scholarly journals Illusory contrast-induced shifts in binocular visual direction bias saccadic eye movements toward the perceived target position

10.1167/7.5.3 ◽  
2007 ◽  
Vol 7 (5) ◽  
pp. 3 ◽  
Author(s):  
Julia A. Weiler ◽  
James S. Maxwell ◽  
Clifton M. Schor
Keyword(s):  
Eye Movements ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Visual Direction

Distributed spatial coding in the superior colliculus: A review

1991 ◽  
Vol 6 (1) ◽  
pp. 3-13 ◽  
Author(s):  
James T. McIlwain
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Receptive Fields ◽  
Saccadic Eye Movements ◽  
Visual Direction ◽  
Saccade Amplitude ◽  
Spatial Coding ◽  
Distributed Coding

AbstractThis paper reviews evidence that the superior colliculus (SC) of the midbrain represents visual direction and certain aspects of saccadic eye movements in the distribution of activity across a population of cells. Accurate and precise eye movements appear to be mediated, in part at least, by cells of the SC that have large sensory receptive fields and/or discharge in association with a range of saccades. This implies that visual points or saccade targets are represented by patches rather than points of activity in the SC. Perturbation of the pattern of collicular discharge by focal inactivation modifies saccade amplitude and direction in a way consistent with distributed coding. Several models have been advanced to explain how such a code might be implemented in the colliculus. Evidence related to these hypotheses is examined and continuing uncertainties are identified.

scholarly journals Neuronal Responses to Moving Targets in Monkey Frontal Eye Fields

2008 ◽  
Vol 100 (3) ◽  
pp. 1544-1556 ◽  
Author(s):  
Carlos R. Cassanello ◽  
Abhay T. Nihalani ◽  
Vincent P. Ferrera
Keyword(s):  
Eye Movements ◽  
Neuronal Response ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Quantitative Model ◽  
Initial Position ◽  
Target Velocity ◽  
Frontal Eye Fields ◽  
Moving Targets ◽  
Velocity Information

Due to delays in visuomotor processing, eye movements directed toward moving targets must integrate both target position and velocity to be accurate. It is unknown where and how target velocity information is incorporated into the planning of rapid (saccadic) eye movements. We recorded the activity of neurons in frontal eye fields (FEFs) while monkeys made saccades to stationary and moving targets. A substantial fraction of FEF neurons was found to encode not only the initial position of a moving target, but the metrics (amplitude and direction) of the saccade needed to intercept the target. Many neurons also encoded target velocity in a nearly linear manner. The quasi-linear dependence of firing rate on target velocity means that the neuronal response can be directly read out to compute the future position of a target moving with constant velocity. This is demonstrated using a quantitative model in which saccade amplitude is encoded in the population response of neurons tuned to retinal target position and modulated by target velocity.

Effects of eye position on electrically evoked saccades: a theoretical note

1988 ◽  
Vol 1 (2) ◽  
pp. 239-244 ◽  
Author(s):  
James T. McIlwain
Keyword(s):  
Eye Movements ◽  
Internal Representation ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Brain Structures ◽  
Initial Position ◽  
Eye Position ◽  
Saccadic System ◽  
Early Processing ◽  
The Difference

AbstractThe trajectories of saccadic eye movements evoked electrically from many brain structures are dependent to some degree on the initial position of the eye. Under certain conditions, likely to occur in stimulation experiments, local feedback models of the saccadic system can yield eye movements which behave in this way. The models in question assume that an early processing stage adds an internal representation of eye position to retinal error to yield a signal representing target position with respect to the head. The saccadic system is driven by the difference between this signal and one representing the current position of the eye. Albano & Wurtz (1982) pointed out that lesions perturbing the computation of eye position with respect to the head can result in initial position dependence of visually evoked saccades. It is shown here that position-dependent saccades will also result if electrical stimulation evokes a signal equivalent to retinal error but fails to effect a complete addition of eye position to this signal. Also, when multiple or staircase saccades are produced, as during long stimulus trains, they will have identical directions but decrease progressively in amplitude by a factor related to the fraction of added eye position.

Oculomotor Factors In Visual Perceptual Response Efficiency

1979 ◽  
Vol 21 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Gerald Leisman
Keyword(s):  
Eye Movements ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Visual Display ◽  
Motor Programming ◽  
Backward Masking ◽  
Perceptual Response ◽  
Perceptual Analysis ◽  
Oculomotor Response ◽  
Stimulus Identification

The preprogramming of saccadic eye movements is examined by studying the pattern of oculomotor sequences while scanning a visual display. The effects of interference employing a backward masking paradigm on the oculomotor response as well as on position judgment and stimulus identification are examined. Data indicate that the motor programming of an ocular saccade is linked to the perceptual analysis of target position and cannot be set in motion with an impairment in perceptual localization.

A theory of visual stability across saccadic eye movements

1994 ◽  
Vol 17 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Bruce Bridgeman ◽  
A. H. C. Van der Heijden ◽  
Boris M. Velichkovsky
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Direction ◽  
Visual Stability ◽  
Perceptual Stability ◽  
Adequate Information ◽  
Psychological Evidence ◽  
Calibration Solution ◽  
Final Question ◽  
Direction Constancy

AbstractWe identify two aspects of the problem of maintaining perceptual stability despite an observer's eye movements. The first, visual direction constancy, is the (egocentric) stability of apparent positions of objects in the visual world relative to the perceiver. The second, visual position constancy, is the (exocentric) stability of positions of objects relative to each other. We analyze the constancy of visual direction despite saccadic eye movements.Three information sources have been proposed to enable the visual system to achieve stability: the structure of the visual field, proprioceptive inflow, and a copy of neural efference or outflow to the extraocular muscles. None of these sources by itself provides adequate information to achieve visual direction constancy; present evidence indicates that all three are used.Our final question concerns how information processing operations result in a stable world. The three traditionally suggested means have been elimination, translation, or evaluation. All are rejected. From a review of the physiological and psychological evidence we conclude that no subtraction, compensation, or evaluation need take place. The problem for which these solutions were developed turns out to be a false one. We propose a “calibration” solution: correct spatiotopic positions are calculated anew for each fixation. Inflow, outflow, and retinal sources are used in this calculation: saccadic suppression of displacement bridges the errors between these sources and the actual extent of movement.

The neural encoding of the location of targets for saccadic eye movements

1989 ◽  
Vol 146 (1) ◽  
pp. 195-207
Author(s):  
D. L. Sparks
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Target Location ◽  
Visual Target ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Neural Encoding ◽  
Neural Representations ◽  
Neurophysiological Data ◽  
Motor Error

Current models of the saccadic system imply that there are at least three neural representations of a visual target to which a saccade is made: representations in retinal, spatial (head or body) and motor coordinates. This paper presents the evidence supporting these models and summarizes the available neurophysiological data concerning neural representations of target location. In the superior colliculus, neurones in the superficial layers encode target location in retinal coordinates. Neurones in the deeper layers responsive to auditory and visual stimuli carry motor error signals. Evidence is also accumulating that some neurones in the thalamus and the frontal and parietal cortex convey information about target position with respect to the head or body, but these studies are far from complete.

The Relationship between Eye Movements and Spatial Attention

1986 ◽  
Vol 38 (3) ◽  
pp. 475-491 ◽  
Author(s):  
Martin Shepherd ◽  
John M. Findlay ◽  
Robert J. Hockey
Keyword(s):  
Eye Movements ◽  
Spatial Attention ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Saccade Target ◽  
Peripheral Stimulus ◽  
Peripheral Stimulation ◽  
Voluntary Eye Movements ◽  
Automatic Capture ◽  
Saccade Preparation

Most previous studies of the attentional consequences of making saccadic eye movements have used peripheral stimuli to elicit eye movements. It is argued that in the light of evidence showing automatic “capture” of attention by peripheral stimuli, these experiments do not distinguish between attentional effects due to peripheral stimuli and those due to eye movements. In the present study, spatial attention was manipulated by varying the probability that peripheral probe stimuli would appear in different positions, while saccades were directed by a central arrow, enabling the effects of attention and eye movements to be separated. The results showed that the time to react to a peripheral stimulus could be shortened both by advance knowledge of its likely position and, separately, by preparing to make a saccade to that position. When the saccade was directed away from the most likely position of the probe, the targets for attention and eye movements were on opposite sides of the display. In this condition, the effects of preparing to make a saccade proved to be stronger than the effects of attentional allocation until well after the saccade had finished, suggesting that making a saccade necessarily involves the allocation of attention to the target position. The effects of probe stimuli on saccade latencies were also examined: probe stimuli that appeared before the saccade shortened saccade latencies if they appeared at the saccade target, and lengthened saccade latencies if they appeared on the opposite side of fixation. These facilitatory and inhibitory effects were shown to occur at different stages of saccade preparation and suggest that attention plays an important role in the generation of voluntary eye movements. The results of this study indicate that while it is possible to make attention movements without making corresponding eye movements, it is not possible to make an eye movement (in the absence of peripheral stimulation) without making a corresponding shift in the focus of attention.

Illusory shifts in visual direction accompany adaptation of saccadic eye movements

Nature ◽  
10.1038/23693 ◽  
1999 ◽  
Vol 400 (6747) ◽  
pp. 864-866 ◽  
Author(s):  
Dan O. Bahcall ◽  
Eileen Kowler
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Visual Direction

The effect of task set on fixational saccadic eye movements

2013 ◽  
Author(s):  
Sara Spotorno ◽  
Guillaume S. Masson ◽  
Anna Montagnini
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Task Set
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