Spectral Analysis of Low-Frequency, Active-Head Vestibulo-Ocular Reflex Responses

1998 ◽  
Vol 8 (4) ◽  
pp. 313-324
Author(s):  
Dennis P. O'Leary ◽  
Linda L. Davis
Keyword(s):  
Spectral Analysis ◽  
Low Frequency ◽  
Reflex Responses ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Effect of Incisions in the Brainstem Commissural Network on the Short-Term Vestibulo-Ocular Adaptation of the CAT

1991 ◽  
Vol 1 (3) ◽  
pp. 223-239
Author(s):  
G. Cheron
Keyword(s):  
Low Frequency ◽  
Adaptive Plasticity ◽  
Training Procedure ◽  
Optokinetic Response ◽  
Mean Values ◽  
Ocular Reflex ◽  
Optokinetic Reflex ◽  
Before And After ◽  
Vestibulo Ocular Reflex ◽  
Vor Adaptation

This study was intended to test the adaptive plasticity of the vestibulo-ocular reflex before and after either a midsagittal or parasagittal incision in the brainstem. Eye movements were measured with the electromagnetic search coil technique during the vestibulo-ocular reflex (VORD) in the dark, the optokinetic reflex (OKN), and the visuo-vestibular adaptive training procedure. Two types of visual-vestibular combined stimulation were applied by means of low frequency stimuli (0.05 to 0.10 Hz). In order to increase or decrease the VORD gain, the optokinetic drum was oscillated either 180∘ out-of-phase or in-phase with the vestibular stimulus turntable. This “training” procedure was applied for 4 hours. Initial measurements of the VORD were normal with a mean gain value of 0.92 ± 0.08. After 4 hours of “training” with the out-of-phase condition (180∘), VORD gain reached mean values of 1.33 ± 0.11 (n = 6 cats). In the in-phase combination, the mean VORD gain decreased from 1.0 to 0.63 ± 0.02 (n = 2 cats). No significant change of VORD phase was found in any of the cats. Midsagittal or parasagittal pontomedullary brainstem incisions were performed in 4 cats. Recovery of the VOR was tested on the 2nd, 7th, and 30th day after operation. After the 30th day, recovery of the VORD gain stabilized at about 66% of the initial preoperative value. At this stage of the recovery, the optokinetic response (OKN) of the midsagittal-Iesioned cats was practically normal: in the parasagittal-Jesioned cats, the postoperative OKN responses were asymmetric. After stabilization of recovery, lesioned cats were trained with the same adaptation procedure. Although the direct effect of the visuo-vestibular combined stimulation during the training was still operative in all lesioned cats, the adaptive plasticity was completely abolished by the lesions. These results suggest that the commissural brainstem network may play a crucial role in the acquisition of the forced VOR adaptation.

The vertical vestibulo-ocular reflex, and its interaction with vision during active head motion: Effects of aging

2001 ◽  
Vol 11 (1) ◽  
pp. 3-12
Author(s):  
Ji Soo Kim ◽  
James A. Sharpe
Keyword(s):  
Smooth Pursuit ◽  
Low Frequency ◽  
The Elderly ◽  
Head Motion ◽  
Head Tracking ◽  
Elderly Age ◽  
Ocular Reflex ◽  
Visual Enhancement ◽  
Vestibulo Ocular Reflex ◽  
Effects Of Aging

The effects of aging on the vertical vestibulo-ocular reflex (VOR), and its interactions with vision during active head motion had not been investigated. We measured smooth pursuit, combined eye-head tracking, the VOR, and its visual enhancement and cancellation during active head motion in pitch using a magnetic search coil technique in 21 younger (age < 65) and 10 elderly (age ⩾ 65) subjects. With the head immobile, subjects pursued a target moving sinusoidally with a frequency range of 0.125 to 2.0 Hz, and with peak target accelerations (PTAs) ranging from 12 to 789Âř/s 2 . Combined eye-head tracking, the VOR in darkness, and its visual enhancement during fixation of an earth-fixed target (VVOR) were measured during active sinusoidal head motion with a peak-to-peak amplitude of 20Âř at frequencies of 0.25, 0.5, 1.0 and 2.0 Hz. The efficacy of VOR cancellation was determined from VOR gains during combined eye-head tracking. VOR and VVOR gains were symmetrical in both directions and did not change with aging, except for reduced gains of the downward VOR and VVOR at low frequency (0.25 Hz). However, in the elderly, smooth pursuit, and combined eye-head tracking gains and the efficacy of cancellation of the VOR were significantly lower than in younger subjects. In both the young and elderly groups, VOR gain in darkness did not vary with the frequency of active head motion while the gains of smooth pursuit, combined eye-head tracking, and VVOR declined with increasing target frequency. VOR and VVOR performance in the elderly implicates relative preservation of neural structures subserving vertical vestibular smooth eye motion in senescence.

Torsional vestibulo-ocular reflex during whole-body oscillation in the upright and the supine position: II. Responses in patients after vestibular neuritis

2004 ◽  
Vol 14 (4) ◽  
pp. 353-359
Author(s):  
A. Schmid-Priscoveanu ◽  
A.A. Kori ◽  
D. Straumann
Keyword(s):  
Supine Position ◽  
Semicircular Canal ◽  
Low Frequency ◽  
Phase Changes ◽  
Vestibular Neuritis ◽  
Whole Body ◽  
Healthy Human ◽  
Phase Lead ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

In a recent study we demonstrated that otolith input modifies the torsional angular vestibulo-ocular reflex (torVOR) of healthy human subjects: Compared to turntable oscillations in supine position, oscillations in upright position increased the gain of torVOR by 0.1 and cancelled the phase lead originating from low-frequency semicircular canal signals. We asked whether these otolith-related changes of torVOR are still present in patients after vestibular neuritis (VN). Eight patients were sinusoidally oscillated about their naso-occipital axis in supine (canal-only stimulation) and upright (canal-and-otolith stimulation) position. Three-dimensional eye movements were recorded with dual search coils. The patients showed similar otolith-related gain and phase changes of the torVOR as healthy subjects: the gain increased by about 0.1 (p < 0.05) and the low-frequency phase lead from semicircular canal signals was abolished. These results indicate that otolith function after VN is still sufficient to interact with semicircular canal signals to optimize torsional gaze stabilization when the head is upright.

Recovery of vestibulo-ocular reflex-function in subjects with an acute unilateral peripheral vestibular deficit

1999 ◽  
Vol 9 (2) ◽  
pp. 135-144 ◽  
Author(s):  
J.H.J. Allum ◽  
T. Ledin
Keyword(s):  
Low Frequency ◽  
Vestibular Function ◽  
Vertical Axis ◽  
Whole Body ◽  
Horizontal Semicircular Canal ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Central Compensation ◽  
Head Rotations ◽  
Vestibular Deficit

The centrally controlled compensation for a reduced horizontal vestibulo-ocular reflex (VOR) gain caused by a unilateral afferent deficit is usually studied following a selective surgical procedure which completely lesions the vestibular nerve or blocks the horizontal semicircular canal. The more common, unilateral, vestibular deficit encountered clinically, is a partial loss of peripheral vestibular function, following which peripheral recovery and/or central compensation may occur. We investigated changes of the VOR gain in response to a sudden, idiopathic, unilateral vestibular deficit in 64 subjects by examining the responses to low-frequency, whole-body, rotations about an earth vertical axis with different accelerations (5, 20 and 40 deg / sec 2 ) during in- and out-patient visits separated by 4 months in an attempt to identify changes brought about by peripheral recovery and by central compensation processes. Peripheral function was assumed to be measured by the response to caloric irrigation. It improved some 30% between the two visits. VOR responses for rotations towards the deficit side also improved between the two visits. Most improvement occurred for 20 deg / sec 2 accelerations. However, the correlation coefficient between rotation and caloric responses was always less than 0.6. Unlike caloric responses which improved over time, responses for rotations to the intact side did not change between the visits. For this reason, the majority of observed VOR rotation responses were nearly symmetrical at the time of the second visit, despite being below normal levels. These findings suggest that both peripheral recovery and central compensation processes help restore symmetrical VOR function for head rotations after a partial unilateral vestibular deficit. However the improvement of VOR response symmetry, particularly to slow ( < 40 deg / sec 2 ) accelerations, is largely independent of the recovery of peripheral sensitivity.

Anterior canal neurons in cat vestibular nuclei have large phase leads during low frequency vertical axis pitch

2007 ◽  
Vol 16 (6) ◽  
pp. 245-256
Author(s):  
Sandra C. Brettler ◽  
James F. Baker
Keyword(s):  
Low Frequency ◽  
Vertical Axis ◽  
Vestibular Nuclei ◽  
Whole Body ◽  
Posterior Canal ◽  
Spatial Sensitivity ◽  
Ocular Reflex ◽  
Vestibular Afferents ◽  
Vestibulo Ocular Reflex ◽  
Anterior Canal

Vestibulo-ocular and second-order neurons in medial and superior vestibular nuclei of alert cats were identified by antidromic and orthodromic electrical stimulation, and their responses to whole body rotations were recorded in the dark. Neurons that had spatial sensitivity most closely aligned with the anterior canal (anterior canal neurons) were compared with neurons that had spatial sensitivity most closely aligned with the posterior canal (posterior canal neurons). Responses were recorded during low frequency earth-horizontal axis pitch rotations in the normal upright posture, and during earth-vertical axis pitch with the head and body lying on the left side. During upright pitch, response phases of anterior canal neurons slightly lagged those of posterior canal neurons or primary vestibular afferents, as previously reported. During on-side pitch, anterior canal neurons showed far greater phase leads with respect to head velocity than posterior canal neurons, primary vestibular afferents, or previously reported vestibulo-ocular reflex eye movements. These results provide challenges for vestibulo-ocular reflex models to incorporate central mechanisms for phase leads among the inputs to anterior canal neurons and to explain how the anterior canal neuron signals reported here combine with other signals to produce observed vestibulo-ocular reflex behavior.

Clinical Prevalence of Enhanced Vestibulo-Ocular Reflex Responses on Video Head Impulse Test

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Aitor Vargas-Alvarez ◽  
Elisabeth Ninchritz-Becerra ◽  
Miren Goiburu ◽  
Frank Betances ◽  
Jorge Rey-Martinez ◽  
...  
Keyword(s):  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Reflex Responses ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Effects of Infrasound on Involuntary Eye Movement during Fixation

1989 ◽  
Vol 8 (4) ◽  
pp. 130-133 ◽  
Author(s):  
Hiroshi Takigawa ◽  
Fukiko Kawade ◽  
Hiroshi Sakamoto
Keyword(s):  
Eye Movement ◽  
Frequency Band ◽  
Low Frequency ◽  
Octave Band ◽  
Ocular Reflex ◽  
Eyes Closed ◽  
Band Noise ◽  
Vestibulo Ocular Reflex ◽  
Eyes Open ◽  
Healthy Males

This study was undertaken in order to clarify the effects of infrasound on vestibular functions by comparing observations of eye movement under exposure to infrasound and audible noise. Twenty-five healthy males were exposed to a wide octave-band noise, (approx. 125 Hz to 4kHz) or to 16 Hz or 5 Hz at 95 dB for 3 minutes. Their involuntary eye movement with the eyes visually fixed in the horizontal direction was measured before and during exposure with their eyes open and closed. The extent of eye movement before the exposure was significantly greater with eyes closed than with eyes open. This difference was intensified by 5-Hz exposure, but exposure to the noise of 16-Hz infrasound had no effect. The power percentage in the low frequency-band, determined by spectral analysis of the eye movement, was significantly greater with eyes closed than with eyes open before the exposure. This increase in the power percentage in the low frequency-band was reinforced by the 16- and 5-Hz exposures, while no effect was observed upon exposure to the noise. These results suggest that the potential of the vestibulo-ocular reflex was increased upon exposure to infrasound, regardless of whether or not the subjects perceived any sensation.

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