Oculomotor Data Research Articles

Visual Recognition Analysis of Optically Long Tunnels: Interaction of Dynamic Vision and Visual Perception

To understand the relation between the geometric design of optically long tunnels and visibility of the exit area, in this study oculomotor (eye movement) data are collected from several drivers in Yunnan Province, China, and drivers’ fixation rate and saccade amplitude in the visible zone of the tunnel are measured as key indicators. The driver’s visual recognition is analyzed and key elements in the optimal design of the exit points of optically long tunnels are discussed. The results show that visual recognition is closely associated with the radius of the road curvature: as the radius of curve decreases, the visual focus is gradually attracted to the inner side of the curve, the proportion of small-angle saccade increases, and the dispersion of the saccade amplitude decreases.

Neural substrates of saccadic adaptation: Plastic changes versus error processing and forward versus backward learning

Previous behavioral, clinical, and neuroimaging studies suggest that the neural substrates of adaptation of saccadic eye movements involve, beyond the central role of the cerebellum, several, still incompletely determined, cortical areas. Furthermore, no neuroimaging study has yet tackled the differences between saccade lengthening (“forward adaptation”) and shortening (“backward adaptation”) and neither between their two main components, i.e. error processing and oculomotor changes. The present fMRI study was designed to fill these gaps. Blood-oxygen-level-dependent (BOLD) signal and eye movements of 24 healthy volunteers were acquired while performing reactive saccades under 4 conditions repeated in short blocks of 16 trials: systematic target jump during the saccade and in the saccade direction (forward: FW) or in the opposite direction (backward: BW), randomly directed FW or BW target jump during the saccade (random: RND) and no intra-saccadic target jump (stationary: STA). BOLD signals were analyzed both through general linear model (GLM) approaches applied at the whole-brain level and through sensitive Multi-Variate Pattern Analyses (MVPA) applied to 34 regions of interest (ROIs) identified from independent 'Saccade Localizer’ functional data. Oculomotor data were consistent with successful induction of forward and backward adaptation in FW and BW blocks, respectively. The different analyses of voxel activation patterns (MVPAs) disclosed the involvement of 1) a set of ROIs specifically related to adaptation in the right occipital cortex, right and left MT/MST, right FEF and right pallidum; 2) several ROIs specifically involved in error signal processing in the left occipital cortex, left PEF, left precuneus, Medial Cingulate cortex (MCC), left inferior and right superior cerebellum; 3) ROIs specific to the direction of adaptation in the occipital cortex and MT/MST (left and right hemispheres for FW and BW, respectively) and in the pallidum of the right hemisphere (FW). The involvement of the left PEF and of the (left and right) occipital cortex were further supported and qualified by the whole brain GLM analysis: clusters of increased activity were found in PEF for the RND versus STA contrast (related to error processing) and in the left (right) occipital cortex for the FW (BW) versus STA contrasts [related to the FW (BW) direction of error and/or adaptation]. The present study both adds complementary data to the growing literature supporting a role of the cerebral cortex in saccadic adaptation through feedback and feedforward relationships with the cerebellum and provides the basis for improving conceptual frameworks of oculomotor plasticity and of its link with spatial cognition.

Visual attention and inhibitory control in children, teenagers and adults with autism without intellectual disability: results of oculomotor tasks from a 2-year longitudinal follow-up study (InFoR)

BackgroundInhibitory control and attention processing atypicalities are implicated in various diseases, including autism spectrum disorders (ASD). These cognitive functions can be tested by using visually guided saccade-based paradigms in children, adolescents and adults to determine the time course of such disorders.MethodsIn this study, using Gap, Step, Overlap and Antisaccade tasks, we analyzed the oculomotor behavior of 82 children, teenagers and adults with high functioning ASD and their peer typically developing (TD) controls in a two-year follow-up study under the auspices of the InFoR-Autism project. Analysis of correlations between oculomotors task measurements and diagnostic assessment of attentional (ADHD-RS and ADHD comorbidity indices) and executive functioning (BRIEF scales) were conducted in order to evaluate their relationship with the oculomotor performance of participants with ASD.ResultsAs indicated by the presence of a Gap and Overlap effects in all age groups, the oculomotor performances of ASD participants showed a preserved capability in overt attention switching. In contrast, the difference in performances of ASD participants in the Antisaccade task, compared to their TD peers, indicated an atypical development of inhibition and executive functions. From correlation analysis between our oculomotor data and ADHD comorbidity index, and scores of attention and executive function difficulties, our findings support the hypothesis that a specific dysfunction of inhibition skills occurs in ASD participants that is independent of the presence of ADHD comorbidity.LimitationsThese include the relatively small sample size of the ASD group over the study’s two-year period, the absence of an ADHD-only control group and the evaluation of a TD control group solely at the study’s inception.ConclusionsChildren and teenagers with ASD have greater difficulty in attention switching and inhibiting prepotent stimuli. Adults with ASD can overcome these difficulties, but, similar to teenagers and children with ASD, they make more erroneous and anticipatory saccades and display a greater trial-to-trial variability in all oculomotor tasks compared to their peers. Our results are indicative of a developmental delay in the maturation of executive and attentional functioning in ASD and of a specific impairment in inhibitory control.

Preserved eye movements in adults with spinal muscular atrophy.

Spinal muscular atrophy (SMA) most prominently affects proximal limb and bulbar muscles. Despite older case descriptions, ocular motor neuron palsies or other oculomotor abnormalities are not considered part of the phenotype. We investigated oculomotor function by testing saccadic eye movements of 15 patients with SMA. Their performance was compared with that of age-matched healthy controls. Horizontal rightward and leftward saccades were recorded by means of video-oculography, whereas subjects looked at light-emitting diode targets placed at ±5°, ±10°, and ±15° eccentricities. No differences in saccade amplitude gains, peak velocities, peak velocity-to-amplitude ratios, or durations were observed between controls and patients. More specifically, for 5° target eccentricities, patients had a mean saccadic peak velocity of 153°/s, whereas for 10° and 15° these values were 268°/s and 298°/s, respectively. The corresponding mean peak velocities of the control group were 151°/s, 264°/s, and 291°/s. Our results indicate that patients with SMA perform fast and accurate horizontal saccades without evidence of extraocular muscle weakness. These quantitative oculomotor data corroborate clinical experience that neuro-ophthalmic symptoms in SMA are not common and, if present, should prompt suspicion for an alternative neuromuscular disorder.

Incidental learning of a visuo-motor sequence modulates saccadic amplitude: Evidence from the serial reaction time task.

This study examined the changes in saccadic amplitude associated with learning a visual sequence. The oculomotor system gradually adjusts saccadic parameters when tracking a visual stimulus, which has a predictable trajectory. In these contexts, the change in saccadic amplitudes leads to predictive fixations. That is, fixations made to a position in the visual field, where a visual stimulus is anticipated to appear. This study tested whether learning a sequence of visual target movements on the serial reaction time (SRT) task would affect saccadic amplitudes and in turn lead to predictive fixations. Participants in this study were 40 healthy adults who completed the SRT task. Both manual reaction times (RTs) and eye movements were recorded. Analyses of manual RT data showed that at the group level, the sequence was learnt. Analyses of the oculomotor data revealed saccadic amplitudes decreased, following repeated exposures to the visual sequence. Also, increasingly more accurate predictive fixations were observed, following multiple exposures to the sequence. Additional analyses revealed sequence learning related changes in manual RTs, and saccadic amplitudes were not correlated. This study demonstrates the oculomotor system can acquire information about the sequence on the SRT task to update saccadic amplitudes. The nonsignificant correlation between manual RTs and saccadic amplitudes may be indicating sequences are represented differently by the manual and oculomotor systems. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Eye tracking metrics to screen and assess cognitive impairment in patients with neurological disorders

Eye tracking is a powerful method to investigate the relationship between behavior and neural mechanisms. In recent years, eye movement analysis has been used in patients with neurological disorders to assess cognitive function. In this review, we explore the latest eye tracking researches in neurological disorders that are commonly associated with cognitive deficits, specifically, amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and epilepsy. We focus on the application of ocular measures in these disorders, with the goal of understanding how eye tracking technology can be used in the clinical setting. Eye tracking tasks (especially saccadic tasks) are often used as an adjunct to traditional scales for cognitive assessment. Eye tracking data confirmed that executive dysfunction is common in PD and ALS, whereas AD and MS are characterized by attention deficits. Research in evaluating cognitive function in epilepsy using eye tracking is still in its early stages, but this approach has shown advantages as a sensitive quantitative method with high temporal and spatial resolution. Eye tracking technology can facilitate the assessment of cognitive impairment with higher temporal resolution and finer granularity than traditional cognitive assessment. Oculomotor data collected during cognitive tasks can provide insight into biological processes. Eye tracking provides a nonverbal and less cognitively demanding method of measuring disease progression in cognitively impaired patients.

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

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

Normative Oculomotor and Vestibular Data in Pediatric Population

Normative Oculomotor and Vestibular Data in Pediatric Population

Quantitative comparison of a mobile and a stationary video-based eye-tracker

Vision represents the most important sense of primates. To understand visual processing, various different methods are employed—for example, electrophysiology, psychophysics, or eye-tracking. For the latter method, researchers have recently begun to step outside the artificial environments of laboratory setups toward the more natural conditions we usually face in the real world. To get a better understanding of the advantages and limitations of modern mobile eye-trackers, we quantitatively compared one of the most advanced mobile eye-trackers available, the EyeSeeCam, with a commonly used laboratory eye-tracker, the EyeLink II, serving as a gold standard. We aimed to investigate whether or not fully mobile eye-trackers are capable of providing data that would be adequate for direct comparisons with data recorded by stationary eye-trackers. Therefore, we recorded three different, commonly used eye movements—fixations, saccades, and smooth-pursuit eye movements—with both eye-trackers, in successive standardized paradigms in a laboratory setting with eight human subjects. Despite major technical differences between the devices, most eye movement parameters were not statistically different between the two systems. Differences could only be found in overall gaze accuracy and for time-critical parameters such as saccade duration, for which a higher sample frequency is especially useful. Although the stationary EyeLink II system proved to be superior, especially on a single-subject or even a single-trial basis, the ESC showed similar performance for the averaged parameters across both trials and subjects. We concluded that modern mobile eye-trackers are well-suited to providing reliable oculomotor data at the required spatial and temporal resolutions.

LACTOSE control scoring helps predict surgical outcomes for childhood intermittent exotropia

ObjectiveTo determine whether preoperative Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scores can predict surgical outcomes in children with intermittent exotropia. DesignRetrospective interventional case series from a university-based tertiary eye care centre. ParticipantsA total of 350 patients with basic-type intermittent exotropia who underwent bilateral lateral rectus recession between 3 and 10 years of age from January 2014 to December 2017. MethodsAll patients were preoperatively assessed for their degree of control at both distance and near according to LACTOSE scoring system. Demographic, clinical, and oculomotor data before and after surgery were collected and analyzed with regard to the degree of control. Surgical success was defined as an alignment between 10 prism diopters (PD) of exodeviation and 5 PD of esodeviation at both distance and near. ResultsYounger age, lower visual acuity, worse stereoacuity, and larger angle of deviation were associated with higher (i.e., worse) LACTOSE control scores. Of the 350 patients having surgery, 169 (48.3%) were followed for more than 12 months postoperatively. Surgical success was achieved in 132 (78.1%) patients at 12 months after surgery. The only significant predictor of surgical success was preoperative LACTOSE score. There was a significant inverse relationship between LACTOSE scores and surgical success rates for both distance and near scores (p = 0.004 and 0.023, respectively). ConclusionsHigher distance and near LACTOSE scores representing worse control of deviation were associated with higher rates of surgical failure in children with intermittent exotropia. This finding indicates that surgical outcome of intermittent exotropia can be predicted by preoperative LACTOSE scores.

Oculometric assessment of dynamic visual processing.

Eye movements are the most frequent (∼3/s), shortest-latency (∼150-250 ms), and biomechanically simplest (one joint, no inertial complexities) voluntary motor behavior in primates, providing a model system to assess sensorimotor disturbances arising from trauma, fatigue, aging, or disease states. We have developed a 15-min behavioral tracking protocol consisting of randomized Rashbass (1961) step-ramp radial target motion to assess several aspects of the behavioral response to visual motion, including pursuit initiation, steady-state tracking, direction tuning, and speed tuning. We show how oculomotor data can be converted into direction- and speed-tuning oculometric functions, with large increases in efficiency over traditional button-press psychophysics. We also show how the latter two can be converted into standard visual psychometric thresholds. To assess our paradigm, we first tested for the psychometric criterion of repeatability, and report that our metrics are reliable across repeated sessions. Second, we tested for the psychometric criterion of validity, and report that our metrics show the anticipated changes as the motion stimulus degrades due to spatiotemporal undersampling. Third, we documented the distribution of these metrics across a population of 41 normal observers to provide a thorough quantitative picture of normal human ocular tracking performance, with practice and expectation effects minimized. Our method computes 10 metrics that quantify various aspects of the eye-movement response during a simple 15-min clinical test, which could be used as a screening or assessment tool for disorders affecting sensorimotor processing, including degenerative retinal disease; developmental, neurological or psychiatric disorders; strokes; and traumatic brain injury.

Formal Detection of Attentional Tunneling in Human Operator–Automation Interactions

The allocation of visual attention is a key factor for the humans when operating complex systems under time pressure with multiple information sources. In some situations, attentional tunneling is likely to appear and leads to excessive focus and poor decision making. In this study, we propose a formal approach to detect the occurrence of such an attentional impairment that is based on machine learning techniques. An experiment was conducted to provoke attentional tunneling during which psycho-physiological and oculomotor data from 23 participants were collected. Data from 18 participants were used to train an adaptive neuro-fuzzy inference system (ANFIS). From a machine learning point of view, the classification performance of the trained ANFIS proved the validity of this approach. Furthermore, the resulting classification rules were consistent with the attentional tunneling literature. Finally, the classifier was robust to detect attentional tunneling when performing over test data from four participants.

Intersegmental eye-head-body interactions during complex whole body movements.

Using state-of-the-art technology, interactions of eye, head and intersegmental body movements were analyzed for the first time during multiple twisting somersaults of high-level gymnasts. With this aim, we used a unique combination of a 16-channel infrared kinemetric system; a three-dimensional video kinemetric system; wireless electromyography; and a specialized wireless sport-video-oculography system, which was able to capture and calculate precise oculomotor data under conditions of rapid multiaxial acceleration. All data were synchronized and integrated in a multimodal software tool for three-dimensional analysis. During specific phases of the recorded movements, a previously unknown eye-head-body interaction was observed. The phenomenon was marked by a prolonged and complete suppression of gaze-stabilizing eye movements, in favor of a tight coupling with the head, spine and joint movements of the gymnasts. Potential reasons for these observations are discussed with regard to earlier findings and integrated within a functional model.

Effect of subthalamic deep brain stimulation on turning kinematics and related saccadic eye movements in Parkinson disease

BackgroundPersons with Parkinson disease (PD) experience turning difficulty, often leading to freezing of gait and falls. Visual information plays a significant role in locomotion and turning, and while the effects of deep brain stimulation (DBS) on oculomotor function have been well documented, the effects of DBS on oculomotor function during turning and on turning itself have yet to be fully elucidated. ObjectiveTo determine the effects of STN DBS on turning performance and related oculomotor performance in PD. MethodsEleven subjects with PD and DBS of the subthalamic nucleus performed a seated voluntary saccade task and standing 180° turns in DBS OFF and DBS ON conditions. Oculomotor data were captured using an infrared eye tracking system while segment rotations were measured using 3-D motion capture. ResultsDuring the seated saccade task, DBS did not improve saccade amplitude or latency. DBS also did not improve gait velocity and stride length during forward walking. During turning, DBS improved turn performance (turn duration), reduced the number of saccades performed during the turns, and increased the amplitude and velocity of the saccade initiating the turn. DBS decreased the intersegmental latencies (eye–head, eye–foot, and head–trunk) but this effect was lost for eye–head and eye–foot after controlling for the duration of the first gait cycle. ConclusionsDBS significantly improves turn performance and related oculomotor performance. These findings add to the growing list of therapeutic benefits offered by DBS.

Saccadic Eye Movements are Related to Turning Performance in Parkinson Disease

Persons with Parkinson disease (PD) experience difficulty turning, leading to freezing of gait and falls. We hypothesized that saccade dysfunction may relate to turning impairments, as turns are normally initiated with a saccade. Determine whether saccades are impaired during turns in PD and if characteristics of the turn-initiating saccade are predictive of ensuing turn performance. 23 persons with PD off medication and 19 controls performed 90 and 180 degree in-place turns to the right and left. Body segment rotations were measured using 3-D motion capture and oculomotor data were captured using a head-mounted eye tracking system and electrooculography. Total number of saccades and the amplitude, velocity, and timing of the first saccade were determined. Turn performance (turn duration, number of steps to turn) was impaired in PD (p<0.05). PD performed more saccades, and the velocity and timing of the first saccade was impaired for both turn amplitudes (p<0.05). Amplitude of the first saccade was decreased in PD during 180 degree turns. Turn duration correlated with oculomotor function. Characteristics of the first saccade explained 48% and 58% of the variance in turn duration for 90 and 180 degree turns, respectively. Turning performance is impaired in PD and may be influenced by saccade dysfunction. An association between saccade function and turning performance may be indicative of the key role of saccades in initiating proper turning kinematics. Future work should focus on improving saccade performance during functional tasks and testing the effects of therapeutic interventions on related outcomes.

Pursuing motion illusions: A realistic oculomotor framework for Bayesian inference

Accuracy in estimating an object’s global motion over time is not only affected by the noise in visual motion information but also by the spatial limitation of the local motion analyzers (aperture problem). Perceptual and oculomotor data demonstrate that during the initial stages of the motion information processing, 1D motion cues related to the object’s edges have a dominating influence over the estimate of the object’s global motion. However, during the later stages, 2D motion cues related to terminators (edge-endings) progressively take over, leading to a final correct estimate of the object’s global motion. Here, we propose a recursive extension to the Bayesian framework for motion processing ( Weiss, Simoncelli, & Adelson, 2002) cascaded with a model oculomotor plant to describe the dynamic integration of 1D and 2D motion information in the context of smooth pursuit eye movements. In the recurrent Bayesian framework, the prior defined in the velocity space is combined with the two independent measurement likelihood functions, representing edge-related and terminator-related information, respectively to obtain the posterior. The prior is updated with the posterior at the end of each iteration step. The maximum-a posteriori (MAP) of the posterior distribution at every time step is fed into the oculomotor plant to produce eye velocity responses that are compared to the human smooth pursuit data. The recurrent model was tuned with the variance of pursuit responses to either “pure” 1D or “pure” 2D motion. The oculomotor plant was tuned with an independent set of oculomotor data, including the effects of line length (i.e. stimulus energy) and directional anisotropies in the smooth pursuit responses. The model not only provides an accurate qualitative account of dynamic motion integration but also a quantitative account that is close to the smooth pursuit response across several conditions (three contrasts and three speeds) for two human subjects.

Eye movements during fixation as velocity noise in minimum motion detection

AbstractThe functional roles and perceptual consequences of fixational eye movements are argued. The retinal image motions due to these eye movements are viewed as normally unnoticed velocity noise that limits performance of minimum motion detection without reference. When the motion detection threshold and the variability of eye velocity during fixation were measured for a group of normal adult observers, an interobserver correlation was established between psychophysical and oculomotor data. In particular, when both eyes were open, the threshold of unreferenced motion was positively correlated with the fixation instability of the eye, making larger drifts. Preliminary data also suggested the possibility that the fixation instability of this eye still dominates the detection threshold if this eye was occluded during the task. Possible schemes of living with such velocity noise as originating from fixation instability are discussed.

Bayesian modeling of dynamic motion integration

The quality of the representation of an object’s motion is limited by the noise in the sensory input as well as by an intrinsic ambiguity due to the spatial limitation of the visual motion analyzers ( aperture problem). Perceptual and oculomotor data demonstrate that motion processing of extended objects is initially dominated by the local 1D motion cues, related to the object’s edges and orthogonal to them, whereas 2D information, related to terminators (or edge-endings), takes progressively over and leads to the final correct representation of global motion. A Bayesian framework accounting for the sensory noise and general expectancies for object velocities has proven successful in explaining several experimental findings concerning early motion processing [Weiss, Y., Adelson, E., 1998. Slow and smooth: a Bayesian theory for the combination of local motion signals in human vision. MIT Technical report, A.I. Memo 1624]. In particular, these models provide a qualitative account for the initial bias induced by the 1D motion cue. However, a complete functional model, encompassing the dynamical evolution of object motion perception, including the integration of different motion cues, is still lacking. Here we outline several experimental observations concerning human smooth pursuit of moving objects and more particularly the time course of its initiation phase, which reflects the ongoing motion integration process. In addition, we propose a recursive extension of the Bayesian model, motivated and constrained by our oculomotor data, to describe the dynamical integration of 1D and 2D motion information. We compare the model predictions for object motion tracking with human oculomotor recordings.

Coordination of feeding, locomotor and visual systems in parrotfishes(Teleostei: Labridae)

Fishes require complex coordinated motions of the jaws, body and fins during feeding in order to successfully execute the strike or bite and then move away from the predation site. In conjunction with locomotor systems, sensory modalities guide coordinated feeding behavior, with vision playing an important role in many fishes. Although often studied separately, the locomotor, feeding and visual systems have not previously been examined together during fish feeding. To explore feeding coordination, we examined the kinematics of feeding behavior in two species of herbivorous parrotfish, Sparisoma radians and Scarus quoyi, which exhibit different single bite and repetitive bite strategies. Kinematic data on pectoral fin movements and body position show distinctive differences in strategies for the approach and post-strike motion between these species. Sparisoma and Scarus exhibited significant differences in the magnitude of jaw protrusion, time to maximum jaw protrusion, cranial elevation, and order of events in the feeding sequence. Oculomotor data show that both species orient the pupil forward and downward directed at the site of jaw contact until 100 ms before the bite, at which point the visual field is rotated laterally. Combinations of kinematic variables show repeated patterns of synchrony (onset and duration) for the approach to the food (distance, velocity, eye movement), prey capture (eye movement, jaw movement, fin movement) and post-capture maneuvering (fin movement, distance). Kinematic analyses of multiple functional systems reveal coordination mechanisms for detecting and approaching prey and executing the rapid opening and closing of the jaws during acquisition of food. Comparison of the coordination of feeding, swimming and sensory systems among fish species can elucidate alternative coordination strategies involved in herbivory in coral reef fishes.

Abstracts of the 13th European Conference on Eye Movements 2005

This issue contains the abstracts submitted for presentation at the Thirteenth European Conference on Eye Movements (ECEM13), Bern, August 14 – 18, 2005, and reviewed by the Scientific Board, consisting of W. Becker, Ulm; C.J. Erkelens, Utrecht; J.M. Findlay, Durham; A.G. Gale, Derby; C.W. Hess, Bern; J. Hyönä, Turku; A. Kennedy, Dundee; K. Koga, Nagoya; G. Lüer, Göttingen; M. Menozzi, Zürich; W. Perrig, Bern; G. d’Ydewalle, Leuven; D. Zambarbieri, Pavia. A quarter of a century ago, in 1980 initiated by Rudolf Groner and Dieter Heller, a transdisciplinary network called European Group of Scientists active in Eye Movement Research was founded. This group included scientists who used eye movement registration as a research tool and developed models based on oculomotor data obtained from a wide spectrum of phenomena, ranging from the neurophysiological to the perceptual and the cognitive level. The group was intended to serve the purpose of (1) exchanging information about current research, equipment and software, (2) organizing a conference (ECEM) at a different location all over Europe every other year. Over the years ECEM has grown. At the first conference in Bern the relatively small number of participants made it possible for the organisers to avoid conflicting parallel sessions, whereas with the ECEM’s steady growth, the introduction of parallel sessions soon became necessary. Although we are very happy about this year’s new record of 273 scientific contributions, we regret at the same time that this large number of participants necessitated the introduction of no less than four parallel sessions for oral presentations. Part of the ECEM culture are the books with a selection of edited contributions which have traditionally always been published after the conferences. Unfortunately, over the years the sale prices of books have become prohibitively expensive and book chapters have increasingly been given a low rating in comparison to publications in peer reviewed journals. As a consequence of this trend, we are now considering to launch an online journal Eye Movement Research which would publish scientific papers either on the base of individual submissions by the authors or as a follow-up of workshops or thematic sessions at ECEM. In either case, a fair peer reviewing process should guarantee a high quality of the contributions. Acknowledgements Last but not least, we are happy to express our deep gratitude to the main sponsors of our conference and to all the people who helped to keep it going. The Max and Elsa Beer-Brawand Foundation generously funded the invited speakers. The Swiss Academy of Humanities and Social Sciences (SAGW) sponsored the organization of workshops and made it possible for us to reduce fees for students. Novartis Neuroscience sponsored the reception at the Zentrum Paul Klee Bern. The University of Bern hosted the conference in its magnificent historical building. A team of devoted young scientists acted as staff during the conference: Eva Siegenthaler, Liliane Braun, Miriam Lörtscher, Esther Schollerer, Daniel Stricker, Simon Raess, Philipp Sury, Bartholomäus Wissmath, Linda Bodmer, Martina Brunnthaler, Daniela Häberli, Nadine Messerli, Felicie Notter, Didier Plaschy, Svetlana Ognjanovi, David Weibel, Yves Steiner and Dominik Moser. We dedicate this book to the memory of two important men in eye movement research: Dieter Heller as one of the founders of the ECEM group, and Lawrence W. Stark as pioneer in cognitive modelling of oculomotor control. In an early planning stage of ECEM13 both had been invited as keynote speakers, but their untimely death made this plan impossible. In many sessions of ECEM13 the influence of their work will prevail.