scholarly journals The reference frames in saccade adaptation

2013 ◽  
Vol 109 (7) ◽  
pp. 1815-1823 ◽  
Author(s):  
Eckart Zimmermann
Keyword(s):  
Reference Frames ◽  
Visual Target ◽  
Saccade Target ◽  
Presentation Duration ◽  
Coordinate Frames ◽  
Intended Target ◽  
Target Signal ◽  
External Space ◽  
Saccade Adaptation ◽  
Voluntary Saccades

Saccade adaptation is a mechanism that adjusts saccade landing positions if they systematically fail to reach their intended target. In the laboratory, saccades can be shortened or lengthened if the saccade target is displaced during execution of the saccade. In this study, saccades were performed from different positions to an adapted saccade target to dissociate adaptation to a spatiotopic position in external space from a combined retinotopic and spatiotopic coding. The presentation duration of the saccade target before saccade execution was systematically varied, during adaptation and during test trials, with a delayed saccade paradigm. Spatiotopic shifts in landing positions depended on a certain preview duration of the target before saccade execution. When saccades were performed immediately to a suddenly appearing target, no spatiotopic adaptation was observed. These results suggest that a spatiotopic representation of the visual target signal builds up as a function of the duration the saccade target is visible before saccade execution. Different coordinate frames might also explain the separate adaptability of reactive and voluntary saccades. Spatiotopic effects were found only in outward adaptation but not in inward adaptation, which is consistent with the idea that outward adaptation takes place at the level of the visual target representation, whereas inward adaptation is achieved at a purely motor level.

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.

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 Signals driving the adaptation of saccades that require spatial updating

2018 ◽  
Vol 120 (2) ◽  
pp. 525-538
Author(s):  
Robijanto Soetedjo
Keyword(s):  
Visual Target ◽  
Real Life ◽  
Spatial Updating ◽  
Adaptation Process ◽  
Visually Guided ◽  
Double Step ◽  
Target Signal ◽  
Motor Error ◽  
Saccade Adaptation

Saccades adapt to persistent natural or artificially imposed dysmetrias. The characteristics and circuitry of saccade adaptation have been revealed using a visually guided task (VGT) where the vectors of the target step and the intended saccade command are the same. However, in real life, another saccade occasionally intervenes before the saccade to the target occurs. This necessitates an updating of the intended saccade to account for the intervening saccadic displacement, which dissociates the visual target signal and the intended saccade command. We determined whether the adaptation process is similar for VGT and updated saccades by studying the transfer of adaptation between them. The ultimate visual target was dissociated from the intended saccade command with double-step saccade tasks (DSTs) in which two targets are flashed sequentially at different locations while the monkey maintains fixation. The resulting saccades toward the first and second targets occur in the dark. The transfer of visually guided saccade adaptation to the second saccades of a DST and vice versa depended on the eccentricity of the second visual target, and not the second saccade command. If a target with the same eccentricity as the adapted target appears briefly during the intersaccadic interval of a DST, more adaptation transfers. Because a brief appearance of the visual target either before the first saccade or during the intersaccadic interval influences how much adaptation transfer the second saccade will express, the processing of adaptation and DST updating may overlap. NEW & NOTEWORTHY Adaptation and the spatial updating of saccades are thought to be independent processes. When we dissociate the visual target and the intended saccade command, the transfer of visually guided saccade adaptation to the saccades of the double-step saccade tasks (DST) and vice versa is driven by a visual not motor error. The visual target has an effect until the second saccade of a DST occurs. Therefore, the processing of adaptation and the spatial updating of saccades may overlap.

Competition Between Saccade Goals in the Superior Colliculus Produces Saccade Curvature

2003 ◽  
Vol 89 (5) ◽  
pp. 2577-2590 ◽  
Author(s):  
Robert M. McPeek ◽  
Jae H. Han ◽  
Edward L. Keller
Keyword(s):  
Superior Colliculus ◽  
Search Task ◽  
Visual Target ◽  
Temporal Structure ◽  
Saccade Target ◽  
Stimulation Site ◽  
Electrical Microstimulation ◽  
Saccade Onset ◽  
Significant Difference ◽  
Increased Activity

When saccadic eye movements are made in a search task that requires selecting a target from distractors, the movements show greater curvature in their trajectories than similar saccades made to single stimuli. To test the hypothesis that this increase in curvature arises from competitive interactions between saccade goals occurring near the time of movement onset, we performed single-unit recording and microstimulation experiments in the superior colliculus (SC). We found that saccades that ended near the target but curved toward a distractor were accompanied by increased presaccadic activity of SC neurons coding the distractor site. This increased activity occurred ∼30 ms before saccade onset and was abruptly quenched on saccade initiation. The magnitude of increased activity at the distractor site was correlated with the amount of curvature toward the distractor. In contrast, neurons coding the target location did not show any significant difference in discharge for curved versus straight saccades. To determine whether this pattern of SC discharge is causally related to saccade curvature, we performed a second series of experiments using electrical microstimulation. Monkeys made saccades to single visual stimuli presented without distractors, and we stimulated sites in the SC that would have corresponded to distractor sites in the search task. The stimulation was subthreshold for evoking saccades, but when its temporal structure mimicked the activity recorded for curved saccades in search, the subsequent saccades to the visual target showed curvature toward the location coded by the stimulation site. The effect was larger for higher stimulation frequencies and when the stimulation site was in the same colliculus as the representation of the visual target. These results support the hypothesis that the increased saccade curvature observed in search arises from rivalry between target and distractor goals and are consistent with the idea that the SC is involved in the competitive neural interactions underlying saccade target selection.

Microstimulation of the Lateral Wall of the Intraparietal Sulcus Compared With the Frontal Eye Field During Oculomotor Tasks

1999 ◽  
Vol 81 (3) ◽  
pp. 1443-1448 ◽  
Author(s):  
Hajime Mushiake ◽  
Naotaka Fujii ◽  
Jun Tanji
Keyword(s):  
Dynamic Process ◽  
Lateral Wall ◽  
Reference Points ◽  
Saccade Target ◽  
Frontal Eye Field ◽  
Intracortical Microstimulation ◽  
Intraparietal Sulcus ◽  
Voluntary Saccade ◽  
Eye Field ◽  
Voluntary Saccades

Microstimulation of the lateral wall of the intraparietal sulcus compared with the frontal eye field during oculomotor tasks. We compared the effects of intracortical microstimulation (ICMS) of the lateral wall of the intraparietal sulcus (LIP) with those of ICMS of the frontal eye field (FEF) on monkeys performing oculomotor tasks. When ICMS was applied during a task that involved fixation, contraversive saccades evoked in the LIP and FEF appeared similar. When ICMS was applied to the FEF at the onset of voluntary saccades, the evoked saccades collided with the ongoing voluntary saccade so that the trajectory of voluntary saccade was compensated by the stimulus. Thus the resultant saccade was redirected and came close to the endpoint of saccades evoked from the fixation point before the start of voluntary saccade. In contrast, when ICMS was applied to the LIP at the onset of voluntary saccades, the resultant saccade followed a trajectory that was different from that evoked from the FEF. In that case, the colliding saccades were redirected toward an endpoint that was close to the endpoint of saccades evoked when animals were already fixating at the target of the voluntary saccade. This finding suggests that the colliding saccade was directed toward an endpoint calculated with reference to the target of the voluntary saccade. We hypothesize that, shortly before initiation of voluntary saccades, a dynamic process occurs in the LIP so that the reference point for calculating the saccade target shifts from the fixation point to the target of a voluntary saccade. Such predictive updating of reference points seems useful for immediate reprogramming of upcoming saccades that can occur in rapid succession.

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 Reference Systems and Frames as Proposed by the Working Group on Reference Systems

1992 ◽  
Vol 9 ◽  
pp. 121-124
Author(s):  
J. Kovalevsky
Keyword(s):  
Working Group ◽  
Reference Frames ◽  
Reference Systems ◽  
Coordinate Frames ◽  
Virginia Beach

Among the nine recommendations of the Working Group on Reference Frames as finalized during the Virginia Beach meeting, four are directly addressing the reference systems. They are the result of the work of the subgroup on coordinate frames and origins and other contributors whose names are given in section 6. The resulting document (Kovalevsky, 1991) was further revised by the working group as a whole and recommendations published (1991).

scholarly journals Saccadic adaptation in the presence of artificial central scotomas

2019 ◽  
Author(s):  
Youngmin Song ◽  
Lydia Ouchene ◽  
Aarlenne Z. Khan
Keyword(s):  
Macular Degeneration ◽  
Visual Function ◽  
Age Related Macular Degeneration ◽  
Saccade Target ◽  
Central Vision ◽  
Double Step ◽  
Saccadic Adaptation ◽  
Age Related ◽  
Short Period ◽  
Saccade Adaptation

AbstractSaccadic adaptation can occur over a short period of time through a constant adjustment of the saccade target during the saccade, resulting in saccadic re-referencing which directs the saccade to a location different from the target that elicited the saccade. Saccade re-referencing could be used to help patients with age-related macular degeneration (AMD) to optimally use their residual visual function. However, it remains unknown whether saccade adaptation can take place in the presence of central scotomas (i.e., without central vision).We tested participants in two experiments in a conventional double-step paradigm with a central gaze-contingent artificial scotoma. Experiment 1 (N = 12) comprised a backward adaptation paradigm with a visible and an invisible 3° diameter scotomas. Experiment 2 (N = 13) comprised a forward adaptation paradigm with invisible 2° and 4° diameter scotomas.In Experiment 1, we observed significant adaptation in both the visible and invisible scotoma conditions comparable to the control condition with no scotoma. This was the case even when the saccade landed such that the target was occluded by the scotoma. We observed that adaptation occurred based on peripheral viewing of the stepped target during the deceleration period.In Experiment 2, we found that both scotoma conditions showed adaptation again comparable to the control condition with no scotoma. We conclude that saccadic adaptation can occur with central scotomas, showing that it does not require central vision and is driven primarily by peripheral retinal error.

scholarly journals Impairment of saccade adaptation in a patient with a focal thalamic lesion

2015 ◽  
Vol 113 (7) ◽  
pp. 2351-2359 ◽  
Author(s):  
E. Zimmermann ◽  
F. Ostendorf ◽  
C. J. Ploner ◽  
M. Lappe
Keyword(s):  
Oculomotor System ◽  
Saccade Target ◽  
Control Group ◽  
Thalamic Lesion ◽  
Landing Position ◽  
Saccade Adaptation ◽  
Feedback Pathway ◽  
Strong Adaptation ◽  
Contralesional Side ◽  
Ventrolateral Thalamic Nucleus

The frequent jumps of the eyeballs—called saccades—imply the need for a constant correction of motor errors. If systematic errors are detected in saccade landing, the saccade amplitude adapts to compensate for the error. In the laboratory, saccade adaptation can be studied by displacing the saccade target. Functional selectivity of adaptation for different saccade types suggests that adaptation occurs at multiple sites in the oculomotor system. Saccade motor learning might be the result of a comparison between a prediction of the saccade landing position and its actual postsaccadic location. To investigate whether a thalamic feedback pathway might carry such a prediction signal, we studied a patient with a lesion in the posterior ventrolateral thalamic nucleus. Saccade adaptation was tested for reactive saccades, which are performed to suddenly appearing targets, and for scanning saccades, which are performed to stationary targets. For reactive saccades, we found a clear impairment in adaptation retention ipsilateral to the lesioned side and a larger-than-normal adaptation on the contralesional side. For scanning saccades, adaptation was intact on both sides and not different from the control group. Our results provide the first lesion evidence that adaptation of reactive and scanning saccades relies on distinct feedback pathways from cerebellum to cortex. They further demonstrate that saccade adaptation in humans is not restricted to the cerebellum but also involves cortical areas. The paradoxically strong adaptation for outward target steps can be explained by stronger reliance on visual targeting errors when prediction error signaling is impaired.

Distinct Short-Term and Long-Term Adaptation to Reduce Saccade Size in Monkey

2006 ◽  
Vol 96 (3) ◽  
pp. 1030-1041 ◽  
Author(s):  
Farrel R. Robinson ◽  
Robijanto Soetedjo ◽  
Christopher Noto
Keyword(s):  
Saccade Target ◽  
Short Term ◽  
Target Movement ◽  
Adaptation Mechanism ◽  
Starting Position ◽  
Saccade Size ◽  
Short And Long Term ◽  
Saccade Adaptation ◽  
Term Maintenance

In monkeys, saccades that repeatedly overshoot their targets adapt to become smaller by the time the monkey has made 1,000–2,000 saccades. In life, adaptation must keep movements accurate for long periods of time. Previous work describes only saccade adaptation that occurs within a few hours. Here we describe long-term saccade adaptation elicited in three monkeys by 19 days of training. Each day a monkey made saccades to track 16° leftward and rightward target movements. During saccades, the target stepped back toward its starting position 6.4° (40%) in two monkeys or 8° (50%) in the third. After each day's adaptation, we blindfolded the monkey with goggles and returned it to its cage overnight. We found that adapting saccades for 19 days elicited significantly larger, long-lasting reduction in saccade size than did adapting for only 1 day. Further, after 19 days of adaptation we could elicit additional, apparently normal, short-term reduction in saccade size by increasing the size of the intra-saccade target movement. In contrast, we could elicit only small additional size reduction after only 1 day of adaptation. A simple model using separate short- and long-term adaptation mechanisms can reproduce many of the features of saccade gain exhibited by monkeys during a 19-day adaptation. We conclude that there is a long-term saccade-adaptation mechanism that is distinct from the well-characterized short-term system and that this newly recognized system is responsible for long-term maintenance of saccade accuracy.

Sign in / Sign up

Export Citation Format

Share Document