Rapid monocular adaptation of saccade amplitude in constant strabismus

2020 ◽  
pp. 45-49
Author(s):  
H.J. Griffiths ◽  
D. Buckley ◽  
J.P. Whittle
Keyword(s):  
Saccade Amplitude

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.

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 084 Separating stroke from vestibular neuritis by vestibular function test parameters

2019 ◽  
Vol 90 (e7) ◽  
pp. A27.1-A27
Author(s):  
Zeljka Calic ◽  
Benjamin Nham ◽  
Rachel Taylor ◽  
Allison Young ◽  
Craig Anderson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Vestibular Function ◽  
Vestibular Neuritis ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Saccade Amplitude ◽  
Vestibular Tests ◽  
Acute Vestibular Syndrome ◽  
Significant Difference ◽  
Catch Up

IntroductionVestibular neuritis (VN) and posterior circulation stroke (PCS) are the commonest causes of acute vestibular syndrome (AVS). We aim to identify discriminators of VN from PCS by testing all five vestibular end-organs in patients presenting with AVS.MethodsThree-dimensional video-head impulse test (v-HIT), cervical and ocular-vestibular evoked myogenic potentials (c-and oVEMP) and subjective visual horizontal (SVH) tests were performed in 22 patients with VN and 22 with PCS. Ipsilesional horizontal, anterior and posterior canal (HC, AC, PC) v-HIT gain and first catch-up saccade characteristics, VEMP amplitude asymmetry-ratios were compared.ResultsAll VN and 6 PCS patients had positive clinical HIT. Mean time to testing was 4.7 days for VN, 7.0 days for PCS. VN mean ipsilesional HC and AC first saccade amplitude was larger, peak-velocities faster and onset latencies earlier compared to PCS (p<0.05). No significant difference between VN and PCS in first saccade characteristics was found in PC. Ipsilesional first saccade amplitude, peak-velocity and duration were significantly different between PCS and controls for all canals (p<0.05). A gain <0.68 and first saccade amplitudes >2.2°separated VN from PCS with sensitivities of 95.5% and 86.4% and specificities of 72.7% and 63.6%. First saccade amplitude of >0.91°identified PCS from controls with sensitivity of 68.2% and specificity of 70%. Abnormality rates for AC cVEMP, BC oVEMP and SVH were 42.9%, 50% and 91% for VN and 38.1%, 9% 72% for PCS.Conclusion v-HIT gain and catch-up saccade metrics are useful separators of VN from PCS. Detailed saccade analysis complements existing vestibular tests.

scholarly journals Immediate saccade amplitude disconjugacy induced by unequal images

1995 ◽  
Vol 35 (23-24) ◽  
pp. 3505-3518 ◽  
Author(s):  
Zoï Kapoula ◽  
Thomas Eggert ◽  
Maria Pia Bucci
Keyword(s):  
Saccade Amplitude

scholarly journals Subtle Oculomotor Difficulties and Their Relation to Motor Skill in Children with Autism Spectrum Disorder

2020 ◽  
Author(s):  
Emma Sumner ◽  
Samuel B. Hutton ◽  
Elisabeth L. Hill
Keyword(s):  
Smooth Pursuit ◽  
Motor Skill ◽  
Visual Information ◽  
Autism Spectrum ◽  
Oculomotor Control ◽  
Future Research ◽  
Saccade Amplitude ◽  
Amplitude Variability ◽  
Children With Asd ◽  
Fixation Stability

Abstract Objectives Sensorimotor difficulties are often reported in autism spectrum disorders (ASD). Visual and motor skills are linked in that the processing of visual information can help in guiding motor movements. The present study investigated oculomotor skill and its relation to general motor skill in ASD by providing a comprehensive assessment of oculomotor control. Methods Fifty children (25 ASD; 25 typically developing [TD]), aged 7–10 years, completed a motor assessment (comprising fine and gross motor tasks) and oculomotor battery (comprising fixation, smooth pursuit, prosaccade and antisaccade tasks). Results No group differences were found for antisaccade errors, nor saccade latencies in prosaccade and antisaccade tasks, but increased saccade amplitude variability was observed in children with ASD, suggesting a reduced consistency in saccade accuracy. Children with ASD also demonstrated poorer fixation stability than their peers and spent less time in pursuit of a moving target. Motor skill was not correlated with saccade amplitude variability. However, regression analyses revealed that motor skill (and not diagnosis) accounted for variance in fixation performance and fast smooth pursuit. Conclusions The findings highlight the importance of considering oculomotor paradigms to inform the functional impact of neuropathologies in ASD and also assessing the presentation of co-occurring difficulties to further our understanding of ASD. Avenues for future research are suggested.

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 Influence of soundtrack on eye movements during video exploration

2012 ◽  
Vol 5 (4) ◽  
Author(s):  
Antoine Coutrot ◽  
Nathalie Guyader ◽  
Gelu Ionescu ◽  
Alice Caplier
Keyword(s):  
Eye Movements ◽  
Visual Attention ◽  
Fixation Duration ◽  
Visual Features ◽  
Eye Position ◽  
Saccade Amplitude ◽  
The Gaze ◽  
Spatial Sound ◽  
Complex Scenes ◽  
The Impact

Models of visual attention rely on visual features such as orientation, intensity or motion to predict which regions of complex scenes attract the gaze of observers. So far, sound has never been considered as a possible feature that might influence eye movements. Here, we evaluate the impact of non-spatial sound on the eye movements of observers watching videos. We recorded eye movements of 40 participants watching assorted videos with and without their related soundtracks. We found that sound impacts on eye position, fixation duration and saccade amplitude. The effect of sound is not constant across time but becomes significant around one second after the beginning of video shots.

scholarly journals Variations in Naturalistic Driving Behavior and Visual Perception at the Entrances of Short, Medium, and Long Tunnels

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xinsha Fu ◽  
Shijian He ◽  
Jintao Du ◽  
Xiaofei Wang ◽  
Ting Ge
Keyword(s):  
Visual Perception ◽  
Traffic Accident ◽  
Driving Behavior ◽  
Accident Risk ◽  
Saccade Amplitude ◽  
Driver Performance ◽  
General Variation ◽  
Naturalistic Driving ◽  
Short Tunnel ◽  
Correlation Factors

Driver behavior and visual perception are very important factors in the management of traffic accident risk at tunnel entrances. This study was undertaken to analyze the differences in driving behavior and visual perception at the entrances of three types of tunnels, namely, short, medium-length, and long tunnels, under naturalistic driving conditions. Using three driving behavior indicators (speed, deceleration, and position) and two visual perception indicators (fixation and saccade), the driving performance of twenty drivers at six tunnels (two tunnels per condition) was comparatively analyzed. The results revealed that the speed maintained by the drivers prior to deceleration with braking under the short-tunnel condition was significantly larger than that under the medium- and long-tunnel conditions and that the drivers had a greater average and maximum deceleration rates under the short-tunnel condition. A similar general variation of driver visual perception appeared under the respective tunnel conditions, with the number of fixations gradually increasing and the maximum saccade amplitude gradually decreasing as the drivers approached the tunnel portal. However, the variation occurred approximately 60 m earlier under the short-tunnel condition than under the medium- and long-tunnel conditions. Interactive correlations between driving behavior and visual perception under the three conditions were established. The commencement of active deceleration was significantly associated (with correlation factors of 0.80, 0.77, and 0.79 under short-, medium-, and long-tunnel conditions, respectively) with the point at which the driver saccade amplitude fell below 10 degrees for more than 3 s. The results of this study add to the sum of knowledge of differential driver performance at the entrances of tunnels of different lengths.

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