Vestibulo-Ocular Reflex and Optokinetic Nystagmus in Microgravity

2015 ◽  
pp. 1-4 ◽  
Author(s):  
Gilles Cl�ment ◽  
Alain Berthoz
Keyword(s):  
Optokinetic Nystagmus ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Spatial orientation of the angular vestibulo-ocular reflex

1999 ◽  
Vol 9 (3) ◽  
pp. 163-172
Author(s):  
Bernard Cohen ◽  
Susan Wearne ◽  
Mingjia Dai ◽  
Theodore Raphan
Keyword(s):  
Spatial Orientation ◽  
Optokinetic Nystagmus ◽  
Vestibular Nuclei ◽  
Velocity Storage ◽  
Gravitational Acceleration ◽  
Ocular Reflex ◽  
Eye Rotation ◽  
Slow Velocity ◽  
Vestibulo Ocular Reflex ◽  
Vector Sum

During vestibular nystagmus, optokinetic nystagmus (OKN), and optokinetic afternystagmus (OKAN), the axis of eye rotation tends to align with the vector sum of linear accelerations acting on the head. This includes gravitational acceleration and the linear accelerations generated by translation and centrifugation. We define the summed vector of gravitational and linear accelerations as gravito-inertial acceleration (GIA) and designate the phenomenon of alignment as spatial orientation of the angular vestibuloocular reflex (aVOR). On the basis of studies in the monkey, we postulated that the spatial orientation of the aVOR is dependent on the slow (velocity storage) component of the aVOR, not on the short latency, compensatory aVOR component, which is in head-fixed coordinates. Experiments in which velocity storage was abolished by midline medullary section support this postulate. The velocity storage component of the aVOR is likely to be generated in the vestibular nuclei, and its spatial orientation was shown to be controlled through the nodulus and uvula of the vestibulo-cerebellum. Separate regions of the nodulus/uvula appear to affect the horizontal and vertical/torsional components of the response differently. Velocity storage is weaker in humans than in monkeys, but responds in a similar fashion in both species. We postulate that spatial orientation of the aVOR plays an important role in aligning gaze with the GIA and in maintaining balance during angular locomotion.

A review of the effects of space flight on the asymmetry of vertical optokinetic and vestibulo-ocular reflexes

2003 ◽  
Vol 13 (4-6) ◽  
pp. 255-263
Author(s):  
Gilles Clément
Keyword(s):  
Phase Velocity ◽  
Optokinetic Nystagmus ◽  
Visual Stimulation ◽  
Head Movements ◽  
Slow Phase ◽  
Eye Position ◽  
Slow Phase Velocity ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Eye Velocity

Prolonged microgravity during orbital flight is a unique way to modify the otolith inputs and to determine the extent of their contribution to the vertical vestibulo-ocular reflex (VOR) and optokinetic nystagmus (OKN). This paper reviews the data collected on 10 astronauts during several space missions and focuses on the changes in the up-down asymmetry. Both the OKN elicited by vertical visual stimulation and the active VOR elicited by voluntary pitch head movements showed an asymmetry before flight, with upward slow phase velocity higher than downward slow phase velocity. Early in-flight, this asymmetry was inverted, and a symmetry of both responses was later observed. An upward shift in the vertical mean eye position in both OKN and VOR suggests that these effects may be related to otolith-dependent changes in eye position which, in themselves, affect slow phase eye velocity.

scholarly journals Analysis of the vestibulo-ocular reflex and optokinetic nystagmus in mice for the development of new treatments for patients complaining of vertigo

2019 ◽  
Vol 78 (3) ◽  
pp. 203-211
Author(s):  
Takao Imai ◽  
Yasumitsu Takimoto ◽  
Noriaki Takeda ◽  
Tetsuo Morihana ◽  
Hidenori Inohara
Keyword(s):  
Optokinetic Nystagmus ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
New Treatments

scholarly journals Vectoelectronystagmography in children with dyslexia and learning disorder

Revista CEFAC ◽  
2018 ◽  
Vol 20 (4) ◽  
pp. 442-449 ◽  
Author(s):  
Ana Carla Leite Romero ◽  
Mariana Banzato Stenico ◽  
Letícia Sampaio de Oliveira ◽  
Eloisa Sartori Franco ◽  
Simone Aparecida Capellini ◽  
...  
Keyword(s):  
Optokinetic Nystagmus ◽  
Saccadic Eye Movements ◽  
Learning Disorders ◽  
Control Group ◽  
Learning Disorder ◽  
Group Iii ◽  
Ocular Reflex ◽  
Group I ◽  
Vestibulo Ocular Reflex ◽  
Group Ii

ABSTRACT Objective: to describe and compare the results of ocular (saccadic, screening, and optokinetic) tests of vectoelectronystagmography among the groups with dyslexia, learning disorder and control. Methods: 28 male and female students aged 8 to 11 years participated in this study. They were divided into three groups: Group I, 10 students with dyslexia, Group II, 9 students with learning disorders and Group III, 9 students with no learning disorders. In this research, digital vectoelectronystagmography - ocular test - was performed. Results: saccadic movement, optokinetic nystagmus, and pendular tracking tests were found to show subtle differences among the three groups. Comparing the saccadic eye movements and the optokinetic nystagmus tests, it was observed that the movement in the left eye was slower for Group I, and even slower for Group II. It was also observed that GI and GII were slower for the pendular tracking of luminous stimulus in relation to the control group. Conclusion: in general, there are differences among the groups in the vectoelectronystagmography, which indicated slower tracking and vestibulo-ocular reflex in children with dyslexia and learning disorders.

The cerebellar nodulus and ventral uvula control the torsional vestibulo-ocular reflex

1994 ◽  
Vol 72 (3) ◽  
pp. 1443-1447 ◽  
Author(s):  
D. E. Angelaki ◽  
B. J. Hess
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Dynamic Control ◽  
Low Frequency ◽  
Slow Phase ◽  
Surgical Ablation ◽  
Ocular Reflex ◽  
Specific Effects ◽  
Before And After ◽  
Vestibulo Ocular Reflex

1. The vestibulo-ocular reflex (VOR) was investigated in rhesus monkeys before and after surgical ablation of the cerebellar nodulus and ventral uvula. The lesion resulted in an alteration of the torsional VOR: compensatory eye movements were poor in the low frequency range and the time constant was reduced to values comparable to those of primary semicircular canal afferents. In addition, animals permanently lost their ability to generate torsional optokinetic nystagmus (OKN). 2. The effects of the lesion on the torsional VOR differed from those observed in the horizontal and vertical vestibulo-ocular systems. While the vertical VOR and OKN were unaltered, the horizontal VOR and OKN were characterized by increased time constants and smaller phase leads during low frequency head oscillations. 3. These results suggest that the cerebellar nodulus and/or ventral uvula exert a distinct and specific dynamic control on the torsional vestibulo-ocular and optokinetic reflexes. Such specific effects on the torsional system could reflect a functional segregation of the vestibulo-cerebellum in terms of the controls of torsional versus horizontal and vertical slow phase eye movements.

Chromatic Contrast Sensitivity During Optokinetic Nystagmus, Visually Enhanced Vestibulo-ocular Reflex, and Smooth Pursuit Eye Movements

2009 ◽  
Vol 101 (5) ◽  
pp. 2317-2327 ◽  
Author(s):  
Alexander C. Schütz ◽  
Doris I. Braun ◽  
Karl R. Gegenfurtner
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus ◽  
Slow Phase ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Slow Eye Movements

Recently we showed that sensitivity for chromatic- and high-spatial frequency luminance stimuli is enhanced during smooth-pursuit eye movements (SPEMs). Here we investigated whether this enhancement is a general property of slow eye movements. Besides SPEM there are two other classes of eye movements that operate in a similar range of eye velocities: the optokinetic nystagmus (OKN) is a reflexive pattern of alternating fast and slow eye movements elicited by wide-field visual motion and the vestibulo-ocular reflex (VOR) stabilizes the gaze during head movements. In a natural environment all three classes of eye movements act synergistically to allow clear central vision during self- and object motion. To test whether the same improvement of chromatic sensitivity occurs during all of these eye movements, we measured human detection performance of chromatic and luminance line stimuli during OKN and contrast sensitivity during VOR and SPEM at comparable velocities. For comparison, performance in the same tasks was tested during fixation. During the slow phase of OKN we found a similar enhancement of chromatic detection rate like that during SPEM, whereas no enhancement was observable during VOR. This result indicates similarities between slow-phase OKN and SPEM, which are distinct from VOR.

Sign in / Sign up

Export Citation Format

Share Document