Visual Versus Motor Vector Inversions in the Antisaccade Task: A Behavioral Investigation With Saccadic Adaptation

2008 ◽  
Vol 99 (5) ◽  
pp. 2708-2718 ◽  
Author(s):  
Thérèse Collins ◽  
Dorine Vergilino-Perez ◽  
Laura Delisle ◽  
Karine Doré-Mazars
Keyword(s):  
Eye Movement ◽  
Visual Target ◽  
Antisaccade Task ◽  
Saccade Amplitude ◽  
Stimulus Position ◽  
Target Vector ◽  
Saccadic Adaptation ◽  
Vector Inversion ◽  
Adaptation Field ◽  
Saccade Adaptation

In the antisaccade task, subjects must execute an eye movement away from a visual target. Correctly executing an antisaccade requires inhibiting a prosaccade toward the visual target and programming a movement to the opposite side. This movement could be based on the inversion of the visual vector, corresponding to the distance between the fixation point and the visual target, or the motor vector of the unwanted prosaccade. We dissociated the two vectors by means of saccadic adaptation. Adaptation can be observed when systematic targeting errors are caused by the displacement of the visual target during the saccade. Adaptation progressively modifies saccade amplitude (defined by the motor vector) such that it becomes appropriate to the postsaccadic stimulus position and thus different from the visual vector of the target. If antisaccade preparation depended on visual vector inversion, rightward prosaccade adaptation should not transfer to leftward antisaccades (which are based on the same visual vector) but should transfer to rightward antisaccades (which are based on a visual vector inside the adaptation field). If antisaccade preparation depended on motor vector inversion, rightward prosaccade adaptation should transfer to leftward antisaccades (which are based on the same, adapted motor vector) but should not transfer to rightward antisaccades (which are based on a nonadapted motor vector). The results are in line with the first hypothesis, showing that vector inversion precedes saccadic adaptation and suggesting that antisaccade preparation depends on the inversion of the visual target vector.

scholarly journals Adaptation of naturally paced saccades

2014 ◽  
Vol 111 (11) ◽  
pp. 2343-2354 ◽  
Author(s):  
Michael J. Gray ◽  
Annabelle Blangero ◽  
James P. Herman ◽  
Josh Wallman ◽  
Mark R. Harwood
Keyword(s):  
Eye Movement ◽  
Learning Process ◽  
Main Sequence ◽  
Intertrial Interval ◽  
Peak Velocity ◽  
Saccade Amplitude ◽  
Sequence Relationship ◽  
Saccade Adaptation ◽  
Interval Observers ◽  
Surprising Finding

In the natural environment, humans make saccades almost continuously. In many eye movement experiments, however, observers are required to fixate for unnaturally long periods of time. The resulting long and monotonous experimental sessions can become especially problematic when collecting data in a clinical setting, where time can be scarce and subjects easily fatigued. With this in mind, we tested whether the well-studied motor learning process of saccade adaptation could be induced with a dramatically shortened intertrial interval. Observers made saccades to targets that stepped left or right either ∼250 ms or ∼1,600 ms after the saccade landed. In experiment I, we tested baseline saccade parameters to four different target amplitudes (5°, 10°, 15°, and 20°) in the two timing settings. In experiments II and III, we adapted 10° saccades via 2° intrasaccadic steps either backwards or forwards, respectively. Seven subjects performed eight separate adaptation sessions (2 intertrial timings × 2 adaptation direction × 2 session trial lengths). Adaptation proceeded remarkably similarly in both timing conditions across the multiple sessions. In the faster-paced sessions, robust adaptation was achieved in under 2 min, demonstrating the efficacy of our approach to streamlining saccade adaptation experiments. Although saccade amplitudes were similar between conditions, the faster-paced condition unexpectedly resulted in significantly higher peak velocities in all subjects. This surprising finding demonstrates that the stereotyped “main sequence” relationship between saccade amplitude and peak velocity is not as fixed as originally thought.

scholarly journals The relative importance of retinal error and prediction in saccadic adaptation

2012 ◽  
Vol 107 (12) ◽  
pp. 3342-3348 ◽  
Author(s):  
Thérèse Collins ◽  
Josh Wallman
Keyword(s):  
Prediction Error ◽  
Visual Target ◽  
Target Position ◽  
Oculomotor System ◽  
Relative Importance ◽  
Saccadic Adaptation ◽  
Position Errors ◽  
The Difference ◽  
Saccade Adaptation ◽  
First Session

When saccades systematically miss their visual target, their amplitude adjusts, causing the position errors to be progressively reduced. Conventionally, this adaptation is viewed as driven by retinal error (the distance between primary saccade endpoint and visual target). Recent work suggests that the oculomotor system is informed about where the eye lands; thus not all “retinal error” is unexpected. The present study compared two error signals that may drive saccade adaptation: retinal error and prediction error (the difference between predicted and actual postsaccadic images). Subjects made saccades to a visual target in two successive sessions. In the first session, the target was extinguished during saccade execution if the amplitude was smaller (or, in other experiments, greater) than the running median, thereby modifying the average retinal error subjects experienced without moving the target during the saccade as in conventional adaptation paradigms. In the second session, targets were extinguished at the start of saccades and turned back on at a position that reproduced the trial-by-trial retinal error recorded in the first session. Despite the retinal error in the first and second sessions having been identical, adaptation was severalfold greater in the second session, when the predicted target position had been changed. These results argue that the eye knows where it lands and where it expects the target to be, and that deviations from this prediction drive saccade adaptation more strongly than retinal error alone.

Mislocalization of stationary and flashed bars after saccadic inward and outward adaptation of reactive saccades

2012 ◽  
Vol 107 (11) ◽  
pp. 3062-3070 ◽  
Author(s):  
Fabian Schnier ◽  
Markus Lappe
Keyword(s):  
Saccade Target ◽  
Saccade Amplitude ◽  
Presentation Duration ◽  
Target Presentation ◽  
Adaptation Mechanisms ◽  
Long Duration ◽  
Neuronal Mechanisms ◽  
The Difference ◽  
Saccade Adaptation

Recent studies have shown that saccadic inward adaptation (i.e., the shortening of saccade amplitude) and saccadic outward adaptation (i.e., the lengthening of saccade amplitude) rely on partially different neuronal mechanisms. There is increasing evidence that these differences are based on differences at the target registration or planning stages since outward but not inward adaptation transfers to hand-pointing and perceptual localization of flashed targets. Furthermore, the transfer of reactive saccade adaptation to long-duration overlap and scanning saccades is stronger after saccadic outward adaptation than that after saccadic inward adaptation, suggesting that modulated target registration stages during outward adaptation are increasingly used in the execution of saccades when the saccade target is visually available for a longer time. The difference in target presentation duration between reactive and scanning saccades is also linked to a difference in perceptual localization of different targets. Flashed targets are mislocalized after inward adaptation of reactive and scanning saccades but targets that are presented for a longer time (stationary targets) are mislocalized stronger after scanning than after reactive saccades. This link between perceptual localization and adaptation specificity suggests that mislocalization of stationary bars should be higher after outward than that after inward adaptation of reactive saccades. In the present study we test this prediction. We show that the relative amount of mislocalization of stationary versus flashed bars is higher after outward than that after inward adaptation of reactive saccades. Furthermore, during fixation stationary and flashed bars were mislocalized after outward but not after inward adaptation. Thus, our results give further evidence for different adaptation mechanisms between inward and outward adaptation and harmonize some recent research.

Visual-vestibular interaction during OVAR in the elderly

2002 ◽  
Vol 11 (6) ◽  
pp. 365-370 ◽  
Author(s):  
Joseph M. Furman ◽  
Mark S. Redfern
Keyword(s):  
Eye Movement ◽  
Visual Target ◽  
Vertical Axis ◽  
The Elderly ◽  
Otolith Organs ◽  
Fixation Target ◽  
Visual Vestibular Interaction ◽  
Older Subjects ◽  
Young Subjects ◽  
Axis Rotation

This study assessed visual-otolith interaction in healthy older humans and compared responses from older subjects to those of younger subjects. Using off-vertical axis rotation (OVAR) to stimulate the otolith organs, eye movement responses, measured using electro-oculography, were recorded during rotation in the dark, rotation with an earth-fixed lighted visual surround, and rotation with a subject-fixed fixation target. Results indicated that older subjects, like young subjects, exhibit a modulation component that was as large during rotation with a lighted earth-fixed visual surround as that seen in the dark and a modulation component during rotation with a subject-fixed visual target that was incompletely suppressed. The modulation component was, in general, larger in the older subjects. This study confirms findings from a previous study of visual-otolith interaction in young subjects and suggests that older subjects, like young subjects, have difficulty visually suppressing the modulation component induced by off-vertical axis rotation.

Complexity-Based Analysis of the Relation Between Fractal Visual Stimuli and Fractal Eye Movements

2019 ◽  
Vol 18 (03) ◽  
pp. 1950012 ◽  
Author(s):  
Hedieh Alipour ◽  
Farzad Towhidkhah ◽  
Sajad Jafari ◽  
Avinash Menon ◽  
Hamidreza Namazi
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Fractal Structure ◽  
Visual Target ◽  
Fractal Theory ◽  
Complex Structure ◽  
Vision Science ◽  
Human Eye ◽  
Field Of Vision ◽  
External Stimuli

Human eye movement is a key concept in the field of vision science. It has already been established that human eye movement responds to external stimuli. Hence, investigating the reaction of the human eye movement to various types of external stimuli is important in this field. There have been many researches on human eye movement that were previously done, but this is the first study to show a relation between the complex structure of human eye movement and the complex structure of static visual stimulus. Fractal theory was implemented and we showed that the fractal dynamics of the human eye movement is related to the fractal structure of visual target as stimulus. The outcome of this research provides new platforms to scientists to further investigate on the relation between eye movement and other applied stimuli.

scholarly journals Saccade Adaptation Specific to Visual Context

2009 ◽  
Vol 101 (4) ◽  
pp. 1713-1721 ◽  
Author(s):  
James P. Herman ◽  
Mark R. Harwood ◽  
Josh Wallman
Keyword(s):  
Target Stimulus ◽  
Separate Experiment ◽  
Physical Parameters ◽  
Visual Context ◽  
Saccade Amplitude ◽  
Repair Mechanism ◽  
Adaptive Process ◽  
Differential Adaptation ◽  
Saccade Adaptation ◽  
Visual Properties

When saccades consistently overshoot their targets, saccade amplitudes gradually decrease, thereby maintaining accuracy. This adaptive process has been seen as a form of motor learning that copes with changes in physical parameters of the eye and its muscles, brought about by aging or pathology. One would not expect such a motor-repair mechanism to be specific to the visual properties of the target stimulus. We had subjects make saccades to sudden movements of either of two targets—a steadily illuminated circle or a flickering circle—one of which stepped back during each saccade it elicited, simulating the effect of a hypermetric saccade. Saccade gain (saccade amplitude/target amplitude) decreased by 15% for the target that stepped back versus 6% for the target that did not step back. Most of the change in gain between successive blocks of trials of each type occurred on the first saccade of the block, decreasing by 0.12 on the first trial of a step-back block and increasing by 0.1 on the first trial of a no-step-back block. The differential adaptation of the two targets required postsaccadic feedback of both target types, as shown in a separate experiment, in which saccades to only one target received feedback, and the gain did not differ between the two target types. This demonstration that a context defined by a visual stimulus can serve as an effective cue for switching saccade gain between states suggests that saccade adaptation may have a heretofore unsuspected dimension of adaptability.

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.

scholarly journals Pursuit disorder and saccade dysmetria after caudal fastigial inactivation in the monkey

2018 ◽  
Vol 120 (4) ◽  
pp. 1640-1654 ◽  
Author(s):  
Clara Bourrelly ◽  
Julie Quinet ◽  
Laurent Goffart
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Target ◽  
Fastigial Nucleus ◽  
Gaze Direction ◽  
Moving Target ◽  
Horizontal Meridian ◽  
Pursuit Eye Movements ◽  
Neural Processes ◽  
Slow Eye Movements

The caudal fastigial nuclei (cFN) are the output nuclei by which the medio-posterior cerebellum influences the production of saccadic and pursuit eye movements. We investigated the consequences of unilateral inactivation on the pursuit eye movement made immediately after an interceptive saccade toward a centrifugal target. We describe here the effects when the target moved along the horizontal meridian with a 10 or 20°/s speed. After muscimol injection, the monkeys were unable to track the present location of the moving target. During contralesional tracking, the velocity of postsaccadic pursuit was reduced. This slowing was associated with a hypometria of interceptive saccades such that gaze direction always lagged behind the moving target. No correlation was found between the sizes of saccade undershoot and the decreases in pursuit speed. During ipsilesional tracking, the effects on postsaccadic pursuit were variable across the injection sessions, whereas the interceptive saccades were consistently hypermetric. Here also, the ipsilesional pursuit disorder was not correlated with the saccade hypermetria either. The lack of correlation between the sizes of saccade dysmetria and changes of postsaccadic pursuit speed suggests that cFN activity exerts independent influences on the neural processes generating the saccadic and slow eye movements. It also suggests that the cFN is one locus where the synergy between the two motor categories develops in the context of tracking a moving visual target. We explain how the different fastigial output channels can account for these oculomotor tracking disorders. NEW & NOTEWORTHY Inactivation of the caudal fastigial nucleus impairs the ability to track a moving target. The accuracy of interceptive saccades and the velocity of postsaccadic pursuit movements are both altered, but these changes are not correlated. This absence of correlation is not compatible with an impaired common command feeding the circuits producing saccadic and pursuit eye movements. However, it suggests an involvement of caudal fastigial nuclei in their synergy to accurately track a moving target.

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