Eye Tracking and Oculomotor Control

The advancement of wireless sensor networks yields a variety of wireless sensor network for wildlife tracking. One typical application for wireless sensor networks is in animal tracking and monitoring in wildlife environments. A significant number of studies have been done in tracking animals with sensor networks. However from the recent literature it is observed that there is no much study has been done on an intelligent real time sensor network that is capable to alerting the rangers an incidence of animal poaching before it happened. In this paper an intelligent wireless sensor system for tracking and monitoring rhinos and elephants is proposed.

Football penalty kicks are having increasing influence in today’s professional game. Despite this, little scientific evidence currently exists to ascertain the mechanisms behind performance failure in this task and/or the efficacy of training designed to improve penalty shooting. In a football penalty kick it has been reported that the majority of kickers do not look to the area they wish to place the ball; preferring to focus on the ‘keeper and predict anticipatory movements before shooting. Such a strategy seems counterproductive and contradictory to current research findings regarding visually guided aiming. Coordination of eye and limb movements has been shown to be essential for the production of accurate motor responses. A disruption to this coordination not only seems to negatively affect performance, but subsequent motor responses seem to follow direction of gaze. Thus, where the eyes lead actions tend to follow. In study 1, ten participants were asked to kick a standard sized football to alternate corners of a goal, whilst looking centrally and whilst looking where they intended to hit. This disruption of eye-limb coordination brought about a 15% reduction in kicking accuracy. When participants were asked to fixate centrally, their shots hit more centrally (17cm) than when they were allowed to look where they intended to hit. These results were in spite of no significant differences between the number of missed shots, preparation time and ball speed data across conditions. We concluded that centrally focused fixations dragged resultant motor actions inwards towards more central target locations. Put simply, where the eyes looked shots tended to follow. The second study sought to test the predictions of attentional control theory (ACT) in a sporting environment in order to establish how anxiety affects performance in penalty kicks. Fourteen experienced footballers took penalty kicks under low- and high-threat counterbalanced conditions while wearing a gaze registration system. Fixations to target locations (goalkeeper and goal area) were determined using frame-by-frame analysis. When anxious, footballers made faster first fixations and fixated for significantly longer toward the goalkeeper. This disruption in gaze behaviour brought about significant reductions in shooting accuracy, with shots becoming significantly centralized and within the goalkeeper’s reach. These findings support the predictions of ACT, as anxious participants were more likely to focus on the “threatening” goalkeeper, owing to an increased influence of the stimulus-driven attentional control system. A further prediction of ACT is that when anxious, performers are more likely to be distracted, particularly if the distracter is threat related. When facing penalty kicks in football (soccer), goalkeepers frequently incorporate strategies that are designed to distract the kicker. However, no direct empirical evidence exists to ascertain what effect such visual distractions have on the attentional control, and performance, of footballers. In the third study, eighteen experienced footballers took five penalty kicks under counterbalanced conditions of threat (low vs. high) and goalkeeper movement (stationary vs. waving arms) while wearing eye-tracking equipment. Results suggested that participants were more distracted by a moving goalkeeper than a stationary one and struggled to disengage from a moving goalkeeper under situations of high threat. Significantly more penalties were saved on trials when the goalkeeper was moving and shots were also generally hit closer to the goalkeeper (centrally) on these trials. The results provide partial support for the predictions of attentional control theory and implications for kickers and goalkeepers are discussed. The previous studies showed that anxiety can disrupt visual attention, visuomotor control and subsequent shot location in penalty kicks. However, optimal visual attention has been trained in other far aiming skills, improving performance and resistance to pressure. In study 4, we therefore asked a team of ten university soccer players to follow a quiet eye (QE; Vickers, 1996) training program, designed to align gaze with aiming intention to optimal scoring zones, over a seven week period. Performance and gaze parameters were compared to a placebo group (ten players) who received no instruction, but practiced the same number of penalty kicks over the same time frame. Results from a retention test indicated that the QE trained group had more effective visual attentional control; were significantly more accurate; and had 50% fewer shots saved by the goalkeeper than the placebo group. Both groups then competed in a penalty shootout to explore the influence of anxiety on attentional control and shooting accuracy. Under the pressure of the shootout the QE trained group failed to maintain their accuracy advantage, despite maintaining more distal aiming fixations of longer duration. The results therefore provide only partial support for the effectiveness of brief QE training interventions for experienced performers. This series of studies are the first to explore the gaze behaviour of football penalty takers in a quest to uncover and understand anxiety’s negative influence on attentional control and performance. They are also the first to explore the efficacy of goalkeeper distractions and training in improving performance from both the goalkeeper’s and kicker’s perspective. The results of these studies conclude that when anxious, penalty takers show an attentional bias toward the ‘threatening’ goalkeeper that can be increased and utilised by a goalkeeper employing distraction techniques and that penalty takers do benefit, to some extent, from a gaze-based pre-shot routine

Visual perception is most often studied as a "passive" process in which an observer fixates steadily at point in space so that stimuli can be delivered to the system with spatial precision. Analysis of neuronal signals related to vision is generally keyed to stimulus onset, stimulus movement, etc.; i.e., events external to the observer. In natural "active" vision, however, information is systematically acquired by using eye movements including rapid (saccadic) eye movements, as well as smooth ocular pursuit of moving objects and slower drifts. Here we consider the use of alternating saccades and fixations to gather information from a visual scene. The underlying motor sampling plan contains highly reliable information regarding "where" and "when" the eyes will land, this information can be used predictively to modify firing properties of neurons precisely at the time when this "contextual" information is most useful-when a volley of retinal input enters the system at the onset of each fixation. Analyses focusing on neural events leading to and resulting from shifts in fixation, as well as visual events external to the observer, can provide a more complete and mechanistic understanding of visual information processing. Studies thus far suggest that active vision may be a fundamentally different from that process we usually study with more traditional passive viewing paradigms. In this Perspective we note that active saccadic sampling behavior imposes robust temporal patterning on the activity of neuron ensembles and large-scale neural dynamics throughout the brain's visual pathways whose mechanistic effects on information processing are not yet fully understood. The spatio-temporal sequence of eye movements elicits a succession of temporally predictable quasi-rhythmic sensory inputs, whose encoding is enhanced by entrainment of low frequency oscillations to the rate of eye movements. Review of the pertinent findings underscores the fact that temporal coordination between motor and visual cortices is critical for understanding neural dynamics of active vision and posits that phase entrainment of neuronal oscillations plays a mechanistic role in this process.

This study examined the range and reliability of individual differences in several oculomotor measures. One thousand participants were tested using standard smooth pursuit and pro- and antisaccade paradigms. In the smooth pursuit task, the variables of interest were the root mean square error of eye position, gain (ratio of eye velocity to target velocity), and number and type of intruding saccades. In the saccadic tasks, the variables of interest were accuracy, latency distribution and velocity characteristics. We report the range and distribution of these variables, as well as correlations between them. We also report a number of internal consistency reliability measures for these variables, as well as test–retest reliabilities based on a randomly selected 10% of the sample.

Anxiety has been shown to disrupt visual attention, visuomotor control and subsequent shot location in soccer penalty kicks. However, optimal visual attention has been trained in other far aiming skills, improving performance and resistance to pressure. We therefore asked a team of ten university soccer players to follow a quiet eye (QE; Vickers, 1996) training program, designed to align gaze with aiming intention to optimal scoring zones, over a seven week period. Performance and gaze parameters were compared to a placebo group (ten players) who received no instruction, but practiced the same number of penalty kicks over the same time frame. Results from a retention test indicated that the QE trained group had more effective visual attentional control; were significantly more accurate; and had 50% fewer shots saved by the goalkeeper than the placebo group. Both groups then competed in a penalty shootout to explore the influence of anxiety on attentional control and shooting accuracy. Under the pressure of the shootout the QE trained group failed to maintain their accuracy advantage, despite maintaining more distal aiming fixations of longer duration. The results therefore provide only partial support for the effectiveness of brief QE training interventions for experienced performers.

People with anxiety disorders show an attentional bias for threat (AB), and Attention Bias Modification (ABM) procedures have been found to reduce this bias. However, the underlying processes accounting for this effect remain poorly understood. One explanation suggests that ABM requires the modification of attention control, driven by the recruitment of the dorsolateral prefrontal cortex (DLPFC). In the present double-blind study, we examined whether modifying left DLPFC activation influences the effect of ABM on AB. We used transcranial direct current stimulation (tDCS) to directly modulate cortical excitability of the left DLPFC during an ABM procedure designed to reduce AB to threat. Anodal tDCS increases excitability, whereas cathodal tDCS decreases it. We randomly assigned highly trait-anxious individuals to one of three conditions: 1) ABM combined with cathodal tDCS, 2) ABM combined with anodal tDCS, or 3) ABM combined with sham tDCS. We assessed the effects of these manipulat...

When facing penalty kicks in football (soccer), goalkeepers frequently incorporate strategies that are designed to distract the kicker. However, no direct empirical evidence exists to ascertain what effect such visual distractions have on the attentional control, and performance, of footballers. Eighteen experienced footballers took five penalty kicks under counterbalanced conditions of threat (low vs. high) and goalkeeper movement (stationary vs. waving arms) while wearing eye-tracking equipment. Results suggested that participants were more distracted by a moving goalkeeper than a stationary one and struggled to disengage from a moving goalkeeper under situations of high threat. Significantly more penalties were saved on trials when the goalkeeper was moving and shots were also generally hit closer to the goalkeeper (centrally) on these trials. The results provide partial support for the predictions of attentional control theory and implications for kickers and goalkeepers are discussed.

This thesis investigates the expenditure of cognitive effort in post-editing of machine translation. A mixed-method approach involving the use of eye movements, subjective ratings and think-aloud protocols was adopted for the investigation. The project aims at revealing connections between cognitive effort and variables including linguistic characteristics of the source text and the machine-translation output, post-editors’ individual traits, different linguistic aspects of the activity attended to during the task, and the quality of the post-edited texts, assessed by human translators in terms of fluency (linguistic quality) and adequacy (faithfulness to the source text). Two tasks were conducted to pursue these aims: one involving eye tracking and a self-report scale of cognitive effort, and another carried out by a different, but comparable, sample of participants, under a think-aloud condition. Results indicate that variables such as an automatic machine-translation quality score and source-text type-token ratio are good predictors of cognitive effort in post-editing. The relationship between cognitive effort and post-editors’ traits was found to be a complex one, with significant links in this respect only appearing in the context of interactions between variables. A complex relationship was also found between editing behaviour and the quality of the post-edited text: the number of changes implemented was found to have a generally positive association with post-edited fluency, though cognitive effort was found to be negatively correlated with both the fluency and adequacy of the post-edited texts. Mental processes involving grammar and lexis were significantly related to the levels of cognitive effort expended by participants. These were also the aspects most frequently attended to in the activity. From a methodological perspective, despite the criticisms received by the think-aloud method in previous research, empirical data obtained in this project indicates that think-aloud protocols correlate with eye movements and subjective ratings as measures of cognitive effort.

The consequences of very preterm birth are long-lasting and cognitive outcomes do not seem to have improved over the last decades. Adolescents born very preterm showed impairments in neurocognitive processes that are involved in cognitive control. On the contrary, processes that do not require cognitive control, such as the involuntary control of eye movements and implicit sequence learning, were not impaired. The deficits in cognitive control were found to play an important role in the impairments in intelligence, academic performance, inattentive behavior, and social problems that were observed in adolescents born very preterm. In future research, a shift is to be made from studying group-level outcomes to studying the large individual differences in outcomes after very preterm birth. This will provide more insight in the specific difficulties of certain subgroups of children and will help us understand which children have an increased risk for poor outcomes. This aids the early identification of high-risk infants that may benefit from close monitoring and early support and the development of prevention and intervention strategies targeting factors that contribute to adverse outcomes after very preterm birth. In addition, there is a need for a more holistic approach of child development, in which the contribution of various interacting biological and environmental factors to functioning across a range of developmental
domains should be considered. The findings in this thesis emphasize that the improvement of outcomes after very preterm birth should receive the highest priority.

The aim of this study was to test the predictions of attentional control theory using the quiet eye period as an objective measure of attentional control. Ten basketball players took free throws in two counterbalanced experimental conditions designed to manipulate the anxiety they experienced. Point of gaze was measured using an ASL Mobile Eye tracker and fixations including the quiet eye were determined using frame-byframe analysis. The manipulation of anxiety resulted in significant reductions in the duration of the quiet eye period and free throw success rate, thus supporting the predictions of attentional control theory. Anxiety impaired goal-directed attentional control (quiet eye period) at the expense of stimulus-driven control (more fixations of shorter duration to various targets). The findings suggest that attentional control
theory may be a useful theoretical framework for examining the relationship between anxiety and performance in visuomotor sport skills.

The current study sought to test the predictions of attentional control theory (ACT) in a sporting environment. Fourteen experienced footballers took penalty kicks under low- and high threat counterbalanced conditions while wearing a gaze registration system. Fixations to target locations (goalkeeper and goal area) were determined using frame-by-frame analysis. When anxious, footballers made faster first fixations and fixated for significantly longer toward the goalkeeper. This disruption in gaze behavior brought about significant reductions in shooting accuracy, with shots becoming significantly centralized and within the goalkeeper’s reach. These findings support the predictions of ACT, as anxious participants were more likely to focus on the “threatening” goalkeeper, owing to an increased influence of the stimulus-driven attentional control system.

Brain-electric correlates of reading have traditionally been studied with word-by-word presentation, a condition that eliminates important aspects of the normal reading process and precludes direct comparisons between neural activity and oculomotor behavior. In the present study, we investigated effects of word predictability on eye movements (EM) and fixation-related brain potentials (FRPs) during natural sentence reading. Electroencephalogram (EEG) and EM (via video-based eye track- ing) were recorded simultaneously while subjects read heterogeneous German sentences, moving their eyes freely over the text. FRPs were time-locked to first-pass reading fixations and analyzed according to the cloze probability of the currently fixated word. We replicated robust effects of word predictability on EMs and the N400 component in FRPs. The data were then used to model the relation among fixation duration, gaze duration, and N400 amplitude, and to trace the time course of EEG effects relative to effects in EM behavior. In an extended Methodological Discussion section, we review 4 technical and data-analytical problems that need to be addressed when FRPs are recorded in free-viewing situations (such as reading, visual search, or scene perception) and propose solutions. Results suggest that EEG recordings during normal vision are feasible and useful to consolidate findings from EEG and eye-tracking studies.

Our visual system is fovea-heavy, which means that in-depth processing occurs only in the centre of
the retina, forcing the eyes to make constant movements in order to bring visual elements into focus. Despite this, eye movements go largely unnoticed and the environment is perceived as visually stable. Pre-saccadic shifts of attention might be guaranteeing this stability by easing the transition from one foveated image to another. Before an eye movement attention shifts to the location where the eyes will land and visual elements presented there are preferentially processed. A similar mechanism, also based on the allocation of attention in eye-centred coordinates, is known as remapping. It allows attention to be maintained on locations of interest across eye movements, while accounting for the retinal displacement caused by each upcoming movement. In the current thesis, we are concerned with how the visual elements present in the environment shape the allocation of attention before eye movements. We first aimed to determine whether pre-saccadic shifts of attention are a precondition of all saccades, irrespective of goals. We showed that whether the saccade was goal-directed, to the intended target, or involuntary, erroneously directed to a capturing distractor, made little difference to the pre-saccadic shift of attention. Retinal displacement caused by involuntary saccades was also accounted for by the visual system. Next, the project focused on how the presented visual elements affect the programming of eye movements, by investigating how the decision to make an eye movement is affected by the number of target alternatives. We saw evidence that a larger set-size can reduce saccadic reaction times without increasing the error rate, a finding not predicted by a popular model. Further, whether the presence of visual elements in and around the saccade landing point influences the shifts of attention was investigated. We demonstrate that objects and their arrangement shape the distribution of attention, and that the effect is not driven by saccade metrics alone. Finally, we look at the spatial and temporal distribution of visual attention when a saccade target is removed shortly before the eye movement.

Neural correlates of word recognition are commonly studied
with (rapid) serial visual presentation (RSVP), a condition
that eliminates three fundamental properties of natural reading:
parafoveal preprocessing, saccade execution, and the fast
changes in attentional processing load occurring from fixation
to fixation. We combined eye-tracking and EEG to systematically
investigate the impact of all three factors on brainelectric
activity during reading. Participants read lists of
words either actively with eye movements (eliciting fixationrelated
potentials) or maintained fixation while the text moved
passively through foveal vision at a matched pace (RSVP-withflankers
paradigm, eliciting ERPs). The preview of the upcoming
word was manipulated by changing the number of
parafoveally visible letters. Processing load was varied by presenting
words of varying lexical frequency. We found that all
three factors have strong interactive effects on the brain’s responses
to words: Once a word was fixated, occipitotemporal
N1 amplitude decreased monotonically with the amount of
parafoveal information available during the preceding fixation;
hence, the N1 component was markedly attenuated
under reading conditions with preview. Importantly, this preview
effect was substantially larger during active reading (with
saccades) than during passive RSVP with flankers, suggesting
that the execution of eye movements facilitates word recognition
by increasing parafoveal preprocessing. Lastly, we
found that the N1 component elicited by a word also reflects
the lexical processing load imposed by the previously inspected
word. Together, these results demonstrate that, under
more natural conditions, words are recognized in a spatiotemporally
distributed and interdependent manner across multiple
eye fixations, a process that is mediated by active motor
behavior.

Random variables and probabilistic decision making are important elements in most theories of reading eye movements, but they tend to receive little theoretical attention. This paper attempts to address this problem by introducing the Stochastic, Hierarchical Architecture for Reading Eye-movements (SHARE). The SHARE framework formalizes reading eye movements as observable outcomes of a latent stochastic process. By modeling eye movements as time-series random variables, the goal of the model is to uncover statistical regularities in the data, which help to identify conditions and constraints the underlying mechanism must satisfy. In the univariate analysis, it is shown that a 3-component Lognormal mixture model provides a good fit to the marginal distribution function of fixation duration, and a hierarchical model is required for modeling saccade length. As a comprehensive model of reading eye movements, SHARE was implemented as an Input–Output Hidden Markov model. With a few simple hypotheses, SHARE is able to capture reading eye movement patterns of beginning readers and proficient adults, and to reproduce well-known psycholinguistic effects. The rationale of the model, its relations with other modeling endeavors, and its implications are discussed.

Human locomotion through natural environments requires precise coordination between the biomechanics of the bipedal gait cycle and the eye movements that gather the information needed to guide foot placement. However, little is known about how the visual and locomotor systems work together to support movement through the world. We developed a system to simultaneously record gaze and full-body kinematics during locomotion over different outdoor terrains. We found that not only do walkers tune their gaze behavior to the specific information needed to traverse paths of varying complexity but that they do so while maintaining a constant temporal look-ahead window across all terrains. This strategy allows walkers to use gaze to tailor their energetically optimal preferred gait cycle to the upcoming path in order to balance between the drive to move efficiently and the need to place the feet in stable locations. Eye movements and locomotion are intimately linked in a way that reflects the integration of energetic costs, environmental uncertainty, and momentary informational demands of the locomotor task. Thus, the relationship between gaze and gait reveals the structure of the sensorimotor decisions that support successful performance in the face of the varying demands of the natural world.

The visual performance of athletes should be considered high on the list of variables fundamental to elite sport performance. One particular aspect of visual performance that has gained dominance over the last 25 years is the quiet eye. Quiet eye is the final visual fixation of long, steady duration prior to the execution of a motor skill. However, as the concept of quiet eye has achieved dominance in the field of motor control, we know increasingly less about the visual behavior that precedes the onset of it. This is especially true for externally-paced interceptive tasks such as baseball hitting. The present study collected data on the visual scene using mobile eye trackers, as experienced by 58 professional baseball players during batting practice. The results suggest that athletes exhibit multiple dynamic shifts in visual fixation prior to the onset of quiet eye and the pitcher's action. Furthermore, cluster analysis revealed a significant positive relationship between the number of shifts in visual fixations and batting average, indicating that this visual skill may contribute to more efficient interception of the ball. The purpose of these dynamic shifts in visual fixation are proposed, alongside a call for further research to develop a deeper understanding of this pre-task visual behavior and its role in sport performance.

Purpose A primary task of the eye care professional is determining the refraction, or optical correction , of a patient. The duochrome red-green test is a standard tool for verification of the final refraction. Traditionally, it is recommended for use both prior to and subsequent to determining the cylindrical or astigmatic component of the refraction. In order for it to be effective when used before correcting the cylinder it is necessary that the COLC (Circle of Least Confusion) be on the retina. This study examined whether it is necessarily true that the duo-chrome response in uncorrected astigmatism will be as trustworthy as it is with corrected cylinders. Methods The red-green examination was performed monocularly under the following three conditions: a. fully corrected refraction for the subgroup of eyes that had spherical refractions and for the subgroup of eyes with sphero-cylindrical refractions. b. best sphere-only correction without cylinder correction in sphero-cylindrical eyes c. an induced cylinder error in spherical eyes. The interval between the last " red " response and the first " green " response for the right eyes as a group and separately for the physiological cylinder and induced cylinder correction subgroups was calculated and compared using a paired, two-tailed t-test. Results The intervals between " red " and " green " responses were not significantly different in the population as a whole and in the uncorrected physiological cylinder and induced cylinder subgroups examined.

A primary task of the eye care professional is determining the refraction, or optical correction, of a patient. The duochrome red-green test is a standard tool for verification of the final refraction. Traditionally, it is recommended for use both prior to and subsequent to determining the cylindrical or astigmatic component of the refraction. In order for it to be effective when used before correcting the cylinder it is necessary that the COLC (Circle of Least Confusion) be on the retina. This study examined whether it is necessarily true that the duochrome response in uncorrected astigmatism will be as trustworthy as it is with corrected cylinders. Methods The red-green examination was performed monocularly under the following three conditions: a. fully corrected refraction for the subgroup of eyes that had spherical refractions and for the subgroup of eyes with sphero-cylindrical refractions. b. best sphere-only correction without cylinder correction in sphero-cylindrical eyes c. an induced cylinder error in spherical eyes. The interval between the last "red" response and the first "green" response for the right eyes as a group and separately for the physiological cylinder and induced cylinder correction subgroups was calculated and compared using a paired, two-tailed t-test. Results The intervals between "red" and "green" responses were not significantly different in the population as a whole and in the uncorrected physiological cylinder and induced cylinder subgroups examined.

In this paper gaze shifts are considered as a realization of a stochastic process with non-local transition probabilities in a saliency ÿeld that represents a landscape upon which a constrained random walk is performed. The search is driven by a Langevin equation whose random term is generated by a Levy distribution, and by a Metropolis algorithm. Results of the simulations are compared with experimental data, and a notion of complexity is introduced to quantify the behavior of the system in di erent conditions.

It has been suggested that when footballers take penalty kicks they generally focus on the goalkeeper, ignoring the target area. In experiment 1, we tested the implications of this strategy by constraining gaze centrally while asking participants to hit distal locations. When gaze was constrained, resultant shots became significantly centralised despite the participants striving to hit distal locations. In experiment 2, the gaze behaviour of kickers was analysed when taking penalty kicks with a goalkeeper present. Three distinct shooting strategies were identified and the most prominent strategy implemented was a ‘keeper-focused strategy. Individual analyses revealed that the utilisation of these strategies is highly variable within and between participants. However, better shooters used a target-focused approach more frequently, while the poorer shooters used a ‘keeper-focused strategy. Implications and future research directions are outlined

There has been growing interest of late in the cognitive effort required by post-editing of machine translation. Compared to number of editing operations, cogni-tive (or mental) effort is frequently considered a more decisive indicator of the overall effort expended by post-editors. Estimating cognitive effort is not straightforward, however. Previous studies often triangulate different measures to obtain a consensus, but little post-editing research to date has attempted to show how measures of cogni-tive effort relate to each other in a multivariate analysis. This paper addresses this by presenting an exploratory comparison of cognitive measures based on eye tracking, pauses, editing time, and subjective ratings collected in a post-editing task carried out by professional and non-professional participants. All measures correlated with each other, but a principal components analysis showed that the measures cluster together in different ways. In particular, measures that increase with task time alone behaved differently from the others, with higher mutual associations and higher reliability. Regarding differences between professional and non-professional participants, it was observed that subjective ratings were overall more strongly associated with objective measures in the case of professionals. Surprising findings from previous research based on pause ratio are discussed. The paper argues that a pause typology will benefit the study of pause lengths and cognitive effort in post-editing.

Degrading real-world scenes in the central or the peripheral visual field yields a characteristic pattern: Mean saccade amplitudes increase with central and decrease with peripheral degradation. Does this pattern reflect corresponding modulations of selective attention? If so, the observed saccade amplitude pattern should reflect more focused attention in the central region with peripheral degradation and an attentional bias toward the periphery with central degradation. To investigate this hypothesis, we measured the detectability of peripheral (Experiment 1) or central targets (Experiment 2) during scene viewing when low or high spatial frequencies were gaze-contingently filtered in the central or the peripheral visual field. Relative to an unfiltered control condition, peripheral filtering induced a decrease of the detection probability for peripheral but not for central targets (tunnel vision). Central filtering decreased the detectability of central but not of peripheral targets. Additional post hoc analyses are compatible with the interpretation that saccade amplitudes and direction are computed in partial independence. Our experimental results indicate that task-induced modulations of saccade amplitudes reflect attentional modulations.

Why does English have spaces between words but not Chinese or Japanese? What did we invent punctuations? I argue in this paper that spaces and punctuations were created -- at least in part -- to guide eye movements. I call them paraorthographics.

Objectives: To compare the wettability and wetting time between open and closed eyes of post menopausal women using Schirmer's test without anaesthesia (ST) and to assess the number of dry eyes in open (STO) and closed (STC) schirmer test. Methods: One-Hundred and Twenty eyes of 60 normal Post-Menopausal women were recruited from Sri Ramachandra University. Schirmer test (ST) was performed in a closed environment with the absence of air flow. This procedure was performed with the subjects both eyes open and closed with an interval of 1 hour and were conducted in 5 minutes. If wetting values are 35 mm before 5 minutes, wetting time should be recorded. Results: In this study 120 eyes of 60 Post-menopausal women were included. Measurements of ST I performed with open eyes (27.0 ± 9.5) were higher statistical different from those performed with closed eyes (17.5 ± 11.0) in right eye of the patients. Measurements of ST I performed with open eyes (27.5 ± 9.9) were higher statistical different from those performed with closed eyes (19.0 ± 11.4) in left eye of the patients. Wetting time of ST I performed with open eyes (4.1 ± 1.2) were lower statistical different from those performed with closed eyes (4.7 ± 0.8) in right eye of the patients. Wetting time of ST I performed with open eyes (4.1 ± 1.2) were lower statistical different from those performed with closed eyes (4.6 ± 0.8) in left eye of the patients. The p value from measurements of ST I for right and left eye was 0.0005 and the p value from wetting time for right and left eye was 0.0005, so, there was a significant change between open and closed eyes. Conclusion: ST performed with open and closed eyes can have an important influence in the diagnosis of dry eyes in post-menopausal women.

The pro and anti-saccade task (PAT) is a widely used tool in the study of overt and covert attention with promising potential role in neurocognitive and psychiatric assessment. However, specific PAT protocols can vary significantly between labs, potentially resulting in large variations in findings across studies. In light of recent calls towards a standardization of PAT the current study's objective was to systematically and purposely evaluate the effects of block vs. interleaved administration-a fundamental consideration-on PAT measures in a within subject design. Additionally, this study evaluated whether measures of a Posner-type cueing paradigm parallels measures of the PAT paradigm. As hypothesized, results indicate that PAT performance is highly susceptible to administration mode. Interleaved mode resulted in larger error rates not only for anti (blocks: M = 22%; interleaved: M = 42%) but also for pro-saccades (blocks: M = 5%; interleaved: M = 12%). This difference between block and interleaved administration was significantly larger in anti-saccades compared to pro-saccades and cannot be attributed to a 'speed/accuracy tradeoff'. Interleaved mode produced larger pro and anti-saccade differences in error rates while block administration produced larger latency differences. Results question the reflexive nature of pro-saccades, suggesting they are not purely reflexive. These results were further discussed and compared to previous studies that included within subject data of blocks and interleaved trials.

Vestibulo-Ocular Reflex (VOR) abnormalities in cerebellar ataxias are a matter of renewed interest. We have previously reported vestibular areflexia in a group of Yemenite-Jews with Spinocerebellar Ataxia Type 3 (SCA3) who had clear bilateral pathological horizontal Head Impulse Test (HIT). The objective of this study was to evaluate the VOR of ten SCA3 patients who have variable bedside HIT responses by recording their eye movements using magnetic search coils and to correlate these results with their clinical and genetic data. Eight out of the ten patients have abnormal horizontal HIT detected by both clinical bedside examination and laboratory tests. Results of bedside HIT testing were significantly correlated with the VOR gain recorded using magnetic search coils. No significant correlations were found between VOR gain and other clinical or genetic data. Our study confirms the presence of defective VOR in SCA3 patients and corroborates the useful of the HIT as a reliable bedside test for diagnosis of VOR deficits.

Prior to an eye movement, attention is gradually shifted towards the point where the saccade will land. Our goal was to better understand the allocation of attention in an oculomotor capture paradigm for saccades that go straight to the eye movement target and for saccades that go to a distractor and are followed by corrective saccades to the target (i.e., involuntary saccades). We also sought to test facilitation at the future retinotopic location of target and non-target objects, with the principal aim of verifying whether the remapping process accounts for the retinal displacement caused by involuntary saccades. Two experiments were run employing a dual-task design, primarily requiring participants to perform saccades towards a target while discriminating an asymmetric cross presented briefly before saccade onset. The results clearly show perceptual facilitation at the target location for goal-directed saccades and at the distractor location when oculomotor capture occurred. Facilitation was observed at a location relating to the remapping of a future saccade landing point, in sequences of oculomotor capture. In contrast, performance remained unaffected at the remapped location of a salient distracting object, which was not looked at. The findings are taken as evidence that pre-saccadic enhancement occurs prior to involuntary and voluntary saccades alike and that the remapping process also indiscriminately accounts for the retinal displacement caused by either.

Very preterm birth is associated with attention deficits that interfere with academic performance. A better understanding of attention processes is necessary to support very preterm born children. This study examined voluntary and involuntary attentional control in very preterm born adolescents by measuring saccadic eye movements. Additionally, these control processes were related to symptoms of inattention, intelligence, and academic performance. Participants included 47 very preterm and 61 full-term born 13-years-old adolescents. Oculomotor control was assessed using the antisaccade and oculomotor capture paradigm. Very preterm born adolescents showed deficits in antisaccade but not in oculomotor capture performance, indicating impairments in voluntary but not involuntary attentional control. These impairments mediated the relation between very preterm birth and inattention, intelligence, and academic performance.

Brain-electric correlates of reading have traditionally been studied with word-by-word presentation, a condition that eliminates important aspects of the normal reading process and precludes direct comparisons between neural activity and oculomotor behavior. In the present study, we investigated effects of word predictability on eye movements (EM) and fixation-related brain potentials (FRPs) during natural sentence reading. Electroencephalogram (EEG) and EM (via video-based eye tracking) were recorded simultaneously while subjects read heterogeneous German sentences, moving their eyes freely over the text. FRPs were time-locked to first-pass reading fixations and analyzed according to the cloze probability of the currently fixated word. We replicated robust effects of word predictability on EMs and the N400 component in FRPs. The data were then used to model the relation among fixation duration, gaze duration, and N400 amplitude, and to trace the time course of EEG effects relative to effects in EM behavior. In an extended Methodological Discussion section, we review 4 technical and data-analytical problems that need to be addressed when FRPs are recorded in free-viewing situations (such as reading, visual search, or scene perception) and propose solutions. Results suggest that EEG recordings during normal vision are feasible and useful to consolidate findings from EEG and eye-tracking studies.

PURPOSE:

The purpose of the current research is to understand if the different eye movement abnormalities in patients with the same neurologic disease are related to varied disease processes or, alternately, do different patients adopt different strategies to overcome a singular brain deficiency.
METHODS:

Using a magnetic search coil, we measured saccade dynamics, that is position and velocity waveforms, for patients diagnosed with spinocerebellar ataxia type 3 (SCA-3), also known as Machado-Joseph disease (MJD).
RESULTS:

We observed that the saccadic waveform of the majority of the SCA-3 patients (7 of 10) exhibited dynamic overshoot, with the eye passing the desired endpoint and making a rapid correction before coming to rest. Patients with normal waveforms, that is with no dynamic overshoot, had saccades with relatively low peak velocity.
CONCLUSIONS:

Velocity feedback in a closed loop control system is essential for providing a fast response without overshoot. Lack of a velocity feedback or an imbalance between position and velocity gains yields a tradeoff between response time and overshoot. While the goal of a saccade is to get to the desired position, models based on animal research suggest that the saccadic control also incorporates a velocity feedback. Results presented here indicated that all SCA-3 patients had deviations in the saccadic waveform, albeit of two types, either slow saccades or dynamic overshooting saccades. Using saccadic models based on animal research can explain how a single deficit, that is a mismatched velocity control of the motor error due to the disease, can yield these two different abnormalities in human patients.

PURPOSE:

Dyslexia is a language-based learning disability characterized by difficulties with reading, spelling, and writing. Persons with dyslexia often have deficits in processing rapid temporal sensory information. There is also evidence of sensorimotor deficits in persons with dyslexia. Whether these deficits include ocular motor problems is still an open question. Some previous studies have shown an increased saccadic latency in dyslexics, whereas others have not reproduced this finding. The purpose of the present study was to investigate saccadic latency in young adults with dyslexia during the double-step paradigm, a task that requires rapid sequential visual information processing and saccade generation. The study hypothesis was that dyslexics have a longer saccadic latency in the second orthogonal saccade, a task that nondyslexics parallel process and perform rapidly.
METHODS:

Eight students with dyslexia and eight age-matched control subjects participated in the study. Their eye movements were monitored with the scleral search coil technique in simple saccade trials and in the double-step paradigm. The second saccade was either orthogonal or colinear to the first. Intersaccadic interval and latency were calculated for the second saccade.
RESULTS:

No difference in saccadic latency was found for colinear second saccades; however, dyslexics had significantly longer latencies for orthogonal second saccades. This included a subset of subjects who had longer latencies for orthogonal than for colinear saccades.
CONCLUSIONS:

The findings indicate that under certain conditions, when the demand for rapid visual information processing is high and a rapid saccade sequence is required, some persons with dyslexia show ocular motor deficits manifested by longer saccadic latencies.

Öz: Göz takip teknolojisi, spor ve egzersiz psikolojisi alanında özel ve uygulamalı birçok çalışma yapılabilmesine imkan tanımaktadır. Sürekli gelişmekte olan bu teknoloji, elit ve amatör sporcuların doğal çevrede gerçekleşen görme ve göz hareketleri davranışlarının araştırılması için heyecan verici imkanlar sunmaktadır. Ancak göz hareketlerini izleme fikri oldukça basit olsa da arkasındaki teknoloji oldukça karmaşık ve hassastır. Ayrıca, göz takip sistemini etkin kullanabilmek için ciddi bir bilgi birikimi ve tecrübe gerekmektedir Göz takip sisteminin çok pahalı olması ve elde edilen verilerin analizinin oldukça uzun sürede tamamlanmasından dolayı, söz konusu sistemlere ayrılan kaynakların etkin şekilde kullanılmasını zorunlu kılmaktadır. Bu çalışmada, göz takip sistemi ile spor bilimleri alanında çalışma yapacak araştırmacılara temel bilgilerin kazandırılması amaçlanmıştır. Bu makalenin, göz takip sistemi ile çalışmaya başlayacak araştırmacıların zihinlerinde oluşabilecek soru işaretlerinin cevaplanmasına ve nasıl bir başlangıç yapmaları gerektiği hususunda fikir sahibi olmalarına yardımcı olacağı düşünülmektedir. Abstract: Eye-tracking technology allows special and applied research in sport and exercise psychology field. This technology, already constantly developing, offers thrilling opportunities for natural gaze and eye movement behavior studies of elite and amateur athletes. Though the idea of observing or tracking the eye movements seems simple, the technology behind is quite complicated and sensitive. Also, it necessitates substantial knowledge and experience in both hardware and software. The high cost of eye-tracking and the long time allocated for data analyses requires efficient use of resources. The purpose of this paper is to present basic information to those aiming to study eye-tracking system in the field of sport science. It is expected to help beginners answer the questions considering eye-tracking research and give an idea on how to start. GİRİŞ Spor biliminin günümüzde geldiği noktada, fiziksel ve taktiksel antrenmanın sınırları zorlanmakta; sporcular, rakiplerine göre daha güçlü, hızlı, çabuk ve esnek fiziksel yapıya sahip olmak için daha yoğun çalışmaktadırlar. Yarışmalar/müsabakalar geçmiş yıllara göre daha hızlı oynanmaktadır. Sporcular arasında bulunan fiziksel ve taktiksel beceri farkları giderek azalmaktadır. Sporcunun performans esnasında fiziksel hareketini gerçekleştirmeden hemen önce hızlı karar verme becerisi onu rakibine göre daha üstün konuma getirmektedir. Sporcunun etkili karar verme sürecinde çevresini, rakibini ve cisimleri doğru biçimde algılayabilmesi gerekir. Vickers (2016), spor branşlarında gerçekleşen başarılı performanslarda; görme becerisinin, odaklanmanın ve uygun bölgeye dikkatin yoğunlaştırılmasının kritik rol oynadığını ifade etmiştir. Spor bilimcilerin motor performans üzerinde yaptıkları birçok araştırmada, çeşitli performans görevlerinin etkin bir şekilde yerine getirilebilmesi için sporcunun görsel bilgileri uygun biçimde toplayabilmesinin önemli olduğu vurgulanmıştır (Kredel ve ark., 2017). Fiziksel aktivitenin hemen öncesinde, çevredeki nesnelerin veya kişilerin yeri, hızı, şekli ve konumu; duyu organları ile görme, işitme, dokunma eylemlerinin biri veya tümü ile elde

Objective: The King-Devick (K-D) test is a rapid visual screening tool that can assess underlying brain trauma such as concussion via impairments in saccadic rhythm. A new tablet version of the K-D test using randomised numbers is now available, but reliability for this new version, as well as comparison to the traditional K-D test has not yet been reported. Known for learning effects in the test, the aim of this study was to determine test-retest reliability and to compare performance of the new ‘randomized’ version to the ‘traditional’ K-D test version. We hypothesized that the ‘traditional’ K-D test would show a greater rate of improvement with repeat application, compared to the ‘randomized’ K-D test.
Methods: Using a cross-sectional, repeated measures design in a healthy university student cohort (n=96; 21.6 ± 2.8 years; 49f: 47m), participants were required to complete the K-D test twice with a one-week break between testing sessions. Participants were randomly assigned into a ‘traditional’ group, where they completed a test-retest of the established K-D protocol, using the same numbers; or the ‘randomized’ group, where they completed test-retest protocol employing two different sets of numbers.
Results: Reliability testing showed strong intraclass correlation coefficient (ICC) for both the ‘traditional’ test group (Control group; 0.95 [CI: 0.91 – 0.97]) and the ‘randomized test group’ (0.97 [CI: 0.95 – 0.98]). However, contrary to our hypothesis, no differences were found between ‘traditional’ or ‘randomized’ groups for baseline (42.5 s [CI: 40.2 – 44.9 s] vs. 41.5 [38.7 – 44.4] respectively, p = 0.23) and repeated testing between groups (40.0 s [37.9 – 42.1 s] vs. 39.5 [36.9 – 42.0], p = 0.55), with both groups showing improved times with repeated testing (2.1 s [CI: 1.1 – 3.2 s] and 1.9 s CI: [0.9 – 2.9 s], p < 0.001, respectively).
Conclusions: The ‘randomized’ version of the K-D test, using different sets of numbers, demonstrates good reliability; comparable to the traditional K-D testing protocol that uses the same number sets. However, similar to the ‘traditional’ K-D test, learning effects were also observed in the ‘randomized’ test, suggesting that learning effects are not due to content memorization, but rather familiarity of the test. As a result, while either test format is suitable for sideline concussion screening or return to play decisions, comparison of data should be made to the individual’s baseline rather than to normative data sets.

Artykuł przedstawia refleksje na temat związku między modalnością percepcji wiersza a jego znaczeniem. Obecnie preferowany przez odbiorców wersyfikacji styl uczestnictwa w komunikacji literackiej jest bez wątpienia nie ustny, ale raczej typograficzny. Tak więc, jeśli chcemy zrozumieć samą naturę czytania poezji (wiersza), musimy zrozumieć sposób, w jaki aktualizujemy tekst lub, innymi słowy, jak spisane strony stają się znaczące w naszych umysłach. Zdaniem autora analiza oparta na okulometrii daje możliwość zrozumienia tych procesów.

Słowa kluczowe: wersyfikacja, modalność, rozumienie, prozodia, czytanie, okulometria

The visual system serves two distinct functions. The information acquired by it is used to both create a percept of the external world and to guide motor actions. In recent years there has been considerable debate regarding whether the same information is utilized and processed in the same manner in the two tasks. The Duncker Illusion, also known as induced motion, is an illusion of motion that results when there is background movement, and it neatly dissociates true from perceived motion. We examined the open-loop period of smooth eye tracking of a target that had an illusory component to its trajectory due to background motion. It was found that the eyes moved in the direction of background motion and of true target motion but not in the illusory direction, despite the strong percept of illusory motion experienced by all subjects. This finding lends support to the hypothesis of separate neurological pathways for the processing of visual information used to create the conscious percept and visual information used to drive motor actions.

The astronomical term “main sequence” has been applied to the relationships between
duration, peak velocity, and magnitude of human saccades over a thousandfold range of
magnitude. Infrared photodiodes aimed at the iris-sclera border and a digital computer
were used in experiments to derive the main sequence curves. In the pulse width
modulation model, the duration of the controller signal pulse determines saccadic amplitude
and peak velocity. The hi&-frequency burst of the oculomotoneurons needs to be
only one-half the duration of the saccade, because of the “apparent inertia” of the eyeball.

Visually guided tracking paradigms can provide insight into the adaptability of motor control strategies. We argue that the question of whether a sensorimotor process, or its absence, is beneficial or detrimental for performance is one that needs to be answered relative to the sensory cues available in the environment and the given task constraints. In this paper we describe how and when environmental cues have task-dependent benefits. We used a new pursuit-tracking paradigm and added, removed, or replaced cues within the same tracking task in either predictable or unpredictable environments to investigate the use and adaptability of different control strategies. Participants were invited to perform a tracking task over six blocks in six different conditions. Compared to a condition where both target and control cursor (cues) were visible, performance was maintained when a cue was added and decreased when a cue was removed. Our results show that participants only learned to use new cues if the old one was removed and the replacement was valid. This means that the sensorimotor system adapts only if forced to do so instead of constantly exploiting optimization strategies.

Purpose was to evaluate the subclinical influence of uncomplicated phacoemulsification surgery on foveal thickness in the early
postoperative period.
Materials and methods: This study was conducted on 50 eyes of 44 subjects who underwent uneventful phacoemulsification
in King Faisal Specialist Hospital and Research center (KFSH&RC). They were divided into
Groups: Diabetes mellitus group consisted of 25 eyes (21 diabetic patients), Control group consisted of 25 eyes (23 non-diabetic
patients). Best corrected visual acuity and Optical coherence tomography were recorded preoperatively, 2 weeks, one month and
two months postoperative.
Results: Despite that Mean foveal thickness was stable 2 weeks, 1 month and 2 months postoperative in the control group;
our study showed significant increase in mean foveal thickness (MFT) 1 month and 2 months post-operative in diabetic group
compared to the 2nd week postoperative. However, after converting the MFT into Log OCT, the MFT in diabetic and control groups
was stable postoperatively without any step deterioration.
Conclusion: Diabetic patients may need prophylactic therapy before cataract surgery.