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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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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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3
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Carr DB, Grover P. The Role of Eye Tracking Technology in Assessing Older Driver Safety. Geriatrics (Basel) 2020; 5:E36. [PMID: 32517336 PMCID: PMC7345272 DOI: 10.3390/geriatrics5020036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022] Open
Abstract
A growing body of literature is focused on the use of eye tracking (ET) technology to understand the association between objective visual parameters and higher order brain processes such as cognition. One of the settings where this principle has found practical utility is in the area of driving safety. METHODS We reviewed the literature to identify the changes in ET parameters with older adults and neurodegenerative disease. RESULTS This narrative review provides a brief overview of oculomotor system anatomy and physiology, defines common eye movements and tracking variables that are typically studied, explains the most common methods of eye tracking measurements during driving in simulation and in naturalistic settings, and examines the association of impairment in ET parameters with advanced age and neurodegenerative disease. CONCLUSION ET technology is becoming less expensive, more portable, easier to use, and readily applicable in a variety of clinical settings. Older adults and especially those with neurodegenerative disease may have impairments in visual search parameters, placing them at risk for motor vehicle crashes. Advanced driver assessment systems are becoming more ubiquitous in newer cars and may significantly reduce crashes related to impaired visual search, distraction, and/or fatigue.
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Affiliation(s)
- David B. Carr
- Department of Medicine and Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Prateek Grover
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA;
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4
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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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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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6
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Pogson JM, Taylor RL, McGarvie LA, Bradshaw AP, D’Souza M, Flanagan S, Kong J, Halmagyi GM, Welgampola MS. Head impulse compensatory saccades: Visual dependence is most evident in bilateral vestibular loss. PLoS One 2020; 15:e0227406. [PMID: 31940394 PMCID: PMC6961882 DOI: 10.1371/journal.pone.0227406] [Citation(s) in RCA: 8] [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: 03/20/2019] [Accepted: 12/18/2019] [Indexed: 11/19/2022] Open
Abstract
The normal vestibulo-ocular reflex (VOR) generates almost perfectly compensatory smooth eye movements during a 'head-impulse' rotation. An imperfect VOR gain provokes additional compensatory saccades to re-acquire an earth-fixed target. In the present study, we investigated vestibular and visual contributions on saccade production. Eye position and velocity during horizontal and vertical canal-plane head-impulses were recorded in the light and dark from 16 controls, 22 subjects after complete surgical unilateral vestibular deafferentation (UVD), eight subjects with idiopathic bilateral vestibular loss (BVL), and one subject after complete bilateral vestibular deafferentation (BVD). When impulses were delivered in the horizontal-canal plane, in complete darkness compared with light, first saccade frequency mean(SEM) reduced from 96.6(1.3)-62.3(8.9) % in BVL but only 98.3(0.6)-92.0(2.3) % in UVD; saccade amplitudes reduced from 7.0(0.5)-3.6(0.4) ° in BVL but were unchanged 6.2(0.3)-5.5(0.6) ° in UVD. In the dark, saccade latencies were prolonged in lesioned ears, from 168(8.4)-240(24.5) ms in BVL and 177(5.2)-196(5.7) ms in UVD; saccades became less clustered. In BVD, saccades were not completely abolished in the dark, but their amplitudes decreased from 7.3-3.0 ° and latencies became more variable. For unlesioned ears (controls and unlesioned ears of UVD), saccade frequency also reduced in the dark, but their small amplitudes slightly increased, while latency and clustering remained unchanged. First and second saccade frequencies were 75.3(4.5) % and 20.3(4.1) %; without visual fixation they dropped to 32.2(5.0) % and 3.8(1.2) %. The VOR gain was affected by vision only in unlesioned ears of UVD; gains for the horizontal-plane rose slightly, and the vertical-planes reduced slightly. All head-impulse compensatory saccades have a visual contribution, the magnitude of which depends on the symmetry of vestibular-function and saccade latency: BVL is more profoundly affected by vision than UVD, and second saccades more than first saccades. Saccades after UVD are probably triggered by contralateral vestibular function.
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Affiliation(s)
- Jacob M. Pogson
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
- Faculty of Health and Medicine, Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Rachael L. Taylor
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
- Faculty of Health and Medicine, Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Leigh A. McGarvie
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
- Department of Psychology, Faculty of Science, The University of Sydney, Camperdown, New South Wales, Australia
| | - Andrew P. Bradshaw
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
| | - Mario D’Souza
- Department of Clinical Research, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Sean Flanagan
- Otolaryngology, Head and Neck and Skull Base Surgery, St Vincent’s Hospital, Darlinghurst, New South Wales, Australia
- Faculty of Medicine, University of NSW, Kensington, New South Wales, Australia
| | - Jonathan Kong
- Faculty of Health and Medicine, Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
- Department of Neurosurgery, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
- Department of Otolaryngology, Head & Neck Surgery, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - G. Michael Halmagyi
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
- Faculty of Health and Medicine, Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Miriam S. Welgampola
- Royal Prince Alfred Hospital, Institute of Clinical Neuroscience, Camperdown, New South Wales, Australia
- Faculty of Health and Medicine, Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
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7
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Pogson JM, Taylor RL, Bradshaw AP, McGarvie L, D’Souza M, Halmagyi GM, Welgampola MS. The human vestibulo-ocular reflex and saccades: normal subjects and the effect of age. J Neurophysiol 2019; 122:336-349. [DOI: 10.1152/jn.00847.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Here we characterize in 80 normal subjects (16–84 yr (means ± SD, 47 ± 19 yr) the vestibulo-ocular reflex (VOR) and saccades in response to three-dimensional head impulses with a monocular video head impulse test (vHIT) of the right eye. Impulses toward the right lateral, right anterior, and left posterior canals (means: 0.98, 0.91, 0.79) had slightly higher mean gains compared with their counterparts (0.95, 0.86, 0.76). In the older age group (>60 yr), gains of the left posterior canal dropped 0.09 and left anterior canals rose 0.09 resulting in symmetry. All canal gains reduced with increasing head velocity (0.02–0.13 per 100°/s). Comparison of lateral canal gains calculated using five published algorithms yielded lower values (~0.80) when a narrow detection window was used. Low-amplitude refixation saccades (amplitude: 1.11 ± 0.98°, peak velocity: 63.9 ± 34.0°/s at 262.0 ± 93.9 ms) were observed among all age groups (frequency: 40.2 ± 23.4%), increasing in amplitude, peak velocity, and frequency in older subjects. Impulses toward anterior canals showed the least frequent saccades and lateral and posterior canals were similar, but lateral canal impulses showed the smallest saccades and the posterior canal showed the largest saccades. Saccade peak-velocity approximate amplitude “main sequence” slope was steeper for the horizontal canals compared with the vertical planes (60 vs. <40°/s per 1°). In summary, we found small but significant asymmetries in monocular vHIT gain that changed with age. Healthy subjects commonly have minuscule refixation saccades that are moderately to strongly correlated with vHIT gain. NEW & NOTEWORTHY Gaze fixation is normally stabilized during rapid “head-impulse” movements by the bisynaptic vestibulo-ocular reflex (VOR), but earlier studies of normal subjects also report small amplitude saccades. We found that with increased age of the subject the vertical VOR became more variable, while in all semicircular canal directions the saccade frequency, amplitude, and peak velocity increased. We also found that the VOR gain algorithm significantly influences values.
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Affiliation(s)
- Jacob M. Pogson
- Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Rachael L. Taylor
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Andrew P. Bradshaw
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Leigh McGarvie
- Psychology Department, The University of Sydney, Camperdown, New South Wales, Australia
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Mario D’Souza
- Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
- Clinical Research Centre, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - G. Michael Halmagyi
- Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Miriam S. Welgampola
- Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
- Institute of Clinical Neuroscience, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
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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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9
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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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10
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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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