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Willeford KT, Copel V, Rong H. A protocol to quantify cross-sectional and longitudinal differences in duction patterns. Front Neurosci 2024; 18:1324047. [PMID: 38919910 PMCID: PMC11196818 DOI: 10.3389/fnins.2024.1324047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 05/27/2024] [Indexed: 06/27/2024] Open
Abstract
Currently, there is no established system for quantifying patterns of ocular ductions. This poses challenges in tracking the onset and evolution of ocular motility disorders, as current clinical methodologies rely on subjective observations of individual movements. We propose a protocol that integrates image processing, a statistical framework of summary indices, and criteria for evaluating both cross-sectional and longitudinal differences in ductions to address this methodological gap. We demonstrate that our protocol reliably transforms objective estimates of ocular rotations into normative patterns of total movement area and movement symmetry. This is a critical step towards clinical application in which our protocol could first diagnose and then track the progression and resolution of ocular motility disorders over time.
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Affiliation(s)
- Kevin T. Willeford
- Department of Optometric Sciences, NOVA Southeastern University College of Optometry, Fort Lauderdale, FL, United States
| | - Victoria Copel
- Department of Optometric Sciences, NOVA Southeastern University College of Optometry, Fort Lauderdale, FL, United States
| | - Hua Rong
- Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
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2
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Llapashtica E, Sun T, Grattan KTV, Barbur JL. Effects of post-saccadic oscillations on visual processing times. PLoS One 2024; 19:e0302459. [PMID: 38809939 PMCID: PMC11135737 DOI: 10.1371/journal.pone.0302459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 04/03/2024] [Indexed: 05/31/2024] Open
Abstract
Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the peripheral target to the very centre of the fovea. This mechanism extends the use of the superior image processing performance of the fovea over a large visual field. We know that visual information is processed quickly at the end of each saccade but estimates of the times involved remain controversial. This study aims to investigate the processing of visual information during post fixation oscillations of the eyeball. A new psychophysical test measures the combined eye movement response latencies, including fixation duration and visual processing times. When the test is used in conjunction with an eye tracker, each component that makes up the 'integrated saccade latency' time, from the onset of the peripheral stimulus to the correct interpretation of the information carried by the stimulus, can be measured and the discrete components delineated. The results show that the time required to process and encode the stimulus attribute of interest at the end of a saccade is longer than the time needed to carry out the same task in the absence of an eye movement. We propose two principal hypotheses, each of which can account for this finding. 1. The known inhibition of afferent retinal signals during fast eye movements extends beyond the end point of the saccade. 2. The extended visual processing times measured when saccades are involved are caused by the transient loss of spatial resolution due to eyeball instability during post-saccadic oscillations. The latter can best be described as retinal image smear with greater loss of spatial resolution expected for stimuli of low luminance contrast.
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Affiliation(s)
- Emsal Llapashtica
- The Henry Wellcome Laboratories for Vision Science, Centre for Applied Vision Research, School of Health & Psychological Sciences, University of London, London, United Kingdom
| | - Tong Sun
- Department of Engineering, School of Science and Technology, University of London, London, United Kingdom
| | - Kenneth T. V. Grattan
- Department of Engineering, School of Science and Technology, University of London, London, United Kingdom
| | - John L. Barbur
- The Henry Wellcome Laboratories for Vision Science, Centre for Applied Vision Research, School of Health & Psychological Sciences, University of London, London, United Kingdom
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3
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Render A, Eisenbarth H, Oxner M, Jansen P. Arousal, interindividual differences and temporal binding a psychophysiological study. PSYCHOLOGICAL RESEARCH 2024:10.1007/s00426-024-01976-3. [PMID: 38806732 DOI: 10.1007/s00426-024-01976-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/13/2024] [Indexed: 05/30/2024]
Abstract
The sense of agency varies as a function of arousal in negative emotional contexts. As yet, it is unknown whether the same is true for positive affect, and how inter-individual characteristics might predict these effects. Temporal binding, an implicit measure of the sense of agency, was measured in 59 participants before and after watching either an emotionally neutral film clip or a positive film clip with high or low arousal. Analyses included participants' individual differences in subjective affective ratings, physiological arousal (pupillometry, skin conductance, heart rate), striatal dopamine levels via eye blink rates, and psychopathy. Linear mixed models showed that sexual arousal decreased temporal binding whereas calm pleasure had no facilitation effect on binding. Striatal dopamine levels were positively linked whereas subjective and physiological arousal may be negatively associated with binding towards actions. Psychopathic traits reduced the effect of high arousal on binding towards actions. These results provide evidence that individual differences influence the extent to which the temporal binding is affected by high arousing states with positive valence.
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Affiliation(s)
- Anna Render
- Faculty of Human Sciences, University of Regensburg, Regensburg, Germany.
- Victoria University of Wellington, Wellington, New Zealand.
- University of Passau, Passau, Germany.
| | | | - Matt Oxner
- Victoria University of Wellington, Wellington, New Zealand
- Wilhelm Wundt Institute for Psychology, University of Leipzig, Leipzig, Germany
| | - Petra Jansen
- Faculty of Human Sciences, University of Regensburg, Regensburg, Germany
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4
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Guadron L, Titchener SA, Abbott CJ, Ayton LN, van Opstal AJ, Petoe MA, Goossens J. Post-Saccadic Oscillations of the Pupil and Lens Reduce Fixation Stability in Retinitis Pigmentosa and Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2024; 65:39. [PMID: 38787546 PMCID: PMC11129721 DOI: 10.1167/iovs.65.5.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
Purpose Post-saccadic oscillations (PSOs) reflect movements of gaze that result from motion of the pupil and lens relative to the eyeball rather than eyeball rotations. Here, we analyzed the characteristics of PSOs in subjects with age-related macular degeneration (AMD), retinitis pigmentosa (RP), and normal vision (NV). Our aim was to assess the differences in PSOs between people with vision loss and healthy controls because PSOs affect retinal image stability after each saccade. Methods Participants completed a horizontal saccade task and their gaze was measured using a pupil-based eye tracker. Oscillations occurring in the 80 to 200 ms post-saccadic period were described with a damped oscillation model. We compared the amplitude, decay time constant, and frequency of the PSOs for the three different groups. We also examined the correlation between these PSO parameters and the amplitude, peak velocity, and final deceleration of the preceding saccades. Results Subjects with vision loss (AMD, n = 6, and RP, n = 5) had larger oscillation amplitudes, longer decay constants, and lower frequencies than subjects with NV (n = 7). The oscillation amplitudes increased with increases in saccade deceleration in all three groups. The other PSO parameters, however, did not show consistent correlations with either saccade amplitude or peak velocity. Conclusions Post-saccadic fixation stability in AMD and RP is reduced due to abnormal PSOs. The differences with respect to NV are not due to differences in saccade kinematics, suggesting that anatomic and neuronal variations affect the suspension of the iris and the lens in the patients' eyes.
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Affiliation(s)
- Leslie Guadron
- Department of Cognitive Neuroscience, Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
| | - Samuel A. Titchener
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Melbourne, VIC, Australia
| | - Carla J. Abbott
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, VIC, Australia
- Department of Surgery (Ophthalmology), University of Melbourne, Melbourne, VIC, Australia
| | - Lauren N. Ayton
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, Melbourne, VIC, Australia
- Department of Surgery (Ophthalmology), University of Melbourne, Melbourne, VIC, Australia
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - A. John van Opstal
- Section Neurophysics, Donders Institute for Brain Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Matthew A. Petoe
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Melbourne, VIC, Australia
| | - Jeroen Goossens
- Department of Cognitive Neuroscience, Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
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Holmqvist K, Örbom SL, Hooge ITC, Niehorster DC, Alexander RG, Andersson R, Benjamins JS, Blignaut P, Brouwer AM, Chuang LL, Dalrymple KA, Drieghe D, Dunn MJ, Ettinger U, Fiedler S, Foulsham T, van der Geest JN, Hansen DW, Hutton SB, Kasneci E, Kingstone A, Knox PC, Kok EM, Lee H, Lee JY, Leppänen JM, Macknik S, Majaranta P, Martinez-Conde S, Nuthmann A, Nyström M, Orquin JL, Otero-Millan J, Park SY, Popelka S, Proudlock F, Renkewitz F, Roorda A, Schulte-Mecklenbeck M, Sharif B, Shic F, Shovman M, Thomas MG, Venrooij W, Zemblys R, Hessels RS. Eye tracking: empirical foundations for a minimal reporting guideline. Behav Res Methods 2023; 55:364-416. [PMID: 35384605 PMCID: PMC9535040 DOI: 10.3758/s13428-021-01762-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2021] [Indexed: 11/08/2022]
Abstract
In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section "An empirically based minimal reporting guideline").
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Affiliation(s)
- Kenneth Holmqvist
- Department of Psychology, Nicolaus Copernicus University, Torun, Poland.
- Department of Computer Science and Informatics, University of the Free State, Bloemfontein, South Africa.
- Department of Psychology, Regensburg University, Regensburg, Germany.
| | - Saga Lee Örbom
- Department of Psychology, Regensburg University, Regensburg, Germany
| | - Ignace T C Hooge
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
| | - Diederick C Niehorster
- Lund University Humanities Lab and Department of Psychology, Lund University, Lund, Sweden
| | - Robert G Alexander
- Department of Ophthalmology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | | | - Jeroen S Benjamins
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
- Social, Health and Organizational Psychology, Utrecht University, Utrecht, The Netherlands
| | - Pieter Blignaut
- Department of Computer Science and Informatics, University of the Free State, Bloemfontein, South Africa
| | | | - Lewis L Chuang
- Department of Ergonomics, Leibniz Institute for Working Environments and Human Factors, Dortmund, Germany
- Institute of Informatics, LMU Munich, Munich, Germany
| | | | - Denis Drieghe
- School of Psychology, University of Southampton, Southampton, UK
| | - Matt J Dunn
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | | | - Susann Fiedler
- Vienna University of Economics and Business, Vienna, Austria
| | - Tom Foulsham
- Department of Psychology, University of Essex, Essex, UK
| | | | - Dan Witzner Hansen
- Machine Learning Group, Department of Computer Science, IT University of Copenhagen, Copenhagen, Denmark
| | | | - Enkelejda Kasneci
- Human-Computer Interaction, University of Tübingen, Tübingen, Germany
| | | | - Paul C Knox
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Ellen M Kok
- Department of Education and Pedagogy, Division Education, Faculty of Social and Behavioral Sciences, Utrecht University, Utrecht, The Netherlands
- Department of Online Learning and Instruction, Faculty of Educational Sciences, Open University of the Netherlands, Heerlen, The Netherlands
| | - Helena Lee
- University of Southampton, Southampton, UK
| | - Joy Yeonjoo Lee
- School of Health Professions Education, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Jukka M Leppänen
- Department of Psychology and Speed-Language Pathology, University of Turku, Turku, Finland
| | - Stephen Macknik
- Department of Ophthalmology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Päivi Majaranta
- TAUCHI Research Center, Computing Sciences, Faculty of Information Technology and Communication Sciences, Tampere University, Tampere, Finland
| | - Susana Martinez-Conde
- Department of Ophthalmology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Antje Nuthmann
- Institute of Psychology, University of Kiel, Kiel, Germany
| | - Marcus Nyström
- Lund University Humanities Lab, Lund University, Lund, Sweden
| | - Jacob L Orquin
- Department of Management, Aarhus University, Aarhus, Denmark
- Center for Research in Marketing and Consumer Psychology, Reykjavik University, Reykjavik, Iceland
| | - Jorge Otero-Millan
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA
| | - Soon Young Park
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, Vienna, Austria
| | - Stanislav Popelka
- Department of Geoinformatics, Palacký University Olomouc, Olomouc, Czech Republic
| | - Frank Proudlock
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Frank Renkewitz
- Department of Psychology, University of Erfurt, Erfurt, Germany
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA
| | | | - Bonita Sharif
- School of Computing, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Frederick Shic
- Center for Child Health, Behavior and Development, Seattle Children's Research Institute, Seattle, WA, USA
- Department of General Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
| | - Mark Shovman
- Eyeviation Systems, Herzliya, Israel
- Department of Industrial Design, Bezalel Academy of Arts and Design, Jerusalem, Israel
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Ward Venrooij
- Electrical Engineering, Mathematics and Computer Science (EEMCS), University of Twente, Enschede, The Netherlands
| | | | - Roy S Hessels
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
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Development of an Eye Responses-Based Mental Workload Evaluation Method. INTERNATIONAL JOURNAL OF TECHNOLOGY AND HUMAN INTERACTION 2022. [DOI: 10.4018/ijthi.299071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study proposed an eye responses-based mental workload (E-MWL) evaluation method in nuclear power plants (NPPs) when performing the task via a user interface control. The fuzzy theory was used to combine four eye response indices using the entropy weight method. Then, the E-MWL method was validated through experiments by comparison with the NASA-TLX rating and performance measures indices in two different tasks of the State Oriented Procedure (SOP) in NPP. The correlation analysis results between the NASA-TLX and eye response indices showed that four eye response indices used in this study were correlated significantly with the NASA-TLX, indicating that these indices may develop the E-MWL method. The E-MWL score results indicated that it is highly correlated with NASA-TLX and performance measures indices in two different tasks of SOP in NPP. This has proved that E-MWL is an objective method suitable for evaluating and predicting human mental workload (MWL) for interface control task in NPPs.
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7
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Carrieri CR, Rodrigues A, Lopes PS, Andréo-Filho N, Santos YR, Cairolli OB, Stevic M, Duque MD, Minarini PRR, Leite-Silva VR. Sensory Priming: The olfaction as an attention inducer. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e20335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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8
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Rima S, Schmid MC. Reading Specific Small Saccades Predict Individual Phonemic Awareness and Reading Speed. Front Neurosci 2021; 15:663242. [PMID: 34966251 PMCID: PMC8710594 DOI: 10.3389/fnins.2021.663242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
Small fixational eye-movements are a fundamental aspect of vision and thought to reflect fine shifts in covert attention during active viewing. While the perceptual benefits of these small eye movements have been demonstrated during a wide range of experimental tasks including during free viewing, their function during reading remains surprisingly unclear. Previous research demonstrated that readers with increased microsaccade rates displayed longer reading speeds. To what extent increased fixational eye movements are, however, specific to reading and might be indicative of reading skill deficits remains, however, unknown. To address this topic, we compared the eye movement scan paths of 13 neurotypical individuals and 13 subjects diagnosed with developmental dyslexia during short story reading and free viewing of natural scenes. We found that during reading only, dyslexics tended to display small eye movements more frequently compared to neurotypicals, though this effect was not significant at the population level, as it could also occur in slow readers not diagnosed as dyslexics. In line with previous research, neurotypical readers had twice as many regressive compared to progressive microsaccades, which did not occur during free viewing. In contrast, dyslexics showed similar amounts of regressive and progressive small fixational eye movements during both reading and free viewing. We also found that participants with smaller fixational saccades from both neurotypical and dyslexic samples displayed reduced reading speeds and lower scores during independent tests of reading skill. Slower readers also displayed greater variability in the landing points and temporal occurrence of their fixational saccades. Both the rate and spatio-temporal variability of fixational saccades were associated with lower phonemic awareness scores. As none of the observed differences between dyslexics and neurotypical readers occurred during control experiments with free viewing, the reported effects appear to be directly related to reading. In summary, our results highlight the predictive value of small saccades for reading skill, but not necessarily for developmental dyslexia.
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Affiliation(s)
- Samy Rima
- Department of Sport and Neuroscience, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Michael C Schmid
- Department of Sport and Neuroscience, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.,Bioscience Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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9
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Bowers NR, Gautier J, Lin S, Roorda A. Fixational eye movements in passive versus active sustained fixation tasks. J Vis 2021; 21:16. [PMID: 34677574 PMCID: PMC8556553 DOI: 10.1167/jov.21.11.16] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Human fixational eye movements are so small and precise that high-speed, accurate tools are needed to fully reveal their properties and functional roles. Where the fixated image lands on the retina and how it moves for different levels of visually demanding tasks is the subject of the current study. An Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) was used to image, track and present a variety of fixation targets (Maltese cross, disk, concentric circles, Vernier and tumbling-E letter) to healthy subjects. During these different passive (static) or active (discriminating) tasks under natural eye motion, the landing position of the target on the retina was tracked in space and time over the retinal image directly with high spatial (<1 arcmin) and temporal (960 Hz) resolution. We computed both the eye motion and the exact trajectory of the fixated target's motion over the retina. We confirmed that compared to passive tasks, active tasks elicited a partial inhibition of microsaccades, leading to longer drift periods compensated by larger corrective saccades. Consequently, the overall fixation stability during active tasks was on average 57% larger than during passive tasks. The preferred retinal locus of fixation was the same for each task and did not coincide with the location of the peak cone density.
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Affiliation(s)
- Norick R Bowers
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.,
| | - Josselin Gautier
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.,
| | - Samantha Lin
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.,
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.,
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10
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Li M, Wu J, Ma W, Zhang Z, Zhang M, Li X, Ling Z, Xu X. Spatiotemporal characteristics of postsaccadic dynamic overshoot in young and elderly subjects. iScience 2021; 24:102764. [PMID: 34308287 PMCID: PMC8283153 DOI: 10.1016/j.isci.2021.102764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/14/2021] [Accepted: 06/21/2021] [Indexed: 11/10/2022] Open
Abstract
Saccadic eye movements may not stop steadily but fluctuate briefly, known as saccadic dynamic overshoot (SDO). The reported relationships between SDO and saccadic parameters of main saccade and the effect of aging on SDO are controversial. In addition, it is not clear whether aging-related disease, such as mild cognitive impairment (MCI) and Parkinson disease (PD), causes the specific change of SDO. To address these questions, we analyzed the spatiotemporal features of SDO in young healthy subjects, elderly healthy subjects, and subjects with PD and MCI in three oculomotor tasks. We found two types of SDOs—simple and complex SDO. We confirmed that the frequency and amplitude of SDO were positively correlated with the peak velocity and deceleration of main saccades and increased in elderly subjects; however, they were not significantly different among the three elderly groups. Our results support the previous argument that the oculomotor structure in brainstem and cerebellum directly develop SDO. We classify two types of saccadic dynamic overshoot (SDO): SDOsimple and SDOcomplex Saccades with SDO have higher peak velocity and deceleration than saccades without SDO Elderly subjects show a higher frequency and amplitude of SDO than young subjects Saccades with SDOcomplex occur more frequently in reflexive than voluntary saccades
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Affiliation(s)
- Min Li
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Junru Wu
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Wenbo Ma
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Zhihao Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Mingsha Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Division of Psychology, Beijing Normal University, Beijing 100875, China
| | - Xuemei Li
- Cadre Medical Department, the 1st Clinical Center, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
| | - Zhipei Ling
- Department of Neurosurgery, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
| | - Xin Xu
- Department of Neurosurgery, General Hospital of PLA, 28 Fu-Xing Road, Haidian District, Beijing 100853, China
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11
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Abstract
While aiming and shooting, we make tiny eye movements called microsaccades that shift gaze between task-relevant objects within a small region of the visual field. However, in the brief period before pressing the trigger, microsaccades are suppressed. This might be due to the lack of a requirement to shift gaze as the retinal images of the two objects begin to overlap on the fovea. Alternatively, we might actively suppress microsaccades to prevent any disturbances in visual perception caused by microsaccades around the time of their occurrence and their subsequent effect on shooting performance. In this study we looked at microsaccade rates while participants performed a simulated shooting task under two conditions: a normal condition in which they moved their eyes freely, and an eccentric condition in which they maintained gaze on a fixed target while performing the shooting task at 5° eccentricity. As expected, microsaccade rate dropped near the end of the task in the normal viewing condition. However, we also found the same decrease for the eccentric condition in which microsaccades did not shift gaze between the task objects. Microsaccades are also produced in response to shifts in covert attention. To test whether disengagement of covert attention from the eccentric shooting location caused the drop in microsaccade rate, we monitored the location of participants' spatial attention by using a Rapid Serial Visual Presentation (RSVP) task simultaneously at a location opposite to the shooting task. Target letter detection at the RSVP location did not improve during the drop in microsaccade rate, suggesting that covert attention was maintained at the shooting task location. We conclude that in addition to their usual gaze-shifting function, microsaccades during fine-acuity tasks might be modulated by cognitive processes other than spatial attention.
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Affiliation(s)
- Rakesh Nanjappa
- Graduate Center for Vision Research, Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA.,Present address: Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA.,
| | - Robert M McPeek
- Graduate Center for Vision Research, Department of Biological and Visual Sciences, SUNY College of Optometry, New York, NY, USA.,
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12
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Rim NW, Choe KW, Scrivner C, Berman MG. Introducing Point-of-Interest as an alternative to Area-of-Interest for fixation duration analysis. PLoS One 2021; 16:e0250170. [PMID: 33970920 PMCID: PMC8109773 DOI: 10.1371/journal.pone.0250170] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 03/31/2021] [Indexed: 11/18/2022] Open
Abstract
Many eye-tracking data analyses rely on the Area-of-Interest (AOI) methodology, which utilizes AOIs to analyze metrics such as fixations. However, AOI-based methods have some inherent limitations including variability and subjectivity in shape, size, and location of AOIs. In this article, we propose an alternative approach to the traditional AOI dwell time analysis: Weighted Sum Durations (WSD). This approach decreases the subjectivity of AOI definitions by using Points-of-Interest (POI) while maintaining interpretability. In WSD, the durations of fixations toward each POI is weighted by the distance from the POI and summed together to generate a metric comparable to AOI dwell time. To validate WSD, we reanalyzed data from a previously published eye-tracking study (n = 90). The re-analysis replicated the original findings that people gaze less towards faces and more toward points of contact when viewing violent social interactions.
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Affiliation(s)
- Nak Won Rim
- Masters in Computational Social Science, The University of Chicago, Chicago, Illinois, United States of America
| | - Kyoung Whan Choe
- Department of Psychology, The University of Chicago, Chicago, Illinois, United States of America
- Mansueto Institute for Urban Innovation, The University of Chicago, Chicago, Illinois, United States of America
| | - Coltan Scrivner
- Department of Comparative Human Development, The University of Chicago, Chicago, Illinois, United States of America
- Institute for Mind and Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Marc G. Berman
- Department of Psychology, The University of Chicago, Chicago, Illinois, United States of America
- Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
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13
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Abstract
Eye-tracking is widely used throughout the scientific community, from vision science and psycholinguistics to marketing and human-computer interaction. Surprisingly, there is little consistency and transparency in preprocessing steps, making replicability and reproducibility difficult. To increase replicability, reproducibility, and transparency, a package in R (a free and widely used statistical programming environment) called gazeR was created to read and preprocess two types of data: gaze position and pupil size. For gaze position data, gazeR has functions for reading in raw eye-tracking data, formatting it for analysis, converting from gaze coordinates to areas of interest, and binning and aggregating data. For data from pupillometry studies, the gazeR package has functions for reading in and merging multiple raw pupil data files, removing observations with too much missing data, eliminating artifacts, blink identification and interpolation, subtractive baseline correction, and binning and aggregating data. The package is open-source and freely available for download and installation: https://github.com/dmirman/gazer . We provide step-by-step analyses of data from two tasks exemplifying the package's capabilities.
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14
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Mardanbegi D, Wilcockson TDW, Killick R, Xia B, Gellersen H, Sawyer P, Crawford TJ. A comparison of post-saccadic oscillations in European-Born and China-Born British University Undergraduates. PLoS One 2020; 15:e0229177. [PMID: 32097447 PMCID: PMC7041864 DOI: 10.1371/journal.pone.0229177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/02/2020] [Indexed: 11/21/2022] Open
Abstract
Previous research has revealed that people from different genetic, racial, biological, and/or cultural backgrounds may display fundamental differences in eye-tracking behavior. These differences may have a cognitive origin or they may be at a lower level within the neurophysiology of the oculomotor network, or they may be related to environment factors. In this paper we investigated one of the physiological aspects of eye movements known as post-saccadic oscillations and we show that this type of eye movement is very different between two different populations. We compared the post-saccadic oscillations recorded by a video-based eye tracker between two groups of participants: European-born and Chinese-born British students. We recorded eye movements from a group of 42 Caucasians defined as White British or White Europeans and 52 Chinese-born participants all with ages ranging from 18 to 36 during a prosaccade task. The post-saccadic oscillations were extracted from the gaze data which was compared between the two groups in terms of their first overshoot and undershoot. The results revealed that the shape of the post-saccadic oscillations varied significantly between the two groups which may indicate a difference in a multitude of genetic, cultural, physiologic, anatomical or environmental factors. We further show that the differences in the post-saccadic oscillations could influence the oculomotor characteristics such as saccade duration. We conclude that genetic, racial, biological, and/or cultural differences can affect the morphology of the eye movement data recorded and should be considered when studying eye movements and oculomotor fixation and saccadic behaviors.
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Affiliation(s)
- Diako Mardanbegi
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
- * E-mail:
| | - Thomas D. W. Wilcockson
- School of Sport, Exercise, and Health Science, Loughborough University, Loughborough, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
| | - Rebecca Killick
- Department of Mathematics and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Baiqiang Xia
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
| | - Hans Gellersen
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
| | - Peter Sawyer
- School Engineering and Applied Science, Aston University, Birmingham, United Kingdom
| | - Trevor J. Crawford
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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15
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Yamagishi S, Yoneya M, Furukawa S. Relationship of postsaccadic oscillation with the state of the pupil inside the iris and with cognitive processing. J Neurophysiol 2020; 123:484-495. [PMID: 31825707 PMCID: PMC7052648 DOI: 10.1152/jn.00205.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recent studies using video-based eye tracking have presented accumulating evidence that postsaccadic oscillation defined in reference to the pupil center (PSOp) is larger than that to the iris center (PSOi). This indicates that the relative motion of the pupil reflects the viscoelasticity of the tissue of the iris. It is known that the pupil size controlled by the sphincter/dilator pupillae muscles reflects many aspects of cognition. A hypothesis derived from this fact is that cognitive tasks affect the properties of PSOp due to the change in the state of these muscles. To test this hypothesis, we conducted pro- and antisaccade tasks for human participants and adopted the recent physical model of PSO to evaluate the dynamic properties of PSOp/PSOi. The results showed the dependence of the elasticity coefficient of the PSOp on the antisaccade task, but this effect was not significant for the PSOi. This suggests that cognitive tasks such as antisaccade tasks affect elasticity of the muscle of the iris. We found that the trial-by-trial fluctuation in the presaccade absolute pupil size correlated with the elasticity coefficient of PSOp. We also found the task dependence of the viscosity coefficient and overshoot amount of PSOi, which probably reflects the dynamics of the entire eyeball movement. The difference in task dependence between PSOp and PSOi indicates that the separate measures of these two can be means to distinguish factors related to the oculomotor neural system from those related to the physiological states of the iris tissue. NEW & NOTEWORTHY The state of the eyeball varies dynamically moment by moment depending on underlying neural/cognitive processing. Combining simultaneous measurements of pupil-centric and iris-centric movements and a recent physical model of postsaccadic oscillation (PSO), we show that the pupil-centric PSO is sensitive to the type of saccade task, suggesting that the physical state of the iris muscles reflects the underlying cognitive processes.
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Affiliation(s)
| | - Makoto Yoneya
- NTT Communication Science Laboratories, Kanagawa, Japan
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16
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Scrivner C, Choe KW, Henry J, Lyu M, Maestripieri D, Berman MG. Violence reduces attention to faces and draws attention to points of contact. Sci Rep 2019; 9:17779. [PMID: 31780726 PMCID: PMC6883035 DOI: 10.1038/s41598-019-54327-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 11/09/2019] [Indexed: 11/09/2022] Open
Abstract
Although violence is a frequently researched topic, little is known about how different social features influence information gathering from violent interactions. Regions of an interaction that provide contextual information should receive more attention. We predicted the most informative features of a violent social interaction would be faces, points of contact, and objects being held. To test this, we tracked the eyes of 90 participants as they viewed images of social interactions that varied with respect to violence. When viewing violent interactions, participants attended significantly less to faces and significantly more to points of contact. Moreover, first-fixation analysis suggests that some of these biases are present from the beginning of scene-viewing. These findings are the first to demonstrate the visual relevance of faces and contact points in gathering information from violent social interactions. These results also question the attentional dominance of faces in active social scenes, highlighting the importance of using a variety of stimuli and contexts in social cognition research.
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Affiliation(s)
- Coltan Scrivner
- Department of Comparative Human Development, The University of Chicago, Chicago, IL, USA. .,Institute for Mind and Biology, The University of Chicago, Chicago, IL, USA.
| | - Kyoung Whan Choe
- Department of Psychology, The University of Chicago, Chicago, IL, USA.,Mansueto Institute for Urban Innovation, The University of Chicago, Chicago, IL, USA
| | - Joseph Henry
- Institute for Mind and Biology, The University of Chicago, Chicago, IL, USA.,Department of Psychology, The University of Chicago, Chicago, IL, USA
| | - Muxuan Lyu
- Department of Psychology, The University of Chicago, Chicago, IL, USA
| | - Dario Maestripieri
- Department of Comparative Human Development, The University of Chicago, Chicago, IL, USA.,Institute for Mind and Biology, The University of Chicago, Chicago, IL, USA
| | - Marc G Berman
- Department of Psychology, The University of Chicago, Chicago, IL, USA.,Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, Chicago, IL, USA
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17
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Schlegelmilch K, Wertz AE. The Effects of Calibration Target, Screen Location, and Movement Type on Infant Eye-Tracking Data Quality. INFANCY 2019; 24:636-662. [PMID: 32677249 DOI: 10.1111/infa.12294] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 03/31/2019] [Accepted: 04/03/2019] [Indexed: 11/29/2022]
Abstract
During infant eye-tracking, fussiness caused by the repetition of calibration stimuli and body movements during testing are frequent constraints on measurement quality. Here, we systematically investigated these constraints with infants and adults using EyeLink 1000 Plus. We compared looking time and dispersion of gaze points elicited by stimuli resembling commonly used calibration animations. The adult group additionally performed body movements during gaze recording that were equivalent to movements infants spontaneously produce during testing. In our results, infants' preference for a particular calibration target did not predict data quality elicited by that stimulus, but targets exhibiting the strongest contrasts in their center or targets with globally distributed complexity resulted in the highest accuracy. Our gaze measures from the adult movement tasks were differentially affected by the type of movement as well as the location where the target appeared on the screen. These heterogeneous effects of movement on measures should be taken into account when planning infant eye-tracking experiments. Additionally, to improve data quality, infants' tolerance for repeated calibrations can be facilitated by alternating between precise calibration targets.
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Affiliation(s)
- Karola Schlegelmilch
- Max Planck Institute for Human Development, Max Planck Research Group Naturalistic Social Cognition
| | - Annie E Wertz
- Max Planck Institute for Human Development, Max Planck Research Group Naturalistic Social Cognition
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18
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Del Punta JA, Rodriguez KV, Gasaneo G, Bouzat S. Models for saccadic motion and postsaccadic oscillations. Phys Rev E 2019; 99:032422. [PMID: 30999401 DOI: 10.1103/physreve.99.032422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Indexed: 11/07/2022]
Abstract
In a recent letter [S. Bouzat et al., Phys. Rev. Lett. 120, 178101 (2018)10.1103/PhysRevLett.120.178101], a mathematical model for eyeball and pupil motion was developed allowing for the understanding of the postsaccadic oscillations (PSO) as inertial effects. The model assumes that the inner part of the iris, which defines the pupil, moves driven by inertial forces induced by the eyeball rotation, in addition to viscous and elastic forces. Among other achievements, the model correctly reproduces eye-tracking experiments concerning PSO profiles and their dependence on the saccade size. In this paper we propose various extensions of the mentioned model, we provide analytical solutions, and we perform an exhaustive analysis of the dynamics. In particular, we consider a more general time dependence for the eyeball velocity enabling the description of saccades with vanishing initial acceleration. Moreover, we give the analytical solution in terms of hypergeometric functions for the constant parameter version of the model and we provide particular expressions for some cases of interest. We also introduce a new version of the model with inhomogeneous viscosity that can improve the fitting of the experimental results. Our analysis of the solutions explores the dependence of the PSO profiles on the system parameters for varying saccade sizes. We show that the PSO emerge in critical-like ways when parameters such as the elasticity of the iris, the global eyeball velocity, or the saccade size vary. Moreover, we find that the PSO profiles with the first overshoot smaller than the second one, which are usually observed in experiments, can be associated to parameter regions close to criticality.
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Affiliation(s)
- J A Del Punta
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, (8000) Bahía Blanca, Argentina.,Departamento de Matemática, Universidad Nacional del Sur, (8000) Bahía Blanca, Argentina
| | - K V Rodriguez
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, (8000) Bahía Blanca, Argentina.,CINA-Centro Integral de Neurociencias Aplicadas, (8000) Bahía Blanca, Argentina
| | - G Gasaneo
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, (8000) Bahía Blanca, Argentina.,CINA-Centro Integral de Neurociencias Aplicadas, (8000) Bahía Blanca, Argentina
| | - S Bouzat
- Centro Atómico Bariloche (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas, Av. E. Bustillo 9500 R8402AGP San Carlos de Bariloche Río Negro, Argentina
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19
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Pool ER, Pauli WM, Kress CS, O'Doherty JP. Behavioural evidence for parallel outcome-sensitive and outcome-insensitive Pavlovian learning systems in humans. Nat Hum Behav 2019; 3:284-296. [PMID: 30882043 PMCID: PMC6416744 DOI: 10.1038/s41562-018-0527-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 12/21/2018] [Indexed: 02/07/2023]
Abstract
There is a dichotomy in instrumental conditioning between goal-directed actions and habits that are distinguishable on the basis of their relative sensitivity to changes in outcome value. It is less clear whether a similar distinction applies in Pavlovian conditioning, where responses have been found to be predominantly outcome sensitive. To test for both devaluation insensitive and devaluation sensitive Pavlovian conditioning in humans, we conducted four experiments combining Pavlovian conditioning and outcome devaluation procedures while measuring multiple conditioned responses. Our results suggest that Pavlovian conditioning involves two distinct types of learning: one that learns the current value of the outcome which is sensitive to devaluation, and one that learns about the spatial localisation of the outcome which is insensitive to devaluation. Our findings have implications for the mechanistic understanding of Pavlovian conditioning and provide a more nuanced understanding of Pavlovian mechanisms that might contribute to a number of psychiatric disorders.
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Affiliation(s)
- Eva R Pool
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA.
| | - Wolfgang M Pauli
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
- Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA, USA
| | - Carolina S Kress
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
| | - John P O'Doherty
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
- Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA, USA
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20
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Hooge ITC, Hessels RS, Nyström M. Do pupil-based binocular video eye trackers reliably measure vergence? Vision Res 2019; 156:1-9. [PMID: 30641092 DOI: 10.1016/j.visres.2019.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/19/2018] [Accepted: 01/05/2019] [Indexed: 10/27/2022]
Abstract
A binocular eye tracker needs to be accurate to enable the determination of vergence, distance to the binocular fixation point and fixation disparity. These measures are useful in e.g. the research fields of visual perception, binocular control in reading and attention in 3D. Are binocular pupil-based video eye trackers accurate enough to produce meaningful binocular measures? Recent research revealed potentially large idiosyncratic systematic errors due to pupil-size changes. With a top of the line eye tracker (SR Research EyeLink 1000 plus), we investigated whether the pupil-size artefact in the separate eyes may cause the eye tracker to report apparent vergence when the eyeballs do not rotate. Participants were asked to fixate a target at a distance of 77 cm for 160 s. We evoked pupil-size changes by varying the light intensity. With increasing pupil size, horizontal vergence reported by the eye tracker decreased in most subjects, up to two degrees. However, this was not due to a rotation of the eyeballs, as identified from the absence of systematic movement in the corneal reflection (CR) signals. From this, we conclude that binocular pupil-CR or pupil-only video eye trackers using the dark pupil technique are not accurate enough to be used to determine vergence, distance to the binocular fixation point and fixation disparity.
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Affiliation(s)
- Ignace T C Hooge
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, the Netherlands.
| | - Roy S Hessels
- Experimental Psychology, Helmholtz Institute, and Developmental Psychology, Utrecht University, Utrecht, the Netherlands
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21
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Wilcockson TDW, Mardanbegi D, Sawyer P, Gellersen H, Xia B, Crawford TJ. Oculomotor and Inhibitory Control in Dyslexia. Front Syst Neurosci 2019; 12:66. [PMID: 30687026 PMCID: PMC6338055 DOI: 10.3389/fnsys.2018.00066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
Previous research has suggested that people with dyslexia may have an impairment of inhibitory control. The oculomotor system is vulnerable to interference at various levels of the system, from high level cognitive control to peripheral neural pathways. Therefore, in this work we examined two forms of oculomotor inhibition and two forms of oculomotor interference at high and low levels of the control system. This study employed a prosaccade, antisaccade, and a recent distractor eye movement task (akin to a spatial negative priming) in order to explore high level cognitive control and the inhibition of a competing distractor. To explore low-level control we examined the frequency of microsaccades and post-saccade oscillations. The findings demonstrated that dyslexics have an impairment of volitional inhibitory control, reflected in the antisaccade task. In contrast, inhibitory control at the location of a competing distractor was equivalent in the dyslexic and non-dyslexic groups. There was no difference in the frequency of microsaccades between the two groups. However, the dyslexic group generated larger microsaccades prior to the target onset in the prosaccade and the antisaccade tasks.The groups did not differ in the frequency or in the morphology of the post-saccade oscillations. These findings reveal that the word reading and attentional difficulties of dyslexic readers cannot be attributed to an impairment in the inhibition of a visual distractor or interference from low-level oculomotor instability. We propose that the inhibitory impairment in dyslexia occurs at a higher cognitive level, perhaps in relation to the process of attentional disengagement.
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Affiliation(s)
- Thomas D W Wilcockson
- Centre for Ageing Research, Department of Psychology, Lancaster University, Lancaster, United Kingdom.,Sport Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Diako Mardanbegi
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
| | - Peter Sawyer
- School Engineering and Applied Science, Aston University, Birmingham, United Kingdom
| | - Hans Gellersen
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
| | - Baiqiang Xia
- School of Computing and Communications, Lancaster University, Lancaster, United Kingdom
| | - Trevor J Crawford
- Centre for Ageing Research, Department of Psychology, Lancaster University, Lancaster, United Kingdom
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22
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Dalmaso M, Castelli L, Galfano G. Microsaccadic rate and pupil size dynamics in pro-/anti-saccade preparation: the impact of intermixed vs. blocked trial administration. PSYCHOLOGICAL RESEARCH 2019; 84:1320-1332. [PMID: 30603866 DOI: 10.1007/s00426-018-01141-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/21/2018] [Indexed: 01/02/2023]
Abstract
Prolonged fixation can lead to the generation of tiny and fast eye movements called microsaccades, whose dynamics can be associated with higher cognitive mechanisms. Saccade preparation is also reflected in microsaccadic activity, but the few studies on this topic provided mixed results. For instance, fewer microsaccades have been observed when participants were asked to prepare for an anti-saccade (i.e., a saccade in the opposite direction to the target) as compared to a pro-saccade (i.e., a saccade executed towards a target), but null results have also been reported. In the attempt to shed new light on this topic, two experiments were carried out in which the context of presentation of pro- and anti-saccade trials was manipulated. Pupil size was also recorded, as a further index of cognitive load. In Experiment 1, participants were asked to prepare and perform pro- and anti-saccades in response to a peripheral target, according to a central instruction cue provided at the beginning of each trial (intermixed condition). In Experiment 2, the same task was employed, but pro- and anti-saccade trials were delivered in two distinct blocks (blocked condition). In both experiments, greater saccadic latencies and lower accuracy emerged for anti- than for pro-saccades. However, in the intermixed condition, a lower microsaccadic rate and a greater pupil size emerged when participants prepared for anti- rather than pro-saccades, whereas these differences disappeared in the blocked condition. These results suggest that contextual factors may play a key role in shaping oculomotor dynamics linked to saccade preparation.
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Affiliation(s)
- Mario Dalmaso
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padua, Italy.
| | - Luigi Castelli
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padua, Italy
| | - Giovanni Galfano
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padua, Italy
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23
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Lin CJ, Prasetyo YT, Widyaningrum R. Eye Movement Parameters for Performance Evaluation in Projection-based Stereoscopic Display. J Eye Mov Res 2018; 11:10.16910/jemr.11.6.3. [PMID: 33828713 PMCID: PMC7906757 DOI: 10.16910/jemr.11.6.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The current study applied Structural Equation Modeling (SEM) to analyze the rela-tionship among index of difficulty (ID) and parallax on eye gaze movement time (EMT), fixation duration (FD), time to first fixation (TFF), number of fixation (NF), and eye gaze accuracy (AC) simultaneously. EMT, FD, TFF, NF, and AC were measured in the projec-tion-based stereoscopic display by utilizing Tobii eye tracker system. Ten participants were recruited to perform multi-directional tapping task using within-subject design with three different levels of parallax and six different levels of ID. SEM proved that ID had significant direct effects on EMT, NF, and FD also a significant indirect effect on NF. However, ID was found not a strong predictor for AC. SEM also proved that parallax had significant direct effects on EMT, NF, FD, TFF, and AC. Apart from the direct effect, parallax also had significant indirect effects on NF and AC. Regarding the interrelation-ship among dependent variables, there were significant indirect effects of FD and TFF on AC. Our results concluded that higher AC was achieved by lowering parallax (at the screen), longer EMT, higher NF, longer FD, and longer TFF. Practitioner Summary: The SEM could provide valuable theoretical foundations of the interrelationship among eye movement parameters for VR researchers and human-virtual-reality interface developers especially for predicting eye gaze accuracy.
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Affiliation(s)
- Chiuhsiang Joe Lin
- Department of Industrial Management, National Taiwan University of Science and Technology, Taiwan
| | - Yogi Tri Prasetyo
- Department of Industrial Management, National Taiwan University of Science and Technology, Taiwan
| | - Retno Widyaningrum
- Department of Industrial Engineering Sepuluh Nopember Institute of Technology, Kampus ITS Sukolilo Surabaya 60111, Indonesia
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24
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Kehoe DH, Aybulut S, Fallah M. Higher order, multifeatural object encoding by the oculomotor system. J Neurophysiol 2018; 120:3042-3062. [PMID: 30303752 DOI: 10.1152/jn.00834.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous behavioral and physiological research has demonstrated that as the behavioral relevance of potential saccade goals increases, they elicit more competition during target selection processing as evidenced by increased saccade curvature and neural activity. However, these effects have only been demonstrated for lower order feature singletons, and it remains unclear whether more complicated featural differences between higher order objects also elicit vector modulation. Therefore, we measured human saccades curvature elicited by distractors bilaterally flanking a target during a visual search saccade task and systematically varied subsets of features shared between the two distractors and the target, referred to as objective similarity (OS). Our results demonstrate that saccades deviated away from the distractor highest in OS to the target and that there was a linear relationship between the magnitude of saccade deviation and the number of feature differences between the most similar distractor and the target. Furthermore, an analysis of curvature over the time course of the saccade demonstrated that curvature only occurred in the first 20-30 ms of the movement. Given the multifeatural complexity of the novel stimuli, these results suggest that saccadic target selection processing involves dynamically reweighting vector representations for movement planning to several possible targets based on their behavioral relevance. NEW & NOTEWORTHY We demonstrate that small featural differences between unfamiliar, higher order object representations modulate vector weights during saccadic target selection processing. Such effects have previously only been demonstrated for familiar, simple feature singletons (e.g., color) in which features characterize entire objects. The complexity and novelty of our stimuli suggest that the oculomotor system dynamically receives visual/cognitive information processed in the higher order representational networks of the cortical visual processing hierarchy and integrates this information for saccadic movement planning.
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Affiliation(s)
- Devin H Kehoe
- Department of Psychology, York University , Toronto , Canada.,Centre for Vision Research, York University , Toronto , Canada.,VISTA: Vision Science to Applications, York University , Toronto , Canada.,Canadian Action and Perception Network, York University , Toronto , Canada
| | - Selvi Aybulut
- School of Kinesiology and Heath Science, York University , Toronto , Canada
| | - Mazyar Fallah
- Department of Psychology, York University , Toronto , Canada.,Centre for Vision Research, York University , Toronto , Canada.,VISTA: Vision Science to Applications, York University , Toronto , Canada.,Canadian Action and Perception Network, York University , Toronto , Canada.,School of Kinesiology and Heath Science, York University , Toronto , Canada
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25
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Menekse Dalveren GG, Cagiltay NE, Ozcelik E, Maras H. Insights From Pupil Size to Mental Workload of Surgical Residents: Feasibility of an Educational Computer-Based Surgical Simulation Environment (ECE) Considering the Hand Condition. Surg Innov 2018; 25:616-624. [DOI: 10.1177/1553350618800078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The advantage of simulation environments is that they present various insights into real situations, where experimental research opportunities are very limited—for example, in endoscopic surgery. These operations require simultaneous use of both hands. For this reason, surgical residents need to develop several motor skills, such as eye-hand coordination and left-right hand coordination. While performing these tasks, the hand condition (dominant, nondominant, both hands) creates different degrees of mental workload, which can be assessed through mental physiological measures—namely, pupil size. Studies show that pupil size grows in direct proportion to mental workload. However, in the literature, there are very limited studies exploring this workload through the pupil sizes of the surgical residents under different hand conditions. Therefore, in this study, we present a computer-based simulation of a surgical task using eye-tracking technology to better understand the influence of the hand condition on the performance of skill-based surgical tasks in a computer-based simulated environment. The results show that under the both-hand condition, the pupil size of the surgical residents is larger than the one under the dominant and nondominant hand conditions. This indicates that when the computer-simulated surgical task is performed with both hands, it is considered more difficult than in the dominant and nondominant hand conditions. In conclusion, this study shows that pupil size measurements are sufficiently feasible to estimate the mental workload of the participants while performing surgical tasks. The results of this study can be used as a guide by instructional system designers of skill-based training programs.
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26
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Dalrymple KA, Manner MD, Harmelink KA, Teska EP, Elison JT. An Examination of Recording Accuracy and Precision From Eye Tracking Data From Toddlerhood to Adulthood. Front Psychol 2018; 9:803. [PMID: 29875727 PMCID: PMC5974590 DOI: 10.3389/fpsyg.2018.00803] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/04/2018] [Indexed: 11/13/2022] Open
Abstract
The quantitative assessment of eye tracking data quality is critical for ensuring accuracy and precision of gaze position measurements. However, researchers often report the eye tracker's optimal manufacturer's specifications rather than empirical data about the accuracy and precision of the eye tracking data being presented. Indeed, a recent report indicates that less than half of eye tracking researchers surveyed take the eye tracker's accuracy into account when determining areas of interest for analysis, an oversight that could impact the validity of reported results and conclusions. Accordingly, we designed a calibration verification protocol to augment independent quality assessment of eye tracking data and examined whether accuracy and precision varied between three age groups of participants. We also examined the degree to which our externally quantified quality assurance metrics aligned with those reported by the manufacturer. We collected data in standard laboratory conditions to demonstrate our method, to illustrate how data quality can vary with participant age, and to give a simple example of the degree to which data quality can differ from manufacturer reported values. In the sample data we collected, accuracy for adults was within the range advertised by the manufacturer, but for school-aged children, accuracy and precision measures were outside this range. Data from toddlers were less accurate and less precise than data from adults. Based on an a priori inclusion criterion, we determined that we could exclude approximately 20% of toddler participants for poor calibration quality quantified using our calibration assessment protocol. We recommend implementing and reporting quality assessment protocols for any eye tracking tasks with participants of any age or developmental ability. We conclude with general observations about our data, recommendations for what factors to consider when establishing data inclusion criteria, and suggestions for stimulus design that can help accommodate variability in calibration. The methods outlined here may be particularly useful for developmental psychologists who use eye tracking as a tool, but who are not experts in eye tracking per se. The calibration verification stimuli and data processing scripts that we developed, along with step-by-step instructions, are freely available for other researchers.
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Affiliation(s)
- Kirsten A. Dalrymple
- Institute of Child Development, College of Education and Human Development, University of Minnesota, Minneapolis, MN, United States
| | - Marie D. Manner
- Department of Computer Science & Engineering, College of Science & Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Katherine A. Harmelink
- Department of School Counseling, School of Education, North Dakota State University, Fargo, ND, United States
| | - Elayne P. Teska
- Department of Comparative Human Development, University of Chicago, Chicago, IL, United States
| | - Jed T. Elison
- Institute of Child Development, College of Education and Human Development, University of Minnesota, Minneapolis, MN, United States
- Department of Pediatrics, University of Minnesota Medical School, University of Minnesota, Minneapolis, MN, United States
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Marois A, Vachon F. Can pupillometry index auditory attentional capture in contexts of active visual processing? JOURNAL OF COGNITIVE PSYCHOLOGY 2018. [DOI: 10.1080/20445911.2018.1470518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | - François Vachon
- École de psychologie, Université Laval, Québec, QC, Canada
- Department of Building, Energy and Environmental Engineering, University of Gävle, Gävle, Sweden
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28
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Bouzat S, Freije ML, Frapiccini AL, Gasaneo G. Inertial Movements of the Iris as the Origin of Postsaccadic Oscillations. PHYSICAL REVIEW LETTERS 2018; 120:178101. [PMID: 29756830 DOI: 10.1103/physrevlett.120.178101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 02/09/2018] [Indexed: 06/08/2023]
Abstract
Recent studies on the human eye indicate that the pupil moves inside the eyeball due to deformations of the iris. Here we show that this phenomenon can be originated by inertial forces undergone by the iris during the rotation of the eyeball. Moreover, these forces affect the iris in such a way that the pupil behaves effectively as a massive particle. To show this, we develop a model based on the Newton equation on the noninertial reference frame of the eyeball. The model allows us to reproduce and interpret several important findings of recent eye-tracking experiments on saccadic movements. In particular, we get correct results for the dependence of the amplitude and period of the postsaccadic oscillations on the saccade size and also for the peak velocity. The model developed may serve as a tool for characterizing eye properties of individuals.
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Affiliation(s)
- S Bouzat
- Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Atómico Bariloche (CNEA), 8400 Bariloche, Río Negro, Argentina
| | - M L Freije
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, Bahía Blanca 8000, Buenos Aires, Argentina
| | - A L Frapiccini
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, Bahía Blanca 8000, Buenos Aires, Argentina
| | - G Gasaneo
- Neufisur-Departamento de Física, Universidad Nacional del Sur-IFISUR, Bahía Blanca 8000, Buenos Aires, Argentina
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29
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An Ecological Visual Exploration Tool to Support the Analysis of Visual Processing Pathways in Children with Autism Spectrum Disorders. J Imaging 2017. [DOI: 10.3390/jimaging4010009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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30
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Mardanbegi D, Killick R, Xia B, Wilcockson T, Gellersen H, Sawyer P, Crawford TJ. Effect of aging on post-saccadic oscillations. Vision Res 2017; 143:1-8. [PMID: 29197475 DOI: 10.1016/j.visres.2017.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 11/26/2022]
Abstract
Recent research have shown that the eye movement data measured by an eye tracker does not necessarily reflect the exact rotations of the eyeball. For example, post-saccadic eye movements may be more reflecting the relative movements between the pupil and the iris rather than the eyeball oscillations. Since, accurate measurement of eye movements is important in many studies, it is crucial to identify different factors that influence the dynamics of the eye movements measured by an eye tracker. Previous studies have shown that deformation of the internal structure of the iris and size of the pupil directly affect the amplitude of the post-saccadic oscillations that are measured by video-based eye trackers that are pupil-based. In this paper, we look at the effect of aging on post-saccadic oscillations. We recorded eye movements from a group of 43 young and 22 older participants during an abstract and a more natural viewing task. The recording was conducted with a video-based eye tracker using the pupil center and corneal reflection. We anticipated that changes in the muscle strength as an effect of aging might affect, directly or indirectly, the post-saccadic oscillations. Results showed that the size of the post-saccadic oscillations were significantly larger for our older group. The results suggests that aging has to be considered as an important factor when studying the post-saccadic eye movements.
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Affiliation(s)
- Diako Mardanbegi
- School of Computing and Communications, Lancaster University, UK.
| | - Rebecca Killick
- Department of Mathematics and Statistics, Lancaster University, UK.
| | - Baiqiang Xia
- School of Computing and Communications, Lancaster University, UK.
| | | | - Hans Gellersen
- School of Computing and Communications, Lancaster University, UK.
| | - Peter Sawyer
- School Engineering and Applied Science, Aston University, Birmingham, UK.
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31
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Felßberg AM, Dombrowe I. The effect of different brightness conditions on visually and memory guided saccades. Vision Res 2017; 142:20-26. [PMID: 29111439 DOI: 10.1016/j.visres.2017.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/02/2017] [Accepted: 10/23/2017] [Indexed: 11/19/2022]
Abstract
It is commonly assumed that saccades in the dark are slower than saccades in a lit room. Early studies that investigated this issue using electrooculography (EOG) often compared memory guided saccades in darkness to visually guided saccades in an illuminated room. However, later studies showed that memory guided saccades are generally slower than visually guided saccades. Research on this topic is further complicated by the fact that the different existing eyetracking methods do not necessarily lead to consistent measurements. In the present study, we independently manipulated task (memory guided/visually guided) and screen brightness (dark, medium and light) in an otherwise completely dark room, and measured the peak velocity and the duration of the participant's saccades using a popular pupil-cornea reflection (p-cr) eyetracker (Eyelink 1000). Based on a critical reading of the literature, including a recent study using cornea-reflection (cr) eye tracking, we did not expect any velocity or duration differences between the three brightness conditions. We found that memory guided saccades were generally slower than visually guided saccades. In both tasks, eye movements on a medium and light background were equally fast and had similar durations. However, saccades on the dark background were slower and had shorter durations, even after we corrected for the effect of pupil size changes. This means that this is most likely an artifact of current pupil-based eye tracking. We conclude that the common assumption that saccades in the dark are slower than in the light is probably not true, however pupil-based eyetrackers tend to underestimate the peak velocity of saccades on very dark backgrounds, creating the impression that this might be the case.
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32
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Adams DL, Economides JR, Horton JC. Incomitance and Eye Dominance in Intermittent Exotropia. Invest Ophthalmol Vis Sci 2017; 58:4049-4055. [PMID: 28813578 PMCID: PMC5559177 DOI: 10.1167/iovs.17-22155] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine if the deviation angle changes in subjects with intermittent exotropia as they alternate fixation between the right and left eye in primary gaze. Methods In this prospective observational cohort study, 37 subjects with intermittent exotropia were tested for evidence of incomitance. The position of each eye was recorded with a video tracker during fixation on a small central target. A cover-uncover test was performed by occluding one eye with a shutter that passed infrared light, allowing continuous tracking of both eyes. The deviation angle was measured during periods of right eye and left eye fixation. Incomitance was assessed as a function of eye preference, fixation stability, and exotropia variability. Results The mean exotropia was 18.2° ± 8.1°. A difference between right exotropia and left exotropia was detectable in 16/37 subjects. Allowing for potential tracking error, the incomitance had a mean amplitude of 1.7°. It was not related to a difference in accommodative effort, eye preference, fixation stability, or variability in deviation. Conclusions Comitance is regarded as a feature that distinguishes strabismus from paralytic or restrictive processes. Unexpectedly, eye tracking during the cover-uncover test showed that incomitance is present in approximately 40% of subjects with intermittent exotropia. It averages 10% of the exotropia, and can equal up to 5°. When substantial, it may be worth considering when planning surgical correction.
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Affiliation(s)
- Daniel L Adams
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States.,Center for Mind/Brain Sciences, The University of Trento, Trento, Italy
| | - John R Economides
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Jonathan C Horton
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
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Nyström M, Andersson R, Niehorster DC, Hooge I. Searching for monocular microsaccades - A red Hering of modern eye trackers? Vision Res 2017; 140:44-54. [PMID: 28822717 DOI: 10.1016/j.visres.2017.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 07/17/2017] [Accepted: 07/26/2017] [Indexed: 10/19/2022]
Abstract
Despite early reports and the contemporary consensus on microsaccades as purely binocular phenomena, recent work has proposed not only the existence of monocular microsaccades, but also that they serve functional purposes. We take a critical look at the detection of monocular microsaccades from a signal perspective, using raw data and a state-of-the-art, video-based eye tracker. In agreement with previous work, monocular detections were present in all participants using a standard microsaccade detection algorithm. However, a closer look at the raw data invalidates the vast majority of monocular detections. These results again raise the question of the existence of monocular microsaccades, as well as the need for improved methods to study small eye movements recorded with video-based eye trackers.
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Affiliation(s)
| | - Richard Andersson
- IT University of Copenhagen, Copenhagen, Denmark; Lund University Cognitive Science, Lund, Sweden.
| | - Diederick C Niehorster
- Lund University Humanities Lab, Lund, Sweden; Dept. of Psychology, Lund University, Lund, Sweden.
| | - Ignace Hooge
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands.
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34
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Hooge I, Holmqvist K, Nyström M. The pupil is faster than the corneal reflection (CR): Are video based pupil-CR eye trackers suitable for studying detailed dynamics of eye movements? Vision Res 2016; 128:6-18. [PMID: 27656785 DOI: 10.1016/j.visres.2016.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/01/2016] [Accepted: 09/03/2016] [Indexed: 10/21/2022]
Abstract
Most modern video eye trackers use the p-CR (pupil minus CR) technique to deal with small relative movements between the eye tracker camera and the eye. We question whether the p-CR technique is appropriate to investigate saccade dynamics. In two experiments we investigated the dynamics of pupil, CR and gaze signals obtained from a standard SMI Hi-Speed eye tracker. We found many differences between the pupil and the CR signals. Differences concern timing of the saccade onset, saccade peak velocity and post-saccadic oscillation (PSO). We also obtained that pupil peak velocities were higher than CR peak velocities. Saccades in the eye trackers' gaze signal (that is constructed from p-CR) appear to be excessive versions of saccades in the pupil signal. We conclude that the pupil-CR technique is not suitable for studying detailed dynamics of eye movements.
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Affiliation(s)
- Ignace Hooge
- Experimental Psychology, Helmholtz Institute, Utrecht University, Heidelberglaan 1, 3584 CS Utrecht, The Netherlands.
| | - Kenneth Holmqvist
- Lund University Humanities Lab, Lund University, Helgonabacken 12, 22362 Lund, Sweden; School of Languages and Academic Literacy, Vaal Triangle Campus, North-West University, Vanderbijlpark 1900, South Africa
| | - Marcus Nyström
- Lund University Humanities Lab, Lund University, Helgonabacken 12, 22362 Lund, Sweden
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