulted from sympathoinhibition via the activation of VGLUT2-expressing neurons in the VNC. Chikara Abe, Yusuke Yamaoka et al. show that chemogenetic activation of VGLUT2-expressing neurons in the vestibular nuclear complex induces hypothermia, while their deletion suppresses hypergravity load-induced hypothermia in mice. These findings suggest an important role for these glutamatergic neurons in thermoregulation.
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Affiliation(s)
- Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan.
| | - Yusuke Yamaoka
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yui Maejima
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Tomoe Mikami
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Shigefumi Yokota
- Department of Anatomy and Neuroscience, Shimane University School of Medicine, Izumo, Shimane, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, Gifu, Japan.
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25
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Ando T, Ueda M, Luo Y, Sugihara I. Heterogeneous vestibulocerebellar mossy fiber projections revealed by single axon reconstruction in the mouse. J Comp Neurol 2020; 528:1775-1802. [PMID: 31904871 DOI: 10.1002/cne.24853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 02/01/2023]
Abstract
A significant population of neurons in the vestibular nuclei projects to the cerebellum as mossy fibers (MFs) which are involved in the control and adaptation of posture, eye-head movements, and autonomic function. However, little is known about their axonal projection patterns. We studied the morphology of single axons of medial vestibular nucleus (MVN) neurons as well as those originating from primary afferents, by labeling with biotinylated dextran amine (BDA). MVN axons (n = 35) were classified into three types based on their major predominant termination patterns. The Cbm-type terminated only in the cerebellum (15 axons), whereas others terminated in the cerebellum and contralateral vestibular nuclei (cVN/Cbm-type, 13 axons), or in the cerebellum and ipsilateral vestibular nuclei (iVN/Cbm-type, 7 axons). Cbm- and cVN/Cbm-types mostly projected to the nodulus and uvula without any clear relationship with longitudinal stripes in these lobules. They were often bilateral, and sometimes sent branches to the flocculus and to other vermal lobules. Also, the iVN/Cbm-type projected mainly to the ipsilateral nodulus. Neurons of these types of axons showed different distribution within the MVN. The number of MF terminals of some vestibulocerebellar axons, iVN/Cbm-type axons in particular, and primary afferent axons were much smaller than observed in previously studied MF axons originating from major precerebellar nuclei and the spinal cord. The results demonstrated that a heterogeneous population of MVN neurons provided divergent MF inputs to the cerebellum. The cVN/Cbm- and iVN/Cbm-types indicate that some excitatory neuronal circuits within the vestibular nuclei supply their collaterals to the vestibulocerebellum as MFs.
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Affiliation(s)
- Takahiro Ando
- Department of Systems Neurophysiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mitsuhito Ueda
- Department of Systems Neurophysiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuanjun Luo
- Department of Systems Neurophysiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Izumi Sugihara
- Department of Systems Neurophysiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
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26
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Abe C, Yamaoka Y, Maejima Y, Mikami T, Morita H. Hypergravity-induced plastic alteration of the vestibulo-sympathetic reflex involves decrease in responsiveness of CAMK2-expressing neurons in the vestibular nuclear complex. J Physiol Sci 2019; 69:903-917. [PMID: 31435871 PMCID: PMC10942005 DOI: 10.1007/s12576-019-00705-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/09/2019] [Indexed: 01/18/2023]
Abstract
The vestibular system contributes to not only eye movement and posture but also the sympathetic response. Plastic alteration of the vestibulo-sympathetic reflex is induced by hypergravity load; however, the mechanism remains unknown. Here, we examined 2 g-induced changing in responsiveness of CAMK2-expressing neurons in the vestibular nucleus complex using optogenetic tools. The excitatory photostimulation of the CAMK2-expressing neurons in the unilateral vestibular nuclear complex induced body tilt to the contralateral side, while inhibitory photostimulation showed the opposite response. Photoactivation of either cell body or the axonal terminal in the rostral ventrolateral medulla showed sympathoexcitation followed by the pressor response. Furthermore, this response was significantly attenuated (49.8 ± 4%) after the 1st day of 2 g loading, and this value was further reduced by the 5th day (22.4 ± 3%), suggesting that 2 g-induced attenuation of the vestibulo-sympathetic reflex involves at least decrease in responsiveness of CAMK2-expressing neurons in the vestibular nuclear complex.
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Affiliation(s)
- Chikara Abe
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
| | - Yusuke Yamaoka
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Yui Maejima
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Tomoe Mikami
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
| | - Hironobu Morita
- Department of Physiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan
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27
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Hernández RG, Djebari S, Vélez-Ortiz JM, de la Cruz RR, Pastor AM, Benítez-Temiño B. Short-term plasticity after partial deafferentation in the oculomotor system. Brain Struct Funct 2019; 224:2717-2731. [PMID: 31375981 DOI: 10.1007/s00429-019-01929-2] [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: 01/31/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
Medial rectus motoneurons are innervated by two main pontine inputs. The specific function of each of these two inputs remains to be fully understood. Indeed, selective partial deafferentation of medial rectus motoneurons, performed by the lesion of either the vestibular or the abducens input, initially induces similar changes in motoneuronal discharge. However, at longer time periods, the responses to both lesions are dissimilar. Alterations on eye movements and motoneuronal discharge induced by vestibular input transection recover completely 2 months post-lesion, whereas changes induced by abducens internuclear lesion are more drastic and permanent. Functional recovery could be due to some kind of plastic process, such as reactive synaptogenesis, developed by the remaining intact input, which would occupy the vacant synaptic spaces left after lesion. Herein, by means of confocal microscopy, immunocytochemistry and retrograde labeling, we attempt to elucidate the possible plastic processes that take place after partial deafferentation of medial rectus motoneuron. 48 h post-injury, both vestibular and abducens internuclear lesions produced a reduced synaptic coverage on these motoneurons. However, 96 h after vestibular lesion, there was a partial recovery in the number of synaptic contacts. This suggests that there was reactive synaptogenesis. This recovery was preceded by an increase in somatic neurotrophin content, suggesting a role of these molecules in presynaptic axonal sprouting. The rise in synaptic coverage might be due to terminal sprouting performed by the remaining main input, i.e., abducens internuclear neurons. The present results may improve the understanding of this apparently redundant input system.
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Affiliation(s)
- Rosendo G Hernández
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain
| | - Souhail Djebari
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain
| | - José Miguel Vélez-Ortiz
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain
| | - Rosa R de la Cruz
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain
| | - Angel M Pastor
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain.
| | - Beatriz Benítez-Temiño
- Departamento de Fisiología, Universidad de Sevilla, Avda. Reina Mercedes, 6, 41012, Seville, Spain
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Abstract
The vestibular system provides a critical role to coordinate balance and movement, yet it remains an underappreciated sense. Functional MRI (fMRI) reveals much information about brain-wide sensory and cognitive processes. However, fMRI mapping of regions that actively process vestibular information remains technically challenging, as it can permit only limited movement during scanning. Here, we deploy fMRI and optogenetic stimulation of vestibular excitatory neurons to visualize numerous brain-wide central vestibular pathways and interrogate their functional roles in multisensory processing. Our study highlights multiple routes to investigate vestibular functions and their integration with other sensory systems. We reveal a method to gain critical knowledge into this critical brain system. Blood oxygen level-dependent functional MRI (fMRI) constitutes a powerful neuroimaging technology to map brain-wide functions in response to specific sensory or cognitive tasks. However, fMRI mapping of the vestibular system, which is pivotal for our sense of balance, poses significant challenges. Physical constraints limit a subject’s ability to perform motion- and balance-related tasks inside the scanner, and current stimulation techniques within the scanner are nonspecific to delineate complex vestibular nucleus (VN) pathways. Using fMRI, we examined brain-wide neural activity patterns elicited by optogenetically stimulating excitatory neurons of a major vestibular nucleus, the ipsilateral medial VN (MVN). We demonstrated robust optogenetically evoked fMRI activations bilaterally at sensorimotor cortices and their associated thalamic nuclei (auditory, visual, somatosensory, and motor), high-order cortices (cingulate, retrosplenial, temporal association, and parietal), and hippocampal formations (dentate gyrus, entorhinal cortex, and subiculum). We then examined the modulatory effects of the vestibular system on sensory processing using auditory and visual stimulation in combination with optogenetic excitation of the MVN. We found enhanced responses to sound in the auditory cortex, thalamus, and inferior colliculus ipsilateral to the stimulated MVN. In the visual pathway, we observed enhanced responses to visual stimuli in the ipsilateral visual cortex, thalamus, and contralateral superior colliculus. Taken together, our imaging findings reveal multiple brain-wide central vestibular pathways. We demonstrate large-scale modulatory effects of the vestibular system on sensory processing.
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29
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Kalla R, Strupp M. Aminopyridines and Acetyl-DL-leucine: New Therapies in Cerebellar Disorders. Curr Neuropharmacol 2019; 17:7-13. [PMID: 30182858 PMCID: PMC6341500 DOI: 10.2174/1570159x16666180905093535] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/23/2017] [Accepted: 08/30/2018] [Indexed: 12/27/2022] Open
Abstract
Cerebellar ataxia is a frequent and often disabling syndrome severely impairing motor functioning and quality of life. Patients suffer from reduced mobility, and restricted autonomy, experiencing an even lower quality of life than, e.g., stroke survivors. Aminopyridines have been demonstrated viable for the symptomatic treatment of certain forms of cerebellar ataxia. This article will give an outline of the present pharmacotherapy of different cerebellar disorders. As a current key-therapy for the treatment of downbeat nystagmus 4-aminopyridine (4-AP) is suggested for the treatment of downbeat nystagmus (5-10 mg Twice a day [TID]), a frequent type of persisting nystagmus, due to a compromise of the vestibulo-cerebellum. Studies with animals have demonstrated, that a nonselective blockage of voltage-gated potassium channels (mainly Kv1.5) increases Purkinje- cell (PC) excitability. In episodic ataxia type 2 (EA2), which is frequently caused by mutations of the PQ-calcium channel, the efficacy of 4-AP (5-10 mg TID) has been shown in a randomized controlled trial (RCT). 4-AP was well tolerated in the recommended dosages. 4-AP was also effective in elevating symptoms in cerebellar gait ataxia of different etiologies (2 case series). A new treatment option for cerebellar disease is the amino-acid acetyl-DL-leucine, which has significantly improved cerebellar symptoms in three case series. There are on-going randomized controlled trials for cerebellar ataxia (acetyl-DL-leucine vs placebo; ALCAT), cerebellar gait disorders (SR-form of 4-AP vs placebo; FACEG) and EA2 (sustained-release/SR-form of 4-AP vs acetazolamide vs placebo; EAT2TREAT), which will provide new insights into the pharmacological treatment of cerebellar disorders.
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Affiliation(s)
- Roger Kalla
- Department of Neurology, University Hospital Bern, Bern, Switzerland.,Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich, Germany
| | - Michael Strupp
- Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich, Germany
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30
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Frank SM, Greenlee MW. The parieto-insular vestibular cortex in humans: more than a single area? J Neurophysiol 2018; 120:1438-1450. [DOI: 10.1152/jn.00907.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Here, we review the structure and function of a core region in the vestibular cortex of humans that is located in the midposterior Sylvian fissure and referred to as the parieto-insular vestibular cortex (PIVC). Previous studies have investigated PIVC by using vestibular or visual motion stimuli and have observed activations that were distributed across multiple anatomical structures, including the temporo-parietal junction, retroinsula, parietal operculum, and posterior insula. However, it has remained unclear whether all of these anatomical areas correspond to PIVC and whether PIVC responds to both vestibular and visual stimuli. Recent results suggest that the region that has been referred to as PIVC in previous studies consists of multiple areas with different anatomical correlates and different functional specializations. Specifically, a vestibular but not visual area is located in the parietal operculum, close to the posterior insula, and likely corresponds to the nonhuman primate PIVC, while a visual-vestibular area is located in the retroinsular cortex and is referred to, for historical reasons, as the posterior insular cortex area (PIC). In this article, we review the anatomy, connectivity, and function of PIVC and PIC and propose that the core of the human vestibular cortex consists of at least two separate areas, which we refer to together as PIVC+. We also review the organization in the nonhuman primate brain and show that there are parallels to the proposed organization in humans.
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Affiliation(s)
- Sebastian M. Frank
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, Rhode Island
| | - Mark W. Greenlee
- Institute for Experimental Psychology, University of Regensburg, Regensburg, Germany
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31
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Chen MM, Xu LH, Chang L, Yin P, Jiang ZL. Reduction of Motion Sickness Through Targeting Histamine N-Methyltransferase in the Dorsal Vagal Complex of the Brain. J Pharmacol Exp Ther 2018; 364:367-376. [PMID: 29298819 DOI: 10.1124/jpet.117.244475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/20/2017] [Indexed: 11/22/2022] Open
Abstract
To investigate the role of histamine N-methyltransferase (HNMT) activity in the development of motion sickness (MS) in the dorsal vagal complex (DVC) to inform the development of new drugs for MS, Beagle dogs and Sprague-Dawley rats were rotated to simulate MS. HNMT expression in the brain stem and DVC was measured. The effects of systemic application of tacrine, an HNMT inhibitor, on the development of MS were observed. Moreover, we microinjected a histamine receptor H1 inhibitor, promethazine, into the DVC to verify the involvement of histaminergic neurotransmission in MS. Finally, lentiviral vectors were microinjected into the DVC to determine the effects of altered HNMT expression on MS. We found the following: 1) HNMT expression in the medulla oblongata of dogs and rats insusceptible to MS was higher than in susceptible animals; 2) tacrine dose-dependently promoted MS in both animals and raised histamine level in rat medulla oblongata; 3) blocking histaminergic neurotransmission in the DVC with promethazine inhibited MS; 4) rotatory stimulus induced an elevation in HNMT expression, and vestibular training elevated the basal level of HNMT in the DVC during habituation to MS; 5) in vivo transfection of a lentiviral vector packaged with the HNMT gene increased HNMT expression in the DVC and reduced MS; and 6) microinjection of a lentiviral vector driving the interference of HNMT gene expression in vivo significantly inhibited HNMT expression in the DVC and exacerbated MS. In conclusion, HNMT expression in the brain stem is inversely correlated with MS development. Increasing HNMT expression or stimulating its activity in the DVC could inhibit MS.
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Affiliation(s)
- Miao-Miao Chen
- Department of Neurophysiology and Neuropharmacology, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Chongchuan District, Nantong, Jiangsu, People's Republic of China
| | - Li-Hua Xu
- Department of Neurophysiology and Neuropharmacology, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Chongchuan District, Nantong, Jiangsu, People's Republic of China
| | - Li Chang
- Department of Neurophysiology and Neuropharmacology, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Chongchuan District, Nantong, Jiangsu, People's Republic of China
| | - Peng Yin
- Department of Neurophysiology and Neuropharmacology, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Chongchuan District, Nantong, Jiangsu, People's Republic of China
| | - Zheng-Lin Jiang
- Department of Neurophysiology and Neuropharmacology, Institute of Nautical Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Chongchuan District, Nantong, Jiangsu, People's Republic of China
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Effect of common antivertiginous agents on the high velocity vestibulo-ocular reflex. Clin Neurophysiol 2017; 128:2211-2216. [PMID: 28985517 DOI: 10.1016/j.clinph.2017.08.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/14/2017] [Accepted: 08/13/2017] [Indexed: 11/23/2022]
Abstract
OBJECTIVE It has long been suggested that antivertiginous medications exert their symptomatic effect through inhibition of the vestibulo-ocular reflex (VOR). We tested this hypothesis by directly measuring the VOR after administration of three agents from different substance classes: an antihistamine, a benzodiazepine and a calcium channel antagonist. METHODS The gain and the variability of the high velocity VOR was assessed using video head impulses (vHIT) under the following conditions: baseline, after dimenhydrinate, after diazepam and after cinnarizine. RESULTS We found that all three medications did not change any VOR gain or variability parameter: At 60ms, the gain was 0.95 at baseline, 0.99 under dimenhydrinate, 0.99 under diazepam and 0.96 under cinnarizine. The gain variability across repetitive head impulses remained also uninfluenced. CONCLUSIONS The human high frequency VOR remains robust to pharmacological perturbations at common clinical doses and the assumption that symptomatic vertigo relief is achieved merely through impairment of the VOR requires re-examination. SIGNIFICANCE Alternative mechanisms of pharmacological action might be operant, such as the modulation of vestibulo-cortical pathways, a differential effect on the low frequency VOR and an altered sensitivity to drugs in acute unilateral vestibulopathy.
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Gaze-Stabilizing Central Vestibular Neurons Project Asymmetrically to Extraocular Motoneuron Pools. J Neurosci 2017; 37:11353-11365. [PMID: 28972121 PMCID: PMC5700419 DOI: 10.1523/jneurosci.1711-17.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 12/22/2022] Open
Abstract
Within reflex circuits, specific anatomical projections allow central neurons to relay sensations to effectors that generate movements. A major challenge is to relate anatomical features of central neural populations, such as asymmetric connectivity, to the computations the populations perform. To address this problem, we mapped the anatomy, modeled the function, and discovered a new behavioral role for a genetically defined population of central vestibular neurons in rhombomeres 5–7 of larval zebrafish. First, we found that neurons within this central population project preferentially to motoneurons that move the eyes downward. Concordantly, when the entire population of asymmetrically projecting neurons was stimulated collectively, only downward eye rotations were observed, demonstrating a functional correlate of the anatomical bias. When these neurons are ablated, fish failed to rotate their eyes following either nose-up or nose-down body tilts. This asymmetrically projecting central population thus participates in both upward and downward gaze stabilization. In addition to projecting to motoneurons, central vestibular neurons also receive direct sensory input from peripheral afferents. To infer whether asymmetric projections can facilitate sensory encoding or motor output, we modeled differentially projecting sets of central vestibular neurons. Whereas motor command strength was independent of projection allocation, asymmetric projections enabled more accurate representation of nose-up stimuli. The model shows how asymmetric connectivity could enhance the representation of imbalance during nose-up postures while preserving gaze stabilization performance. Finally, we found that central vestibular neurons were necessary for a vital behavior requiring maintenance of a nose-up posture: swim bladder inflation. These observations suggest that asymmetric connectivity in the vestibular system facilitates representation of ethologically relevant stimuli without compromising reflexive behavior. SIGNIFICANCE STATEMENT Interneuron populations use specific anatomical projections to transform sensations into reflexive actions. Here we examined how the anatomical composition of a genetically defined population of balance interneurons in the larval zebrafish relates to the computations it performs. First, we found that the population of interneurons that stabilize gaze preferentially project to motoneurons that move the eyes downward. Next, we discovered through modeling that such projection patterns can enhance the encoding of nose-up sensations without compromising gaze stabilization. Finally, we found that loss of these interneurons impairs a vital behavior, swim bladder inflation, that relies on maintaining a nose-up posture. These observations suggest that anatomical specialization permits neural circuits to represent relevant features of the environment without compromising behavior.
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Effects of Selective Deafferentation on the Discharge Characteristics of Medial Rectus Motoneurons. J Neurosci 2017; 37:9172-9188. [PMID: 28842421 DOI: 10.1523/jneurosci.1391-17.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/11/2017] [Accepted: 08/06/2017] [Indexed: 11/21/2022] Open
Abstract
Medial rectus motoneurons receive two main pontine inputs: abducens internuclear neurons, whose axons course through the medial longitudinal fasciculus (MLF), and neurons in the lateral vestibular nucleus, whose axons project through the ascending tract of Deiters (ATD). Abducens internuclear neurons are responsible for conjugate gaze in the horizontal plane, whereas ATD neurons provide medial rectus motoneurons with a vestibular input comprising mainly head velocity. To reveal the relative contribution of each input to the oculomotor physiology, single-unit recordings from medial rectus motoneurons were obtained in the control situation and after selective deafferentation from cats with unilateral transection of either the MLF or the ATD. Both MLF and ATD transection produced similar short-term alterations in medial rectus motoneuron firing pattern, which were more drastic in MLF of animals. However, long-term recordings revealed important differences between the two types of lesion. Thus, while the effects of the MLF section were permanent, 2 months after ATD lesioning all motoneuronal firing parameters were similar to the control. These findings indicated a more relevant role of the MLF pathway in driving motoneuronal firing and evidenced compensatory mechanisms following the ATD lesion. Confocal immunocytochemistry revealed that MLF transection produced also a higher loss of synaptic boutons, mainly at the dendritic level. Moreover, 2 months after ATD transection, we observed an increase in synaptic coverage around motoneuron cell bodies compared with short-term data, which is indicative of a synaptogenic compensatory mechanism of the abducens internuclear pathway that could lead to the observed firing and morphological recovery.SIGNIFICANCE STATEMENT Eye movements rely on multiple neuronal circuits for appropriate performance. The abducens internuclear pathway through the medial longitudinal fascicle (MLF) and the vestibular neurons through the ascending tract of Deiters (ATD) are a dual system that supports the firing of medial rectus motoneurons. We report the effect of sectioning the MLF or the ATD pathway on the firing of medial rectus motoneurons, as well as the plastic mechanisms by which one input compensates for the lack of the other. This work shows that while the effects of MLF transection are permanent, the ATD section produces transitory effects. A mechanism based on axonal sprouting and occupancy of the vacant synaptic space due to deafferentation is the base for the mechanism of compensation on the medial rectus motoneuron.
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Lee C, Jones TA. Neuropharmacological Targets for Drug Action in Vestibular Sensory Pathways. J Audiol Otol 2017; 21:125-132. [PMID: 28942632 PMCID: PMC5621797 DOI: 10.7874/jao.2017.00171] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/01/2017] [Accepted: 09/01/2017] [Indexed: 01/11/2023] Open
Abstract
The use of pharmacological agents is often the preferred approach to the management of vestibular dysfunction. In the vestibular sensory pathways, the sensory neuroepithelia are thought to be influenced by a diverse number of neuroactive substances that may act to enhance or inhibit the effect of the primary neurotransmitters [i.e., glutamate (Glu) and acetylcholine (ACh)] or alter their patterns of release. This review summarizes various efforts to identify drug targets including neurotransmitter and neuromodulator receptors in the vestibular sensory pathways. Identifying these receptor targets provides a strategic basis to use specific pharmacological tools to modify receptor function in the treatment and management of debilitating balance disorders. A review of the literature reveals that most investigations of the neuropharmacology of peripheral vestibular function have been performed using in vitro or ex vivo animal preparations rather than studying drug action on the normal intact vestibular system in situ. Such noninvasive approaches could aid the development of more accurate and effective intervention strategies for the treatment of dizziness and vertigo. The current review explores the major neuropharmacological targets for drug action in the vestibular system.
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Affiliation(s)
- Choongheon Lee
- Department of Otolaryngology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Timothy A Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE, USA
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Wellings TP, Brichta AM, Lim R. Altered neurofilament protein expression in the lateral vestibular nucleus in Parkinson's disease. Exp Brain Res 2017; 235:3695-3708. [PMID: 28929183 DOI: 10.1007/s00221-017-5092-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/14/2017] [Indexed: 12/27/2022]
Abstract
A major cause of morbidity in Parkinson's disease (PD) is postural instability. The neuropathology underlying postural instability is unknown. Postural control is mediated by Deiters' neurons of the lateral vestibular nucleus (LVN), which are the brainstem origin of descending vestibulospinal reflexes. Deiters' neurons express the cytostructural protein, non-phosphorylated neurofilament protein (NPNFP). In PD, reduced expression of NPNFP in substantia nigra (SN) neurons is believed to contribute to dysfunction. It was the aim of this study to determine if there is altered expression of NPNFP in the LVN in PD. We immunolabeled NPNFP in brainstem sections of six aged controls (mean age 92 yo) and six PD donors (mean age 83 yo). Our results show there was a ~ 50% reduction in NPNFP-positive Deiters' neurons compared to controls (13 ± 2.0/section vs 25.7 ± 3.0/section; p < 0.01, repeated measures ANOVA). In contrast, there was no difference in NPNFP-positive counts in the facial nucleus between control and PD. The normalized intensity of NPNFP labeling in LVN was also reduced in PD (0.87 ± 0.05 vs 1.09 ± 0.03; p < 0.01). There was a 35% concurrent reduction in NPNFP-positive neuropil in PD relative to controls (p < 0.01). We also show there was an 84% increase (p < 0.05) in somatic lipofuscin in PD patients compared to control. Lipofuscin aggregation has been shown to increase not only with age but also with neurodegeneration. Furthermore, decreased NPNFP intensity was strongly correlated with increasing lipofuscin autofluorescence across all cases (R 2 = 0.81, p < 0.01). These results show two alterations in cellular content with PD, reduced expression and intensity of NPNFP and increased lipofuscin aggregation in Deiter's neurons. These changes may contribute to degeneration of postural reflexes observed in PD.
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Affiliation(s)
- Thomas P Wellings
- Department of Neurology, John Hunter Hospital, New Lambton Heights, NSW, 2305, Australia.
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, 2308, Australia.
- Centre for Brain and Mental Health Research, HMRI, New Lambton Heights, NSW, 2305, Australia.
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, 2308, Australia
- Centre for Brain and Mental Health Research, HMRI, New Lambton Heights, NSW, 2305, Australia
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, 2308, Australia
- Centre for Brain and Mental Health Research, HMRI, New Lambton Heights, NSW, 2305, Australia
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37
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Puri PR, Sijapati A. Bilateral internuclear and internal ophthalmoplegia due to artery of Percheron infarction. Clin Case Rep 2017; 5:280-284. [PMID: 28265391 PMCID: PMC5331246 DOI: 10.1002/ccr3.837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/16/2016] [Accepted: 01/03/2017] [Indexed: 12/04/2022] Open
Abstract
The artery of Percheron (AOP) infarction always manifests as paramedian bilateral thalamic infarcts and might present as paramedian midbrain infarcts. Despite the limited MRA evaluation, due to small size of the artery, careful evaluation of the patient's history, the clinical presentation with imaging findings can facilitate the proper diagnosis.
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Affiliation(s)
| | - Astha Sijapati
- Department of Radiology Slagelse Hospital Slagelse Denmark
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Feil K, Adrion C, Teufel J, Bösch S, Claassen J, Giordano I, Hengel H, Jacobi H, Klockgether T, Klopstock T, Nachbauer W, Schöls L, Stendel C, Uslar E, van de Warrenburg B, Berger I, Naumann I, Bayer O, Müller HH, Mansmann U, Strupp M. Effects of acetyl-DL-leucine on cerebellar ataxia (ALCAT trial): study protocol for a multicenter, multinational, randomized, double-blind, placebo-controlled, crossover phase III trial. BMC Neurol 2017; 17:7. [PMID: 28068987 PMCID: PMC5223431 DOI: 10.1186/s12883-016-0786-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 12/14/2016] [Indexed: 01/06/2023] Open
Abstract
Background Cerebellar ataxia (CA) is a frequent and often disabling condition that impairs motor functioning and impacts on quality of life (QoL). No medication has yet been proven effective for the symptomatic or even causative treatment of hereditary or non-hereditary, non-acquired CA. So far, the only treatment recommendation is physiotherapy. Therefore, new therapeutic options are needed. Based on three observational studies, the primary objective of the acetyl-DL-leucine on ataxia (ALCAT) trial is to examine the efficacy and tolerability of a symptomatic therapy with acetyl-DL-leucine compared to placebo on motor function measured by the Scale for the Assessment and Rating of Ataxia (SARA) in patients with CA. Methods/Design An investigator-initiated, multicenter, European, randomized, double-blind, placebo-controlled, 2-treatment 2-period crossover phase III trial will be carried out. In total, 108 adult patients who meet the clinical criteria of CA of different etiologies (hereditary or non-hereditary, non-acquired) presenting with a SARA total score of at least 3 points will be randomly assigned in a 1:1 ratio to one of two different treatment sequences, either acetyl-DL-leucine (up to 5 g per day) followed by placebo or vice versa. Each sequence consists of two 6-week treatment periods, separated by a 4-week wash-out period. A follow-up examination is scheduled 4 weeks after the end of treatment. The primary efficacy outcome is the absolute change in the SARA total score. Secondary objectives are to demonstrate that acetyl-DL-leucine is effective in improving (1) motor function measured by the Spinocerebellar Ataxia Functional Index (SCAFI) and SARA subscore items and (2) QoL (EuroQoL 5 dimensions and 5 level version, EQ-5D-5 L), depression (Beck Depression Inventory, BDI-II) and fatigue (Fatigue Severity Score, FSS). Furthermore, the incidence of adverse events will be investigated. Discussion The results of this trial will inform whether symptomatic treatment with the modified amino-acid acetyl-DL-leucine is a worthy candidate for a new drug therapy to relieve ataxia symptoms and to improve patient care. If superiority of the experimental drug to placebo can be established it will also be re-purposing of an agent that has been previously used for the symptomatic treatment of dizziness. Trial registration The trial was prospectively registered at www.clinicaltrialsregister.eu (EudraCT no. 2015–000460–34) and at https://www.germanctr.de (DRKS-ID: DRKS00009733).
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Affiliation(s)
- Katharina Feil
- Department of Neurology with Friedrich-Baur-Institute, University Hospital, Munich, Germany. .,German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany. .,Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Campus Grosshadern, Marchioninistrasse 15, Munich, 81377, Germany.
| | - Christine Adrion
- Institute for Medical Informatics, Biometry and Epidemiology (IBE), University Hospital, Munich, Germany
| | - Julian Teufel
- Department of Neurology with Friedrich-Baur-Institute, University Hospital, Munich, Germany.,German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany
| | - Sylvia Bösch
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Jens Claassen
- Department of Neurology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ilaria Giordano
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
| | - Holger Hengel
- Department of Neurology and Hertie Institute for Clinical Brain Research, University Hospital Tübingen, Tübingen, Germany
| | - Heike Jacobi
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
| | - Thomas Klockgether
- German Center for Neurodegenerative Diseases (DZNE), Center for Clinical Research, Bonn, Germany
| | - Thomas Klopstock
- Department of Neurology with Friedrich-Baur-Institute, University Hospital, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, 80336, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, 80336, Germany
| | - Wolfgang Nachbauer
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Ludger Schöls
- Department of Neurology and Hertie Institute for Clinical Brain Research, University Hospital Tübingen, Tübingen, Germany
| | - Claudia Stendel
- Department of Neurology with Friedrich-Baur-Institute, University Hospital, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, 80336, Germany
| | - Ellen Uslar
- Department of Neurology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Ingrid Berger
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany
| | - Ivonne Naumann
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany
| | - Otmar Bayer
- German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany
| | - Hans-Helge Müller
- Institute for Medical Biometry and Epidemiology, Philipps University Marburg, Marburg, Germany
| | - Ulrich Mansmann
- Institute for Medical Informatics, Biometry and Epidemiology (IBE), University Hospital, Munich, Germany
| | - Michael Strupp
- Department of Neurology with Friedrich-Baur-Institute, University Hospital, Munich, Germany.,German Center for Vertigo and Balance Disorders (DSGZ), University Hospital, Munich, Germany
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Wegmann-Vicuña R, Muñoz-Hernández DE, Gallegos-Constantino V, Domínguez-Echavarri P, Irimia-Sieira P, Pérez-Fernández N. Acute vestibular syndrome with down-beat nystagmus as a sole clinical presentation in AICA transient ischemic attack with an uncommon clinical course. ACTA OTO-LARYNGOLOGICA CASE REPORTS 2017. [DOI: 10.1080/23772484.2017.1367255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
| | - Diana E. Muñoz-Hernández
- Department of Otorhinolaryngology, Instituto Nacional de Rehabilitación, Distrito Federal, Mexico
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BK Channels Are Required for Multisensory Plasticity in the Oculomotor System. Neuron 2016; 93:211-220. [PMID: 27989457 DOI: 10.1016/j.neuron.2016.11.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 07/29/2016] [Accepted: 11/03/2016] [Indexed: 02/04/2023]
Abstract
Neural circuits are endowed with several forms of intrinsic and synaptic plasticity that could contribute to adaptive changes in behavior, but circuit complexities have hindered linking specific cellular mechanisms with their behavioral consequences. Eye movements generated by simple brainstem circuits provide a means for relating cellular plasticity to behavioral gain control. Here we show that firing rate potentiation, a form of intrinsic plasticity mediated by reductions in BK-type calcium-activated potassium currents in spontaneously firing neurons, is engaged during optokinetic reflex compensation for inner ear dysfunction. Vestibular loss triggers transient increases in postsynaptic excitability, occlusion of firing rate potentiation, and reductions in BK currents in vestibular nucleus neurons. Concurrently, adaptive increases in visually evoked eye movements rapidly restore oculomotor function in wild-type mice but are profoundly impaired in BK channel-null mice. Activity-dependent regulation of intrinsic excitability may be a general mechanism for adaptive control of behavioral output in multisensory circuits.
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Grasso C, Li Volsi G, Cataldo E, Manzoni D, Barresi M. Effects of bicuculline application on the somatosensory responses of secondary vestibular neurons. Neuroscience 2016; 335:122-33. [PMID: 27579770 DOI: 10.1016/j.neuroscience.2016.08.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/19/2016] [Accepted: 08/21/2016] [Indexed: 01/05/2023]
Abstract
Limb somatosensory signals modify the discharge of vestibular neurons and elicit postural reflexes, which stabilize the body position. The aim of this study was to investigate the contribution of the γ-amino-butyric-acid (GABA) to the responsiveness of vestibular neurons to somatosensory inputs. The activity of 128 vestibular units was recorded in anesthetized rats in resting conditions and during sinusoidal foreleg rotation around the elbow or shoulder joints (0.026-0.625Hz, 45° peak amplitude). None of the recorded units was influenced by elbow rotation, while 40% of them responded to shoulder rotation. The selective GABAA antagonist receptor, bicuculline methiodine (BIC), was applied by microiontophoresis on single vestibular neurons and the changes in their activity at rest and during somatosensory stimulation was studied. In about half of cells the resting activity increased after the BIC application: 75% of these neurons showed also an increased response to somatosensory inputs whereas 17% exhibited a decrease. Changes in responsiveness in both directions were detected also in the units whose resting activity was not influenced by BIC. These data suggest that the responses of vestibular neurons to somatosensory inputs are modulated by GABA through a tonic release, which modifies the membrane response to the synaptic current. It is also possible that a phasic release of GABA occurs during foreleg rotation, shaping the stimulus-elicited current passing through the membrane. If this is the case, the changes in the relative position of body segments would modify the GABA release inducing changes in the vestibular reflexes and in learning processes that modify their spatio-temporal development.
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Affiliation(s)
- C Grasso
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, I-95125 Catania, Italy
| | - G Li Volsi
- Department of Biomedical and Biotechnological Sciences - Section of Physiology, University of Catania, I-95125 Catania, Italy
| | - E Cataldo
- Department of Physics, University of Pisa, I-56127 Pisa, Italy
| | - D Manzoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, I-56127 Pisa, Italy
| | - M Barresi
- Department of Drug Sciences, University of Catania, I-95125 Catania, Italy.
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Matsuno H, Kudoh M, Watakabe A, Yamamori T, Shigemoto R, Nagao S. Distribution and Structure of Synapses on Medial Vestibular Nuclear Neurons Targeted by Cerebellar Flocculus Purkinje Cells and Vestibular Nerve in Mice: Light and Electron Microscopy Studies. PLoS One 2016; 11:e0164037. [PMID: 27711146 PMCID: PMC5053601 DOI: 10.1371/journal.pone.0164037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 09/19/2016] [Indexed: 01/28/2023] Open
Abstract
Adaptations of vestibulo-ocular and optokinetic response eye movements have been studied as an experimental model of cerebellum-dependent motor learning. Several previous physiological and pharmacological studies have consistently suggested that the cerebellar flocculus (FL) Purkinje cells (P-cells) and the medial vestibular nucleus (MVN) neurons targeted by FL (FL-targeted MVN neurons) may respectively maintain the memory traces of short- and long-term adaptation. To study the basic structures of the FL-MVN synapses by light microscopy (LM) and electron microscopy (EM), we injected green florescence protein (GFP)-expressing lentivirus into FL to anterogradely label the FL P-cell axons in C57BL/6J mice. The FL P-cell axonal boutons were distributed in the magnocellular MVN and in the border region of parvocellular MVN and prepositus hypoglossi (PrH). In the magnocellular MVN, the FL-P cell axons mainly terminated on somata and proximal dendrites. On the other hand, in the parvocellular MVN/PrH, the FL P-cell axonal synaptic boutons mainly terminated on the relatively small-diameter (< 1 μm) distal dendrites of MVN neurons, forming symmetrical synapses. The majority of such parvocellular MVN/PrH neurons were determined to be glutamatergic by immunocytochemistry and in-situ hybridization of GFP expressing transgenic mice. To further examine the spatial relationship between the synapses of FL P-cells and those of vestibular nerve on the neurons of the parvocellular MVN/PrH, we added injections of biotinylated dextran amine into the semicircular canal and anterogradely labeled vestibular nerve axons in some mice. The MVN dendrites receiving the FL P-cell axonal synaptic boutons often closely apposed vestibular nerve synaptic boutons in both LM and EM studies. Such a partial overlap of synaptic boutons of FL P-cell axons with those of vestibular nerve axons in the distal dendrites of MVN neurons suggests that inhibitory synapses of FL P-cells may influence the function of neighboring excitatory synapses of vestibular nerve in the parvocellular MVN/PrH neurons.
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Affiliation(s)
- Hitomi Matsuno
- Laboratory for Motor Learning Control, Riken Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
- * E-mail: (HM); (SN)
| | - Moeko Kudoh
- Laboratory for Motor Learning Control, Riken Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - Akiya Watakabe
- Laboratory for Molecular Analysis of Higher Brain Function, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - Tetsuo Yamamori
- Laboratory for Molecular Analysis of Higher Brain Function, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - Ryuichi Shigemoto
- Division of Cerebral Structure, National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Soichi Nagao
- Laboratory for Motor Learning Control, Riken Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
- * E-mail: (HM); (SN)
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Haji-Abolhassani I, Guitton D, Galiana HL. Modeling eye-head gaze shifts in multiple contexts without motor planning. J Neurophysiol 2016; 116:1956-1985. [PMID: 27440248 DOI: 10.1152/jn.00605.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/14/2016] [Indexed: 11/22/2022] Open
Abstract
During gaze shifts, the eyes and head collaborate to rapidly capture a target (saccade) and fixate it. Accordingly, models of gaze shift control should embed both saccadic and fixation modes and a mechanism for switching between them. We demonstrate a model in which the eye and head platforms are driven by a shared gaze error signal. To limit the number of free parameters, we implement a model reduction approach in which steady-state cerebellar effects at each of their projection sites are lumped with the parameter of that site. The model topology is consistent with anatomy and neurophysiology, and can replicate eye-head responses observed in multiple experimental contexts: 1) observed gaze characteristics across species and subjects can emerge from this structure with minor parametric changes; 2) gaze can move to a goal while in the fixation mode; 3) ocular compensation for head perturbations during saccades could rely on vestibular-only cells in the vestibular nuclei with postulated projections to burst neurons; 4) two nonlinearities suffice, i.e., the experimentally-determined mapping of tectoreticular cells onto brain stem targets and the increased recruitment of the head for larger target eccentricities; 5) the effects of initial conditions on eye/head trajectories are due to neural circuit dynamics, not planning; and 6) "compensatory" ocular slow phases exist even after semicircular canal plugging, because of interconnections linking eye-head circuits. Our model structure also simulates classical vestibulo-ocular reflex and pursuit nystagmus, and provides novel neural circuit and behavioral predictions, notably that both eye-head coordination and segmental limb coordination are possible without trajectory planning.
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Affiliation(s)
- Iman Haji-Abolhassani
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada; and
| | - Daniel Guitton
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Henrietta L Galiana
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada; and
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Peng SY, Zhuang QX, Zhang YX, Zhang XY, Wang JJ, Zhu JN. Excitatory effect of norepinephrine on neurons in the inferior vestibular nucleus and the underlying receptor mechanism. J Neurosci Res 2016; 94:736-48. [PMID: 27121461 DOI: 10.1002/jnr.23745] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/26/2016] [Accepted: 03/16/2016] [Indexed: 12/20/2022]
Abstract
The central noradrenergic system, originating mainly from the locus coeruleus in the brainstem, plays an important role in many physiological functions, including arousal and attention, learning and memory, anxiety, and nociception. However, little is known about the roles of norepinephrine (NE) in somatic motor control. Therefore, using extracellular recordings on rat brainstem slices and quantitative real-time RT-PCR, we investigate the effect and mechanisms of NE on neuronal activity in the inferior vestibular nucleus (IVN), the largest nucleus in the vestibular nuclear complex, which holds an important position in integration of information signals controlling body posture. Here, we report that NE elicits an excitatory response on IVN neurons in a concentration-dependent manner. Activation of α1 - and β2 -adrenergic receptors (ARs) induces an increase in firing rate of IVN neurons, whereas activation of α2 -ARs evokes a decrease in firing rate of IVN neurons. Therefore, the excitation induced by NE on IVN neurons is a summation of the excitatory components mediated by coactivation of α1 - and β2 -ARs and the inhibitory component induced by α2 -ARs. Accordingly, α1 -, α2 -, and β2 -AR mRNAs are expressed in the IVN. Although β1 -AR mRNAs are also detected, they are not involved in the direct electrophysiological effect of NE on IVN neurons. All these results demonstrate that NE directly regulates the activity of IVN neurons via α1 -, α2 -, and β2 -ARs and suggest that the central noradrenergic system may actively participate in IVN-mediated vestibular reflexes and postural control. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Shi-Yu Peng
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Qian-Xing Zhuang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Yong-Xiao Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiao-Yang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jian-Jun Wang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jing-Ning Zhu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
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Head position and increased head velocity to optimize video head impulse test sensitivity. Eur Arch Otorhinolaryngol 2016; 273:3595-3602. [PMID: 26980338 DOI: 10.1007/s00405-016-3979-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
This study investigated the effects of head position on gain values during video head impulse tests (vHITs). Different head positions were used for vHIT of the horizontal semicircular canals of 20 healthy controls and 18 patients with unilateral vestibular loss (UVL), with head velocities ranging from 150°/s to 200°/s. Differences in vestibulo-ocular reflex gain in the control and patient groups according to head position (0° and 30° downward pitch) were analyzed. In the unaffected control group, the 30° pitched-down position resulted in a mean gain increase of up to 1.0 in both ears (right ear: 0.85 ± 0.26 for head-up and 1.05 ± 0.12 for head-down, p = 0.004; left ear: 0.75 ± 0.18 for head-up and 0.98 ± 0.16 for head-down, p < 0.001). In patients with UVL, the mean gains on the diseased side were 0.92 ± 0.16 in the head-up position and 0.82 ± 0.2 in the head-down position, at similar head velocities (p = 0.046). The pitched-down position also increased the asymmetry between ears in patients with UVL, at the same head velocity. A 30° head-down position can increase vHIT sensitivity, which resulted in increased mean gain in unaffected people and decreased mean gain in most of the patients with UVL in this study. This method may more effectively stimulate the horizontal semicircular canal. This vHIT modification may be helpful for more precisely evaluating vestibular function, thus reducing false-negative findings.
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Holstein GR, Friedrich VLJ, Martinelli GP. Glutamate and GABA in Vestibulo-Sympathetic Pathway Neurons. Front Neuroanat 2016; 10:7. [PMID: 26903817 PMCID: PMC4744852 DOI: 10.3389/fnana.2016.00007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 01/25/2016] [Indexed: 12/19/2022] Open
Abstract
The vestibulo-sympathetic reflex (VSR) actively modulates blood pressure during changes in posture. This reflex allows humans to stand up and quadrupeds to rear or climb without a precipitous decline in cerebral perfusion. The VSR pathway conveys signals from the vestibular end organs to the caudal vestibular nuclei. These cells, in turn, project to pre-sympathetic neurons in the rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively). The present study assessed glutamate- and GABA-related immunofluorescence associated with central vestibular neurons of the VSR pathway in rats. Retrograde FluoroGold tract tracing was used to label vestibular neurons with projections to RVLM or CVLM, and sinusoidal galvanic vestibular stimulation (GVS) was employed to activate these pathways. Central vestibular neurons of the VSR were identified by co-localization of FluoroGold and cFos protein, which accumulates in some vestibular neurons following galvanic stimulation. Triple-label immunofluorescence was used to co-localize glutamate- or GABA- labeling in the identified VSR pathway neurons. Most activated projection neurons displayed intense glutamate immunofluorescence, suggestive of glutamatergic neurotransmission. To support this, anterograde tracer was injected into the caudal vestibular nuclei. Vestibular axons and terminals in RVLM and CVLM co-localized the anterograde tracer and vesicular glutamate transporter-2 signals. Other retrogradely-labeled cFos-positive neurons displayed intense GABA immunofluorescence. VSR pathway neurons of both phenotypes were present in the caudal medial and spinal vestibular nuclei, and projected to both RVLM and CVLM. As a group, however, triple-labeled vestibular cells with intense glutamate immunofluorescence were located more rostrally in the vestibular nuclei than the GABAergic neurons. Only the GABAergic VSR pathway neurons showed a target preference, projecting predominantly to CVLM. These data provide the first demonstration of two disparate chemoanatomic VSR pathways.
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Affiliation(s)
- Gay R. Holstein
- Department of Neurology, Icahn School of Medicine at Mount SinaiNew York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount SinaiNew York, NY, USA
- Department of Anatomy/Functional Morphology, Icahn School of Medicine at Mount SinaiNew York, NY, USA
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AVP modulation of the vestibular nucleus via V1b receptors potentially contributes to the development of motion sickness in rat. Mol Brain 2015; 8:86. [PMID: 26651338 PMCID: PMC4676835 DOI: 10.1186/s13041-015-0175-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 12/01/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Arginine vasopressin (AVP) is considered to be an etiologic hormone in motion sickness (MS). The present study was designed to investigate whether individual differences in AVP expression in the paraventricular nucleus (PVN) and in modulation on the vestibular nucleus (VN) are involved in MS. Systemic application or microinjection of AVP into rat VN and rotatory stimulus were used to induce conditioned taste aversion (CTA) to 0.15 % saccharin sodium solution as a model of MS. RESULTS Intra-VN use of SSR149415, an antagonist of V1b receptors (V1bRs), blunted CTA. AVP inhibited Ca(2+) influxes through L-type Ca(2+) channels and NMDA receptor channels in cultured VN neurones, but antagonised by SSR149415. More AVP and V1bRs were expressed respectively in the PVN and VN after rotatory stimulus, especially in rats susceptible to MS. In the VN, AVP content was low, the AVP mRNA was less expressed, a few AVP-positive fibres were sparsely distributed, and fewer AVP/synaptophysin-positive terminals were identified. Almost no fluoro-ruby-labelled AVP-positive neurones in the PVN were found with retrograde tracing from the VN. SNP analysis of the reported 9 sites of the AVP gene showed significant difference between the groups susceptible and insusceptible to MS at the site rs105235842 in the allele frequencies and genotypes. However, there was not any difference between these two groups in the SNP of the reported 38 sites of V1bR gene. CONCLUSIONS AVP, through its modulatory, possibly humoral action on the VN neurones via the mediation of V1bR, may contribute to the development of motion sickness in rats; AVP gene polymorphisms may contribute to the individual difference in the responsive expression of AVP in the PVN; and higher expressions of AVP in the PVN and V1bRs in the VN may contribute to the development of motion sickness in rats after vestibular stimulation.
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Yu L, Zhang XY, Cao SL, Peng SY, Ji DY, Zhu JN, Wang JJ. Na(+) -Ca(2+) Exchanger, Leak K(+) Channel and Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel Comediate the Histamine-Induced Excitation on Rat Inferior Vestibular Nucleus Neurons. CNS Neurosci Ther 2015; 22:184-93. [PMID: 26387685 DOI: 10.1111/cns.12451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 12/11/2022] Open
Abstract
AIMS Antihistaminergic drugs have traditionally been used to treat vestibular disorders in the clinic. As a potential central target for antihistaminergic drugs, the inferior vestibular nucleus (IVN) is the largest subnucleus of the central vestibular nuclear complex and is considered responsible for vestibular-autonomic responses and integration of vestibular, cerebellar, and multisensory signals. However, the role of histamine on the IVN, particularly the underlying mechanisms, is still not clear. METHODS Using whole-cell patch-clamp recordings on rat brain slices, histamine-induced effect on IVN neurons and the underlying receptor and ionic mechanisms were investigated. RESULTS We found that histamine remarkably depolarized both spontaneous firing neurons and silent neurons in IVN via both histamine H1 and histamine H2 receptors. Furthermore, Na(+) -Ca(2+) exchangers (NCXs) and background leak K(+) channels linked to H1 receptors and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels coupled to H2 receptors comediate the histamine-induced depolarization on IVN neurons. CONCLUSION These results demonstrate the multiple ionic mechanisms underlying the excitatory modulation of histamine/central histaminergic system on IVN neurons and the related vestibular reflexes and functions. The findings also suggest potential targets for the treatment of vestibular disorders in the clinic, at the level of ionic channels in central vestibular nuclei.
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Affiliation(s)
- Lei Yu
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiao-Yang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Shu-Liang Cao
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Shi-Yu Peng
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Deng-Yu Ji
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jing-Ning Zhu
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jian-Jun Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biological Science and Technology, School of Life Sciences, Nanjing University, Nanjing, China
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Modifications of perineuronal nets and remodelling of excitatory and inhibitory afferents during vestibular compensation in the adult mouse. Brain Struct Funct 2015; 221:3193-209. [PMID: 26264050 DOI: 10.1007/s00429-015-1095-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/27/2015] [Indexed: 12/13/2022]
Abstract
Perineuronal nets (PNNs) are aggregates of extracellular matrix molecules surrounding several types of neurons in the adult CNS, which contribute to stabilising neuronal connections. Interestingly, a reduction of PNN number and staining intensity has been observed in conditions associated with plasticity in the adult brain. However, it is not known whether spontaneous PNN changes are functional to plasticity and repair after injury. To address this issue, we investigated PNN expression in the vestibular nuclei of the adult mouse during vestibular compensation, namely the resolution of motor deficits resulting from a unilateral peripheral vestibular lesion. After unilateral labyrinthectomy, we found that PNN number and staining intensity were strongly attenuated in the lateral vestibular nucleus on both sides, in parallel with remodelling of excitatory and inhibitory afferents. Moreover, PNNs were completely restored when vestibular deficits of the mice were abated. Interestingly, in mice with genetically reduced PNNs, vestibular compensation was accelerated. Overall, these results strongly suggest that temporal tuning of PNN expression may be crucial for vestibular compensation.
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Vestibular-evoked myogenic potentials in central vestibular disorders. J Neurol 2015; 263:210-220. [DOI: 10.1007/s00415-015-7860-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/13/2015] [Accepted: 07/13/2015] [Indexed: 12/20/2022]
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