Complexity-Based Analysis of the Relation Between Fractal Visual Stimuli and Fractal Eye Movements

2019 ◽  
Vol 18 (03) ◽  
pp. 1950012 ◽  
Author(s):  
Hedieh Alipour ◽  
Farzad Towhidkhah ◽  
Sajad Jafari ◽  
Avinash Menon ◽  
Hamidreza Namazi
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Fractal Structure ◽  
Visual Target ◽  
Fractal Theory ◽  
Complex Structure ◽  
Vision Science ◽  
Human Eye ◽  
Field Of Vision ◽  
External Stimuli

Human eye movement is a key concept in the field of vision science. It has already been established that human eye movement responds to external stimuli. Hence, investigating the reaction of the human eye movement to various types of external stimuli is important in this field. There have been many researches on human eye movement that were previously done, but this is the first study to show a relation between the complex structure of human eye movement and the complex structure of static visual stimulus. Fractal theory was implemented and we showed that the fractal dynamics of the human eye movement is related to the fractal structure of visual target as stimulus. The outcome of this research provides new platforms to scientists to further investigate on the relation between eye movement and other applied stimuli.

COMPLEXITY-BASED ANALYSIS OF THE RELATION BETWEEN MOVING VISUAL STIMULI AND HUMAN EYE MOVEMENT

Fractals ◽  
2019 ◽  
Vol 27 (03) ◽  
pp. 1950024 ◽  
Author(s):  
HEDIEH ALIPOUR ◽  
HAMIDREZA NAMAZI ◽  
HAMED AZARNOUSH ◽  
SAJAD JAFARI
Keyword(s):  
Eye Movement ◽  
Visual Target ◽  
Fractal Theory ◽  
Complex Structure ◽  
Visual Stimuli ◽  
Vision Science ◽  
Human Eye ◽  
Different Types ◽  
External Stimuli ◽  
The Relationship

Investigating human eye movement is one of the major research topics in vision science. It is known that human eye movement is related to external stimuli. In this way, the analysis of human eye movement due to different types of external stimuli is very important in vision science. Beside all reported analysis, no one has discovered any relation between the complex structure of moving visual stimuli and the complex structure of human eye movement. This study reveals the relationship between the complexity of human eye movement signal and the applied visual stimuli. For this purpose, we employ fractal theory. We demonstrated that the fractal dynamics of human eye movement in both horizontal and vertical directions shifts toward the fractal dynamics of moving visual target as stimulus. The capability observed in this research opens new doors to scientists to study the relation between the human eye movement and the applied stimuli.

FRACTAL-BASED ANALYSIS OF THE INFLUENCE OF COLOR TONALITY ON HUMAN EYE MOVEMENTS

Fractals ◽  
2019 ◽  
Vol 27 (03) ◽  
pp. 1950040 ◽  
Author(s):  
HEDIEH ALIPOUR ◽  
HAMIDREZA NAMAZI ◽  
HAMED AZARNOUSH ◽  
SAJAD JAFARI
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Environmental Changes ◽  
Fractal Theory ◽  
Visual Stimuli ◽  
Color Intensity ◽  
Vision Science ◽  
Human Eye ◽  
Human Eye Movements ◽  
Different Color

An important category of studies in vision science is related to the analysis of the influence of environmental changes on human eye movement. In this way, scientists analyze human eye movement in different conditions using different methods. An important category of works is devoted to the decoding of eye reaction to color tonality. In this research for the first time, we examined the application of fractal theory for decoding of eye reaction to variations in color intensity of visual stimuli. Three green visual stimuli with different color intensities have been applied to subjects and accordingly the fractal dimension of their eye movements has been analyzed. We also tested the eye movement in non-stimulation condition (rest). Based on the obtained results, increasing the color intensity of visual stimuli caused a lower complexity in subject’s eye movement. We also observed that eye movement is less complex in case of non-stimulation compared to different stimulation conditions. The application of fractal theory in analysis of eye movement can be extended to analyze the effect of other stimulation conditions on eye movement to investigate about the decoding behavior of human eye, which is very important in vision science.

COMPLEXITY-BASED ANALYSIS OF THE INFLUENCE OF VISUAL STIMULUS COLOR ON HUMAN EYE MOVEMENT

Fractals ◽  
2019 ◽  
Vol 27 (02) ◽  
pp. 1950002 ◽  
Author(s):  
HEDIEH ALIPOUR ◽  
HAMIDREZA NAMAZI ◽  
HAMED AZARNOUSH ◽  
SAJAD JAFARI
Keyword(s):  
Eye Movement ◽  
Visual Stimulus ◽  
Movement Time ◽  
Complex Structure ◽  
Visual Stimuli ◽  
Vision Science ◽  
Human Eye ◽  
Research Areas ◽  
Lower Complexity ◽  
First Time

Analysis of eye movement due to different visual stimuli always has been one of the major research areas in vision science. An important category of works belongs to decoding of eye movement due to variations of color of visual stimuli. In this research, for the first time, we employ fractal analysis in order to investigate the variations of complex structure of eye movement time series in response to variations of color of visual stimuli. For this purpose, we applied two different images in three different colors (red, green, blue) to subjects. The result of our analysis showed that eye movement has the greatest complexity in case of green visual stimulus. On the other hand, the lowest complexity of eye movement was observed in case of red stimulus. In addition, the results showed that except for red visual stimulus, applying the visual stimulus with greater complexity causes the lower complexity in eye movements. The employed methodology in this research can be further applied to analyze the influence of other variations of visual stimuli on human eye movement.

FRACTAL-BASED ANALYSIS OF THE INFLUENCE OF AUDITORY STIMULI ON EYE MOVEMENTS

Fractals ◽  
2018 ◽  
Vol 26 (03) ◽  
pp. 1850040 ◽  
Author(s):  
HAMIDREZA NAMAZI ◽  
ASIEH DANESHI ◽  
HAMED AZARNOUSH ◽  
SAJAD JAFARI ◽  
FARZAD TOWHIDKHAH
Keyword(s):  
Eye Movements ◽  
Fractal Structure ◽  
Fractal Theory ◽  
Auditory Stimuli ◽  
Applied Music ◽  
Important Challenge ◽  
Human Eye Movements ◽  
Process Complexity ◽  
External Stimuli ◽  
First Time

Analyzing the influence of external stimuli on human eye movements is an important challenge in vision research. In this paper, we investigate the plasticity of eye movements due to the applied auditory stimuli (music). For this purpose, we use fractal theory, which provides us with tools such as fractal dimension as an indicator of process complexity. This study, for the first time, reveals the correlation between fractal dynamics of eye movements and fractal dynamics of auditory stimuli. Based on the performed analysis, the fractal structure of the eye movements shifts toward the fractal structure of the applied auditory stimuli, where the greater variation in fractal dynamics of auditory stimuli causes greater variation in the fractal dynamics of eye movements. The observed behavior is explained through the nervous system. As a rehabilitation purpose, the employed methodology in this research can be investigated in case of patients with vision problems, where the applied music could potentially improve their vision.

scholarly journals Pursuit disorder and saccade dysmetria after caudal fastigial inactivation in the monkey

2018 ◽  
Vol 120 (4) ◽  
pp. 1640-1654 ◽  
Author(s):  
Clara Bourrelly ◽  
Julie Quinet ◽  
Laurent Goffart
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Target ◽  
Fastigial Nucleus ◽  
Gaze Direction ◽  
Moving Target ◽  
Horizontal Meridian ◽  
Pursuit Eye Movements ◽  
Neural Processes ◽  
Slow Eye Movements

The caudal fastigial nuclei (cFN) are the output nuclei by which the medio-posterior cerebellum influences the production of saccadic and pursuit eye movements. We investigated the consequences of unilateral inactivation on the pursuit eye movement made immediately after an interceptive saccade toward a centrifugal target. We describe here the effects when the target moved along the horizontal meridian with a 10 or 20°/s speed. After muscimol injection, the monkeys were unable to track the present location of the moving target. During contralesional tracking, the velocity of postsaccadic pursuit was reduced. This slowing was associated with a hypometria of interceptive saccades such that gaze direction always lagged behind the moving target. No correlation was found between the sizes of saccade undershoot and the decreases in pursuit speed. During ipsilesional tracking, the effects on postsaccadic pursuit were variable across the injection sessions, whereas the interceptive saccades were consistently hypermetric. Here also, the ipsilesional pursuit disorder was not correlated with the saccade hypermetria either. The lack of correlation between the sizes of saccade dysmetria and changes of postsaccadic pursuit speed suggests that cFN activity exerts independent influences on the neural processes generating the saccadic and slow eye movements. It also suggests that the cFN is one locus where the synergy between the two motor categories develops in the context of tracking a moving visual target. We explain how the different fastigial output channels can account for these oculomotor tracking disorders. NEW & NOTEWORTHY Inactivation of the caudal fastigial nucleus impairs the ability to track a moving target. The accuracy of interceptive saccades and the velocity of postsaccadic pursuit movements are both altered, but these changes are not correlated. This absence of correlation is not compatible with an impaired common command feeding the circuits producing saccadic and pursuit eye movements. However, it suggests an involvement of caudal fastigial nuclei in their synergy to accurately track a moving target.

scholarly journals Seeing Beyond Salience and Guidance: The Role of Bias and Decision in Visual Search

Vision ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 46
Author(s):  
Alasdair D. F. Clarke ◽  
Anna Nowakowska ◽  
Amelia R. Hunt
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
Signal Detection ◽  
Future Research ◽  
Search Performance ◽  
Guided Search ◽  
Vision Science ◽  
Search Tasks ◽  
Field Of Vision

Visual search is a popular tool for studying a range of questions about perception and attention, thanks to the ease with which the basic paradigm can be controlled and manipulated. While often thought of as a sub-field of vision science, search tasks are significantly more complex than most other perceptual tasks, with strategy and decision playing an essential, but neglected, role. In this review, we briefly describe some of the important theoretical advances about perception and attention that have been gained from studying visual search within the signal detection and guided search frameworks. Under most circumstances, search also involves executing a series of eye movements. We argue that understanding the contribution of biases, routines and strategies to visual search performance over multiple fixations will lead to new insights about these decision-related processes and how they interact with perception and attention. We also highlight the neglected potential for variability, both within and between searchers, to contribute to our understanding of visual search. The exciting challenge will be to account for variations in search performance caused by these numerous factors and their interactions. We conclude the review with some recommendations for ways future research can tackle these challenges to move the field forward.

Anticipatory VOR Suppression Induced by Visual and Nonvisual Stimuli in Humans

2004 ◽  
Vol 92 (3) ◽  
pp. 1501-1511 ◽  
Author(s):  
G. R. Barnes ◽  
G. D. Paige
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Target ◽  
Head Motion ◽  
Vestibuloocular Reflex ◽  
Fixed Target ◽  
Target Movement ◽  
Anticipatory Eye Movements ◽  
Predictive Behavior ◽  
Anticipatory Smooth Eye Movements

We compared the predictive behavior of smooth pursuit (SP) and suppression of the vestibuloocular reflex (VOR) in humans by examining anticipatory smooth eye movements, a phenomenon that arises after repeated presentations of sudden target movement preceded by an auditory warning cue. We investigated whether anticipatory smooth eye movements also occur prior to cued head motion, particularly when subjects expect interaction between the VOR and either real or imagined head-fixed targets. Subjects were presented with horizontal motion stimuli consisting of a visual target alone (SP), head motion in darkness (VOR), or head motion in the presence of a real or imagined head-fixed target (HFT and IHFT, respectively). Stimulus sequences were delivered as single cycles of a velocity sinusoid (frequency: 0.5 or 1.0 Hz) that were either cued (a sound cue 400 ms earlier) or noncued. For SP, anticipatory smooth eye movements developed over repeated trials in the cued, but not the noncued, condition. In the VOR condition, no such anticipatory eye movements were observed even when cued. In contrast, anticipatory responses were observed under cued, but not noncued, HFT and IHFT conditions, as for SP. Anticipatory HFT responses increased in proportion to the velocity of preceding stimuli. In general, anticipatory gaze responses were similar in cued SP, HFT, and IHFT conditions and were appropriate for expected target motion in space. Anticipatory responses may represent the output of a central mechanism for smooth-eye-movement generation that operates during predictive SP as well as VOR modulations that are linked with SP even in the absence of real visual targets.

scholarly journals Human Visual Search Follows Suboptimal Bayesian Strategy Revealed by a Spatiotemporal Computational Model

2019 ◽  
Author(s):  
Yunhui Zhou ◽  
Yuguo Yu
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
Visual System ◽  
Eye Movement ◽  
Search Strategy ◽  
Memory Capacity ◽  
Search Performance ◽  
Human Eye ◽  
Visibility Map ◽  
Temporal Course

AbstractHumans perform sequences of eye movements to search for a target in complex environment, but the efficiency of human search strategy is still controversial. Previous studies showed that humans can optimally integrate information across fixations and determine the next fixation location. However, their models ignored the temporal control of eye movement, ignored the limited human memory capacity, and the model prediction did not agree with details of human eye movement metrics well. Here, we measured the temporal course of human visibility map and recorded the eye movements of human subjects performing a visual search task. We further built a continuous-time eye movement model which considered saccadic inaccuracy, saccadic bias, and memory constraints in the visual system. This model agreed with many spatial and temporal properties of human eye movements, and showed several similar statistical dependencies between successive eye movements. In addition, our model also predicted that the human saccade decision is shaped by a memory capacity of around 8 recent fixations. These results suggest that human visual search strategy is not strictly optimal in the sense of fully utilizing the visibility map, but instead tries to balance between search performance and the costs to perform the task.Author SummaryDuring visual search, how do humans determine when and where to make eye movement is an important unsolved issue. Previous studies suggested that human can optimally use the visibility map to determine fixation locations, but we found that such model didn’t agree with details of human eye movement metrics because it ignored several realistic biological limitations of human brain functions, and couldn’t explain the temporal control of eye movements. Instead, we showed that considering the temporal course of visual processing and several constrains of the visual system could greatly improve the prediction on the spatiotemporal properties of human eye movement while only slightly affected the search performance in terms of median fixation numbers. Therefore, humans may not use the visibility map in a strictly optimal sense, but tried to balance between search performance and the costs to perform the task.

Information-Based Analysis of the Relation Between Visual Stimuli and Human Eye Movements

2019 ◽  
Vol 18 (01) ◽  
pp. 1950010 ◽  
Author(s):  
Hamidreza Namazi ◽  
Asieh Daneshi ◽  
Touraj Shirzadian ◽  
Hamed Azarnoush ◽  
Sajad Jafari
Keyword(s):  
Time Series ◽  
Eye Movements ◽  
Information Content ◽  
Shannon Entropy ◽  
Visual Stimuli ◽  
Human Eye ◽  
Important Challenge ◽  
Human Eye Movements ◽  
External Stimuli ◽  
First Time

Analysis of the influence of external stimuli on human eye movements is an important challenge in vision research. In this paper, we investigate the influence of applied visual stimuli on variations of eye movements. For this purpose, we employ information theory, which provides us with tools such as Shannon entropy as the indicator of information content of process. This study for the first time reveals the relation between the information content of eye movements and the information content of visual stimuli. Based on the performed analysis, the information content of eye movements time series shifts toward the information content of applied visual stimuli, where the greater variation in Shannon entropy of visual stimuli causes the greater variation in the Shannon entropy of eye movements time series. The observed behavior is explained through nervous system. As a rehabilitation purpose, the employed methodology in this research can be investigated in case of patients with vision problems, with the aim of improving patients’ vision.

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