scholarly journals An inverse-linear logistic model of the main sequence

2017 ◽  
Vol 10 (3) ◽  
Author(s):  
Andrew Duchowski ◽  
Krzysztof Krejtz ◽  
Cezary Biele ◽  
Anna Niedzielska ◽  
Peter Kiefer ◽  
...  
Keyword(s):  
Eye Movements ◽  
Linear Relation ◽  
Large Amplitude ◽  
Logistic Model ◽  
Main Sequence ◽  
Peak Velocity ◽  
Logistic Function ◽  
Velocity Amplitude ◽  
S Curve ◽  
Linear Logistic Model

A model of the main sequence is proposed based on the logistic function. The model’s fit to the peak velocity-amplitude relation resembles an S curve, simulta- neously allowing control of the curve’s asymptotes at very small and very large amplitudes, as well as its slope over the mid amplitude range. The proposed inverse-linear logistic model is also able to express the linear relation of duration and amplitude. We demonstrate the utility and robustness of the model when fit to aggregate data at the small- and mid-amplitude ranges, namely when fitting microsaccades, saccades, and superposition of both. We are confident the model will suitably extend to the large-amplitude range of eye movements.

scholarly journals Alteration of the microsaccadic velocity-amplitude main sequence relationship after visual transients: implications for models of saccade control

2017 ◽  
Vol 117 (5) ◽  
pp. 1894-1910 ◽  
Author(s):  
Antimo Buonocore ◽  
Chih-Yang Chen ◽  
Xiaoguang Tian ◽  
Saad Idrees ◽  
Thomas A. Münch ◽  
...  
Keyword(s):  
Eye Movements ◽  
Main Sequence ◽  
Visual Stimulation ◽  
Peak Velocity ◽  
Rhesus Macaques ◽  
Oculomotor System ◽  
Oculomotor Control ◽  
Velocity Amplitude ◽  
Sequence Relationship ◽  
Saccade Control

Microsaccades occur during gaze fixation to correct for miniscule foveal motor errors. The mechanisms governing such fine oculomotor control are still not fully understood. In this study, we explored microsaccade control by analyzing the impacts of transient visual stimuli on these movements’ kinematics. We found that such kinematics can be altered in systematic ways depending on the timing and spatial geometry of visual transients relative to the movement goals. In two male rhesus macaques, we presented peripheral or foveal visual transients during an otherwise stable period of fixation. Such transients resulted in well-known reductions in microsaccade frequency, and our goal was to investigate whether microsaccade kinematics would additionally be altered. We found that both microsaccade timing and amplitude were modulated by the visual transients, and in predictable manners by these transients’ timing and geometry. Interestingly, modulations in the peak velocity of the same movements were not proportional to the observed amplitude modulations, suggesting a violation of the well-known “main sequence” relationship between microsaccade amplitude and peak velocity. We hypothesize that visual stimulation during movement preparation affects not only the saccadic “Go” system driving eye movements but also a “Pause” system inhibiting them. If the Pause system happens to be already turned off despite the new visual input, movement kinematics can be altered by the readout of additional visually evoked spikes in the Go system coding for the flash location. Our results demonstrate precise control over individual microscopic saccades and provide testable hypotheses for mechanisms of saccade control in general. NEW & NOTEWORTHY Microsaccadic eye movements play an important role in several aspects of visual perception and cognition. However, the mechanisms for microsaccade control are still not fully understood. We found that microsaccade kinematics can be altered in a systematic manner by visual transients, revealing a previously unappreciated and exquisite level of control by the oculomotor system of even the smallest saccades. Our results suggest precise temporal interaction between visual, motor, and inhibitory signals in microsaccade control.

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.

scholarly journals Changes in the disparity vergence main sequence after treatment of symptomatic convergence insufficiency in children

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Mitchell Scheiman ◽  
Chang Yaramothu ◽  
Tara L. Alvarez
Keyword(s):  
Eye Movements ◽  
Neural Control ◽  
Main Sequence ◽  
Peak Velocity ◽  
Objective Assessment ◽  
Prospective Trial ◽  
Saccadic Eye Movements ◽  
Response Amplitude ◽  
Time To Peak ◽  
Convergence Insufficiency

This study investigates the underlying physiological mechanisms that may lead to improved outcomes for symptomatic convergence insufficiency (CI) patients after 12 weeks of office-based vergence/accommodation therapy (OBVAT) by evaluating the change in the main sequence of vergence and saccadic eye movements. In this prospective trial, 12 participants with symptomatic CI were recruited and treated with 12 weeks of OBVAT. Outcome measures included the objective assessment of the following: peak velocity, time to peak velocity, latency, response amplitude, and clinical changes in the near point of convergence (NPC), positive fusional vergence (PFV) and symptoms via the Convergence Insufficiency Symptom Survey (CISS). Ten of the twelve participants (83%) were categorized as “successful” and two were “improved” based on pre-determined published criteria (CISS, NPC, PFV). There were statistically significant changes in peak velocity, time to peak velocity, and response amplitude for both 4° and 6° symmetrical convergence and divergence eye movements. There was a significant change in the main sequence ratio for convergence post-OBVAT compared to baseline measurements (P=0.007) but not for divergence or saccadic responses. Phasic/step vergence movements adjust the underlying neural control of convergence and are critical within a vision therapy program for CI patients.

The Main Sequence of Human Optokinetic Afternystagmus (OKAN)

2009 ◽  
Vol 101 (6) ◽  
pp. 2889-2897 ◽  
Author(s):  
Andre Kaminiarz ◽  
Kerstin Königs ◽  
Frank Bremmer
Keyword(s):  
Neural Networks ◽  
Eye Movements ◽  
Main Sequence ◽  
Critical Role ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Visually Guided ◽  
Background Characteristics ◽  
Optokinetic Afternystagmus

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters—peak velocity and duration—on saccadic amplitude has been termed “main sequence.” The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

Microsaccades and the Velocity-Amplitude Relationship for Saccadic Eye Movements

Science ◽  
1965 ◽  
Vol 150 (3702) ◽  
pp. 1459-1460 ◽  
Author(s):  
B. L. Zuber ◽  
L. Stark ◽  
G. Cook
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Velocity Amplitude

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.

The main sequence, a tool for studying human eye movements

1975 ◽  
Vol 24 (3-4) ◽  
pp. 191-204 ◽  
Author(s):  
A.Terry Bahill ◽  
Michael R. Clark ◽  
Lawrence Stark
Keyword(s):  
Eye Movements ◽  
Main Sequence ◽  
Human Eye ◽  
Human Eye Movements
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