scholarly journals Gap effect and express saccades generation in amblyopia

2019 ◽  
Vol 19 (4) ◽  
pp. 17 ◽  
Author(s):  
Maciej Perdziak ◽  
Wojciech Gryncewicz ◽  
Dagmara Witkowska ◽  
Piotr Sawosz ◽  
Jan Ober
Keyword(s):  
Gap Effect ◽  
Express Saccades

Properties of visually-guided saccadic behavior and bottom-up attention in marmoset, macaque, and human

2020 ◽  
Author(s):  
Chih-Yang Chen ◽  
Denis Matrov ◽  
Richard Edmund Veale ◽  
Hirotaka Onoe ◽  
Masatoshi Yoshida ◽  
...  
Keyword(s):  
New World ◽  
World Monkey ◽  
Gap Effect ◽  
Visually Guided ◽  
Express Saccades ◽  
Bottom Up ◽  
Cortical Areas ◽  
Saliency Model ◽  
Free Viewing ◽  
The Brain

Saccades are stereotypic behaviors whose investigation improves our understanding of how primate brains implement precise motor control. Furthermore, saccades offer an important window into the cognitive and attentional state of the brain. Historically, saccade studies have largely relied on macaque. However, the cortical network giving rise to the saccadic command is difficult to study in macaque because relevant cortical areas lie in deep sulci and are difficult to access. Recently, a New World monkey -the marmoset- has garnered attention as an alternative to macaque because of advantages including its smooth cortical surface. However, adoption of marmoset for oculomotor research has been limited due to a lack of in-depth descriptions of marmoset saccade kinematics and their ability to perform psychophysical tasks. Here, we directly compare free-viewing and visually-guided behavior of marmoset, macaque, and human engaged in identical tasks under similar conditions. In video free-viewing task, all species exhibited qualitatively similar saccade kinematics up to 25º in amplitude although with different parameters. Furthermore, the conventional bottom-up saliency model predicted gaze targets at similar rates for all species. We further verified their visually-guided behavior by training them with step and gap saccade tasks. In the step paradigm, marmoset did not show shorter saccade reaction time for upward saccades whereas macaque and human did. In the gap paradigm, all species showed similar gap effect and express saccades. Our results suggest that the marmoset can serve as a model for oculomotor, attentional, and cognitive research while being aware of their difference from macaque or human.

scholarly journals The role of the superior colliculus in saccade initiation: a study of express saccades and the gap effect

2000 ◽  
Vol 40 (20) ◽  
pp. 2763-2777 ◽  
Author(s):  
David Sparks ◽  
W.H. Rohrer ◽  
Yihong Zhang
Keyword(s):  
Superior Colliculus ◽  
Gap Effect ◽  
Express Saccades

The underrated role of the “move system” in determining saccade latency

1999 ◽  
Vol 22 (4) ◽  
pp. 681-682 ◽  
Author(s):  
Michael C. Dorris ◽  
Douglas P. Munoz
Keyword(s):  
Superior Colliculus ◽  
Target Location ◽  
Saccade Latency ◽  
Gap Effect ◽  
Target Specificity ◽  
Express Saccades ◽  
Latency Reduction ◽  
Extensive Training ◽  
Target Article

The Findlay & Walker target article emphasizes the role of the target-nonspecific “fixate” system while downplaying the role of the target-specific “move” system in determining saccade latency. We agree that disengagement of the fixate system is responsible for the target-nonspecific latency reduction associated with the gap effect. However, high target predictability and extensive training at a target location can also result in latency reductions, the culmination of this being express saccades. The target-specificity associated with the latter forms of latency reduction implicate a mechanism involving the move system. Recently discovered neurophysiological correlates underlying these behavioural phenomena reside in the superior colliculus.

The gap effect and express saccades in the auditory modality

1998 ◽  
Vol 118 (2) ◽  
pp. 221-229 ◽  
Author(s):  
R. Shafiq ◽  
Geoffrey W. Stuart ◽  
Jennifer Sandbach ◽  
Paul Maruff ◽  
Jon Currie
Keyword(s):  
Gap Effect ◽  
Auditory Modality ◽  
Express Saccades

scholarly journals Control of Reflexive Saccades following Hemispherectomy

2011 ◽  
Vol 23 (6) ◽  
pp. 1368-1378 ◽  
Author(s):  
Patricia A. Reuter-Lorenz ◽  
Troy M. Herter ◽  
Daniel Guitton
Keyword(s):  
Superior Colliculus ◽  
Inhibitory Control ◽  
Intractable Epilepsy ◽  
Short Latency ◽  
Gap Effect ◽  
Express Saccades ◽  
Antisaccade Task ◽  
Intact Side ◽  
Reflexive Saccades ◽  
Saccade Generation

Individuals who have undergone hemispherectomy for treatment of intractable epilepsy offer a rare and valuable opportunity to examine the ability of a single cortical hemisphere to control oculomotor performance. We used peripheral auditory events to trigger saccades, thereby circumventing dense postsurgical hemianopia. In an antisaccade task, patients generated numerous unintended short-latency saccades toward contralesional auditory events, indicating pronounced limitations in the ability of a single hemicortex to exert normal inhibitory control over ipsilateral (i.e., contralesional) reflexive saccade generation. Despite reflexive errors, patients retained an ability to generate correct antisaccades in both directions. The prosaccade task revealed numerous contralesional express saccades, a robust contralesional gap effect, but the absence of both effects for ipsilesional saccades. These results indicate limits to the saccadic control capabilities following hemispherectomy: A single hemicortex can mediate antisaccades in both directions, but plasticity does not extend fully to the bilateral inhibition of reflexive saccades. We posit that these effects are due to altered control dynamics that reduce the responsivity of the superior colliculus on the intact side and facilitate the release of an auditory-evoked ocular grasp reflex into the blind hemifield that the intact hemicortex has difficulty suppressing.

Saccadic reaction time in the monkey: advanced preparation of oculomotor programs is primarily responsible for express saccade occurrence

1996 ◽  
Vol 76 (6) ◽  
pp. 3666-3681 ◽  
Author(s):  
M. Pare ◽  
D. P. Munoz
Keyword(s):  
Target Location ◽  
Spatial Location ◽  
Saccade Latency ◽  
Visual Fixation ◽  
Gap Effect ◽  
Saccade Target ◽  
Fixation Target ◽  
Express Saccades ◽  
Express Saccade ◽  
Saccade Direction

1. The introduction of a period of darkness between the disappearance of an initial fixation target and the appearance of a peripheral saccade target produces a general reduction in saccadic reaction time (SRT)-known as the gap effect- and often very short latency express saccades. To account for these phenomena, premotor processes may be facilitated by release of visual fixation and advanced preparation of saccadic programs. The experiments described in this paper were designed to test the relevance of the ocular fixation disengagement and oculomotor preparation hypotheses by identifying the influence of different factors on SRTs and the occurrence of express saccades in the monkey. 2. The SRTs of two monkeys were measured in two behavioral paradigms. A peripheral saccade target appeared at the time of disappearance of a central fixation target in the no-gap task, whereas a 200-ms period of no stimuli was interposed between the fixation target disappearance and the saccade target appearance in the gap task. The distribution of SRTs in these tasks was generally bimodal; the first and second mode was composed of express and regular saccades, respectively. We measured the mean SRT, mean regular saccade latency, mean express saccade latency, and percentage of express saccades in both tasks. We also estimated the gap effect, i.e., the difference between the SRTs in no-gap trial and the SRTs in gap trials. 3. Once the animals were trained to make saccades to a single target location and produce express saccades, SRTs in both no-gap and gap trials displayed a broad tuning with respect to the spatial location of the trained target when the target location was varied randomly in a block of trials. Express saccades were made only to a restricted region of the visual field surrounding the trained target location. A gap effect was present for nearly all target locations tested, irrespective of express saccade occurrence. Finally, the probability of generating an express saccade at the trained target location decreased with the introduction of uncertainty about target location. 4. The occurrence of express saccades increased with the duration of the visual and nonvisual (gap) fixation that the animal was required to maintain before the onset of a saccade target. The gap duration was effective in reducing the mean SRT for gaps < or = 300 ms, and it was more influential than comparable variation in the visual fixation duration. 5. The occurrence of express saccades made to targets of identical eccentricity increased when the initial eye fixation position was shifted eccentric in a direction opposite to the saccade direction. Concomitantly, mean SRT decreased by approximately 2 ms for each 1-deg change in initial eye fixation position. 6. The occurrence of express saccades depended upon contextual factors, i.e., on both the behavioral task (no-gap or gap) and the latency of the saccade that the monkey executed to the same target in the preceding trial. The highest percentage of express saccades was observed after an express saccade in a no-gap trial, whereas the lowest percentage was obtained after a regular saccade in a gap trial. 7. These findings indicate that training-dependent express saccades are restricted to a specific spatial location dictated by the training target, and their incidence is facilitated by high predictability of target presentation, long-duration foreperiod, absence of visual fixation, eccentric initial eye position opposite to the saccade direction, and express saccade occurrence in the previous trial. The release of fixation afforded by the gap accounts for the general gap effect, but has only a modulatory influence on express saccade generation. We conclude that advanced motor preparation of saccadic programs generally reduces SRT and is primarily responsible for the occurrence of express saccades, which therefore may be caused mainly by neuronal changes restricted to a specific locus-coding for the trained movemen

Reflexive or Not? Examining Attentional Orienting and the Gap Effect

2008 ◽  
Author(s):  
Kaitlin Laidlaw ◽  
Sara Stevens ◽  
Jim McAuliffe ◽  
Jay Pratt
Keyword(s):  
Gap Effect ◽  
Attentional Orienting

The Gap Effect for Eye and Hand Movements

1994 ◽  
Author(s):  
Jay Pratt ◽  
Heather Oonk ◽  
Harold Bekkering ◽  
Richard A. Abrams ◽  
Mark B. Law
Keyword(s):  
Gap Effect ◽  
Hand Movements
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