Labyrinthectomy

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform

Emile Godaux - One of the best experts on this subject based on the ideXlab platform.

  • long term plasticity of ipsilesional medial vestibular nucleus neurons after unilateral Labyrinthectomy
    Journal of Neurophysiology, 2003
    Co-Authors: Mathieu Beraneck, E. Idoux, Pierre-paul Vidal, Emile Godaux, M Hachemaoui, L E Moore, Nicolas Vibert
    Abstract:

    Unilateral Labyrinthectomy results in oculomotor and postural disturbances that regress in a few days during vestibular compensation. The long-term (after 1 mo) consequences of unilateral labyrinth...

  • Effect of Labyrinthectomy on the spike generator of vestibular neurons in the guinea pig
    Neuroreport, 2002
    Co-Authors: M Hachemaoui, Emile Godaux
    Abstract:

    In the guinea pig, in the absence of any stimulation, all the neurons of the vestibular nuclei are tonically firing. After an ipsilateral Labyrinthectomy, these neurons first cease to fire but recover their previous discharge in 7 days. Here, we tested whether a modification of the spike generator, the process transforming synaptic currents into spike patterns, could be a factor underlying this restoration. For this purpose, we studied the firing rate responses of neuronsof the medial vestibular nucleus in brain stem slices to intracellularly injected currents. We conclude that although Labyrinthectomy induces some plastic changes in the excitability of the neurons of the medial vestibular nucleus, these changes do not underlie the restoration of activity which occurs in these neurons when they are deprived of their labyrinthine input.

  • neck muscle activity after unilateral Labyrinthectomy in the alert guinea pig
    Experimental Brain Research, 1999
    Co-Authors: Brigitte Capron, Pierre-paul Vidal, Catherine De Waele, Emile Godaux
    Abstract:

    In the guinea pig, lateral deviation of the head is a cardinal symptom of the vestibular syndrome caused by unilateral Labyrinthectomy. In the course of recovery from this syndrome (vestibular compensation), lateral deviation of the head disappears completely in 2–3 days. Because this symptom is known to be due to the lesion of the horizontal semicircular canal system, and since obliquus capitis inferior (OCI) muscle is activated predominantly by yaw rotation (horizontal vestibulocollic reflex), we hypothesized that changes in the activity of this muscle could be at least in part responsible for the lateral head deviation caused by unilateral Labyrinthectomy. In order to test this hypothesis, electromyographic (EMG) activities of the right and left OCI muscles, as well as eye movements, were recorded in 12 head-fixed alert guinea pigs at various times after left surgical Labyrinthectomy (performed with the animals under halothane anesthesia). After the operation, a decrease in tonic EMG activity was observed in the right (contralateral to the lesion) OCI muscle while an increase in tonic EMG activity was detected in the left (ipsilateral) OCI muscle. In addition, phasic changes in EMG activity associated with ocular nystagmic beats occurred in the OCI muscles. These phasic changes were in the opposite direction to those of the tonic changes. There were bursts of activity in the right OCI and pauses in the left OCI. From measurements of rectified averaged EMG activities which took into account both parts (tonic and phasic) of the phenomenon, it was concluded that the Labyrinthectomy-induced asymmetry between the activities of the left and right OCI muscles was high enough and lasted long enough to be an important mechanism in the lateral deviation of the head caused by unilateral Labyrinthectomy.

  • neuronal activity in the vestibular nuclei after contralateral or bilateral Labyrinthectomy in the alert guinea pig
    Journal of Neurophysiology, 1998
    Co-Authors: Emile Godaux
    Abstract:

    Ris, Laurence and Emile Godaux. Neuronal activity in the vestibular nuclei after contralateral or bilateral Labyrinthectomy in the alert guinea pig. J. Neurophysiol. 80: 2352–2367, 1998. In the gui...

Nicolas Vibert - One of the best experts on this subject based on the ideXlab platform.

  • Evidence against a role of gap junctions in vestibular compensation
    Neuroscience Letters, 2008
    Co-Authors: Mathieu Beraneck, E. Idoux, Isabelle Vassias, Pierre-paul Vidal, Catherine De Waele, Nicolas Vibert
    Abstract:

    Vestibular compensation following unilateral Labyrinthectomy is associated with modifications of the membrane and firing properties of central vestibular neurons. To determine whether gap junctions could be involved in this process, immunofluorescent detection of neuronal connexin 36 and astrocytic connexin 43 was performed in the medial vestibular nucleus (MVN) of rats. In non-lesioned animals, strong staining was observed with anti-connexin 43 antibodies, while moderate staining was obtained with the anti-connexin 36 antibody. However, the expression of either type of connexin was not modified following unilateral Labyrinthectomy. These morphological observations were complemented by pharmacological tests performed during extracellular recordings of MVN neurons in guinea pig brainstem slices. In non-lesioned animals, the gap junction blocker carbenoxolone reversibly decreased or suppressed the spontaneous discharge of about 60% of MVN neurons. This reduction was often associated with a long-duration disruption of the regularity of spike discharge. Both effects were mimicked by several other gap junction blockers, but not by glycyrrhizic acid, an analog of carbenoxolone that does not block gap junctions but reproduces its non-specific effects, nor by the selective inhibitor of astrocytic connexin-based networks endothelin-1. Similar effects of carbenoxolone were obtained on the spontaneous activity of ipsilesional MVN neurons recorded in brainstem slices taken from labyrinthectomized animals. Altogether, these results suggest that neuronal gap junctions are involved in shaping the spontaneous activity of MVN neurons. However, unilateral Labyrinthectomy does not affect the expression of gap junctions in vestibular nuclei nor their implication in the regulation of neuronal activity.

  • long term plasticity of ipsilesional medial vestibular nucleus neurons after unilateral Labyrinthectomy
    Journal of Neurophysiology, 2003
    Co-Authors: Mathieu Beraneck, E. Idoux, Pierre-paul Vidal, Emile Godaux, M Hachemaoui, L E Moore, Nicolas Vibert
    Abstract:

    Unilateral Labyrinthectomy results in oculomotor and postural disturbances that regress in a few days during vestibular compensation. The long-term (after 1 mo) consequences of unilateral labyrinth...

Lloyd B Minor - One of the best experts on this subject based on the ideXlab platform.

Richard R Gacek - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Labyrinthectomy and vestibular neurectomy in the control of vertigo.
    The Laryngoscope, 1996
    Co-Authors: Richard R Gacek, Mark R Gacek
    Abstract:

    One hundred twenty-six patients who were treated with Labyrinthectomy (81 patients) or vestibular neurectomy (45) between the years 1979 and 1994 were reviewed. The cause for vertigo in 124 of the 126 patients was Meniere's disease (89 patients), labyrinthitis (15), delayed endolymphatic hydrops (8), vestibular neuritis (7), and failed Labyrinthectomy (5). In the remaining 2 patients, a normal labyrinth was sacrificed to fistulize a petrous apex cyst. Both procedures were equally effective in relieving vertigo (Labyrinthectomy 98.8%; neurectomy 97.8%), but the length of hospitalization, length of disability before return to work, and cost were twice as great with vestibular neurectomy than with Labyrinthectomy. More patients exhibited prolonged ataxia following neurectomy (5 patients) than after Labyrinthectomy (2). Vestibular neurectomy was associated with several complications: reversible facial paresis (15 patients), meningitis (1), cerebrospinal fluid leak (1), and epidural hematoma (1). Labyrinthectomy was complicated by postoperative hyponatremia in 1 patient. Selective vestibular neurectomy preserved hearing in 32 (82%) of 39 patients. Criteria for recommending either ablation procedure are discussed. The incidence of sequential involvement of the contralateral ear was 1.5%.

  • comparison of Labyrinthectomy and vestibular neurectomy in the control of vertigo
    Laryngoscope, 1996
    Co-Authors: Richard R Gacek, Mark R Gacek
    Abstract:

    One hundred twenty-six patients who were treated with Labyrinthectomy (81 patients) or vestibular neurectomy (45) between the years 1979 and 1994 were reviewed. The cause for vertigo in 124 of the 126 patients was Meniere's disease (89 patients), labyrinthitis (15), delayed endolymphatic hydrops (8), vestibular neuritis (7), and failed Labyrinthectomy (5). In the remaining 2 patients, a normal labyrinth was sacrificed to fistulize a petrous apex cyst. Both procedures were equally effective in relieving vertigo (Labyrinthectomy 98.8% ; neurectomy 97.8%), but the length of hospitalization, length of disability before return to work, and cost were twice as great with vestibular neurectomy than with Labyrinthectomy. More patients exhibited prolonged ataxia following neurectomy (5 patients) than after Labyrinthectomy (2). Vestibular neurectomy was associated with several serious complications : reversible facial paresis (15 patients), meningitis (1), cerebrospinal fluid leak (1), and epidural hematoma (1). Labyrinthectomy was complicated by postoperative hyponatremia in 1 patient. Selective vestibular neurectomy preserved hearing in 32 (82%) of 39 patients. Criteria for recommending either ablation procedure are discussed. The incidence of sequential involvement of the contralateral ear was 1.5%.

  • Morphologic Changes in Superior Vestibulo-ocular Neurons and Vestibular Nerve Following Labyrinthectomy in the Cat
    Acta Oto-laryngologica, 1995
    Co-Authors: Richard R Gacek, Joanne Schoonmaker, Michael J. Lyon
    Abstract:

    Morphologic changes in ipsilateral superior vestibulo-ocular neurons (SVON) and the vestibular nerve were measured in 4 cats 8 weeks after Labyrinthectomy and 4 cats 1 year after Labyrinthectomy. There is a 20% decrease in SVON size and 30% decrease in rough endoplasmic reticulum and ribosomes with no change in the volume fractions of Golgi apparatus or mitochondria. In the central nervous system degeneration of the vestibular nerve terminals ipsilateral to the Labyrinthectomy was represented by a 25% loss of synaptic profiles (SP) on SVON at 8 weeks and 57% loss of SP at 1 year after Labyrinthectomy. There was no significant loss of fiber number in the vestibular nerve at 8 weeks post lesion but a 35% loss of fibers primarily of the large size at 1 year post lesion.

Paul F Smith - One of the best experts on this subject based on the ideXlab platform.

  • methylprednisolone reduces spontaneous nystagmus following unilateral Labyrinthectomy in guinea pig
    European Journal of Pharmacology, 1995
    Co-Authors: Annabelle H Jerram, Cynthia L Darlington, Paul F Smith
    Abstract:

    The present study investigated the effects of methylprednisolone on the vestibular compensation process following unilateral Labyrinthectomy in guinea pigs. A single injection of methylprednisolone (15, 30 or 60 mg/kg s.c.), 15 min pre-Labyrinthectomy, had no significant effect on either the severity or the rate of compensation of spontaneous ocular nystagmus or yaw head tilt; roll head tilt showed a significant change in the rate of compensation (P < 0.005), due to increased roll head tilt in the 60 mg/kg group. However, a pre-Labyrinthectomy injection of 30 mg/kg s.c. methylprednisolone followed by a second 30 mg/kg injection at 4 h post-Labyrinthectomy resulted in a significant reduction in spontaneous nystagmus frequency (P < 0.005) and a significant change in the rate of spontaneous nystagmus compensation (P < 0.005). The additional 30 mg/kg injection had no significant effect on the magnitude or compensation of the postural symptoms. These results indicate that, at the optimal dose of 30 mg/kg, 2 injections of methylprednisolone (15 min pre-Labyrinthectomy and 4 h post-Labyrinthectomy) result in a significant reduction in spontaneous nystagmus frequency.

  • pretreatment with mk 801 reduces spontaneous nystagmus following unilateral Labyrinthectomy
    European Journal of Pharmacology, 1992
    Co-Authors: Andrew J Sansom, Cynthia L Darlington, Paul F Smith
    Abstract:

    Abstract Unilateral Labyrinthectomy results in a syndrome of ocular motor and postural symptoms which abate over time in a process of behavioural recovery known as vestibular compensation. We have previously suggested that an increased Ca2+ influx in ipsilateral vestibular nucleus (VN) neurons at the time of the unilateral Labyrinthectomy may exacerbate the depresssion of VN resting activity caused by the loss of excitatory input from the VIIIth nerve. In order to further test this hypothesis, we administered ( + )-5-methyl-10,11-dihydro-5H-dibcnzo[a,d]cyclohcptcn-5,10-imine hydrogen maleate (MK-801; 1.0 or 2.5 mg/kg i.p.), which blocks Ca2+ influx via NMDA receptor-mediated ion channels, to guinea pigs 0.5 h before unilateral Labyrinthectomy and examined the effects on three symptoms of unilateral Labyrinthectomy: spontaneous ocular nystagmus, yaw head tilt and roll head tilt. Pretreatment with MK-801 significantly altered the time course of the vestibular compensation of spontaneous nystagmus and yaw head tilt but had no significant effect on roll head tilt; in particular, 2.5 mg/kg MK-801 depressed spontaneous nystagmus frequency at 10 and 20 h post-Labyrinthectomy relative to saline controls (P

Related terms

Labyrinthectomy - 15 days free trial to Access Experts & Abstracts