Fixational eye movements comprise of fast microsaccades alternating with slow inter-saccadic drifts. These physiologic eye movements play an important role in visual perception. Amblyopic patients are known to have fixation instability, particularly of the amblyopic eye. We examined eye movement abnormalities that contribute to this instability. We found that fixation stability is affected by the presence of fusion maldevelopment nystagmus (FMN). However, some amblyopes can have nystagmus without nasally directed slow phases and reversal in direction of the quick phase on ocular occlusion, features seen in FMN. In patients without nystagmus, we found increased amplitude of fixational saccades and inter-saccadic drifts. We categorized amblyopia patients by type (anisometropic, strabismic, or mixed) and eye movement waveform (no nystagmus, nystagmus without FMN, and FMN). We found specific fast and slow eye movement abnormalities of the fellow and amblyopic eye during fellow, amblyopic and both ...
One hallmark study by Baba et al. in 2004 found that in patients with known vestibular dysfunction, 100 out of 100 demonstrated abnormal eye movements as measured by ENG, and the same 100 out of 100 demonstrated abnormal eye movements with infrared video goggles. However, only 33 out of 100 had identifiable abnormal eye movements with use of Frenzel lens goggles, indicative of their decreased ability to reduce room light. Presumably, although not included in the study, visualizing these patients eyes in room light (no goggles of any kind) would yield even fewer than 33 out of 100 with observable abnormal eye movements.. This makes sense because your brain tries to reduce imbalance and nausea (symptoms of vestibular dysfunction) by using visual information when in room light. Unfortunately, this also reduces or eliminates the very eye movements that a clinician can use to assist in accurate diagnosis and subsequent best treatment of vestibular conditions. ...
Purpose: When tested under monocular viewing conditions, humans and monkeys with infantile strabismus often show strong eye movement responses to nasally directed visual motion stimuli and weak responses to temporally directed stimuli. The goal of this study was to compare and contrast these naso-temporal asymmetries during three visually mediated eye movement responses - optokinetic nystagmus (OKN), smooth-pursuit (SP) and ocular following (OFR).. Methods: Two strabismic monkeys (1 esotrope (ET) and 1 exotrope (XT)) were tested under monocular viewing conditions during nasal or temporal OKN, SP or OFR stimulation. OKN stimulus was unidirectional motion of a 70°X50° random dot pattern at 20, 40 or 80 °/s for 1 minute. SP stimulus was foveal step-ramp target motion at 10, 20 or 40 °/s. OFR stimulus was brief (200ms) unidirectional motion of a 38°X29° random dot pattern at 20, 40 or 80 °/s. Data from both left and right eye viewing conditions were combined for statistical analysis of eye ...
Individual differences in childrens online language processing were explored by monitoring their eye movements to objects in a visual scene as they listened to spoken sentences. Eleven skilled and 11 less-skilled comprehenders were presented with sentences containing verbs that were either neutral with respect to the visual context (e.g., Jane watched her mother choose the cake, where all of the objects in the scene were choosable) or supportive (e.g., Jane watched her mother eat the cake, where the cake was the only edible object). On hearing the supportive verb, the children made fast anticipatory eye movements to the target object (e.g., the cake), suggesting that children extract information from the language they hear and use this to direct ongoing processing. Less-skilled comprehenders did not differ from controls in the speed of their anticipatory eye movements, suggesting normal sensitivity to linguistic constraints. However, less-skilled comprehenders made a greater number of fixations to
In this project, we use a switching hidden Markov model (EMSHMM) approach to analyze eye movement data in cognitive tasks involving cognitive state changes. We used a switching hidden Markov model (SHMM) to capture a participants cognitive state transitions during the task, with eye movement patterns during each cognitive state being summarized using a regular HMM.. We applied EMSHMM to a face preference decision-making task with two pre-assumed cognitive states-exploration and preference-biased periods-and we discovered two common eye movement patterns through clustering the cognitive state transitions. One pattern showed both a later transition from the exploration to the preference-biased cognitive state and a stronger tendency to look at the preferred stimulus at the end, and was associated with higher decision inference accuracy at the end; the other pattern entered the preference-biased cognitive state earlier, leading to earlier above-chance inference accuracy in a trial but lower ...
Purpose: To determine whether the patterns of fixational eye movements are altered when images are defocused (low pass-filtered).. Methods: Six subjects (3 male, 3 female, 22 - 32 years of age, Caucasian origin) were asked to inspect an image on the computer screen which was either in focus or low-pass filtered by convolution with a point spread function that was equivalent to 5D of myopic defocus. The screen was at 79 cm distance and one pixel on the screen subtended a visual angle of 1.45 arcmin. The movements of the right eye were tracked at 166 Hz sampling rate in a highly magnified video image (39.9 pixels/mm) by custom-developed software (Visual C++ 8.0). A commercial IR camera (DMK 22AUC03, www.theimagingsource.com) was used and a single IR LED that generated a bright first Purkinje image. The angular resolution in natural eyes was determined to be 1-2 arcmin. Differences in eye movements variables were determined in the pooled data of all subjects using t-tests, analyzing the ...
TY - JOUR. T1 - Eye movement patterns in solving scientific graph problems. AU - Yen, Miao Hsuan. AU - Lee, Chieh Ning. AU - Yang, Yu Chun. PY - 2012/7/13. Y1 - 2012/7/13. N2 - Eye movement patterns of science- and non-science students in solving scientific graph problems were compared. Experts (science-students) tended to spend more time, compared to novices, to comprehend the questions during the first run / inspection. Concerning the main graph region, both the True and False subregions (corresponding to correct and wrong answer choices, respectively) were inspected carefully during the first run. Significant differences were observed in the second run, in which the False region was fixated longer when participants made wrong responses.. AB - Eye movement patterns of science- and non-science students in solving scientific graph problems were compared. Experts (science-students) tended to spend more time, compared to novices, to comprehend the questions during the first run / inspection. ...
Eye movement includes the voluntary or involuntary movement of the eyes, helping in acquiring, fixating and tracking visual stimuli. Specific systems are used in maintaining fixation, when reading and in music reading. A special type of eye movement, rapid eye movement, occurs during REM sleep. The eyes are the visual organs of the human body, and move using a system of six muscles. The retina, a specialised type of tissue containing photoreceptors, senses light. These specialised cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as vision in the visual cortex. Primates and many other vertebrates use three types of voluntary eye movement to track objects of interest: smooth pursuit, vergence shifts and saccades. These movements appear to be initiated by a small cortical region in the brains frontal lobe. This is corroborated by removal of the frontal lobe. In this case, the reflexes (such as reflex ...
The present disclosure is intended to describe embodiments for improving image data acquisition and processing in accelerated dynamic magnetic resonance imaging sequences. One embodiment is described where a method includes an acquisition sequence configured to acquire an undersampled set of magnetic resonance data. The undersampled set of magnetic resonance data has a pseudo-random sampling pattern within a data space acquired at a first time, the pseudo-random sampling pattern being influenced by other pseudo-random sampling patterns within the data space arising from the acquisition of additional undersampled sets of magnetic resonance data at respective times. In some embodiments, the pseudo-random sampling patterns of the undersampled sets of magnetic resonance data interleave to yield a desired sampling pattern.
The present disclosure is intended to describe embodiments for improving image data acquisition and processing in accelerated dynamic magnetic resonance imaging sequences. One embodiment is described where a method includes an acquisition sequence configured to acquire an undersampled set of magnetic resonance data. The undersampled set of magnetic resonance data has a pseudo-random sampling pattern within a data space acquired at a first time, the pseudo-random sampling pattern being influenced by other pseudo-random sampling patterns within the data space arising from the acquisition of additional undersampled sets of magnetic resonance data at respective times. In some embodiments, the pseudo-random sampling patterns of the undersampled sets of magnetic resonance data interleave to yield a desired sampling pattern.
There was a lot of past effort to figure out what fixational eye movements contribute to our vision, adds lead author Ziad Hafed, Ph.D., Sloan-Swartz Fellow in the Systems Neurobiology Laboratory, but nobody had looked at the neural mechanism that generates these movements. Without such knowledge, one could only go so far in evaluating microsaccades significance and why they actually exist. Wondering whether the command center responsible for generating fixational eye movements resides within the same brain structure that is in charge of initiating and directing large voluntary eye movements, Hafed decided to measure neural activity in the superior colliculus before and during microsaccades. He not only discovered that the superior colliculus is an integral part of the neural mechanism that controls microsaccades, but he also found that individual neurons in the superior colliculus are highly specific about which particular microsaccade directions and amplitudes they command-whether they be, ...
Neural data and models have proposed that the brain achieves invariant object recognition by learning and combining several views of a three-dimensional object. How such invariant codes are learned when active eye movements scan a scene, given that the cortical magnification introduces a large source of variability in the visual representation even for the same view of the object? How does the brain avoid the problem of erroneously classifying together parts of different objects when an eye movement changes the cortical representation from one to the other? How does the brain differentiate between saccades on the same object and saccades between different objects? A biologically inspired ARTSCAN model of visual object learning and recognition with active eye movements proposes answers to these questions. The model explains how surface attention interacts with eye movement generating modules and object recognition modules so that the views that correspond to the same object are selectively ...
Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and twenty healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward versus leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting
The spatial alignment of gaze location between the measuring eye tracker and the responding display system is obviously crucial in gaze-contingent studies. However, a misalignment is almost inevitable during eye movements due to time delays between the eye tracker and the display equipment. This system latency includes the time for data transmission from the eye tracker to the display, the processing time for image manipulation, and the time for refreshing the display. The total delay varies based on the equipment and software, and reported values have ranged between 9 and 50 ms (Dorr & Bex, 2011; Saunders & Woods, in press; Schumacher, Allison, & Herpers, 2004; Triesch, Sullivan, Hayhoe, & Ballard, 2002; Yang, Wang, Tong, & Rayner, 2012). For fast saccadic eye movements, that time delay may cause a large misalignment. Take a 20° saccade as an example: the peak velocity can be 350°/s-450°/s (Enderle, Blanchard, & Bronzino, 2005), which may lead to 8° displacement on average within 20 ms. ...
Rapid eye movement in babies - My four month old baby son seems to have rapid eye movement at different times during the day. Is that normal. Its not very fast movement either. REM. Rapid eye movements may be entirely normal in infants HOWEVER THIS is the kind of observation your Pediatrician will NOT be annoyed about if you question him/her......suggest you check this out.... Hope this is helpful Dr Z
Child Development Research is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles in all areas of child development research.
Purpose: To investigate whether glaucoma produces measurable changes in eye movements.. Methods: Fifteen glaucoma patients with asymmetric vision loss (difference in mean deviation [MD] , 6 dB between eyes) were asked to monocularly view 120 images of natural scenes, presented sequentially on a computer monitor. Each image was viewed twice-once each with the better and worse eye. Patients eye movements were recorded with an Eyelink 1000 eye-tracker. Eye-movement parameters were computed and compared within participants (better eye versus worse eye). These parameters included a novel measure: saccadic reversal rate (SRR), as well as more traditional metrics such as saccade amplitude, fixation counts, fixation duration, and spread of fixation locations (bivariate contour ellipse area [BCEA]). In addition, the associations of these parameters with clinical measures of vision were investigated.. Results: In the worse eye, saccade ...
Reading requires very accurate saccadics which are fixations from one spot to another. A second type of eye movement which involves tracking is, also, related to attention and reading. Children who have poor eye movements are easily distracted and loose their place. Remember, the eye movement system was designed so that peripheral vision detects motion and danger. Imagine what happens when the system works correctly in the class room. As soon as there is peripheral movement the eyes move towards the source of movement. This results in the complaint of inattention. Thus, reflexive eye movement skills must be socialized so that they do not respond reflexively to peripheral information. In addition, speed and accuracy must be trained so that one does not loose ones place.. The skills are easily improvable with vision therapy (See testimonial for patient comments). Once the information is brought into the eyes it must be sent back to the brain for appropriate processing. The information must be ...
This study examined performance measures and eye movements associated with complex arithmetic strategies in young and older adults. Participants added pairs of three-digit numbers using two different strategies, under choice and no-choice conditions. Older adults made more errors but were not significantly slower than young adults, and response times and errors showed no interaction between age and the number of carries. Older adults chose strategies less adaptively than young adults. Eye movements were consistent with use of required strategies on no-choice trials and reported strategies on choice trials. Eye movement data also suggested that young adults more successfully distinguished between strategies. Implications of these findings for understanding aging effects in complex arithmetic are discussed ...
ORCID: 0000-0002-8579-8546 and Rayner, Keith (2011) Linguistic and cognitive influences on eye movements during reading. In: The Oxford Handbook of Eye Movements. Oxford Library of Psychology . Oxford University Press, pp. 751-766. ISBN 978-0-19-953978-9 (Unpublished) Full text not available from this repository.. Official URL: https://global.oup.com/academic/product/the-oxford... ...
p,Humans can distinguish visual stimuli that differ by features the size of only a few photoreceptors. This is possible despite the incessant image motion due to fixational eye movements, which can be many times larger than the features to be distinguished. To perform well, the brain must identify the retinal firing patterns induced by the stimulus while discounting similar patterns caused by spontaneous retinal activity. This is a challenge since the trajectory of the eye movements, and consequently, the stimulus position, are unknown. We derive a decision rule for using retinal spike trains to discriminate between two stimuli, given that their retinal image moves with an unknown random walk trajectory. This algorithm dynamically estimates the probability of the stimulus at different retinal locations, and uses this to modulate the influence of retinal spikes acquired later. Applied to a simple orientation-discrimination task, the algorithm performance is consistent with human acuity, whereas ...
Kawaii, a positive adjective that denotes such positive connotations as cute, lovable, and charming, becomes more important as one kansei value. It plays an important role in the success of many products. Based on this success, we believe that kawaii will be a key factor for future product design. In one of our previous study, we experimentally evaluated kawaii illustrations using eye tracking device. The result clarified relationship between kawaii feelings and eye movement indexes. In our other study, we experimentally evaluated kawaiiness of spoon designs. However, we have not employed the eye tracking in the study yet. Then, in this study, we evaluated the kawaiiness of spoon designs using eye tracking. The participant compared and selected more kawaii spoon designs from the pairs on the display, and eye movements had been recording meanwhile. Finally, we obtained the suggestion for the relationship between kawaii feelings and eye movement indexes for spoon designs ...
An eye movement measuring apparatus comprises: an image forming part configured to obtain data optically to form a fundus oculi image of an eye based on the obtained data; and an image analysis part configured to analyze the formed fundus oculi image to determine eye movement of the eye.
A pair of Beckman Institute researchers has discovered that by directing the eye movements of test subjects they were able to affect the participants ability to solve a problem, demonstrating that eye movement is not just a function of cognition but can actually affect our cognitive processes.
Task execution time is one of components used to estimate systems usability. Since information search is one of the most important tasks in any computer system, the eye movement should be taken into account while designing systems interface. Fitts law allows to estimate probable eye movement time based on the distance between objects and their size. Users motivation can significantly influence the eye movement speed. In this paper we analyze experimentally how Fitts law parameter (slope) changes when user is motivated and when there is less motivation to execute the task. Our experiments confirm that gamma brainwave activity can be used as a metric to estimate the motivation level. This allows a more objective estimation of the motivation level as compared to situation when motivation level is estimated by an experts observation. It is also demonstrated that the slope in Fitts law is up to five times smaller when children of age two to four years are motivated to reach the object and the ...
This paper introduces an approach to use eye movement data in the context of program comprehension studies. The central aspect is the development of coding schemes, which reflect cognitive processes behind the observable visual behavior of programmers. For this purpose, we discuss to first use a quantitative approach to find those episodes in the eye movements that yield the most potential for analysis. Subsequently, qualitative methods can be used on this subset.. ...
Apparatus for recording eye movement. A light source has its rays directed toward the eye of a subject and a glass dome secured to spectacle frames worn by the subject. The primary and secondary glints reflected off the glass dome and eye cornea, respectively, are transmitted via mirrors, lenses and a fiber optic image guide to a video camera tube. The position of the glints on an XY axis is electronically determined and the information is fed to a computer which compares the data from the two glints and compensates for the head movement which corresponds to movement of the primary glint.
Extraocular eye movement is a function of cranial nerves and can be easily assesed. This article briefly discusses extraocular eye movement at an appropriate level for medical providers like nurses, EMTs, and paramedics.
Adults from Eastern (e.g., China) and Western (e.g., USA) cultural groups display pronounced differences in a range of visual processing tasks. For example, the eye movement strategies used for information extraction during a variety of face processing tasks (e.g., identification and facial expressions of emotion categorization) differs across cultural groups. Currently, many of the differences reported in previous studies have asserted that culture itself is responsible for shaping the way we process visual information, yet this has never been directly investigated. In the current study, we assessed the relative contribution of genetic and cultural factors by testing face processing in a population of British Born Chinese adults using face recognition and expression classification tasks. Contrary to predictions made by the cultural differences framework, the majority of British Born Chinese adults deployed Eastern eye movement strategies, while approximately 25% of participants displayed ...
The arrangement of the contents of real-world scenes follows certain spatial rules that allow for extremely efficient visual exploration. What remains underexplored is the role different types of objects hold in a scene. In the current work, we seek to unveil an important building block of scenes-anchor objects. Anchors hold specific spatial predictions regarding the likely position of other objects in an environment. In a series of three eye tracking experiments we tested what role anchor objects occupy during visual search. In all of the experiments, participants searched through scenes for an object that was cued in the beginning of each trial. Critically, in half of the scenes a target relevant anchor was swapped for an irrelevant, albeit semantically consistent, object. We found that relevant anchor objects can guide visual search leading to faster reaction times, less scene coverage, and less time between fixating the anchor and the target. The choice of anchor objects was confirmed through an
Video created by Duke University for the course Medical Neuroscience. At this juncture in our exploration of motor control, lets focus on one of the best studied paradigms for understanding the neural control of movement: the eye movement system.
TY - JOUR. T1 - Accounting for regressive eye-movements in models of sentence processing. T2 - A reappraisal of the Selective Reanalysis hypothesis. AU - Mitchell, Don C.. AU - Shen, Xingjia. AU - Green, Matthew James. AU - Hodgson, Timothy L.. PY - 2008/10. Y1 - 2008/10. N2 - When people read temporarily ambiguous sentences, there is often an increased prevalence of regressive eye-movements launched from the word that resolves the ambiguity. Traditionally, such regressions have been interpreted at least in part as reflecting readers efforts to re-read and reconfigure earlier material, as exemplified by the Selective Reanalysis hypothesis [Frazier, L., & Rayner, K. (1982). Making and correcting errors during sentence comprehension: Eye movements in the analysis of structurally ambiguous sentences. Cognitive Psychology, 14, 178-210]. Within such frameworks it is assumed that the selection of saccadic landing-sites is linguistically supervised. As an alternative to this proposal, we consider the ...
Are the eyes able to fixate, track, and jump from object to object efficiently? In the classroom, normal eye movements allow rapid and accurate shifting of the eyes along a line of print while reading or from book to desk to chalkboardboard. Individuals with poor eye movement skills tend to be poor readers. In sports, efficient eye movements contribute to eye-hand coordination, visual reaction time, and accurate tracking. Recent research has shown that poor eye movement skills influence scores on the Weschler Intelligence Scale for Children and the Iowa Test of Basic Skills. Research has also shown that eye movements can be improved!. ...
Research has shown that students responses to conceptual questions correlate with their eye movements. However, to what extent is it possible to predict whether a particular learner might answer a question correctly by monitoring their eye movements in real time? To answer this question, we used spatial-temporal eye-movement data from about 400 participants, as well as their responses to four conceptual physics questions with diagrams. Half of these data were used as a training set for a machine learning algorithm (MLA) that would predict the correctness of students responses to these questions. The other half of the data were used as a test set to determine the performance of the MLA in terms of the accuracy of the prediction. We will discuss the results of our study with specific attention to the prediction accuracy of the MLA under different conditions ...
The fundamental role of the visual system is to guide behavior in natural environments. In order to optimize information transmission many animals have evolved a non-homogeneous retina and serially sample visual scenes by saccadic eye movements. Such eye movements, however, introduce high-speed retinal motion and decouple external and internal reference frames. Until now, these processes have only been studied with unnatural stimuli, eye movement behavior, and tasks. These experiments confound retinotopic and geotopic coordinate systems and may probe a non-representative functional range. Here we develop a real-time gaze-contingent display with precise spatio-temporal control over high-definition natural movies. In an active condition, human observers freely watched nature documentaries and indicated the location of periodic narrow-band contrast increments relative to their gaze position. In a passive condition under central fixation, the same retinal input was replayed to each observer by ...
L. Itti, Keynote lecture: Computational modeling of bottom-up and top-down visual attention in complex dynamic environments, European Conference on Eye Movements (ECEM 2015), Vienna, Austria, Aug 2015.. Abstract: Visual attention and eye movements in primates have been widely shown to be guided by a combination of stimulus-dependent or bottom-up cues, as well as task-dependent or top-down cues. Both the bottom-up and top-down aspects of attention and eye movements have been modeled computationally. Yet, is is not until recent work which I will describe that bottom-up models have been strictly put to the test, predicting significantly above chance the eye movement patterns, functional neuroimaging activation patterns, or most recently neural activity in the superior colliculus of human or monkey participants inspecting complex static or dynamic scenes. In recent developments, models that increasingly attempt to capture top-down aspects have been proposed. In one system which I will describe, ...
In two experiments, we investigated the relationship between experience-dependent eye movements, awareness, and hippocampus-dependent memory. In Experiment 1, young adults and older adults viewed 120 novel scenes and 120 repeated scenes and made an old-new judgment for each scene together with a confidence rating. Both groups sampled fewer regions and made fewer fixations when viewing repeated scenes than when viewing novel scenes. The important finding was that the two groups exhibited these eye movement effects only when they were aware of the familiar or novel status of the scenes. First, they exhibited these effects only when they were confident (and accurate) in their old-new judgment and not when they were guessing (and inaccurate). Second, they exhibited these effects only when their old-new judgments were correct and not when they were incorrect. In contrast, memory-impaired patients failed to view the familiar and the novel scenes differently, and they were also impaired at remembering ...
Humans shift their gaze from detail to detail by using eye movements. Although each eye movement changes the position of the image that is reflected to the retinas of the eyes, we experience a spatially stable stream of vision that is uninterrupted by eye movements. To achieve this stable stream of vision, the brain must take into account the eye movement, and temporarily suppress vision during rapid gaze shifts. How the brain does this, remains to be solved. The present research approaches this question from two perspectives. First, we test a theory according to which visual stability is achieved by suppressing in the ability of visual brain areas to communicate with higher brain areas during eye movements. Second, we study whether the disruption of these mechanisms leads to a breakdown in visual stability in specific clinical populations (e.g. Parkinsons disease). Deficits in visual stability could compromise spatial cognition and lead to symptoms such as vertigo and hallucinations ...
This page is under construction. Here we list upcoming conferences and meetings related to eye movements and vision research, which you can browse on the left menu. Please contact us if you would like your event listed here. Other events to be added to menu left:The SWAET (Scandinavian Workshop on Applied Eye Tracking) - a regional variety of the ECEM.
Out Of Body Experience mini-print. double-sided print on 300g uncoated cream white paper. size: 14,8 x 21cm / 5,8 x 8,3 inch. open edition. comes with the official Rabbit Eye Movement stamp. Out Of Body Experience is #8 of a series of thirty artworks presented in the book 1111. Illustrated and narrated by NYCHOS, published by Rabbit Eye Movement in 2020.. ...
It had long been thought that rodents primarily use their heads rather than their eyes to orient toward salient stimuli (Schneider, 1969). However, with recent advances in high-speed video technology (Stahl, 2004) saccade-like eye movements have been documented in mice with amplitude and speed similar to that of other species (Sakatani and Isa, 2004, 2007). In this study we show that saccadic eye movements can be evoked by microstimulation in the SC, and the amplitudes of these eye movements depend on the stimulation locations. Our results suggest that eye movements in mice and their topographic representations may share similar circuit mechanisms with other well studied species. Given the abundance of genetic tools available in mice, our findings provide an important foundation for future studies using mice to investigate the organization and developmental of sensorimotor transformations in the SC.. In primates, the purpose of saccades is to target the fovea toward locations of interests in ...
FIGURE 5-1. Clinical evaluation of range of eye movements. Versions and cover test measurements allow the examiner to decide whether the eye movements are normal (no limitation) or limited. Forced duction testing is used to differentiate a restriction (positive resistance to movement of the globe) from a paresis (no resistance to movement of the globe).. FIGURE 5-1. Clinical evaluation of range of eye movements. Versions and cover test measurements allow the examiner to decide whether the eye movements are normal (no limitation) or limited. Forced duction testing is used to differentiate a restriction (positive resistance to movement of the globe) from a paresis (no resistance to movement of the globe).. Was this article helpful?. ...
In the paper by Thurtell and colleagues,1 two patients with epilepsy are described in whom in one stimulation over the frontal eye field (FEF) resulted in dysconjugate contraversive horizontal eye movements and in the other similar eye movements were observed as a result of focal seizures (see page 683). The neural system controlling eye movements, particularly rapid conjugate versive movements, called saccades, is one of the most thoroughly understood neural circuits in the brain. It contains a number of cortical centres, … ...
Human visual perception almost completely relies on the fact that the eyes are able to fixate points within a visual scene. But the term fixation may easily be misunderstood. We never fixate perfectly and we can count ourselfes lucky in this regard, since small eye movements during fixation clearly mediate perception. Fixational eye movements prevent the visual world from fading. My research focusses mainly on microsaccades, small flicks of the eye during intended fixation. For some decades, there was reasonable doubt in the purpose of these small movements. Over the last ten years, however, neurophysiological findings and improved eye-movement-recording techniques pushed the topic over the surface again and doubts diminished in the light of new evidence. If youre interested, take a look at my fairly exhaustive review on that topic in Vision Research.. During my PhD I studied what microsaccades tell us about the workings of the oculomotor system and had a few key insights. In one series of ...
The proposed PhD project will develop and study pattern recognition methods and machine learning techniques for context inference based on eye movement analysis. Potential applications are in activity and health monitoring, location-awareness, assisted living, and cognition-aware user interfaces. The research will be experimental, using portable eye tracking equipment and wearable sensor systems, and will involve user studies and data collection in daily life settings. In addition to experimental skills, the work will require to develop a thorough understanding of pattern recognition, machine learning and statistical signal processing techniques suitable for inferring various aspects of context from eye movements ...
Recent research suggests that when people retrieve information from memory they tend to fixate on the location where the information had appeared during encoding. We used this phenomenon to investigate if different information is activated in memory when people use a rule- versus a similarity-based decision strategy. In two studies, participants first memorized multiple pieces of information about various job candidates (exemplars). In subsequent test trials they judged the suitability of new candidates that varied in their similarity to the previously learned exemplars. Results show that when using similarity, but not when using a rule, participants fixated longer on the previous location of exemplars that resembled the new candidates than on the location of dissimilar exemplars. This suggests that people using similarity retrieve previously learned exemplars, whereas people using a rule do not. The study illustrates that eye movements can provide new insights into the memory processes ...
submitted by [email protected] We are seeking research participants in a study investigating how our eyes move when locating hidden objects. Participants will have their eye movements monitored while they complete a series of computerized visual search tasks. Eligible participants will be given $5 for their participation in this brief experiment.. All adults over 18 years of age with normal or corrected-to-normal vision are eligible to participate. The task takes less than 30 minutes to complete, and there are no anticipated risks to participation. Please contact Samantha Kong via email ([email protected]) if you are interested in participating.. ...
Looking for online definition of oculomotor response in the Medical Dictionary? oculomotor response explanation free. What is oculomotor response? Meaning of oculomotor response medical term. What does oculomotor response mean?
Background/hypothesis: With the video head impulse test (vHIT), the vertical VOR gain is defined as (vertical eye velocity/vertical head velocity), but compensatory eye movements to vertical canal stimulation usually have a torsional component. To minimize the contribution of torsion to the eye movement measurement, the horizontal gaze direction should be directed 40° from straight ahead so it is in the plane of the stimulated canal plane pair. Hypothesis: as gaze is systematically moved horizontally away from canal plane alignment, the measured vertical VOR gain should decrease.Study design: Ten healthy subjects, with vHIT measuring vertical eye movement to head impulses in the plane of the left anterior-right posterior (LARP) canal plane, with gaze at one of five horizontal gaze positions [40°(aligned with the LARP plane), 20°, 0°, −20°, −40°].Methods: Every head impulse was in the LARP plane. The compensatory eye movement was measured by the vHIT prototype system. The one operator delivered
The purpose of eye movements is to ensure clear, optimal vision. In order to see clearly, images must be held steady on the retina. Best visual acuity is achieved when the image of the object of interest is brought to and held on the fovea of the retina. Two main types of eye movements are responsible for that: those that keep images stable on the retina (gaze holding mechanisms) and those that change the line of sight (gaze shifting mechanisms). Several functional classes of eye movements have been defined; each has distinctive physiological properties that suit best to its particular task. Thus, vestibular and optokinetic eye movements hold images of the seen world steady on the retina during perturbations of the head. Saccades are rapid eye movements that bring the image of an object of interest, detected in the periphery of vision, onto the fovea where it can be seen best. Smooth pursuit eye movements place the images of a moving target close to fovea. Vergence eye movements place the images ...
Eye movement prediction by Kalman filter with integrated linear horizontal oculomotor plant mechanical model - The goal of this paper is to predict future horizontal eye movement trajectories within a specified time interval. To achieve this goal a linear horizontal oculomotor plant mechanical model is developed. The model consists of the eye globe and two extraocular muscles: lateral and medial recti. The model accounts for such anatomical properties of the eye as muscle location, elasticity, viscosity, eyeglobe rotational inertia, muscle active state tension, length tension and force velocity relationships. The mathematical equations describing the oculomotor plant mechanical model are transformed into a Kalman filter form. Such transformation provides continuous eye movement prediction with a high degree of accuracy. The model was tested with 21 subjects and three multimedia files. Practical application of this model lies with direct eye gaze input and interactive displays systems as a method to
Schizophrenic patients are heterogeneous with respect to voluntary eye movement performance, with some showing impairment (e.g., high antisaccade error rates) and others having intact performance. To investigate how this heterogeneity may correlate with different cognitive outcomes after treatment, we used a prosaccade and antisaccade task to investigate the effects of haloperidol in schizophrenic subjects at three time points: baseline (before medication), 3-5days post-medication, and 12-14days post-medication. We also investigated changes on the Stroop Task and the Positive and Negative Syndrome Scale (PANSS) in these same subjects. Results were compared to matched controls. When considered as a single patient group, haloperidol ...
The problem of moving the eyes to fixate a new target in space (or indeed any other movement) entails two separate issues: controlling the amplitude of movement (how far), and controlling the direction of the movement (which way). The amplitude of a saccadic eye movement is encoded by the duration of neuronal activity in the lower motor neurons of the oculomotor nuclei. As shown in Figure 20.6, for instance, neurons in the abducens nucleus fire a burst of action potentials prior to abducting the eye (by causing the lateral rectus muscle to contract) and are silent when the eye is adducted. The amplitude of the movement is correlated with the duration of the burst of action potentials in the abducens neuron. With each saccade, the abducens neurons reach a new baseline level of discharge that is correlated with the position of the eye in the orbit. The steady baseline level of firing holds the eye in its new position. Figure 20.6Motor neuron activity in relation to saccadic eye movements. The experimental
In the past few years, there has been an explosion of eye movement research in cognitive science and neuroscience. This has been due to the availability of off the shelf eye trackers, along with software to allow the easy acquisition and analysis of eye movement data. Accompanying this has been a realisation that eye movement data can be informative about many different aspects of perceptual and cognitive processing.
In the past few years, there has been an explosion of eye movement research in cognitive science and neuroscience. This has been due to the availability of off the shelf eye trackers, along with software to allow the easy acquisition and analysis of eye movement data. Accompanying this has been a realisation that eye movement data can be informative about many different aspects of perceptual and cognitive processing.
Short presentation of a large moving pattern elicits an ocular following response that exhibits many of the properties attributed to low-level motion processing such as spatial and temporal integration, contrast gain control and divisive interaction between competing motions. Similar mechanisms have been demonstrated in V1 cortical activity in response to center-surround gratings patterns measured with real-time optical imaging in awake monkeys (see poster of Reynaud et al., VSS09). Based on a previously developed Bayesian framework, we have developed an optimal statistical decoder of such an observed cortical population activity as recorded by optical imaging. This model aims at characterizing the statistical dependence between early neuronal activity and ocular responses and its performance was analyzed by comparing this neuronal read-out and the actual motor responses on a trial-by-trial basis. First, we show that relative performance of the behavioral contrast response function is similar to the
TY - JOUR. T1 - Reduced rapid eye movement latency. A predictor of recurrence in depression. AU - Giles, Donna E.. AU - Jarrett, Robin B.. AU - Roffwarg, Howard P.. AU - Rush, A. John. PY - 1987/12. Y1 - 1987/12. N2 - In this longitudinal study of 25 successfully treated depressed patients, rapid eye movement (REM) latency during an episode of depression was evaluated as a predictor of recurrence. Patients with reduced REM latency prior to treatment were more likely to develop another episode of depression during the follow-up period.. AB - In this longitudinal study of 25 successfully treated depressed patients, rapid eye movement (REM) latency during an episode of depression was evaluated as a predictor of recurrence. Patients with reduced REM latency prior to treatment were more likely to develop another episode of depression during the follow-up period.. KW - Depression. KW - Longitudinal studies. KW - Rapid eye movement. KW - Sleep. UR - ...
Reflex eye movements occur during linear head movements to maintain ocular fixation on visual targets. Some theoretical considerations and experimental findings are presented in this chapter to support a compensatory role for the LVOR. The discussion is limited to primates since their visual-vestibular interactions and target fixation are improved by binocular foveate vision and depth perception. It is concluded that three LVORS - the horizontal response to IA motion, the vertical response to DV motion, and both the horizontal and vertical responses to 5 Hz NO motion - show characteristics consistent with the kinematics of ideal compensatory eye movements that help maintain stable
List of causes of Abnormal eye movements and Gait disorder, alternative diagnoses, rare causes, misdiagnoses, patient stories, and much more.
Patients with neuropsychiatric disorders, in particular schizophrenia, show a variety of eye movement abnormalities that putatively reflect alterations of perceptual inference, learning and cognitive control. While these abnormalities are consistently found at the group level, a particularly difficult and important challenge is to translate these findings into clinically useful tests for single patients. In this paper, we argue that generative models of eye movement data, which allow for inferring individual computational and physiological mechanisms, could contribute to filling this gap. We present a selective overview of eye movement paradigms with clinical relevance for schizophrenia and review existing computational approaches that rest on (or could be turned into) generative models. We conclude by outlining desirable clinical applications at the individual subject level and discuss the necessary validation studies. ...
We describe an experiment in which the eye movements of participants, carrying out tasks using two contrasting graph designs, were recorded by means of a remote eye tracking device. A variety of eye movement properties were measured and analysed both temporally and spatially. Both graph designs were based on specific psychological theories and established graph design guidelines. One incorporated attributes thought likely to enhance usability, the other included attributes likely to have the opposite effect. The results demonstrate that the design and location of a graphs legend and its spatial relationship to the data area are extremely important in determining a graphs usability. The incorporation of these and other design features may promote or detract from perceptual proximity and therefore influence a displays usability. The paper demonstrates that this influence is reflected in eye movement patterns, which can be readily monitored by means of a remote eye tracking system, and that a ...
The cortical area called frontal eye field (FEF) plays an important role in the control of visual attention and eye movements.[3] Electrical stimulation in the FEF elicits saccadic eye movements. The FEF have a topographic structure and represents saccade targets in retinotopic coordinates.[4]. The frontal eye field is reported to be activated during the initiation of eye movements, such as voluntary saccades[5] and pursuit eye movements.[6] There is also evidence that it plays a role in purely sensory processing and that it belongs to a fast brain system through a superior colliculus - medial dorsal nucleus - FEF ascending pathway.[7]. In humans, its earliest activations in regard to visual stimuli occur at 45 ms with activations related to changes in visual stimuli within 45-60 ms (these are comparable with response times in the primary visual cortex).[7] This fast brain pathway also provides auditory input at even shorter times starting at 24 ms and being affected by auditory ...
The influence of eye movements on hand use and pervasive stereotypies in Rett syndrome was studied, to better understand the developmental abnormality in this disorder. Nine patients in the post-regression phase were offered objects. As expected, the
In internuclear opthalmoplegia, for horizontal movements, the adducting eye is slowed while the abducting eye typically has normal velocity and has a nystagmus. This is covered in much more detail below under the heading of asymmetrical saccadic slowing. For vertical eye movements, the MLF appears to primarily carry posterior canal signals and anterior canal derived eye movements are spared (Cremer et al, 1999). Breaks in binocular fusion may occur in patients with INO (Mills et al, 2008).. Ocular myasthenia may cause weakness of all ocular muscles, or be restricted to individual muscles. Thus, the horizontal-vertical distinction does not help in the diagnosis. Rather, the diagnosis is usually made via observation of fluctuation of ocular alignment from minute to minute, restriction of eye movement to the central range, and post-saccadic drift (see following section on post-saccadic drift for an example). Myasthenics may also develop a progressive slowing of saccades over time, due to fatigue ...
TY - JOUR. T1 - Comparison of eye movements between Developmental Eye Movement test (DEM) and silent reading of sentence. AU - Ikeda, Yuka. AU - Hayakawa, Tomoe. AU - Momose, Keiko. AU - Matsuoka, Kumiko. PY - 2016/7. Y1 - 2016/7. UR - http://www.scopus.com/inward/record.url?scp=84982267277&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=84982267277&partnerID=8YFLogxK. M3 - Article. AN - SCOPUS:84982267277. VL - 9. SP - 573. EP - 580. JO - Folia Japonica de Ophthalmologica Clinica. JF - Folia Japonica de Ophthalmologica Clinica. SN - 1882-5176. IS - 7. ER - ...
The present study aimed to analyze and compare the eye movements of beginning (2nd grade) and more skilled (4th grade) readers, during reading words and pseudo-words aloud, that differ in frequency (just for words), regularity and length. In this way, one intends to analyze the process of visual information extraction, by both groups, and detect experience and practice-related changes in the ocular behavior. The eye movements of 34 children were monitored, while these were reading words/pseudo-words lists, and this was accomplished using eye-tracking technology. The results show statistically significant differences between the two groups, in mean and total fixations duration for high-frequency words, in mean fixation duration for regular words and in the mean saccade amplitude in irregular pseudo-words. However, no significant differences were found between the groups on the study of the other variables. Nevertheless, the results suggest that skilled readers tend to show more effective eye ...
Visual problems can affect up to two thirds of stroke patients. Visual problems can affect up to two thirds of stroke patients, but can sometimes go undetected if patients do not recognise them as an after-effect of the condition or if they are unable to communicate the problem to their medical team or families. Research has often focused on visual field loss, caused by an interruption in the pathways that deliver an image from the eye to the brain for processing. Study led by scientists at Liverpool, however, has shown that damage to the nerve supply that controls eye movement is also a common problem after a stroke. Impaired eye movement can impact on the ability to follow a moving object or read words on a page. Treatments include exercises to strengthen the eye muscles when looking at objects close to the face, as well as prisms that can be fitted to glasses to join double vision. The research highlights the need for developing stricter assessment methods to ensure vision problems are ...
The effect of face inversion has been heavily studied, whereas fewer studies have investigated inversion in scenes. We investigated the influence of scene inversion on decisions and contextual guidance of eye movements during visual search. A saccade contingent display termination paradigm was used to assess the temporal dynamics of the effect. Observers searched for a computer mouse in office scenes and performed a yes/no detection task. Observers sensitivity (d) was lower for inverted images relative to upright. Observers false positive rate decreased with additional eye movements when they viewed upright images, but remained constant during the first three eye movements when viewing inverted images. The average distance of observers eye movements to the target location was greater for inverted than upright scenes. We interpret that inverting an image disrupts the rapid extraction of scene gist, subsequently disrupting guidance in eye movement behavior and slowing the process of rejecting ...
Fixation changes in glaucoma are generally overlooked, as they are not strikingly evident as in macular diseases. Fundus perimetry might give additional insights into this aspect, along with traditional perimetric measures. In this work we propose a novel method to quantify glaucomatous changes in fixation features as detected by fundus perimetry and relate them to the extent of glaucomatous damage. We retrospectively analysed fixation data from 320 people (200 normal subjects and 120 with glaucoma) from the Preferred Retinal Locus (PRL) detection of a Compass perimeter. Fixation stability was measured as Bivariate Contour Ellipse Area (BCEA), and using two novel metrics: (1) Mean Euclidean Distance (MED) from the Preferred Retinal Locus, and (2) Sequential Euclidean Distance (SED) of sequential fixation locations. These measures were designed to capture the spread of fixation points, and the frequency of position changes during fixation, respectively. In the age corrected analysis, SED was
Rapid Eye Movement wasis a brilliant fanzine. Sadly departed R.E.M. ed. Simon Dwyers inspired delving yielded-up a celebrated corpus sublime. Mining a rare seam, Simon hewed from a fissure where music, politics, culture and the occult converged (Occulture); always deftly swerving the decent into accursed obscurantism. Hed go on to do a stint at Sounds and eventually launch Occulture in earnest with the 1989 publication of Rapid Eye vol. 1 - this lavish artefact earned Simon his many plaudits. Of interest here though are the 3 early issues of Rapid Eye Movement featuring collaborators Alan Anger, Mick Dwyer and Lol Loveitt. These fanzines soar way above most other contenders, primarily on account of their searching interviews; check out the in-depth chats with Scritti Politti, The Piranhas (5 pages apiece), Patrik Fitzgerald (7 pages), Tony Parsons & Julie Burchill, and Mark Perry, and you soon get the picture. Theres a profile on the Bridge House (Canning Town) namechecking gaffers Tony ...
Deep brain stimulation; Parkinson??s Disease; Oculomotor function; Neurophysiology; Eye movement; Neurodegeneration; DEEP BRAIN-STIMULATION; SUBTHALAMIC NUCLEUS; OCULAR MOVEMENTS; LEVODOPA; IMPROVEMENT; SACCADES; ...
Crawford, T J and Broerse, A and den Boer, J A (2001) Parsing Cognition in Schizophrenia Using Saccadic Eye Movements. Neuropsychologia, 39. pp. 742-756. ISSN 0028-3932. Full text not available from this repository ...
2004. Beck, J.C., Gilland, E., Tank, D.W., Baker, R. Quantifying the ontogeny of optokinetic and vestibuloocular behaviors in zebrafish, medaka, and goldfish.J. Neurophysiology 92(6), 3546-61 (2004). [Full Text/PDF]. Beck, J.C., Gilland, E., Baker, R., Tank, D.W. Instrumentation for measuring oculomotor performance and plasticity in larval organisms. Methods in Cell Biology (76), 385-413 (2004).. Major, G., Baker, R., Aksay, E., Mensh, B., Seung, H.S. and Tank, D.W., Plasticity and tuning by visual feedback of the stability of a neural integrator. Proc. Natl. Acad. Sci. U.S.A. 101 (20), 7739-7744 (2004). [Fulltext/PDF]. Major, G., Baker, R., Aksay, E., Seung, H.S. and Tank, D.W., Plasticity and tuning of the time course of analog persistent firing in a neural integrator. Proc. Natl. Acad. Sci. U.S.A. 101(20), 7745 (2004) [Fulltext/PDF]. Mensh, B.D., Aksay, E., Lee, D.D., Seung, H.S. and Tank, D.W. Spontaneous eye movements in goldfish: Oculomotor integrator performance, plasticity, and ...
These muscles are innervated by motor neurons that have electrical activity with a tonic component that controls the position of the eye, and a phasic component that controls the velocity of eye movement. Even though the eye position commands and the eye velocity commands are linear functions of the firing frequency of the motor neuron, they are separate sets of commands. The eye velocity commands are sent along a direct path from specialized brain formations or fields to the motor neurons. However, the eye position commands are the products of the integration of eye velocity commands sent along an indirect path to a network of neurons that functions as a neural integrator. It is the output of the integrator that provides eye position commands to the motor neurons.. The integration of signals from different groups of neurons in the oculomotor system control five types of eye movement, each with a unique function and distinctive properties. These types are: saccades, pursuit, vestibular ocular ...
In 9 fetuses studied, the median number of eye movements at 18 weeks after conception were 25 per hour, increasing to 101 per hour at 34 weeks ...
The ability to conduct a visual search for an object in a naturalistic scene is a crucial component of everyday interactions with the environment. This process requires the recognition of different items, accessing stored semantic knowledge about those items and their relationships with other objects, and guiding vision based on that knowledge. Classical models of attention emphasize low-level visual salience maps for attentional guidance. However, behavioral studies increasingly support a role for object knowledge in guiding attention and eye movements. Despite strong behavioral evidence that conceptual information about objects and scenes is critical for real world guidance of attention, very little is known about the neural basis of the guidance of attention based on meaning.. Previous human imaging studies have identified several brain regions that represent object and scene/context knowledge as it relates to visual recognition. In particular, regions of the temporal lobes (inferior temporal ...
Eye movement desensitization and reprocessing (EMDR) is seen as a promising treatment option for fear-related psychiatric diseases such as post-traumatic stress disorder (PTSD). Indeed, experimental studies have shown that performing goal-directed eye movements following recall of autobiographical episodic memories can reduce the vividness and emotionality of these memories. However, the effect of goal-directed eye movements on retention of fear memory has not been tested directly, and critically, the mechanisms by which eye movements may affect mnemonic processes remain poorly understood. Previous research suggests that performing tasks involving endogenous attention suppresses neural activity in the default mode network (DMN), a large-scale brain network which includes the ventromedial prefrontal cortex (vmPFC) and medial temporal lobe regions such as the amygdala and hippocampus. These regions are also critically implicated in fear and safety learning. We therefore hypothesized that ...
Mannan, S.K., Hodgson, T.L., Husain, M. and Kennard, C. (2008) Eye movements in visual search indicate impaired saliency processing in Parkinsons disease. Progress in Brain Research, 171, pp. 559-562. ISSN (print) 0079-6123 ...
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A fundamental task performed by many visual systems is to distinguish apparent motion caused by eye movements from real motion occurring within the environment. During saccadic eye movements, this task is achieved by inhibitory signals of central and retinal origin that suppress the output of motion-detecting neurons. To investigate the retinally-generated component of this suppression, we used a computational model of a locust looming-detecting pathway that experiences saccadic suppression. This model received input from the camera of a mobile robot that performed simple saccade-like movements, allowing the models response to simplified real stimuli to be tested. Retinally-generated saccadic suppression resulted from two inhibitory mechanisms within the looming-detectors input architecture. One mechanism fed inhibition forward through the network, inhibiting the looming-detectors initial response to movement. The second spread inhibition laterally within the network, suppressing the ...