scholarly journals Systematic deviation of eye-movement direction from stimulus-direction during Optokinetic Nystagmus

2013 ◽  
Vol 13 (9) ◽  
pp. 386-386
Author(s):  
A. Kaminiarz ◽  
K. Bartelheimer ◽  
F. Bremmer
Keyword(s):  
Eye Movement ◽  
Optokinetic Nystagmus ◽  
Movement Direction ◽  
Systematic Deviation ◽  
Stimulus Direction

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.

Visual Field Accuracy and Eye Movement Direction: A Child's Eye View

1980 ◽  
Vol 50 (2) ◽  
pp. 631-636
Author(s):  
Evans Mandes
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Eye Movement ◽  
Visual Fields ◽  
Movement Direction

Post-exposural eye movements were studied in 32 adults and 24 7-yr.-old children. Stimuli were binary figures exposed tachistoscopically in both visual fields simultaneously. The data showed significant correlations between direction of eye movement and locus of recognition for both children and adults. No significant differences were found in frequencies of eye movements of children and adults. The data are interpreted in terms of the facilitative effects of post-exposural eye movements upon perception for both groups.

Ergonomics analysis based on intention inference

2021 ◽  
pp. 1-16
Author(s):  
First A. Wenbo Huang ◽  
Second B. Changyuan Wang ◽  
Third C. Hongbo Jia
Keyword(s):  
Eye Movement ◽  
Recognition Rate ◽  
Tactile Feedback ◽  
Movement Direction ◽  
Support Vector ◽  
Eeg Signals ◽  
Intention Recognition ◽  
Baseline Removal ◽  
Inference Methods ◽  
Intention Inference

Traditional intention inference methods rely solely on EEG, eye movement or tactile feedback, and the recognition rate is low. To improve the accuracy of a pilot’s intention recognition, a human-computer interaction intention inference method is proposed in this paper with the fusion of EEG, eye movement and tactile feedback. Firstly, EEG signals are collected near the frontal lobe of the human brain to extract features, which includes eight channels, i.e., AF7, F7, FT7, T7, AF8, F8, FT8, and T8. Secondly, the signal datas are preprocessed by baseline removal, normalization, and least-squares noise reduction. Thirdly, the support vector machine (SVM) is applied to carry out multiple binary classifications of the eye movement direction. Finally, the 8-direction recognition of the eye movement direction is realized through data fusion. Experimental results have shown that the accuracy of classification with the proposed method can reach 75.77%, 76.7%, 83.38%, 83.64%, 60.49%,60.93%, 66.03% and 64.49%, respectively. Compared with traditional methods, the classification accuracy and the realization process of the proposed algorithm are higher and simpler. The feasibility and effectiveness of EEG signals are further verified to identify eye movement directions for intention recognition.

Eye movement abnormalities in somatic tinnitus: Fixation, smooth pursuit and optokinetic nystagmus

2010 ◽  
Vol 37 (3) ◽  
pp. 314-321 ◽  
Author(s):  
Z. Kapoula ◽  
Q. Yang ◽  
M. Vernet ◽  
P. Bonfils ◽  
A. Londero
Keyword(s):  
Eye Movement ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus

Optokinetic Eye Movements Elicited by Radial Optic Flow in the Macaque Monkey

1998 ◽  
Vol 79 (3) ◽  
pp. 1461-1480 ◽  
Author(s):  
Markus Lappe ◽  
Martin Pekel ◽  
Klaus-Peter Hoffmann
Keyword(s):  
Eye Movements ◽  
Flow Field ◽  
Eye Movement ◽  
Optic Flow ◽  
Macaque Monkey ◽  
Flow Fields ◽  
Movement Direction ◽  
Slow Phase ◽  
Eye Position ◽  
Self Motion

Lappe, Markus, Martin Pekel, and Klaus-Peter Hoffmann. Optokinetic eye movements elicited by radial optic flow in the macaque monkey. J. Neurophysiol. 79: 1461–1480, 1998. We recorded spontaneous eye movements elicited by radial optic flow in three macaque monkeys using the scleral search coil technique. Computer-generated stimuli simulated forward or backward motion of the monkey with respect to a number of small illuminated dots arranged on a virtual ground plane. We wanted to see whether optokinetic eye movements are induced by radial optic flow stimuli that simulate self-movement, quantify their parameters, and consider their effects on the processing of optic flow. A regular pattern of interchanging fast and slow eye movements with a frequency of 2 Hz was observed. When we shifted the horizontal position of the focus of expansion (FOE) during simulated forward motion (expansional optic flow), median horizontal eye position also shifted in the same direction but only by a smaller amount; for simulated backward motion (contractional optic flow), median eye position shifted in the opposite direction. We relate this to a change in Schlagfeld typically observed in optokinetic nystagmus. Direction and speed of slow phase eye movements were compared with the local flow field motion in gaze direction (the foveal flow). Eye movement direction matched well the foveal motion. Small systematic deviations could be attributed to an integration of the global motion pattern. Eye speed on average did not match foveal stimulus speed, as the median gain was only ∼0.5–0.6. The gain was always lower for expanding than for contracting stimuli. We analyzed the time course of the eye movement immediately after each saccade. We found remarkable differences in the initial development of gain and directional following for expansion and contraction. For expansion, directional following and gain were initially poor and strongly influenced by the ongoing eye movement before the saccade. This was not the case for contraction. These differences also can be linked to properties of the optokinetic system. We conclude that optokinetic eye movements can be elicited by radial optic flow fields simulating self-motion. These eye movements are linked to the parafoveal flow field, i.e., the motion in the direction of gaze. In the retinal projection of the optic flow, such eye movements superimpose retinal slip. This results in complex retinal motion patterns, especially because the gain of the eye movement is small and variable. This observation has special relevance for mechanisms that determine self-motion from retinal flow fields. It is necessary to consider the influence of eye movements in optic flow analysis, but our results suggest that direction and speed of an eye movement should be treated differently.

Eye Movements in Cerebellar and Combined Cerebellobrainstem Diseases

1983 ◽  
Vol 92 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Carsten Wennmo ◽  
Bengt Hindfelt ◽  
Ilmari Pyykkö
Keyword(s):  
Quantitative Analysis ◽  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus ◽  
Vestibular Nystagmus ◽  
Full Field ◽  
Eye Velocity ◽  
Voluntary Saccades ◽  
Cerebellar Disorders

We report a quantitative analysis of eye movement disturbances in patients with isolated cerebellar disorders and patients with cerebellar disorders and concomitant brainstem involvement. The most characteristic abnormalities in the exclusively cerebellar patients were increased velocities of the slow phases of vestibular nystagmus induced by rotation in the dark and increased peak velocities of the fast phases of optokinetic nystagmus induced by full-field optokinetic stimuli. Dysmetria of saccades was found in three of six cerebellar patients and gaze nystagmus in all six patients. The typical findings in the combined cerebellobrainstem group were reduced peak velocities of voluntary saccades, defective smooth pursuit and reduced peak velocities of the fast component of nystagmus during rotation in both the dark and light. All patients with combined cerebellobrainstem disorder had dysmetric voluntary saccades and gaze nystagmus. The numbers of superimposed saccades during smooth pursuit were uniformly increased. Release of inhibition in cerebellar disorders may explain the hyperresponsiveness and inaccuracy of eye movements found in this study. In addition, when lesions also involve the brainstem, however, integrative centers coding eye velocity are affected, leading to slow and inaccurate eye movements. These features elicited clinically may be useful in the diagnosis of cerebellar and brainstem disorders.

Eye movements in Daphnia pulex (De Geer)

1975 ◽  
Vol 62 (1) ◽  
pp. 175-187
Author(s):  
BJ Frost
Keyword(s):  
Eye Movements ◽  
Fourier Analysis ◽  
Eye Movement ◽  
Horizontal Plane ◽  
High Speed ◽  
Optokinetic Nystagmus ◽  
Sagittal Plane ◽  
Daphnia Pulex ◽  
Saccadic Eye Movements ◽  
Fourth Harmonic

1. The various types of eye movement exhibited by the cyclopean eye of Daphnia pulex were studied using high speed motion photography. 2. This rudimentary eye, which consists of only 22 ommatidia, can move through approximately 150 degrees in the sagittal plane and 60 degrees in the horizontal plane. 3. Four classes of eye movement were found: (1) a high speed tremor at 16 Hz with an amplitude of 3-4 degrees, which resembles physiological nystagmus, (2) a slow rhythmic scanning movement at 4 Hz, and 5-6 degrees amplitude, (3) large fast eye movements similar to saccadic eye movements and (4) optokinetic nystagmus produced by moving striped patterns. 4. Where the fast tremor occurred concurrently with the slow rhythmic scan, a Fourier analysis revealed that the former was the fourth harmonic of the latter.

Adaptive response to ocular muscle weakness in human pursuit and saccadic eye movements

1985 ◽  
Vol 54 (1) ◽  
pp. 110-122 ◽  
Author(s):  
L. M. Optican ◽  
D. S. Zee ◽  
F. C. Chu
Keyword(s):  
Eye Movement ◽  
Muscle Weakness ◽  
Initial Period ◽  
Motor Deficit ◽  
Movement Direction ◽  
Target Velocity ◽  
Eye Position ◽  
Target Movement ◽  
Ocular Muscle ◽  
The Relationship

Eye movement deficits caused by ocular muscle weakness vary according to the position of the eye in the orbit and the direction of eye movement. We studied the ability of both the saccadic and pursuit eye-movement systems to compensate for these anisotropic deficits in four patients with ocular muscle weakness. The eye-position dependence of each patient's motor deficit was characterized by plotting the position of the weak eye against that of the normal eye (in various orbital positions) when fusion was prevented, thus giving a static eye-position curve from which relative muscle strength could be inferred. Movements of the weak eye were smaller and slower than those made by the normal eye, so that the weak eye required more time to acquire a visual target. When patients were forced to view monocularly with their weak eye for several days, both the saccadic and pursuit systems showed changes in the movements of the normal eye consistent with an increased central innervation designed to decrease the time it takes to bring the target's image onto the fovea of the weak eye and to keep it there. These adaptive changes varied with eye position and movement direction and compensated for the weak muscle in both its agonistic and antagonistic actions. Saccadic adaptation consisted of a change in the relationship between saccadic amplitude and retinal error (distance between the target's image and the fovea) to compensate for hypometria (undershoot) and a readjustment of the ratio of the phasic (pulse) and tonic (step) components of the saccadic innervation to suppress postsaccadic ocular drift. Pursuit adaptation consisted of an increase in the relationship between eye acceleration and the rate of motion of the image of the target on the retina during the initial phase of tracking as well as an increase in the velocity during tracking of a target moving at a constant velocity. These changes reflect an increase in pursuit innervation that would cause the weak eye's velocity to approach target velocity sooner. The average acceleration of the normal eye during the initial period of tracking (130 ms) increased by as much as threefold. The corresponding maximum smooth eye velocity increased so that, for example, the pursuit response to a 15 degree/s target movement could be over 50 degree/s in the normal eye.

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