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Hacohen-Brown S, Gilboa-Schechtman E, Zaidel A. Modality-specific effects of threat on self-motion perception. BMC Biol 2024; 22:120. [PMID: 38783286 PMCID: PMC11119305 DOI: 10.1186/s12915-024-01911-3] [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: 10/23/2023] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Threat and individual differences in threat-processing bias perception of stimuli in the environment. Yet, their effect on perception of one's own (body-based) self-motion in space is unknown. Here, we tested the effects of threat on self-motion perception using a multisensory motion simulator with concurrent threatening or neutral auditory stimuli. RESULTS Strikingly, threat had opposite effects on vestibular and visual self-motion perception, leading to overestimation of vestibular, but underestimation of visual self-motions. Trait anxiety tended to be associated with an enhanced effect of threat on estimates of self-motion for both modalities. CONCLUSIONS Enhanced vestibular perception under threat might stem from shared neural substrates with emotional processing, whereas diminished visual self-motion perception may indicate that a threatening stimulus diverts attention away from optic flow integration. Thus, threat induces modality-specific biases in everyday experiences of self-motion.
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Affiliation(s)
- Shira Hacohen-Brown
- Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
| | - Eva Gilboa-Schechtman
- Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel
- Department of Psychology, Bar-Ilan University, 5290002, Ramat-Gan, Israel
| | - Adam Zaidel
- Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat Gan, Israel.
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Alvarado-Navarrete MDC, Pliego-Carrillo AC, Ledesma-Ramírez CI, Cuellar CA. Post-activation depression of the Hoffman reflex is not altered by galvanic vestibular stimulation in healthy subjects. Front Integr Neurosci 2023; 17:1234613. [PMID: 37711909 PMCID: PMC10499171 DOI: 10.3389/fnint.2023.1234613] [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: 06/05/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
The comprehension of the neural elements interacting in the spinal cord affected by vestibular input will contribute to the understanding of movement execution in normal and pathological conditions. In this context, Hoffman's reflex (H-reflex) has been used to evaluate transient excitability changes on the spinal cord descending pathways. The post-activation depression (P-AD) of the H-reflex consists of evoking consecutive responses (>1 Hz) provoking an amplitude depression, which has been shown to diminish in pathological conditions (i.e., spasticity, diabetic neuropathy). Galvanic Vestibular Stimulation (GVS) is a non-invasive method that activates the vestibular afferents and has been used to study the excitability of the H-reflex applied as a conditioning pulse. To our knowledge, there are no reports evaluating the P-AD during and after GVS. Our primary aim was to determine if GVS alters the P-AD evoked by stimulating the tibial nerve at 0.1, 1, 5, and 10 Hz, recording in the gastrocnemius and soleus muscles. Direct current stimulation of 2.0 ± 0.6 mA with the cathode ipsilateral (Ipsi) or contralateral (Contra) to the H-reflex electrode montage was applied bilaterally over the mastoid process in 19 healthy subjects. The P-AD's immediate post-GVS response (P Ipsi, P Contra) was also analyzed. Secondarily, we analyzed the excitability of the H-reflex during GVS. Responses evoked at 0.1 Hz with GVS, post-GVS, and a Control (no GVS) condition were used for comparisons. Our results show that P-AD persisted in all subjects despite increased excitability induced by GVS: statistical significance was found when comparing P-AD at 1, 5, and 10 Hz with the corresponding condition (Control, Ipsi, P Ipsi, Contra, P Contra) at 0.1 Hz (p < 0.001). Additionally, the increase in excitability produced by GVS was quantified for the first H-reflex of each P-AD stimulation frequency. The percentage change for all GVS conditions surpassed the Control by at least 20%, being statistically significant for Contra compared to Control (p < 0.01). In summary, although GVS increases the excitability of the vestibulospinal pathway at a premotor level, the neural inhibitory mechanism present in P-AD remains unaltered in healthy subjects.
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Affiliation(s)
| | - Adriana C. Pliego-Carrillo
- Biomedical Engineering, School of Medicine, Autonomous University of the State of Mexico, Toluca, Mexico
| | | | - Carlos A. Cuellar
- School of Sport Sciences, Universidad Anáhuac México, Huixquilucan, Mexico
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Antons M, Lindner M, Eilles E, Günther L, Delker A, Branner C, Krämer A, Beck R, Oos R, Wuehr M, Ziegler S, Strupp M, Zwergal A. Dose- and application route-dependent effects of betahistine on behavioral recovery and neuroplasticity after acute unilateral labyrinthectomy in rats. Front Neurol 2023; 14:1175481. [PMID: 37538257 PMCID: PMC10395078 DOI: 10.3389/fneur.2023.1175481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/28/2023] [Indexed: 08/05/2023] Open
Abstract
Introduction Betahistine is widely used for the treatment of various vestibular disorders. However, the approved oral administration route and maximum daily dose are evidently not effective in clinical trials, possibly due to a major first-pass metabolism by monoamine oxidases (MAOs). The current study aimed to test different application routes (i.v./s.c./p.o.), doses, and concurrent medication (with the MAO-B inhibitor selegiline) for their effects on behavioral recovery and cerebral target engagement following unilateral labyrinthectomy (UL) in rats. Methods Sixty rats were subjected to UL by transtympanic injection of bupivacaine/arsanilic acid and assigned to five treatment groups: i.v. low-dose betahistine (1 mg/kg bid), i.v. high-dose betahistine (10 mg/kg bid), p.o. betahistine (1 mg/kg bid)/selegiline (1 mg/kg once daily), s.c. betahistine (continuous release of 4.8 mg/day), and i.v. normal saline bid (sham treatment; days 1-3 post-UL), respectively. Behavioral testing of postural asymmetry, nystagmus, and mobility in an open field was performed seven times until day 30 post-UL and paralleled by sequential cerebral [18F]-FDG-μPET measurements. Results The therapeutic effects of betahistine after UL differed in extent and time course and were dependent on the dose, application route, and selegiline co-medication: Postural asymmetry was significantly reduced on 2-3 days post-UL by i.v. high-dose and s.c. betahistine only. No changes were observed in the intensity of nystagmus across groups. When compared to sham treatment, movement distance in the open field increased up to 5-fold from 2 to 30 days post-UL in the s.c., i.v. high-dose, and p.o. betahistine/selegiline groups. [18F]-FDG-μPET showed a dose-dependent rCGM increase in the ipsilesional vestibular nucleus until day 3 post-UL for i.v. high- vs. low-dose betahistine and sham treatment, as well as for p.o. betahistine/selegiline and s.c. betahistine vs. sham treatment. From 1 to 30 days post-UL, rCGM increased in the thalamus bilaterally for i.v. high-dose betahistine, s.c. betahistine, and p.o. betahistine/selegiline vs. saline treatment. Discussion Betahistine has the potential to augment the recovery of dynamic deficits after UL if the administration protocol is optimized toward higher effective plasma levels. This may be achieved by higher doses, inhibition of MAO-based metabolism, or a parenteral route. In vivo imaging suggests a drug-target engagement in central vestibular networks.
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Affiliation(s)
- Melissa Antons
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Magdalena Lindner
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Munich, Germany
| | - Eva Eilles
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Lisa Günther
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Astrid Delker
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Munich, Germany
| | - Christina Branner
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Anja Krämer
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Roswitha Beck
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Rosel Oos
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Munich, Germany
| | - Max Wuehr
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
| | - Sibylle Ziegler
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Munich, Germany
| | - Michael Strupp
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
- Department of Neurology, LMU University Hospital, LMU Munich, Munich, Germany
| | - Andreas Zwergal
- German Center for Vertigo and Balance Disorders, DSGZ, LMU University Hospital, LMU Munich, Munich, Germany
- Department of Neurology, LMU University Hospital, LMU Munich, Munich, Germany
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Čada Z, Balatková Z, Čakrt O, Hrubá S, Komarc M, Plzak J, Černý R. Predictors of central vestibular compensation after surgery for vestibular schwannomas. ACTA ACUST UNITED AC 2019; 39:46-52. [PMID: 30936578 PMCID: PMC6444164 DOI: 10.14639/0392-100x-1963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/22/2018] [Indexed: 11/23/2022]
Abstract
Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo which is the most negative factor affecting quality of life in patients after vestibular schwannoma surgery. The main aim of this study is to determine whether the results from routine electronystagmography with pathological visually-provoked responses can predict poor postoperative compensation. We also investigate whether postoperative central compensation is related to objective parameters such age, tumour size, length of surgery and persistent nystagmus. According to the results from preoperative electronystagmography, patients were divided into three groups: peripheral, central and combined vestibular syndrome. Signs of central compensation were evaluated by the presence of postoperative nystagmus, vertigo, deviation of subjective visual vertical and head impulse test. There were no statistically significant differences between groups in observed signs of compensation. These results suggest that pathological central oculomotor parameters are not a negative predictive factor for central vestibular compensation.
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Affiliation(s)
- Z Čada
- Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine Charles University in Prague and Motol University Hospital, Postgraduate Medical School
| | - Z Balatková
- Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine Charles University in Prague and Motol University Hospital, Postgraduate Medical School
| | - O Čakrt
- Department of Rehabilitation and Sports Medicine, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Postgraduate Medical School
| | - S Hrubá
- Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine Charles University in Prague and Motol University Hospital, Postgraduate Medical School
| | - M Komarc
- Department of Anthropomotorics and Methodology, Faculty of Physical Education and Sport, Charles University in Prague
| | - J Plzak
- Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine Charles University in Prague and Motol University Hospital, Postgraduate Medical School
| | - R Černý
- Department of Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Postgraduate Medical School
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Hatzilazaridis I, Hatzitaki V, Antoniadou N, Samoladas E. Postural and muscle responses to galvanic vestibular stimulation reveal a vestibular deficit in adolescents with idiopathic scoliosis. Eur J Neurosci 2019; 50:3614-3626. [PMID: 31336391 DOI: 10.1111/ejn.14525] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 05/14/2019] [Accepted: 06/10/2019] [Indexed: 11/27/2022]
Abstract
One of the most appealing hypotheses around the aetiopathogenesis of adolescent idiopathic scoliosis attributes the development of the spine deformity to an imbalance in the descending vestibulospinal drive to the muscles resulting in a differential mechanical pull on the spine during the early life stages. In this study, we explored this hypothesis by examining postural and muscle responses to binaural bipolar galvanic vestibular stimulation (GVS) of randomly alternating polarity. Adolescents diagnosed with idiopathic scoliosis (n = 12) and healthy age-matched controls (n = 12) stood quietly with feet together (stance duration 66-102 s), eyes closed and facing forward, while 10 short (2s), transmastoidal, bipolar square wave GVS pulses (0.3-2.0 mA) of randomly alternating polarity were delivered at varying time intervals. Responses depicted in the electromyographic (EMG) activity of bilateral axial and appendicular muscles, vertical reaction forces and segment kinematics were recorded and analysed. Scoliotic patients demonstrated smaller ankle muscle responses and a delayed postural shift to the right relative to controls during anode right/cathode left GVS. When GVS polarity was reversed, patients had a greater soleus short-latency response on the left anodal side, while the rest of the muscle and postural responses were similar between groups. Vestibular stimulation also evoked greater head and upper trunk sway in scoliotic compared with healthy adolescents irrespective of stimulus polarity. Results provide new preliminary evidence for a vestibular imbalance in adolescents with idiopathic scoliosis that is compensated by somatosensory, load-related afferent feedback from the lower limbs during the latter part of the response.
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Affiliation(s)
- Ioannis Hatzilazaridis
- Laboratory of Motor Behavior and Adapted Physical Activity, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Vassilia Hatzitaki
- Laboratory of Motor Behavior and Adapted Physical Activity, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikoleta Antoniadou
- Laboratory of Motor Behavior and Adapted Physical Activity, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Efthimios Samoladas
- Orthopeadics Division of Genimatas Hospital, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Hassanien OA, Younes RL, Dawoud RM, Kotait MA. Vestibular cortex assessment using DTI & MRS complemented by rotatory chair technique in vestibulopathy patients with normal appearing brain MRI. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2017. [DOI: 10.1016/j.ejrnm.2017.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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7
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Wireless inertial measurement of head kinematics in freely-moving rats. Sci Rep 2016; 6:35689. [PMID: 27767085 PMCID: PMC5073323 DOI: 10.1038/srep35689] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/03/2016] [Indexed: 11/22/2022] Open
Abstract
While miniature inertial sensors offer a promising means for precisely detecting, quantifying and classifying animal behaviors, versatile inertial sensing devices adapted for small, freely-moving laboratory animals are still lacking. We developed a standalone and cost-effective platform for performing high-rate wireless inertial measurements of head movements in rats. Our system is designed to enable real-time bidirectional communication between the headborne inertial sensing device and third party systems, which can be used for precise data timestamping and low-latency motion-triggered applications. We illustrate the usefulness of our system in diverse experimental situations. We show that our system can be used for precisely quantifying motor responses evoked by external stimuli, for characterizing head kinematics during normal behavior and for monitoring head posture under normal and pathological conditions obtained using unilateral vestibular lesions. We also introduce and validate a novel method for automatically quantifying behavioral freezing during Pavlovian fear conditioning experiments, which offers superior performance in terms of precision, temporal resolution and efficiency. Thus, this system precisely acquires movement information in freely-moving animals, and can enable objective and quantitative behavioral scoring methods in a wide variety of experimental situations.
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Miffon M, Guyot JP. Difficulties Faced by Patients Suffering from Total Bilateral Vestibular Loss. ORL J Otorhinolaryngol Relat Spec 2015; 77:241-247. [DOI: 10.1159/000433553] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Advances in the diagnosis and treatment of vestibular disorders: psychophysics and prosthetics. J Neurosci 2015; 35:5089-96. [PMID: 25834036 DOI: 10.1523/jneurosci.3922-14.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although vestibular disorders are common and often disabling, they remain difficult to diagnose and treat. For these reasons, considerable interest has been focused on developing new ways to identify peripheral and central vestibular abnormalities and on new therapeutic options that could benefit the numerous patients who remain symptomatic despite optimal therapy. In this review, I focus on the potential utility of psychophysical vestibular testing and vestibular prosthetics. The former offers a new diagnostic approach that may prove to be superior to the current tests in some circumstances; the latter may be a way to provide the brain with information about head motion that restores some elements of the information normally provided by the vestibular labyrinth.
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10
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Nicolson T. Ribbon synapses in zebrafish hair cells. Hear Res 2015; 330:170-7. [PMID: 25916266 DOI: 10.1016/j.heares.2015.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/20/2015] [Accepted: 04/13/2015] [Indexed: 12/31/2022]
Abstract
The basic architecture and functionality of ribbon synapses of mechanosensitive hair cells are well conserved among vertebrates. Forward and reverse genetic methods in zebrafish (Danio rerio) have identified components that are critical for the development and function of ribbon synapses. This review will focus on the findings of these genetic approaches, and discuss some emergent concepts on the role of the ribbon body and calcium in synapse development, and how perturbations in synaptic vesicles lead to a loss of temporal fidelity at ribbon synapses. This article is part of a Special Issue entitled <Auditory Synaptology>.
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Affiliation(s)
- T Nicolson
- Oregon Hearing Research Center and Vollum Institute, 3181 SW Sam Jackson Park Road, Oregon Health & Science University, Portland, OR 97239, USA.
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11
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Elliott KL, Houston DW, DeCook R, Fritzsch B. Ear manipulations reveal a critical period for survival and dendritic development at the single-cell level in Mauthner neurons. Dev Neurobiol 2015; 75:1339-51. [PMID: 25787878 DOI: 10.1002/dneu.22287] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 12/25/2022]
Abstract
Second-order sensory neurons are dependent on afferents from the sense organs during a critical period in development for their survival and differentiation. Past research has mostly focused on whole populations of neurons, hampering progress in understanding the mechanisms underlying these critical phases. To move toward a better understanding of the molecular and cellular basis of afferent-dependent neuronal development, we developed a new model to study the effects of ear removal on a single identifiable cell in the hindbrain of a frog, the Mauthner cell. Ear extirpation at various stages of Xenopus laevis development defines a critical period of progressively-reduced dependency of Mauthner cell survival/differentiation on the ear afferents. Furthermore, ear removal results in a progressively decreased reduction in the number of dendritic branches. Conversely, addition of an ear results in an increase in the number of dendritic branches. These results suggest that the duration of innervation and the number of inner ear afferents play a quantitative role in Mauthner cell survival/differentiation, including dendritic development.
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Affiliation(s)
- Karen L Elliott
- Department of Biology, University of Iowa, Iowa City, IA, 52242
| | | | - Rhonda DeCook
- Department of Statistics and Actuarial Sciences, University of Iowa, Iowa City, IA, 52242
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, 52242
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Beck R, Günther L, Xiong G, Potschka H, Böning G, Bartenstein P, Brandt T, Jahn K, Dieterich M, Strupp M, la Fougère C, Zwergal A. The mixed blessing of treating symptoms in acute vestibular failure — Evidence from a 4-aminopyridine experiment. Exp Neurol 2014; 261:638-45. [DOI: 10.1016/j.expneurol.2014.08.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/07/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
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13
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Sequential [(18)F]FDG µPET whole-brain imaging of central vestibular compensation: a model of deafferentation-induced brain plasticity. Brain Struct Funct 2014; 221:159-70. [PMID: 25269833 DOI: 10.1007/s00429-014-0899-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
Abstract
Unilateral inner ear damage is followed by a rapid behavioural recovery due to central vestibular compensation. In this study, we utilized serial [(18)F]Fluoro-deoxyglucose ([(18)F]FDG)-µPET imaging in the rat to visualize changes in brain glucose metabolism during behavioural recovery after surgical and chemical unilateral labyrinthectomy, to determine the extent and time-course of the involvement of different brain regions in vestibular compensation and test previously described hypotheses of underlying mechanisms. Systematic patterns of relative changes of glucose metabolism (rCGM) were observed during vestibular compensation. A significant asymmetry of rCGM appeared in the vestibular nuclei, vestibulocerebellum, thalamus, multisensory vestibular cortex, hippocampus and amygdala in the acute phase of vestibular imbalance (4 h). This was followed by early vestibular compensation over 1-2 days where rCGM re-balanced between the vestibular nuclei, thalami and temporoparietal cortices and bilateral rCGM increase appeared in the hippocampus and amygdala. Subsequently over 2-7 days, rCGM increased in the ipsilesional spinal trigeminal nucleus and later (7-9 days) rCGM increased in the vestibulocerebellum bilaterally and the hypothalamus and persisted in the hippocampus. These systematic dynamic rCGM patterns during vestibular compensation, were confirmed in a second rat model of chemical unilateral labyrinthectomy by serial [(18)F]FDG-µPET. These findings show that deafferentation-induced plasticity after unilateral labyrinthectomy involves early mechanisms of re-balancing predominantly in the brainstem vestibular nuclei but also in thalamo-cortical and limbic areas, and indicate the contribution of spinocerebellar sensory inputs and vestibulocerebellar adaptation at the later stages of behavioural recovery.
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Mackrous I, Simoneau M. Generalization of vestibular learning to earth-fixed targets is possible but limited when the polarity of afferent vestibular information is changed. Neuroscience 2014; 260:12-22. [DOI: 10.1016/j.neuroscience.2013.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/29/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022]
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15
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Restricted neural plasticity in vestibulospinal pathways after unilateral labyrinthectomy as the origin for scoliotic deformations. J Neurosci 2013; 33:6845-56. [PMID: 23595743 DOI: 10.1523/jneurosci.4842-12.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Adolescent idiopathic scoliosis in humans is often associated with vestibulomotor deficits. Compatible with a vestibular origin, scoliotic deformations were provoked in adult Xenopus frogs by unilateral labyrinthectomy (UL) at larval stages. The aquatic ecophysiology and absence of body-weight-supporting limb proprioceptive signals in amphibian tadpoles as a potential sensory substitute after UL might be the cause for a persistent asymmetric descending vestibulospinal activity. Therefore, peripheral vestibular lesions in larval Xenopus were used to reveal the morphophysiological alterations at the cellular and network levels. As a result, spinal motor nerves that were modulated by the previously intact side before UL remained permanently silent during natural vestibular stimulation after the lesion. In addition, retrograde tracing of descending pathways revealed a loss of vestibular neurons on the ipsilesional side with crossed vestibulospinal projections. This loss facilitated a general mass imbalance in descending premotor activity and a permanent asymmetric motor drive to the axial musculature. Therefore, we propose that the persistent asymmetric contraction of trunk muscles exerts a constant, uncompensated differential mechanical pull on bilateral skeletal elements that enforces a distortion of the soft cartilaginous skeletal elements and bone shapes. This ultimately provokes severe scoliotic deformations during ontogenetic development similar to the human syndrome.
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Presynaptic GABA(B) receptors decrease neurotransmitter release in vestibular nuclei neurons during vestibular compensation. Neuroscience 2012; 223:333-54. [PMID: 22871524 DOI: 10.1016/j.neuroscience.2012.07.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/18/2012] [Accepted: 07/30/2012] [Indexed: 01/25/2023]
Abstract
Unilateral damage to the peripheral vestibular receptors precipitates a debilitating syndrome of oculomotor and balance deficits at rest, which extensively normalize during the first week after the lesion due to vestibular compensation. In vivo studies suggest that GABA(B) receptor activation facilitates recovery. However, the presynaptic or postsynaptic sites of action of GABA(B) receptors in vestibular nuclei neurons after lesions have not been determined. Accordingly, here presynaptic and postsynaptic GABA(B) receptor activity in principal cells of the tangential nucleus, a major avian vestibular nucleus, was investigated using patch-clamp recordings correlated with immunolabeling and confocal imaging of the GABA(B) receptor subunit-2 (GABA(B)R2) in controls and operated chickens shortly after unilateral vestibular ganglionectomy (UVG). Baclofen, a GABA(B) agonist, generated no postsynaptic currents in principal cells in controls, which correlated with weak GABA(B)R2 immunolabeling on principal cell surfaces. However, baclofen decreased miniature excitatory postsynaptic current (mEPSC) and GABAergic miniature inhibitory postsynaptic current (mIPSC) events in principal cells in controls, compensating and uncompensated chickens three days after UVG, indicating the presence of functional GABA(B) receptors on presynaptic terminals. Baclofen decreased GABAergic mIPSC frequency to the greatest extent in principal cells on the intact side of compensating chickens, with concurrent increases in GABA(B)R2 pixel brightness and percentage overlap in synaptotagmin 2-labeled terminals. In uncompensated chickens, baclofen decreased mEPSC frequency to the greatest extent in principal cells on the intact side, with concurrent increases in GABA(B)R2 pixel brightness and percentage overlap in synaptotagmin 1-labeled terminals. Altogether, these results revealed changes in presynaptic GABA(B) receptor function and expression which differed in compensating and uncompensated chickens shortly after UVG. This work supports an important role for GABA(B) autoreceptor-mediated inhibition in vestibular nuclei neurons on the intact side during early stages of vestibular compensation, and a role for GABA(B) heteroreceptor-mediated inhibition of glutamatergic terminals on the intact side in the failure to recover function.
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