Analysis of vertebrate eye movements following intravitreal drug injections. IV. Drug-induced eye movements are unyoked in the turtle

1991 ◽  
Vol 65 (4) ◽  
pp. 1003-1009 ◽  
Author(s):  
M. Ariel
Keyword(s):  
Eye Movements ◽  
Contact Lenses ◽  
Spontaneous Nystagmus ◽  
Slow Phase ◽  
Dependent Manner ◽  
Drug Induced ◽  
Full Field ◽  
Optokinetic Responses ◽  
Vertebrate Eye ◽  
Stimulus Direction

1. Eye movements of awake turtles were measured from both eyes simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was evoked by full field patterns moving horizontally at different stimulus velocities. Intravitreal injections of either bicuculline or 2-amino-4-phosphonobutyrate (APB) were then made into one eye, after which eye movements were again recorded under similar stimulus conditions. Several days later, eye movements were again recorded and recovery was observed. 2. The effects of these two synaptic drugs on the optokinetic responses of the injected eye were similar to those previously reported in turtles, rabbits, and decorticate cats. APB, which blocks the retinal ON pathways, completely blocked visually evoked responses to any stimulus direction or velocity presented to the injected eye. On the other hand, the uninjected eye was still responsive to optokinetic stimuli. This difference between the eyes is consistent with the nonconjugate nature of OKN in the turtle. 3. After bicuclline application, the injected eye displayed a spontaneous nystagmus with its slow phase in the temporal-to-nasal direction. The movements of the injected eye were independent of stimulus direction or a range of stimulus velocities. During that effect, the eye contralateral to the injection still responded to visual stimuli in a direction- and velocity-dependent manner. For example, if the uninjected eye was exposed to optokinetic stimuli moving temporal-to-nasal, both eyes would then move in their respective temporal-to-nasal directions. This nonconjugate ocular behavior is similar to that seen when each eye of a normal turtle was exposed to its temporal-to-nasal stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous nystagmus and gaze-holding ability in monkeys after intravitreal picrotoxin injections

1992 ◽  
Vol 67 (5) ◽  
pp. 1124-1132 ◽  
Author(s):  
M. Ariel ◽  
R. J. Tusa
Keyword(s):  
Steady State ◽  
Eye Movements ◽  
Phase Velocity ◽  
Smooth Pursuit ◽  
Spontaneous Nystagmus ◽  
Velocity Storage ◽  
Slow Phase ◽  
Gamma Aminobutyric Acid ◽  
Full Field ◽  
Slow Phase Velocity

1. Eye movements were measured in three rhesus monkeys after monocular intravitreal injections of picrotoxin, a gamma-aminobutyric acid (GABA) antagonist. The effects of this drug were tested when the animals were in a completely dark room, when they performed a smooth pursuit task, and when they viewed either a stationary pattern or a full-field optokinetic pattern rotating horizontally. 2. Between 15 and 20 min after the injection, a sustained conjugate spontaneous nystagmus developed in the dark, with the slow-phase movement in the temporal-to-nasal direction with respect to the injected eye. Peak slow-phase velocity ranged from 15 to 45 degrees/s. The nystagmus persisted for at least 1 h but stopped by the next day. 3. In a well-lit room, the nystagmus was completely suppressed, even during monocular viewing with the injected eye. When the lights were turned off, the slow-phase velocity of the spontaneous nystagmus slowly increased to a steady-state level within 70-120 s. 4. Horizontal smooth pursuit eye movements to a 1 degree target light moving in front of the animal +/- 20 degrees to either side of center of gaze at constant speeds were normal. Target speeds ranging from 15 to 60 degrees/s for both monocular and binocular viewing conditions were used. Binocular and monocular optokinetic nystagmus (OKN) to a full-field drum rotating at a constant velocity (5-90 degrees/s) were also normal. The initial pursuit and steady-state components of OKN were measured, as well as the velocity-storage component (optokinetic after nystagmus, OKAN).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of vertebrate eye movements following intravitreal drug injections. III. Spontaneous nystagmus is modulated by the GABAa receptor

1989 ◽  
Vol 62 (2) ◽  
pp. 469-480 ◽  
Author(s):  
M. Ariel
Keyword(s):  
Eye Movements ◽  
Gabaa Receptor ◽  
Ganglion Cells ◽  
Drug Effects ◽  
Calibration Procedure ◽  
Spontaneous Nystagmus ◽  
Oculomotor Control ◽  
Slow Phase ◽  
Threshold Doses ◽  
Vertebrate Eye

1. Turtle eye movements were recorded in response to horizontal motion of patterned stimuli and intravitreal injections of selective GABAergic drugs by using a contact lens search-coil technique. Similar to results from rabbit and cat, injection of picrotoxin into the turtle's eye results in a spontaneous horizontal nystagmus, with its slow-phase movement in a temporal-to-nasal direction with respect to the injected eye. In contrast, there were no prominent vertical eye movements in response to either horizontal optokinetic stimuli or drug injections. 2. Injections of bicuculline or bicuculline methyl iodide (BMI), which selectively block the GABAa receptor, had effects similar to those of picrotoxin. The GABAa agonist muscimol, on the other hand, blocked optokinetic nystagmus (OKN). Furthermore, combinations of these drugs demonstrated competitive interactions between the agonists and antagonists. 3. The threshold dose for the eye-movement effects of each drug was ascertained with the use of a radioactive calibration procedure. Tritiated inulin was injected into the vitreous. After 1 h, ocular components were assayed for radioactivity. Then, by the use of an estimate of vitreal/retinal dilution, the retinal concentrations of these threshold doses were calculated. The computed threshold retinal concentrations of the GABAa drugs were found to be in the low micromolar range. 4. These results are discussed in terms of the directionally sensitive (DS) processing which occurs in the retina, and the output of retinal DS cells to pathways involved in oculomotor control of retinal image stabilization. It is known that intravitreal application of picrotoxin makes DS retinal ganglion cells lose their selectivity for any one direction. Based on the effect of picrotoxin on OKN, it is argued that DS retinal cells provide a major input to oculomotor subsystems involved in the stabilization of gaze. Furthermore, these intravitreal drug effects on OKN are selective for GABAa drugs, suggesting that GABAa receptors play a major role in DS processing in the retina.

Slow Cumulative Eye Position to Quantify Optokinetic Afternystagmus

1992 ◽  
Vol 101 (3) ◽  
pp. 255-260 ◽  
Author(s):  
Timothy C. Hain ◽  
Gaurang Patel
Keyword(s):  
Time Constant ◽  
Normal Subjects ◽  
Directional Asymmetry ◽  
Slow Phase ◽  
Velocity Versus ◽  
Eye Position ◽  
Full Field ◽  
Optokinetic Afternystagmus ◽  
Optokinetic Responses ◽  
The Mean

In 30 normal subjects we computed the slow cumulative eye position (SCEP) of optokinetic afternystagmus (OKAN) that followed 60 seconds of full-field optokinetic stimulation at 60°/s. The mean SCEP was 112.8° ± 65.0°. The lower and upper fifth percentile limits for directional preponderance of the SCEP were −38.8% and 44.3%, respectively. The time constant, which we calculated by dividing the SCEP by the initial velocity, was 12.0 ± 7.4 seconds. This value is nearly identical to the time constant obtained from semilogarithmic regression of the decay of OKAN slow-phase velocity versus time. We conclude that the SCEP is a good measure of OKAN and that it reflects the substantial amount of variability and directional asymmetry observed in the optokinetic responses of normal subjects.

Independent eye movements in the turtle

1990 ◽  
Vol 5 (1) ◽  
pp. 29-41 ◽  
Author(s):  
M. Ariel
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Contact Lenses ◽  
The Other ◽  
Slow Phase ◽  
Accessory Optic System ◽  
Retinal Slip ◽  
The Mean ◽  
The Difference ◽  
Eye Velocity

AbstractIn order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).

Analysis of vertebrate eye movements following intravitreal drug injections. II. Spontaneous nystagmus induced by picrotoxin is mediated subcortically

1988 ◽  
Vol 60 (3) ◽  
pp. 1022-1035 ◽  
Author(s):  
M. Ariel ◽  
F. R. Robinson ◽  
A. G. Knapp
Keyword(s):  
Visual Cortex ◽  
Eye Movements ◽  
Visual Stimulation ◽  
Ganglion Cells ◽  
Vestibular Stimulation ◽  
Spontaneous Nystagmus ◽  
Slow Phase ◽  
Directional Information ◽  
Gaba Antagonist ◽  
Horizontal Nystagmus

1. Eye movements were observed following an injection of picrotoxin, a GABA antagonist, into the vitreous of one eye. A spontaneous nystagmus was observed in cats, rabbits, and turtles, even in total darkness, with slow-phase eye movements in the temporal-to-nasal direction for the injected eye. 2. During visual stimulation by a horizontal drifting pattern, injected eyes moved in the temporal-to-nasal direction, irrespective of stimulus direction. In cats, however, the nystagmus was usually slower when the injected eye viewed nasal-to-temporal motion (opposite to the direction of the spontaneous nystagmus). The spontaneous nystagmus could be halted or even reversed by allowing cats to view motion opposite to the direction of the nystagmus with the uninjected eye alone. The nystagmus could not be overridden in this fashion in rabbits or turtles. 3. The nystagmus induced by picrotoxin could also be modified by vestibular stimulation. When cats were placed on their sides, the spontaneous horizontal nystagmus often decreased and spontaneous vertical nystagmus with upward slow phase movements occurred. During sinusoidal horizontal vestibular stimulation, the horizontal nystagmus due to picrotoxin added to the vestibuloocular reflex as a velocity offset in the temporal-to-nasal direction. 4. Following bilateral ablation of the cat visual cortex, picrotoxin's effect became even more pronounced than before the ablation. Therefore, at least some picrotoxin-sensitive cells can use subcortical pathways, perhaps to the accessory optic nuclei. The visual cortex, which also processes directional information, may be able to compensate for changes in retinal processing induced by picrotoxin in intact animals. 5. This study demonstrates the importance of retinal GABA in the control of eye stability. As GABA is known to be responsible for null direction inhibition of directionally sensitive retinal ganglion cells, these results suggest that the output of these cells may be critical for the normal functioning of central optokinetic pathways, even in the absence of visual cortex.

Investigation of the Horizontal, Vertical, and Oblique Optokinetic Nystagmus and Afternystagmus in Squirrel Monkeys

1995 ◽  
Vol 5 (3) ◽  
pp. 171-186
Author(s):  
J. Kröller ◽  
F. Behrens
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Two Dimensions ◽  
Movement Direction ◽  
Slow Phase ◽  
Vertical Search ◽  
Phase Direction ◽  
Pattern Movement ◽  
Eye Velocity ◽  
Stimulus Direction

A moving random dot pattern was projected onto a tangent screen in front of awake untrained monkeys that were always placed in upright position. Eye movements were recorded in two dimensions to study the oblique optokinetic nystagmus (OKN) and compare it to the horizontal and vertical OKN. Any direction of pattern movement across the screen could be achieved. The angular velocity of pattern movement was varied between 6 and 180°/s. To display off-horizontal and off-vertical eye movements, the instantaneous direction and velocity of the eye movements were computed from the horizontal and vertical search coil voltages. At pattern velocities below 90°/s, stimulus-direction and direction of the OKN slow phase matched very precisely. Above 90°/s the slow-phase eye movement direction was systematically shifted toward the horizontal except for pure vertical stimulation. The slow-phase eye velocity at off-horizontal stimulation was inconstant, however; stable periods occurred repeatedly that were used to define the gain of OKN. Up to stimulus speeds of about 90°/s the OKN gain did not depend on the direction of stimulation and of OKN. At higher velocities the gain decreased with the increasing angle between stimulus direction and horizontal. Practically no vertical optokinetic afternystagmus (OKAN) could be observed, in either the up or down direction. At the onset of afternystagmus after oblique stimulation the direction of the OKAN slow phase immediately shifted over to the horizontal. The data indicate that the slow-phase direction and gain of oblique OKN with the monkey’s head upright can be described by the sum of a horizontal and a vertical velocity vector obtained during stimulation in these cardinal directions.

scholarly journals Fixation eye movement abnormalities and stereopsis recovery following strabismus repair

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Talora L. Martin ◽  
Jordan Murray ◽  
Kiran Garg ◽  
Charles Gallagher ◽  
Aasef G. Shaikh ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Functional Improvement ◽  
Slow Phase ◽  
Fixational Eye Movements ◽  
Movement Characteristics ◽  
Adaptive Mechanisms ◽  
Before And After ◽  
Gaze Holding ◽  
Fixational Saccades

AbstractWe evaluated the effects of strabismus repair on fixational eye movements (FEMs) and stereopsis recovery in patients with fusion maldevelopment nystagmus (FMN) and patients without nystagmus. Twenty-one patients with strabismus, twelve with FMN and nine without nystagmus, were tested before and after strabismus repair. Eye-movements were recorded during a gaze-holding task under monocular viewing conditions. Fast (fixational saccades and quick phases of nystagmus) and slow (inter-saccadic drifts and slow phases of nystagmus) FEMs and bivariate contour ellipse area (BCEA) were analyzed in the viewing and non-viewing eye. Strabismus repair improved the angle of strabismus in subjects with and without FMN, however patients without nystagmus were more likely to have improvement in stereoacuity. The fixational saccade amplitudes and intersaccadic drift velocities in both eyes decreased after strabismus repair in subjects without nystagmus. The slow phase velocities were higher in patients with FMN compared to inter-saccadic drifts in patients without nystagmus. There was no change in the BCEA after surgery in either group. In patients without nystagmus, the improvement of the binocular function (stereopsis), as well as decreased fixational saccade amplitude and intersaccadic drift velocity, could be due, at least partially, to central adaptive mechanisms rendered possible by surgical realignment of the eyes. The absence of improvement in patients with FMN post strabismus repair likely suggests the lack of such adaptive mechanisms in patients with early onset infantile strabismus. Assessment of fixation eye movement characteristics can be a useful tool to predict functional improvement post strabismus repair.

EFFECT OF MONOVISION CONTACT LENSES ON READING EYE MOVEMENTS, READING SPEED AND COMPREHENSION.

2002 ◽  
Vol 79 (Supplement) ◽  
pp. 292
Author(s):  
Sandy Johal ◽  
Nazima Sangha ◽  
Bradley Coffey ◽  
Peter Bergenske ◽  
Patrick Caroline
Keyword(s):  
Eye Movements ◽  
Contact Lenses ◽  
Reading Speed

scholarly journals A Fast and Effective System for Analysis of Optokinetic Waveforms with a Low-Cost Eye Tracking Device

Healthcare ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Chong-Bin Tsai ◽  
Wei-Yu Hung ◽  
Wei-Yen Hsu
Keyword(s):  
Eye Movements ◽  
Eye Tracking ◽  
Eye Movement ◽  
Low Cost ◽  
Saccadic Eye Movements ◽  
Slow Phase ◽  
Eye Tracker ◽  
Effective System ◽  
Tracking Device ◽  
Traditional Approaches

Optokinetic nystagmus (OKN) is an involuntary eye movement induced by motion of a large proportion of the visual field. It consists of a “slow phase (SP)” with eye movements in the same direction as the movement of the pattern and a “fast phase (FP)” with saccadic eye movements in the opposite direction. Study of OKN can reveal valuable information in ophthalmology, neurology and psychology. However, the current commercially available high-resolution and research-grade eye tracker is usually expensive. Methods & Results: We developed a novel fast and effective system combined with a low-cost eye tracking device to accurately quantitatively measure OKN eye movement. Conclusions: The experimental results indicate that the proposed method achieves fast and promising results in comparisons with several traditional approaches.

Visually evoked slow eye movements, visual-vestibular interaction, and infratentorial lesions

1983 ◽  
Vol 91 (1) ◽  
pp. 76-80 ◽  
Author(s):  
Carsten Wennmo ◽  
Nils Gunnar Henriksson ◽  
Bengt Hindfelt ◽  
Ilmari PyykkÖ ◽  
MÅNs Magnusson
Keyword(s):  
Eye Movements ◽  
Phase Velocity ◽  
Brain Stem ◽  
Smooth Pursuit ◽  
Maximum Velocity ◽  
Slow Phase ◽  
Slow Phase Velocity ◽  
Velocity Gain ◽  
Visual Vestibular Interaction ◽  
Slow Eye Movements

The maximum velocity gain of smooth pursuit and optokinetic, vestibular, and optovestibular slow phases was examined in 15 patients with pontine, 10 with medullary, 10 with cerebellar, and 5 with combined cerebello — brain stem disorders. Marked dissociations were observed between smooth pursuit and optokinetic slow phases, especially in medullary disease. A cerebellar deficit enhanced slow phase velocity gain during rotation in darkness, whereas the corresponding gain during rotation in light was normal.

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