Visual attention and saccadic eye movements in normal human subjects and in patients with unilateral neglect

1996 ◽  
pp. 95-114 ◽  
Author(s):  
John M Findlay ◽  
Robin Walker
Keyword(s):  
Eye Movements ◽  
Visual Attention ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Unilateral Neglect ◽  
Normal Human

Properties of Horizontal Saccades Accompanied by Blinks

1998 ◽  
Vol 79 (6) ◽  
pp. 2895-2902 ◽  
Author(s):  
Klaus G. Rottach ◽  
Vallabh E. Das ◽  
Walter Wohlgemuth ◽  
Ari Z. Zivotofsky ◽  
R. John Leigh
Keyword(s):  
Eye Movements ◽  
Peak Velocity ◽  
Dynamic Properties ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Stationary Target ◽  
Normal Human ◽  
The Right ◽  
Straight Ahead ◽  
Omnipause Neurons

Rottach, Klaus G., Vallabh E. Das, Walter Wohlgemuth, Ari Z. Zivotofsky, and R. John Leigh. Properties of horizontal saccades accompanied by blinks. J. Neurophysiol. 79: 2895–2902, 1998. Using the magnetic search coil technique to record eye and lid movements, we investigated the effect of voluntary blinks on horizontal saccades in five normal human subjects. The main goal of the study was to determine whether changes in the dynamics of saccades with blinks could be accounted for by a superposition of the eye movements induced by blinks as subjects fixated a stationary target and saccadic movements made without a blink. First, subjects made voluntary blinks as they fixed on stationary targets located straight ahead or 20° to the right or left. They then made saccades between two continuously visible targets 20 or 40° apart, while either attempting not to blink, or voluntarily blinking, with each saccade. During fixation of a target located straight ahead, blinks induced brief downward and nasalward deflections of eye position. When subjects looked at targets located at right or left 20°, similar initial movements were made by four of the subjects, but the amplitude of the adducted eye was reduced by 65% and was followed by a larger temporalward movement. Blinks caused substantial changes in the dynamic properties of saccades. For 20° saccades made with blinks, peak velocity and peak acceleration were decreased by ∼20% in all subjects compared with saccades made without blinks. Blinks caused the duration of 20° saccades to increase, on average, by 36%. On the other hand, blinks had only small effects on the gain of saccades. Blinks had little influence on the relative velocities of centrifugal versus centripetal saccades, and abducting versus adducting saccades. Three of five subjects showed a significantly increased incidence of dynamic overshoot in saccades accompanied by blinks, especially for 20° movements. Taken with other evidence, this finding suggests that saccadic omnipause neurons are inhibited by blinks, which have longer duration than the saccades that company them. In conclusion, the changes in dynamic properties of saccades brought about by blinks cannot be accounted for simply by a summation of gaze perturbations produced by blinks during fixation and saccadic eye movements made without blinks. Our findings, especially the appearance of dynamic overshoots, suggest that blinks affect the central programming of saccades. These effects of blinks need to be taken into account during studies of the dynamic properties of saccades.

scholarly journals Salient Distractors Can Induce Saccade Adaptation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Afsheen Khan ◽  
Sally A. McFadden ◽  
Mark Harwood ◽  
Josh Wallman
Keyword(s):  
Eye Movements ◽  
Visual Attention ◽  
Visual Target ◽  
Random Noise ◽  
Saccadic Eye Movements ◽  
Small Degree ◽  
Error Signal ◽  
Intended Target ◽  
Saccade Adaptation

When saccadic eye movements consistently fail to land on their intended target, saccade accuracy is maintained by gradually adapting the movement size of successive saccades. The proposed error signal for saccade adaptation has been based on the distance between where the eye lands and the visual target (retinal error). We studied whether the error signal could alternatively be based on the distance between the predicted and actual locus of attention after the saccade. Unlike conventional adaptation experiments that surreptitiously displace the target once a saccade is initiated towards it, we instead attempted to draw attention away from the target by briefly presenting salient distractor images on one side of the target after the saccade. To test whether less salient, more predictable distractors would induce less adaptation, we separately used fixed random noise distractors. We found that both visual attention distractors were able to induce a small degree of downward saccade adaptation but significantly more to the more salient distractors. As in conventional adaptation experiments, upward adaptation was less effective and salient distractors did not significantly increase amplitudes. We conclude that the locus of attention after the saccade can act as an error signal for saccade adaptation.

Analysis of Saccadic Eye Movements Using an Infrared Video System in Human Subjects

1991 ◽  
Vol 111 (sup481) ◽  
pp. 382-387 ◽  
Author(s):  
Takeshi Kubo ◽  
Takanori Saika ◽  
Yoshiharu Sakata ◽  
Yasuhiro Morita ◽  
Toru Matsunaga ◽  
...  
Keyword(s):  
Eye Movements ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Video System ◽  
Infrared Video

Short Report: Scrutinization, Spatial Attention, and the Spatial Programming of Saccadic Eye Movements

1992 ◽  
Vol 45 (4) ◽  
pp. 633-647 ◽  
Author(s):  
John M. Findlay ◽  
Zoi Kapoula
Keyword(s):  
Eye Movements ◽  
Visual Attention ◽  
Spatial Attention ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Short Report ◽  
Similar Material ◽  
Visual Tasks ◽  
Corrective Saccade ◽  
Spatial Programming

Results are presented from an experiment in which subjects’ eye movements were recorded while they carried out two visual tasks with similar material. One task was chosen to require close visual scrutiny; the second was less visually demanding. The oculomotor behaviour in the two tasks differed in three ways. (1) When scrutinizing, there was a reduction in the area of visual space over which stimulation influences saccadic eye movements. (2) When moving their eyes to targets requiring scrutiny, subjects were more likely to make a corrective saccade. (3) The duration of fixations on targets requiring scrutiny was increased. The results are discussed in relation to current theories of visual attention and the control of saccadic eye movements.

scholarly journals Visual Attention Through Uncertainty Minimization in Recurrent Generative Models

2020 ◽  
Author(s):  
Kai Standvoss ◽  
Silvan C. Quax ◽  
Marcel A.J. van Gerven
Keyword(s):  
Eye Movements ◽  
Visual Attention ◽  
Intelligent Agents ◽  
Saccadic Eye Movements ◽  
Generative Models ◽  
Task Demands ◽  
Relevant Stimulus ◽  
Predictive Uncertainty ◽  
Proposed Model ◽  
Uncertainty Minimization

AbstractAllocating visual attention through saccadic eye movements is a key ability of intelligent agents. Attention is both influenced through bottom-up stimulus properties as well as top-down task demands. The interaction of these two attention mechanisms is not yet fully understood. A parsimonious reconciliation posits that both processes serve the minimization of predictive uncertainty. We propose a recurrent generative neural network model that predicts a visual scene based on foveated glimpses. The model shifts its attention in order to minimize the uncertainty in its predictions. We show that the proposed model produces naturalistic eye movements focusing on informative stimulus regions. Introducing additional tasks modulates the saccade patterns towards task-relevant stimulus regions. The model’s saccade characteristics correspond well with previous experimental data in humans, providing evidence that uncertainty minimization could be a fundamental mechanisms for the allocation of visual attention.

Initiation of saccades during fixation or pursuit: evidence in humans for a single mechanism

1996 ◽  
Vol 76 (6) ◽  
pp. 4175-4179 ◽  
Author(s):  
R. J. Krauzlis ◽  
F. A. Miles
Keyword(s):  
Eye Movements ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Saccade Latency ◽  
Gap Effect ◽  
Time Interval ◽  
Single Mechanism ◽  
Eccentric Target

1. In four human subjects, we measured the latency of saccadic eye movements made to a second, eccentric target after an initial, foveated target was extinguished. In separate interleaved trails, the targets were either both stationary (“fixation”) or both moving with the same velocity (“pursuit”). For both fixation and pursuit trials, we extinguished the first target at randomized times during maintained fixation or pursuit and varied the time interval (“gap duration”) before the appearance of the second target. 2. During both fixation and pursuit, the presence of a 200-ms gap reduced the latencies of saccades, compared with those obtained with no gap. For two subjects, we imposed additional, intermediate gap durations and found that saccade latencies varied as a function of gap duration. Furthermore, the latencies of saccades elicited during pursuit displayed the same dependence on gap duration as those elicited during fixation. 3. Our results demonstrate that the “gap effect” observed for saccades made during fixation also occurs for saccades made during pursuit. To the extent that the gap effect on saccade latency reflects a mechanism underlying the release of fixation, our results suggest that the same mechanism is invoked for saccades made during pursuit. From the viewpoint of initiating saccades, the existence of separate fixation and pursuit systems may be irrelevant.

scholarly journals Phosphene Induction and the Generation of Saccadic Eye Movements by Striate Cortex

2005 ◽  
Vol 93 (1) ◽  
pp. 1-19 ◽  
Author(s):  
E. J. Tehovnik ◽  
W. M. Slocum ◽  
C. E. Carvey ◽  
P. H. Schiller
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Striate Cortex ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Visual Prosthesis ◽  
Prosthetic Device ◽  
Electrical Microstimulation ◽  
Stimulation Parameters ◽  
Cortex Area

The purpose of this review is to critically examine phosphene induction and saccadic eye movement generation by electrical microstimulation of striate cortex (area V1) in humans and monkeys. The following issues are addressed: 1) Properties of electrical stimulation as they pertain to the activation of V1 elements; 2) the induction of phosphenes in sighted and blind human subjects elicited by electrical stimulation using various stimulation parameters and electrode types; 3) the induction of phosphenes with electrical microstimulation of V1 in monkeys; 4) the generation of saccadic eye movements with electrical microstimulation of V1 in monkeys; and 5) the tasks involved for the development of a cortical visual prosthesis for the blind. In this review it is concluded that electrical microstimulation of area V1 in trained monkeys can be used to accelerate the development of an effective prosthetic device for the blind.

Orienting of Attention

1980 ◽  
Vol 32 (1) ◽  
pp. 3-25 ◽  
Author(s):  
Michael I. Posner
Keyword(s):  
Human Subjects ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Brain Injured ◽  
Ballistic Properties ◽  
Normal Human ◽  
High Level ◽  
Relationship Of ◽  
The Relationship ◽  
Attentional Mechanism

Bartlett viewed thinking as a high level skill exhibiting ballistic properties that he called its “point of no return”. This paper explores one aspect of cognition through the use of a simple model task in which human subjects are asked to commit attention to a position in visual space other than fixation. This instruction is executed by orienting a covert (attentional) mechanism that seems sufficiently time locked to external events that its trajectory can be traced across the visual field in terms of momentary changes in the efficiency of detecting stimuli. A comparison of results obtained with alert monkeys, brain injured and normal human subjects shows the relationship of this covert system to saccadic eye movements and to various brain systems controlling perception and motion. In accordance with Bartlett's insight, the possibility is explored that similar principles apply to orienting of attention toward sensory input and orienting to the semantic structures used in thinking.

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