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Microsaccades

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https://www.readbyqxmd.com/read/29599951/leukocyte-image-segmentation-using-novel-saliency-detection-based-on-positive-feedback-of-visual-perception
#1
Chen Pan, Wenlong Xu, Dan Shen, Yong Yang
This paper presents a novel method for salient object detection in nature image by simulating microsaccades in fixational eye movements. Due to a nucleated cell usually stained that is salient obviously, the proposed method is suitable to segment nucleated cell. Firstly, the existing fixation prediction method is utilized to produce an initial fixation area. Followed EPELM (ensemble of polyharmonic extreme learning machine) is trained on-line by the pixels sampling from the fixation and nonfixation area. Then the model of EPELM could be used to classify image pixels to form new binary fixation area...
2018: Journal of Healthcare Engineering
https://www.readbyqxmd.com/read/29593642/microsaccade-characteristics-in-neurological-and-ophthalmic-disease
#2
REVIEW
Robert G Alexander, Stephen L Macknik, Susana Martinez-Conde
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...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29551962/learning-to-recognize-actions-from-limited-training-examples-using-a-recurrent-spiking-neural-model
#3
Priyadarshini Panda, Narayan Srinivasa
A fundamental challenge in machine learning today is to build a model that can learn from few examples. Here, we describe a reservoir based spiking neural model for learning to recognize actions with a limited number of labeled videos. First, we propose a novel encoding, inspired by how microsaccades influence visual perception, to extract spike information from raw video data while preserving the temporal correlation across different frames. Using this encoding, we show that the reservoir generalizes its rich dynamical activity toward signature action/movements enabling it to learn from few training examples...
2018: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/29529085/a-non-invasive-quantitative-study-of-broadband-spectral-responses-in-human-visual-cortex
#4
Eline R Kupers, Helena X Wang, Kaoru Amano, Kendrick N Kay, David J Heeger, Jonathan Winawer
Currently, non-invasive methods for studying the human brain do not routinely and reliably measure spike-rate-dependent signals, independent of responses such as hemodynamic coupling (fMRI) and subthreshold neuronal synchrony (oscillations and event-related potentials). In contrast, invasive methods-microelectrode recordings and electrocorticography (ECoG)-have recently measured broadband power elevation in field potentials (~50-200 Hz) as a proxy for locally averaged spike rates. Here, we sought to detect and quantify stimulus-related broadband responses using magnetoencephalography (MEG)...
2018: PloS One
https://www.readbyqxmd.com/read/29488842/selective-modulation-of-visual-sensitivity-during-fixation
#5
Chris Scholes, Paul V McGraw, Neil W Roach
During periods of steady fixation, we make small amplitude ocular movements, termed microsaccades, at a rate of 1-2 every second. Early studies provided evidence that visual sensitivity is reduced during microsaccades - akin to the well-established suppression associated with larger saccades. However, the results of more recent work suggest that microsaccades may alter retinal input in a manner that enhances visual sensitivity to some stimuli. Here, we parametrically varied the spatial frequency of a stimulus during a detection task and tracked contrast sensitivity as a function of time relative to microsaccades...
February 28, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29465321/dynamics-of-fixational-eye-position-and-microsaccades-during-spatial-cueing-the-case-of-express-microsaccades
#6
Xiaoguang Tian, Masatoshi Yoshida, Ziad M Hafed
Microsaccades are systematically modulated by peripheral spatial cues, and these eye movements have been implicated in perceptual and motor performance changes in cueing tasks. However, an additional oculomotor factor that may also influence performance in these tasks, fixational eye position itself, has been largely neglected so far. Using precise eye tracking and real-time retinal-image stabilization, we carefully analyzed fixational eye position dynamics and related them to microsaccade generation during spatial cueing...
February 21, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29371320/antagonistic-interactions-between-microsaccades-and-evidence-accumulation-processes-during-decision-formation
#7
Gerard M Loughnane, Daniel P Newman, Sarita Tamang, Simon P Kelly, Redmond G O'Connell
Despite their small size, microsaccades can impede stimulus detections if executed at inopportune times. Although it has been shown that microsaccades evoke both inhibitory and excitatory responses across different visual regions, their impact on the higher-level neural decision processes that bridge sensory responses to action selection has yet to be examined. Here we show that when human observers monitor stimuli for subtle feature changes, the occurrence of microsaccades long after (up to 800ms) change onset predicts slower reaction times, and that this is accounted for by momentary suppression of neural signals at each key stage of decision formation - visual evidence encoding, evidence accumulation, and motor preparation...
January 25, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29340646/visual-fixation-instability-in-multiple-sclerosis-measured-using-slo-oct
#8
Robert M Mallery, Pieter Poolman, Matthew J Thurtell, Jan M Full, Johannes Ledolter, Dorlan Kimbrough, Elliot M Frohman, Teresa C Frohman, Randy H Kardon
Purpose: Precise measurements of visual fixation and its instability were recorded during optical coherence tomography (OCT) as a marker of neural network dysfunction in multiple sclerosis (MS), which could be used to monitor disease progression or response to treatment. Methods: A total of 16 MS patients and 26 normal subjects underwent 30 seconds of scanning laser ophthalmoscope (SLO)-based eye tracking during OCT scanning of retinal layer thickness. Study groups consisted of normal eyes, MS eyes without prior optic neuritis (MS wo ON), and MS eyes with prior optic neuritis (MS + ON)...
January 1, 2018: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29203826/blink-associated-resetting-eye-movements-barms-are-functionally-complementary-to-microsaccades-in-correcting-for-fixation-errors
#9
Mohammad Farhan Khazali, Joern K Pomper, Peter Thier
Blinks do not only protect the eye, but they do also correct for torsional eye position deviations by blink-associated resetting eye movements (BARMs). Although BARMs are functionally distinct from other eye movements in the torsional dimension, it has remained open if BARMs observed in the horizontal and vertical dimensions (fixational BARMs) are not simply microsaccades coinciding with blinks. We show here that fixational BARMs are functionally distinct and complementary to microsaccades in the following way: First, they compensate for large fixational error more efficiently than microsaccades, secondly, their probability to be executed in eccentric eye positions is higher, and thirdly, they reset the eyes into a position zone that is broader as compared to microsaccades...
December 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29184104/dynamic-modulation-of-the-perceptual-load-on-microsaccades-during-a-selective-spatial-attention-task
#10
Linyan Xue, Dan Huang, Tong Wang, Qiyi Hu, Xinyu Chai, Liming Li, Yao Chen
Selective spatial attention enhances task performance at restricted regions within the visual field. The magnitude of this effect depends on the level of attentional load, which determines the efficiency of distractor rejection. Mechanisms of attentional load include perceptual selection and/or cognitive control involving working memory. Recent studies have provided evidence that microsaccades are influenced by spatial attention. Therefore, microsaccade activities may be exploited to help understand the dynamic control of selective attention under different load levels...
November 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29157407/oculomotor-measures-reveal-the-temporal-dynamics-of-preparing-for-search
#11
Katya Olmos-Solis, Anouk M van Loon, Sander A Los, Christian N L Olivers
Theories of visual search assume that selection is driven by an active template representation of the target object. Earlier studies suggest that template activation occurs prior to search, but the temporal dynamics of such preactivation remain unclear. Two experiments employed microsaccades to track both general preparation (i.e., anticipation of the search task as such) and template-specific preparation (i.e., anticipation of target selection) of visual search. Participants memorized a target color (i.e., the template) for an upcoming search task...
2017: Progress in Brain Research
https://www.readbyqxmd.com/read/29095748/central-control-of-eye-movements
#12
Jonathan J D Baird-Gunning, Christian J Lueck
PURPOSE OF REVIEW: Eye-movement research continues to provide an excellent tool for understanding the central control of motor function, both in health and disease. This article reviews recent findings in relation to saccadic eye movements, particularly antisaccades and microsaccades, with particular emphasis on the control of inaction, something which has recently become topical. RECENT FINDINGS: Microsaccades are under the control of the cerebral cortex, particularly the frontal and parietal eye fields...
February 2018: Current Opinion in Neurology
https://www.readbyqxmd.com/read/29081421/microsaccadic-behavior-when-developing-a%C3%A2-complex-dynamical-activity
#13
Gerardo Fernández, Nora P Rotstein, Luis E Politi, Liliana Castro, Osvaldo Agamennoni
Microsaccade are sensitive to changes of perceptual inputs as well as modulations of cognitive states. There are just a few works analyzing microsaccade while subjects are processing complex information and fewer when doing predictions about upcoming events. To evaluate whether contextual predictability would change microsaccadic behavior, we evaluated microsaccade of twenty one persons when reading 40 regular sentences and 40 proverbs. Analysis of microsaccade during reading proverbs and regular sentences revealed that microsaccade rate on words before maxjump, during maxjump and words after maxjump varied depending on the kind of sentence and on the word predictability...
October 25, 2017: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/29060811/identifying-the-effects-of-microsaccades-in-tripolar-eeg-signals
#14
Rachel Bellisle, Preston Steele, Rachel Bartels, Lei Ding, Sridhar Sunderam, Walter Besio
Microsaccades are tiny, involuntary eye movements that occur during fixation, and they are necessary to human sight to maintain a sharp image and correct the effects of other fixational movements. Researchers have theorized and studied the effects of microsaccades on electroencephalography (EEG) signals to understand and eliminate the unwanted artifacts from EEG. The tripolar concentric ring electrode (TCRE) sensors are used to acquire TCRE EEG (tEEG). The tEEG detects extremely focal signals from directly below the TCRE sensor...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29021548/a-self-avoiding-walk-with-neural-delays-as-a-model-of-fixational-eye-movements
#15
Carl J J Herrmann, Ralf Metzler, Ralf Engbert
Fixational eye movements show scaling behaviour of the positional mean-squared displacement with a characteristic transition from persistence to antipersistence for increasing time-lag. These statistical patterns were found to be mainly shaped by microsaccades (fast, small-amplitude movements). However, our re-analysis of fixational eye-movement data provides evidence that the slow component (physiological drift) of the eyes exhibits scaling behaviour of the mean-squared displacement that varies across human participants...
October 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28934359/microsaccades-during-reading
#16
Norick R Bowers, Martina Poletti
Recent research has shown that microsaccades contribute to high acuity vision. However, little is known about whether microsaccades also play a role in daily activities, such as reading, that do not involve stimuli at the limit of spatial resolution. While the functions of larger saccades in reading have been extensively examined, microsaccades are commonly regarded as oculomotor noise in this context. We used high-resolution eyetracking and precise gaze localization to investigate fine oculomotor behavior during reading...
2017: PloS One
https://www.readbyqxmd.com/read/28922090/microsaccades-and-interest-areas-during-free-viewing-sport-task
#17
Alessandro Piras, Milena Raffi, Monica Perazzolo, Ivan Malagoli Lanzoni, Salvatore Squatrito
Microsaccades are important fixation eye movements for visual scene perception. Compared to novices, athletes make fewer fixations of longer duration toward limited interest areas crucial for action prediction. Thus, our aim was to study the microsaccade features during those fixations. Gaze behaviour of expert and novice table tennis players was recorder during a task in which subjects were instructed to predict the direction of the ball after the opponent's throw. Three interest areas from the opponent's body and one from the ball trajectory were identified...
September 18, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28870284/microsaccadic-sampling-of-moving-image-information-provides-drosophila-hyperacute-vision
#18
Mikko Juusola, An Dau, Zhuoyi Song, Narendra Solanki, Diana Rien, David Jaciuch, Sidhartha Anil Dongre, Florence Blanchard, Gonzalo G de Polavieja, Roger C Hardie, Jouni Takalo
Small fly eyes should not see fine image details. Because flies exhibit saccadic visual behaviors and their compound eyes have relatively few ommatidia (sampling points), their photoreceptors would be expected to generate blurry and coarse retinal images of the world. Here we demonstrate that Drosophila see the world far better than predicted from the classic theories. By using electrophysiological, optical and behavioral assays, we found that R1-R6 photoreceptors' encoding capacity in time is maximized to fast high-contrast bursts, which resemble their light input during saccadic behaviors...
September 5, 2017: ELife
https://www.readbyqxmd.com/read/28822717/searching-for-monocular-microsaccades-a-red-hering-of-modern-eye-trackers
#19
Marcus Nyström, Richard Andersson, Diederick C Niehorster, Ignace Hooge
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...
November 2017: Vision Research
https://www.readbyqxmd.com/read/28815321/fixational-eye-movements-in-tourette-syndrome
#20
Aasef G Shaikh, Shlomit Ritz Finkelstein, Ronald Schuchard, Glen Ross, Jorge L Juncos
Studies of saccadic eye movements in subjects with Tourette syndrome (TS) have provided additional evidence that there is a link between TS symptoms and deficits in fronto-striato-thalamic networks. These studies revealed impaired timing and inhibition of saccades. We compared fixational eye movements, such as microsaccades and ocular drifts, in subjects with TS and healthy controls.We measured horizontal and vertical eye positions with video-oculography in 14 subjects with Tourette syndrome. We found reduced microsaccade amplitude but increased time between adjacent microsaccades (intersaccadic interval)...
November 2017: Neurological Sciences
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