The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform

Susana Martinez-conde - One of the best experts on this subject based on the ideXlab platform.

  • Microsaccade characteristics in neurological and ophthalmic disease
    Frontiers in Neurology, 2018
    Co-Authors: Robert G. Alexander, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    Microsaccade research has recently reached a critical mass of studies that allows, for the first time, a comprehensive review of how microsaccadic dynamics change in neurological and ophthalmic disease. We discuss the various pathological conditions that affect microsaccades, their impact on microsaccadic and other Fixational Eye Movement dynamics, and the incipient studies that point to microsaccadic features as potential indicators of differential and early diagnoses of multiple clinical conditions, from Movement disorders to Attention Deficit Hyperactivity Disorder to amblyopia. We propose that the objective assessment of Fixational Eye Movement parameters may help refine differential diagnostics in neurological disease, and assist in the evaluation of ongoing therapy regimes. In addition, determining the effects of ophthalmic disease on Fixational Eye Movement features may help evaluate visual impairment in an objective manner, particularly in young patients or those experiencing communication difficulties.

  • Fixational Eye Movements and binocular vision.
    Frontiers in Integrative Neuroscience, 2014
    Co-Authors: Jorge Otero-millan, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    During attempted visual fixation, small involuntary Eye Movements –called Fixational Eye Movements--continuously change of our gaze’s position. Disagreement between the left and right Eye positions during such motions can produce diplopia (double vision). Thus, the ability to properly coordinate the two Eyes during gaze fixation is critical for stable perception. For the last 50 years, researchers have studied the binocular characteristics of Fixational Eye Movements. Here we review classical and recent studies on the binocular coordination (i.e. degree of conjugacy) of each Fixational Eye Movement type: microsaccades, drift and tremor, and its perceptual contribution to increasing or reducing binocular disparity. We also discuss how amblyopia and other visual pathologies affect the binocular coordination of Fixational Eye Movements.

  • Microsaccade and drift dynamics reflect mental fatigue.
    European Journal of Neuroscience, 2013
    Co-Authors: Leandro L. Di Stasi, Michael B Mccamy, Stephen L Macknik, Andrés Catena, José J. Cañas, Susana Martinez-conde
    Abstract:

    Our Eyes are always in motion. Even during periods of relative fixation we produce so-called ‘Fixational Eye Movements’, which include microsaccades, drift and tremor. Mental fatigue can modulate saccade dynamics, but its effects on microsaccades and drift are unknown. Here we asked human subjects to perform a prolonged and demanding visual search task (a simplified air traffic control task), with two difficulty levels, under both free-viewing and fixation conditions. Saccadic and microsaccadic velocity decreased with time-on-task whereas drift velocity increased, suggesting that ocular instability increases with mental fatigue. Task difficulty did not influence Eye Movements despite affecting reaction times, performance errors and subjective complexity ratings. We propose that variations in Eye Movement dynamics with time-on-task are consistent with the activation of the brain’s sleep centers in correlation with mental fatigue. Covariation of saccadic and microsaccadic parameters moreover supports the hypothesis of a common generator for microsaccades and saccades. We conclude that changes in Fixational and saccadic dynamics can indicate mental fatigue due to time-on-task, irrespective of task complexity. These findings suggest that Fixational Eye Movement dynamics have the potential to signal the nervous system’s activation state.

  • Microsaccadic Efficacy and Contribution to Foveal and Peripheral Vision
    The Journal of Neuroscience, 2012
    Co-Authors: Michael B Mccamy, Jorge Otero-millan, Xoana G. Troncoso, Stephen L Macknik, Yan Yang, Steven Baer, Sharon M. Crook, Susana Martinez-conde
    Abstract:

    Our Eyes move constantly, even when we try to fixate our gaze. Fixational Eye Movements prevent and restore visual loss during fixation, yet the relative impact of each type of Fixational Eye Movement remains controversial. For over five decades, the debate has focused on microsaccades, the fastest and largest Fixational Eye Movements. Some recent studies have concluded that microsaccades counteract visual fading during fixation. Other studies have disputed this idea, contending that microsaccades play no significant role in vision. The disagreement stems from the lack of methods to determine the precise effects of microsaccades on vision versus those of other Eye Movements, as well as a lack of evidence that microsaccades are relevant to foveal vision. Here we developed a novel generalized method to determine the precise quantified contribution and efficacy of human microsaccades to restoring visibility compared with other Eye Movements. Our results indicate that microsaccades are the greatest Eye Movement contributor to the restoration of both foveal and peripheral vision during fixation. Our method to calculate the efficacy and contribution of microsaccades to perception can determine the strength of connection between any two physiological and/or perceptual events, providing a novel and powerful estimate of causal influence; thus, we anticipate wide-ranging applications in neuroscience and beyond.

  • Microsaccades and Blinks Trigger Illusory Rotation in the “Rotating Snakes” Illusion
    The Journal of Neuroscience, 2012
    Co-Authors: Jorge Otero-millan, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    Certain repetitive arrangements of luminance gradients elicit the perception of strong illusory motion. Among them, the “Rotating Snakes Illusion” has generated a large amount of interest in the visual neurosciences, as well as in the public. Prior evidence indicates that the Rotating Snakes illusion depends critically on Eye Movements, yet the specific Eye Movement types involved and their associated neural mechanisms remain controversial. According to recent reports, slow ocular drift—a nonsaccadic type of Fixational Eye Movement—drives the illusion, whereas microsaccades produced during attempted fixation fail to do so. Here, we asked human subjects to indicate the presence or absence of rotation during the observation of the illusion while we simultaneously recorded their Eye Movements with high precision. We found a strong quantitative link between microsaccade and blink production and illusory rotation. These results suggest that transient oculomotor events such as microsaccades, saccades, and blinks, rather than continuous drift, act to trigger the illusory motion in the Rotating Snakes illusion.

Stephen L Macknik - One of the best experts on this subject based on the ideXlab platform.

  • Microsaccade characteristics in neurological and ophthalmic disease
    Frontiers in Neurology, 2018
    Co-Authors: Robert G. Alexander, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    Microsaccade research has recently reached a critical mass of studies that allows, for the first time, a comprehensive review of how microsaccadic dynamics change in neurological and ophthalmic disease. We discuss the various pathological conditions that affect microsaccades, their impact on microsaccadic and other Fixational Eye Movement dynamics, and the incipient studies that point to microsaccadic features as potential indicators of differential and early diagnoses of multiple clinical conditions, from Movement disorders to Attention Deficit Hyperactivity Disorder to amblyopia. We propose that the objective assessment of Fixational Eye Movement parameters may help refine differential diagnostics in neurological disease, and assist in the evaluation of ongoing therapy regimes. In addition, determining the effects of ophthalmic disease on Fixational Eye Movement features may help evaluate visual impairment in an objective manner, particularly in young patients or those experiencing communication difficulties.

  • Fixational Eye Movement correction of blink induced gaze position errors
    PLOS ONE, 2014
    Co-Authors: Xoana G. Troncoso, Michael B Mccamy, Stephen L Macknik, Francisco M Costela, Jorge Oteromillan, Ali Najafian Jazi
    Abstract:

    Our Eyes move continuously. Even when we attempt to fix our gaze, we produce “Fixational” Eye Movements including microsaccades, drift and tremor. The potential role of microsaccades versus drifts in the control of Eye position has been debated for decades and remains in question today. Here we set out to determine the corrective functions of microsaccades and drifts on gaze-position errors due to blinks in non-human primates (Macaca mulatta) and humans. Our results show that blinks contribute to the instability of gaze during fixation, and that microsaccades, but not drifts, correct fixation errors introduced by blinks. These findings provide new insights about Eye position control during fixation, and indicate a more general role of microsaccades in fixation correction than thought previously.

  • Fixational Eye Movements and binocular vision.
    Frontiers in Integrative Neuroscience, 2014
    Co-Authors: Jorge Otero-millan, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    During attempted visual fixation, small involuntary Eye Movements –called Fixational Eye Movements--continuously change of our gaze’s position. Disagreement between the left and right Eye positions during such motions can produce diplopia (double vision). Thus, the ability to properly coordinate the two Eyes during gaze fixation is critical for stable perception. For the last 50 years, researchers have studied the binocular characteristics of Fixational Eye Movements. Here we review classical and recent studies on the binocular coordination (i.e. degree of conjugacy) of each Fixational Eye Movement type: microsaccades, drift and tremor, and its perceptual contribution to increasing or reducing binocular disparity. We also discuss how amblyopia and other visual pathologies affect the binocular coordination of Fixational Eye Movements.

  • Microsaccade and drift dynamics reflect mental fatigue.
    European Journal of Neuroscience, 2013
    Co-Authors: Leandro L. Di Stasi, Michael B Mccamy, Stephen L Macknik, Andrés Catena, José J. Cañas, Susana Martinez-conde
    Abstract:

    Our Eyes are always in motion. Even during periods of relative fixation we produce so-called ‘Fixational Eye Movements’, which include microsaccades, drift and tremor. Mental fatigue can modulate saccade dynamics, but its effects on microsaccades and drift are unknown. Here we asked human subjects to perform a prolonged and demanding visual search task (a simplified air traffic control task), with two difficulty levels, under both free-viewing and fixation conditions. Saccadic and microsaccadic velocity decreased with time-on-task whereas drift velocity increased, suggesting that ocular instability increases with mental fatigue. Task difficulty did not influence Eye Movements despite affecting reaction times, performance errors and subjective complexity ratings. We propose that variations in Eye Movement dynamics with time-on-task are consistent with the activation of the brain’s sleep centers in correlation with mental fatigue. Covariation of saccadic and microsaccadic parameters moreover supports the hypothesis of a common generator for microsaccades and saccades. We conclude that changes in Fixational and saccadic dynamics can indicate mental fatigue due to time-on-task, irrespective of task complexity. These findings suggest that Fixational Eye Movement dynamics have the potential to signal the nervous system’s activation state.

  • Simultaneous recordings of ocular microtremor and microsaccades with a piezoelectric sensor and a video-oculography system
    PeerJ, 2013
    Co-Authors: Michael B Mccamy, Niamh Collins, Jorge Otero-millan, Mohammed Al-kalbani, Xoana G. Troncoso, Gerard Boyle, Stephen L Macknik, Vinodh Narayanan, Davis Coakley, Thomas r. Wolf
    Abstract:

    Our Eyes are in continuous motion. Even when we attempt to fix our gaze, we produce so called "Fixational Eye Movements", which include microsaccades, drift, and ocular microtremor (OMT). Microsaccades, the largest and fastest type of Fixational Eye Movement, shift the retinal image from several dozen to several hundred photoreceptors and have equivalent physical characteristics to saccades, only on a smaller scale (Martinez-Conde, Otero-Millan {&} Macknik, 2013). OMT occurs simultaneously with drift and is the smallest of the Fixational Eye Movements (∼1 photoreceptor width, {>}0.5 arcmin), with dominant frequencies ranging from 70 Hz to 103 Hz (Martinez-Conde, Macknik {&} Hubel, 2004). Due to OMT's small amplitude and high frequency, the most accurate and stringent way to record it is the piezoelectric transduction method. Thus, OMT studies are far rarer than those focusing on microsaccades or drift. Here we conducted simultaneous recordings of OMT and microsaccades with a piezoelectric device and a commercial infrared video tracking system. We set out to determine whether OMT could help to restore perceptually faded targets during attempted fixation, and we also wondered whether the piezoelectric sensor could affect the characteristics of microsaccades. Our results showed that microsaccades, but not OMT, counteracted perceptual fading. We moreover found that the piezoelectric sensor affected microsaccades in a complex way, and that the oculomotor system adjusted to the stress brought on by the sensor by adjusting the magnitudes of microsaccades.

Jorge Otero-millan - One of the best experts on this subject based on the ideXlab platform.

  • Fixational Eye Movements and binocular vision.
    Frontiers in Integrative Neuroscience, 2014
    Co-Authors: Jorge Otero-millan, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    During attempted visual fixation, small involuntary Eye Movements –called Fixational Eye Movements--continuously change of our gaze’s position. Disagreement between the left and right Eye positions during such motions can produce diplopia (double vision). Thus, the ability to properly coordinate the two Eyes during gaze fixation is critical for stable perception. For the last 50 years, researchers have studied the binocular characteristics of Fixational Eye Movements. Here we review classical and recent studies on the binocular coordination (i.e. degree of conjugacy) of each Fixational Eye Movement type: microsaccades, drift and tremor, and its perceptual contribution to increasing or reducing binocular disparity. We also discuss how amblyopia and other visual pathologies affect the binocular coordination of Fixational Eye Movements.

  • Simultaneous recordings of ocular microtremor and microsaccades with a piezoelectric sensor and a video-oculography system
    PeerJ, 2013
    Co-Authors: Michael B Mccamy, Niamh Collins, Jorge Otero-millan, Mohammed Al-kalbani, Xoana G. Troncoso, Gerard Boyle, Stephen L Macknik, Vinodh Narayanan, Davis Coakley, Thomas r. Wolf
    Abstract:

    Our Eyes are in continuous motion. Even when we attempt to fix our gaze, we produce so called "Fixational Eye Movements", which include microsaccades, drift, and ocular microtremor (OMT). Microsaccades, the largest and fastest type of Fixational Eye Movement, shift the retinal image from several dozen to several hundred photoreceptors and have equivalent physical characteristics to saccades, only on a smaller scale (Martinez-Conde, Otero-Millan {&} Macknik, 2013). OMT occurs simultaneously with drift and is the smallest of the Fixational Eye Movements (∼1 photoreceptor width, {>}0.5 arcmin), with dominant frequencies ranging from 70 Hz to 103 Hz (Martinez-Conde, Macknik {&} Hubel, 2004). Due to OMT's small amplitude and high frequency, the most accurate and stringent way to record it is the piezoelectric transduction method. Thus, OMT studies are far rarer than those focusing on microsaccades or drift. Here we conducted simultaneous recordings of OMT and microsaccades with a piezoelectric device and a commercial infrared video tracking system. We set out to determine whether OMT could help to restore perceptually faded targets during attempted fixation, and we also wondered whether the piezoelectric sensor could affect the characteristics of microsaccades. Our results showed that microsaccades, but not OMT, counteracted perceptual fading. We moreover found that the piezoelectric sensor affected microsaccades in a complex way, and that the oculomotor system adjusted to the stress brought on by the sensor by adjusting the magnitudes of microsaccades.

  • Microsaccadic Efficacy and Contribution to Foveal and Peripheral Vision
    The Journal of Neuroscience, 2012
    Co-Authors: Michael B Mccamy, Jorge Otero-millan, Xoana G. Troncoso, Stephen L Macknik, Yan Yang, Steven Baer, Sharon M. Crook, Susana Martinez-conde
    Abstract:

    Our Eyes move constantly, even when we try to fixate our gaze. Fixational Eye Movements prevent and restore visual loss during fixation, yet the relative impact of each type of Fixational Eye Movement remains controversial. For over five decades, the debate has focused on microsaccades, the fastest and largest Fixational Eye Movements. Some recent studies have concluded that microsaccades counteract visual fading during fixation. Other studies have disputed this idea, contending that microsaccades play no significant role in vision. The disagreement stems from the lack of methods to determine the precise effects of microsaccades on vision versus those of other Eye Movements, as well as a lack of evidence that microsaccades are relevant to foveal vision. Here we developed a novel generalized method to determine the precise quantified contribution and efficacy of human microsaccades to restoring visibility compared with other Eye Movements. Our results indicate that microsaccades are the greatest Eye Movement contributor to the restoration of both foveal and peripheral vision during fixation. Our method to calculate the efficacy and contribution of microsaccades to perception can determine the strength of connection between any two physiological and/or perceptual events, providing a novel and powerful estimate of causal influence; thus, we anticipate wide-ranging applications in neuroscience and beyond.

  • Microsaccades and Blinks Trigger Illusory Rotation in the “Rotating Snakes” Illusion
    The Journal of Neuroscience, 2012
    Co-Authors: Jorge Otero-millan, Stephen L Macknik, Susana Martinez-conde
    Abstract:

    Certain repetitive arrangements of luminance gradients elicit the perception of strong illusory motion. Among them, the “Rotating Snakes Illusion” has generated a large amount of interest in the visual neurosciences, as well as in the public. Prior evidence indicates that the Rotating Snakes illusion depends critically on Eye Movements, yet the specific Eye Movement types involved and their associated neural mechanisms remain controversial. According to recent reports, slow ocular drift—a nonsaccadic type of Fixational Eye Movement—drives the illusion, whereas microsaccades produced during attempted fixation fail to do so. Here, we asked human subjects to indicate the presence or absence of rotation during the observation of the illusion while we simultaneously recorded their Eye Movements with high precision. We found a strong quantitative link between microsaccade and blink production and illusory rotation. These results suggest that transient oculomotor events such as microsaccades, saccades, and blinks, rather than continuous drift, act to trigger the illusory motion in the Rotating Snakes illusion.

Michael B Mccamy - One of the best experts on this subject based on the ideXlab platform.

  • Fixational Eye Movement correction of blink induced gaze position errors
    PLOS ONE, 2014
    Co-Authors: Xoana G. Troncoso, Michael B Mccamy, Stephen L Macknik, Francisco M Costela, Jorge Oteromillan, Ali Najafian Jazi
    Abstract:

    Our Eyes move continuously. Even when we attempt to fix our gaze, we produce “Fixational” Eye Movements including microsaccades, drift and tremor. The potential role of microsaccades versus drifts in the control of Eye position has been debated for decades and remains in question today. Here we set out to determine the corrective functions of microsaccades and drifts on gaze-position errors due to blinks in non-human primates (Macaca mulatta) and humans. Our results show that blinks contribute to the instability of gaze during fixation, and that microsaccades, but not drifts, correct fixation errors introduced by blinks. These findings provide new insights about Eye position control during fixation, and indicate a more general role of microsaccades in fixation correction than thought previously.

  • Microsaccade and drift dynamics reflect mental fatigue.
    European Journal of Neuroscience, 2013
    Co-Authors: Leandro L. Di Stasi, Michael B Mccamy, Stephen L Macknik, Andrés Catena, José J. Cañas, Susana Martinez-conde
    Abstract:

    Our Eyes are always in motion. Even during periods of relative fixation we produce so-called ‘Fixational Eye Movements’, which include microsaccades, drift and tremor. Mental fatigue can modulate saccade dynamics, but its effects on microsaccades and drift are unknown. Here we asked human subjects to perform a prolonged and demanding visual search task (a simplified air traffic control task), with two difficulty levels, under both free-viewing and fixation conditions. Saccadic and microsaccadic velocity decreased with time-on-task whereas drift velocity increased, suggesting that ocular instability increases with mental fatigue. Task difficulty did not influence Eye Movements despite affecting reaction times, performance errors and subjective complexity ratings. We propose that variations in Eye Movement dynamics with time-on-task are consistent with the activation of the brain’s sleep centers in correlation with mental fatigue. Covariation of saccadic and microsaccadic parameters moreover supports the hypothesis of a common generator for microsaccades and saccades. We conclude that changes in Fixational and saccadic dynamics can indicate mental fatigue due to time-on-task, irrespective of task complexity. These findings suggest that Fixational Eye Movement dynamics have the potential to signal the nervous system’s activation state.

  • Simultaneous recordings of ocular microtremor and microsaccades with a piezoelectric sensor and a video-oculography system
    PeerJ, 2013
    Co-Authors: Michael B Mccamy, Niamh Collins, Jorge Otero-millan, Mohammed Al-kalbani, Xoana G. Troncoso, Gerard Boyle, Stephen L Macknik, Vinodh Narayanan, Davis Coakley, Thomas r. Wolf
    Abstract:

    Our Eyes are in continuous motion. Even when we attempt to fix our gaze, we produce so called "Fixational Eye Movements", which include microsaccades, drift, and ocular microtremor (OMT). Microsaccades, the largest and fastest type of Fixational Eye Movement, shift the retinal image from several dozen to several hundred photoreceptors and have equivalent physical characteristics to saccades, only on a smaller scale (Martinez-Conde, Otero-Millan {&} Macknik, 2013). OMT occurs simultaneously with drift and is the smallest of the Fixational Eye Movements (∼1 photoreceptor width, {>}0.5 arcmin), with dominant frequencies ranging from 70 Hz to 103 Hz (Martinez-Conde, Macknik {&} Hubel, 2004). Due to OMT's small amplitude and high frequency, the most accurate and stringent way to record it is the piezoelectric transduction method. Thus, OMT studies are far rarer than those focusing on microsaccades or drift. Here we conducted simultaneous recordings of OMT and microsaccades with a piezoelectric device and a commercial infrared video tracking system. We set out to determine whether OMT could help to restore perceptually faded targets during attempted fixation, and we also wondered whether the piezoelectric sensor could affect the characteristics of microsaccades. Our results showed that microsaccades, but not OMT, counteracted perceptual fading. We moreover found that the piezoelectric sensor affected microsaccades in a complex way, and that the oculomotor system adjusted to the stress brought on by the sensor by adjusting the magnitudes of microsaccades.

  • Microsaccadic Efficacy and Contribution to Foveal and Peripheral Vision
    The Journal of Neuroscience, 2012
    Co-Authors: Michael B Mccamy, Jorge Otero-millan, Xoana G. Troncoso, Stephen L Macknik, Yan Yang, Steven Baer, Sharon M. Crook, Susana Martinez-conde
    Abstract:

    Our Eyes move constantly, even when we try to fixate our gaze. Fixational Eye Movements prevent and restore visual loss during fixation, yet the relative impact of each type of Fixational Eye Movement remains controversial. For over five decades, the debate has focused on microsaccades, the fastest and largest Fixational Eye Movements. Some recent studies have concluded that microsaccades counteract visual fading during fixation. Other studies have disputed this idea, contending that microsaccades play no significant role in vision. The disagreement stems from the lack of methods to determine the precise effects of microsaccades on vision versus those of other Eye Movements, as well as a lack of evidence that microsaccades are relevant to foveal vision. Here we developed a novel generalized method to determine the precise quantified contribution and efficacy of human microsaccades to restoring visibility compared with other Eye Movements. Our results indicate that microsaccades are the greatest Eye Movement contributor to the restoration of both foveal and peripheral vision during fixation. Our method to calculate the efficacy and contribution of microsaccades to perception can determine the strength of connection between any two physiological and/or perceptual events, providing a novel and powerful estimate of causal influence; thus, we anticipate wide-ranging applications in neuroscience and beyond.

Norio Tagawa - One of the best experts on this subject based on the ideXlab platform.

  • MVA - Differential-Formed Shape from Multiple Images Based on One-Directional Random Small Camera Rotations
    Journal of Machine Vision and Applications, 2020
    Co-Authors: Shoei Koizumi, Norio Tagawa
    Abstract:

    The small vibration of the Eye ball, which occurs when we fix our gaze on an object, is called “Fixational Eye Movement,” and using the analogy of it for the camera motion, differential-formed and integralformed shape recovery method was proposed. We are considering a practical system using both methods selectively and adaptively for the local texture pattern in images. In this study, we analyze the performance especially of the differential-formed method with respect to the relation between a striped-texture and a camera rotation direction. From the results, we argue that, at least for the differential-formed method, suitable onedirectional camera rotations have to be applied adaptively according to the local direction of image texture.

  • ICPR - Depth Perception Model Based on Fixational Eye Movements Using Bayesian Statistical Inference
    2010 20th International Conference on Pattern Recognition, 2010
    Co-Authors: Norio Tagawa
    Abstract:

    Small vibrations of Eyeball, which occur when we fix our gaze on object, is called ``Fixational Eye Movements.'' It has been reported that such the involuntary Eye Movements work also for monocular depth perception. In this study, we focus on ``tremor'' which is the smallest type of Fixational Eye Movement, and construct depth perception model based on tremor using MAP-EM algorithm. Its effectiveness is confirmed through numerical evaluations using artificial images.

  • Depth Perception Model Based on Fixational Eye Movements Using Bayesian Statistical Inference
    2010 20th International Conference on Pattern Recognition, 2010
    Co-Authors: Norio Tagawa
    Abstract:

    Small vibrations of Eyeball, which occur when we fix our gaze on object, is called "Fixational Eye Movements.'' It has been reported that such the involuntary Eye Movements work also for monocular depth perception. In this study, we focus on "tremor'' which is the smallest type of Fixational Eye Movement, and construct depth perception model based on tremor using MAP-EM algorithm. Its effectiveness is confirmed through numerical evaluations using artificial images.