scholarly journals Saccadic inhibition in a guided saccade task

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4493 ◽  
Author(s):  
Isabel Dombrowe
Keyword(s):  
Eye Movement ◽  
Main Sequence ◽  
Dead Time ◽  
Time Window ◽  
Peak Velocity ◽  
Velocity Profiles ◽  
Planning Phase ◽  
Saccade Task ◽  
Saccadic Inhibition ◽  
Movement System

The eye movement system reacts very systematically to visual transients that are presented during the planning phase of a saccade. About 50 to 70 ms after the onset of a transient, the number of saccades that are started decreases, a phenomenon that has been termed saccadic inhibition. Saccades started just before this time window are hypometric compared to regular saccades, presumably because the presentation of the transient stops them in mid-flight. Recent research investigating the properties of repeated saccades to fixed locations found that these early saccades were additionally faster than expected from the main sequence relation, suggesting that a saccadic dead time during which saccades can no longer be modified does not exist. The present study investigated the properties of saccades to random locations in a guided saccade task. As expected, early saccades starting just before the saccadic inhibition dip in frequency were hypometric. Their velocity profiles implied that these saccades were actively stopped after reaching peak velocity. However, the peak velocities of these saccades did not generally deviate from the main sequence relation. The question whether an active stop of early saccades is incompatible with the idea of a saccadic dead time is open to debate.

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.

Saccade–Vergence Interactions in Macaques. I. Test of the Omnipause Multiply Model

2005 ◽  
Vol 94 (4) ◽  
pp. 2295-2311 ◽  
Author(s):  
C. Busettini ◽  
L. E. Mays
Keyword(s):  
Eye Movements ◽  
Main Sequence ◽  
Peak Velocity ◽  
Alternative Models ◽  
Omnipause Neurons ◽  
Velocity Enhancement

Horizontal vergence eye movements are movements in opposite directions used to change fixation between far and near targets. The occurrence of a saccade during vergence causes vergence velocity to be transiently enhanced. The goal of this study was to test in the monkey the previously described Multiply Model (Zee et al. 1992) that holds that, in humans, the speeding of vergence during a saccade may be the result of the disinhibition of a subgroup of vergence-related neurons by the saccadic omnipause neurons (OPNs). In agreement with the Multiply Model: 1) the onset of the enhancement was closely related to saccadic onset, and thus linked to the onset of the OPN pause; 2) the magnitude of the vergence velocity enhancement was strongly dependent on saccade–vergence timing. Contrary to the Multiply Model: 1) the peak of the vergence velocity enhancement was dependent on saccadic peak velocity; 2) the dependency on saccadic peak velocity was not the indirect result of a dependency on saccadic duration and therefore on the duration of the OPN pause; 3) the decline of the vergence enhancement, identified by the time of the peak of the enhancement velocity, occurred too early to be linked to the end of the OPN pause; 4) vergence enhancement had a saccadic-like peak-velocity/size main sequence. Overall, the evidence is incompatible with the OPN Multiply hypothesis of vergence enhancement. Alternative models are described in an accompanying paper.

Smooth pursuit eye movement system using artificial retina chip and shape memory alloy actuator

2005 ◽  
Vol 5 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Won-Cheol Kim ◽  
Jung-Hwan Kim ◽  
Minho Lee ◽  
Jang-Kyoo Shin ◽  
Hyun-Seung Yang ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Artificial Retina ◽  
Shape Memory Alloy Actuator ◽  
Smooth Pursuit Eye Movement ◽  
Retina Chip ◽  
Movement System

A Combined CFD/MRV Study of Flow Through a Pin Bank

2014 ◽  
Author(s):  
Mike Siekman ◽  
David Helmer ◽  
Wontae Hwang ◽  
Gregory Laskowski ◽  
Ek Tsoon Tan ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Velocity Field ◽  
Turbulence Model ◽  
Field Data ◽  
Peak Velocity ◽  
Velocity Profiles ◽  
Mean Velocity ◽  
Magnetic Resonance Velocimetry ◽  
Sst Turbulence Model ◽  
Flow Through

RANS and time averaged URANS simulations of a pin bank are compared quantitatively and qualitatively to full 3D mean velocity field data obtained using magnetic resonance velocimetry (MRV). The ability of the CFD to match MRV velocity profiles through the pin bank is evaluated using the SST turbulence model. Quantitative comparisons of the velocity profiles showed an overprediction of peak velocity by the CFD at the first pin rows, and a smaller oscillatory error that diminishes as it moves through the pins, resulting in better matching towards the exit.

scholarly journals Remembering a Location Makes the Eyes Curve Away

2005 ◽  
Vol 16 (3) ◽  
pp. 196-199 ◽  
Author(s):  
Jan Theeuwes ◽  
Christian N.L. Olivers ◽  
Christopher L. Chizk
Keyword(s):  
Working Memory ◽  
Eye Movement ◽  
Cognitive Processes ◽  
Direct Evidence ◽  
Spatial Working Memory ◽  
Saccadic Eye Movements ◽  
Limited Information ◽  
On Line ◽  
Movement System ◽  
Everyday Life Activities

Working memory is a system that keeps limited information on-line for immediate access by cognitive processes. This type of active maintenance is important for everyday life activities. The present study shows that maintaining a location in spatial working memory affects the trajectories of saccadic eye movements toward visual targets, as the eyes deviate away from the remembered location. This finding provides direct evidence for a strong overlap between spatial working memory and the eye movement system. We argue that curvature is the result of the need to inhibit memory-based eye movement activity in the superior colliculus, in order to allow an accurate saccade to the visual target. Whereas previous research has shown that the eyes may deviate away from visually presented stimuli that need to be ignored, we show that the eyes also curve away from remembered stimuli.

scholarly journals A Dual-Mode Dynamic Model of the Vergence Eye Movement System

1986 ◽  
Vol BME-33 (11) ◽  
pp. 1021-1028 ◽  
Author(s):  
George K. Hung ◽  
John L. Semmlow ◽  
Kenneth J. Ciufferda
Keyword(s):  
Dynamic Model ◽  
Eye Movement ◽  
Dual Mode ◽  
Movement System ◽  
Vergence Eye Movement

Visual Fatigue and Saccadic Eye Movement Parameters

1983 ◽  
Vol 27 (8) ◽  
pp. 728-732 ◽  
Author(s):  
Ted Megaw ◽  
Tayyar Sen
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Peak Velocity ◽  
Cognitive Task ◽  
Saccadic Eye Movements ◽  
Tracking Task ◽  
Frequency Of Occurrence ◽  
Saccadic Eye Movement ◽  
Visual Fatigue ◽  
Movement Parameters

It has been suggested by Bahill and Stark (1975) that visual fatigue can be identified by changes in some of the saccadic eye movement parameters. These include increases in the frequency of occurrence of glissades and overlapping saccades and reductions in the peak velocity and duration of saccades. In their study, fatigue was induced by the same step tracking task that was used to evaluate the changes in saccadic parameters. However, there is evidence that subjects experience extreme feelings of fatigue while performing such a task and that somehow the task is unnatural. The present study was designed to assess whether there are any differences in the various saccadic parameters obtained while subjects perform a step tracking task and a cognitive task involving the comparison of number strings. Both tasks were presented on a VDU screen. The second objective was to establish whether there are any changes in the parameters for either task as a result of prolonged performance. The results showed no major differences in the saccadic eye movements between the two tasks and no consistent changes resulting from prolonged performance.

scholarly journals Detecting Mind-Wandering from Eye Movement and Oculomotor Data during Learning Video Lecture

2020 ◽  
Vol 10 (3) ◽  
pp. 51
Author(s):  
DongMin Jang ◽  
IlHo Yang ◽  
SeoungUn Kim
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Fixation Duration ◽  
Peak Velocity ◽  
Eye Gaze ◽  
Sampling Rate ◽  
Maximum Amplitude ◽  
Mind Wandering ◽  
Video Lecture ◽  
Video Lectures

The purpose of this study was to detect mind-wandering experienced by pre-service teachers during a video learning lecture on physics. The lecture was videotaped and consisted of a live lecture in a classroom. The lecture was about Gauss's law on physics. We investigated whether oculomotor data and eye movements could be used as a marker to indicate the learner’s mind-wandering. Each data was collected in a study in which 24 pre-service teachers (16 females and 8 males) reported mind-wandering experience through self-caught method while learning physics video lecture during 30 minutes. A Tobii Pro Spectrum (sampling rate: 300 Hz) was used to capture their eye-gaze during learning Gauss's law through a course video. After watching the video lecture, we interviewed pre-service teachers about their mind-wandering experience. We first used the self-caught method to capture the mind-wandering timing of pre-service teachers while learning from video lectures. We detected more accurate mind-wandering segments by comparing fixation duration and saccade count. We investigated two types of oculomotor data (blink count, pupil size) and nine eye movements (average peak velocity of saccades; maximum peak velocity of saccades; standard deviation of peak velocity of saccades; average amplitude of saccades; maximum amplitude of saccades; total amplitude of saccades; saccade count/s; fixation duration; fixation dispersion). The result was that the blink count could not be used as a marker for mind-wandering during learning video lectures among them (oculomotor data and eye movements), unlike previous literatures. Based on the results of this study, we identified elements that can be used as mind-wandering markers while learning from video lectures that are similar to real classes, among the oculomotor data and eye movement mentioned in previous literatures. Additionally, we found that most participants focused on past thoughts and felt unpleasant after experiencing mind-wandering through interview analysis.

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