The Effect of Blockage of All Six Semicircular Canal Ducts on Nystagmus Produced by Dynamic Linear Acceleration in the Cat

Correia, Manning J.; Money, K. E.

doi:10.3109/00016487009123331

Cited by 89 publications

(33 citation statements)

References 8 publications

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“…That otolith-dependent cells can also contribute to the generation of a reflex oculomotor response during PSR is suggested by the observations of Correia & Money (1969) and of Janeke (1968 result of the surgical obstruction to canal fluid circulation. They concluded that the residual response was probably of otolithic origin.…”

Section: Discussionmentioning

confidence: 82%

Response of semicircular canal dependent units in vestibular nuclei to rotation of a linear acceleration vector without angular acceleration

Benson¹,

Guedry²,

Jones³

1970

The Journal of Physiology

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SUMAARY1. Recent experiments have shown that rotation of a linear acceleration vector round the head can generate involuntary ocular nystagmus in the absence of angular acceleration. The present experiments examine the suggestion that adequate stimulation of the semicircular canals may contribute to this response.2. Decerebrate cats were located in a stereotaxic device on a platform, slung from four parallel cables, which could be driven smoothly round a circular orbit without inducing significant angular movement of the platform. This Parallel Swing Rotation (PSR) generated a centripetal acceleration of 4-4 m/sec2 which rotated round the head at 052 rev/sec.3. The discharge frequency of specifically lateral canal-dependent neural units in the vestibular nuclei of cats was recorded during PSR to right and left, and in the absence of motion. The dynamic responses to purely angular motion were also examined on a servo-driven turntable.4. Without exception all proven canal-dependent cells examined (twenty-nine cells in nine cats) were more active during PSR in the direction of endolymph circulation assessed to be excitatory to the unit, than during PSR in the opposite direction.5. The observed changes in discharge frequency are assessed to have been of a magnitude appropriate for the generation of the involuntary oculomotor response induced by the same stimulus in the intact animal.6. The findings suggest that a linear acceleration vector which rotates in the plane of the lateral semicircular canals can be an adequate stimulus

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Section: Discussionmentioning

confidence: 82%

Response of semicircular canal dependent units in vestibular nuclei to rotation of a linear acceleration vector without angular acceleration

Benson¹,

Guedry²,

Jones³

1970

The Journal of Physiology

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“…Constant rotation about the same Z axis but oriented perpendicular to gravity ("barbecue" condition) evokes in addition a permanent "barbecue" nystagmus with a sinusoidal component and a bias component (Benson and Bodin, 1966;Bodin, 1968;Benson, 1974). These two components may originate from otolithic stimulation because specific destruction of the utricular nerve entails the suppression of sustained nystagmus (Janeke, 1968) while the blockage of all six semicircular canals does not alter it (Correia and Money, 1968). However, the mechanism of these responses is still unclear.…”

Section: Modeling Of Linear Vectionmentioning

confidence: 99%

Linear Self Motion Perception

Berthoz¹,

Droulez²

1982

Tutorials on Motion Perception

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“…(Raphan et al 1981). The steadystate response is generated by activation of the velocity-storage integrator by a signal arising in the otolith organs (Correia & Money, 1970;Raphan et al 1981;Cohen et al 1983). Typical nystagmus during a step of velocity about a tilted axis is shown in Fig.…”

Section: General Effectsmentioning

confidence: 99%

Baclofen and velocity storage: a model of the effects of the drug on the vestibulo‐ocular reflex in the rhesus monkey.

Cohen

Helwig

Raphan

1987

The Journal of Physiology

127

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SUMMARY1. Baclofen had a characteristic effect on vestibular and optokinetic nystagmus in rhesus monkeys. Each aspect of nystagmus that is dependent on the velocity-storage mechanism in the vestibulo-ocular reflex (v.o.r.) was altered by the drug: (a) Baclofen reduced the dominant time constant of the v.o.r. in a dose-dependent manner up to 5 mg/kg, the highest dosage used. The alteration in v.o.r. time constant began within 15 min of injection, was maximal between 1 and 4 h, and lasted for 14-18 h. This effect mirrors changes in plasma levels of baclofen after oral doses in humans (Faigle, Keberle & Agen, 1980). (b) Slow-phase velocities of steady-state nystagmus induced by rotation about axes tilted from the vertical (off-vertical axis rotation, o.v.a.r.) were reduced after baclofen and could not be maintained at previous levels. (c) There was a dose-dependent decline in the steady-state gain of optokinetic nystagmus (o.k.n.), and at the highest dosages little o.k.n. was induced. In parallel, the peak velocity and falling time constant of optokinetic after-nystagmus (o.k.a.n.) were reduced. Since baclofen is a GABA agonist, systems utilizing GABA and acting on GABAB receptors appear to produce inhibitory control of velocity storage.2. The step gain of the v.o.r., measured at the beginning and end of constantvelocity rotation in darkness, was unaffected by baclofen, as were saccades, quick phases of nystagmus, and the ability to hold positions of fixation or to generate linear slow phases of nystagmus. This indicates that it is possible to use baclofen to manipulate the dominant time constant of the v.o.r. and of o.k.a.n. in relative isolation from effects on other oculomotor components.3. Baclofen caused a dose-dependent reduction in the initial jump in eye velocity at the onset of o.k.n., suggesting that the initial jump is also under inhibitory control of GABAB receptors. However, there were still occasional slow phases with velocities up to [30][31][32][33][34][35][36][37][38][39][40] . The effect of baclofen was reproduced by shortening the falling time constant of the velocity-storage integrator, reducing the gain of the direct visual-oculomotor pathway and modifying the structure of the non-linearity that couples the visual system to the indirect pathway and the velocity-storage integrator. Alterations in the non-linearity explain why the time course of the slow rise in o.k.n. and the rising time constant of o.k.a.n. were longer at low or moderate doses of baclofen and shorter at high doses.5. The functional effect of inhibition of velocity storage would be to reduce the responsiveness of compensatory oculomotor reflexes to low frequencies of head rotation and high rates of retinal slip. Similar effects are produced by habituation and during rapid discharge of activity from the v.o.r. by visual suppression or by tilting the head. GABA and GABAB receptors may also be utilized in mediating these processes.

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The Effect of Blockage of All Six Semicircular Canal Ducts on Nystagmus Produced by Dynamic Linear Acceleration in the Cat

Cited by 89 publications

References 8 publications

Response of semicircular canal dependent units in vestibular nuclei to rotation of a linear acceleration vector without angular acceleration

Response of semicircular canal dependent units in vestibular nuclei to rotation of a linear acceleration vector without angular acceleration

Linear Self Motion Perception

Baclofen and velocity storage: a model of the effects of the drug on the vestibulo‐ocular reflex in the rhesus monkey.

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