scholarly journals The control of saccade size and fixation duration in reading: The limits of linguistic control

1980 ◽  
Vol 28 (2) ◽  
pp. 112-117 ◽  
Author(s):  
J. Kevin O’Regan
Keyword(s):  
Fixation Duration ◽  
Saccade Size ◽  
Linguistic Control

scholarly journals The Relation between Physiological Parameters and Colour Modifications in Text Background and Overlay during Reading in Children with and without Dyslexia

2021 ◽  
Vol 11 (5) ◽  
pp. 539
Author(s):  
Tamara Jakovljević ◽  
Milica M. Janković ◽  
Andrej M. Savić ◽  
Ivan Soldatović ◽  
Gordana Čolić ◽  
...  
Keyword(s):  
Fixation Duration ◽  
Physiological Parameters ◽  
School Age Children ◽  
Control Group ◽  
School Age ◽  
Time Duration ◽  
The Relationship ◽  
White Colour ◽  
Saccade Duration ◽  
40 Hz

Reading is one of the essential processes during the maturation of an individual. It is estimated that 5–10% of school-age children are affected by dyslexia, the reading disorder characterised by difficulties in the accuracy or fluency of word recognition. There are many studies which have reported that coloured overlays and background could improve the reading process, especially in children with reading disorders. As dyslexia has neurobiological origins, the aim of the present research was to understand the relationship between physiological parameters and colour modifications in the text and background during reading in children with and without dyslexia. We have measured differences in electroencephalography (EEG), heart rate variability (HRV), electrodermal activities (EDA) and eye movements of the 36 school-age (from 8 to 12 years old) children (18 with dyslexia and 18 of control group) during the reading task in 13 combinations of background and overlay colours. Our findings showed that the dyslexic children have longer reading duration, fixation count, fixation duration average, fixation duration total, and longer saccade count, saccade duration total, and saccade duration average while reading on white and coloured background/overlay. It was found that the turquoise background, turquoise overlay, and yellow background colours are beneficial for dyslexic readers, as they achieved the shortest time duration of the reading tasks when these colours were used. Additionally, dyslexic children have higher values of beta (15–40 Hz) and the broadband EEG (0.5–40 Hz) power while reading in one particular colour (purple), as well as increasing theta range power while reading with the purple overlay. We have observed no significant differences between HRV parameters on white colour, except for single colours (purple, turquoise overlay, and yellow overlay) where the control group showed higher values for mean HR, while dyslexic children scored higher with mean RR. Regarding EDA measure, we found systematically lower values in children with dyslexia in comparison to the control group. Based on the present results, we can conclude that both pastel and intense background/overlays are beneficial for reading of both groups and all sensor modalities could be used to better understand the neurophysiological origins in dyslexic children.

Anatomy and Physiology of the Primate Interstitial Nucleus of Cajal. II. Discharge Pattern of Single Efferent Fibers

1998 ◽  
Vol 80 (6) ◽  
pp. 3100-3111 ◽  
Author(s):  
Y. Dalezios ◽  
C. A. Scudder ◽  
S. M. Highstein ◽  
A. K. Moschovakis
Keyword(s):  
Smooth Pursuit ◽  
Discharge Pattern ◽  
Eye Position ◽  
Interstitial Nucleus Of Cajal ◽  
Anatomy And Physiology ◽  
Saccade Size ◽  
Saccade Velocity ◽  
Behaving Monkeys ◽  
Eye Velocity ◽  
Vertical Up

Dalezios, Y., C. A. Scudder, S. M. Highstein, and A. K. Moschovakis. Anatomy and physiology of the primate interstitial nucleus of Cajal. II. Discharge pattern of single efferent fibers. J. Neurophysiol. 80: 3100–3111, 1998. Single efferent fibers of the interstitial nucleus of Cajal (NIC) were characterized physiologically and injected with biocytin in alert behaving monkeys. Quantitative analysis demonstrated that their discharge encodes a constellation of oculomotor variables. Tonic and phasic signals were related to vertical (up or down) eye position and saccades, respectively. Depending on how they encoded eye position, saccade velocity, saccade size, saccade duration, and smooth-pursuit eye velocity, fibers were characterized as regular or irregular, bi- or unidirectionally modulated, more or less sensitive, and reliable or unreliable. Further, fibers that did not burst for saccades (tonic) and fibers the eye-position and saccade-related signals of which increased in the same (in-phase) or in the opposite (anti-phase) directions were encountered. A continuum of discharge properties was the rule. We conclude that NIC efferent fibers send a combination of eye-position, saccade-, and smooth-pursuit-related signals, mixed in proportions that differ for different fibers, to targets of the vertical neural integrator such as extraocular motoneurons.

Predicting readers’ domain knowledge based on eye-tracking measures

2018 ◽  
Vol 36 (6) ◽  
pp. 1027-1042 ◽  
Author(s):  
Quan Lu ◽  
Jiyue Zhang ◽  
Jing Chen ◽  
Ji Li
Keyword(s):  
Logistic Regression ◽  
Eye Tracking ◽  
Information Search ◽  
Domain Knowledge ◽  
Fixation Duration ◽  
Baseline Model ◽  
Content Type ◽  
Knowledge Based ◽  
Total Fixation ◽  
Negative Predictor

Purpose This paper aims to examine the effect of domain knowledge on eye-tracking measures and predict readers’ domain knowledge from these measures in a navigational table of contents (N-TOC) system. Design/methodology/approach A controlled experiment of three reading tasks was conducted in an N-TOC system for 24 postgraduates of Wuhan University. Data including fixation duration, fixation count and inter-scanning transitions were collected and calculated. Participants’ domain knowledge was measured by pre-experiment questionnaires. Logistic regression analysis was leveraged to build the prediction model and the model’s performance was evaluated based on baseline model. Findings The results showed that novices spent significantly more time in fixating on text area than experts, because of the difficulty of understanding the information of text area. Total fixation duration on text area (TFD_T) was a significantly negative predictor of domain knowledge. The prediction performance of logistic regression model using eye-tracking measures was better than baseline model, with the accuracy, precision and F(β = 1) scores to be 0.71, 0.86, 0.79. Originality/value Little research has been reported in literature on investigation of domain knowledge effect on eye-tracking measures during reading and prediction of domain knowledge based on eye-tracking measures. Most studies focus on multimedia learning. With respect to the prediction of domain knowledge, only some studies are found in the field of information search. This paper makes a good contribution to the literature on the effect of domain knowledge on eye-tracking measures during N-TOC reading and predicting domain knowledge.

scholarly journals Comparison of Two Methods of Producing Adaptation of Saccade Size and Implications for the Site of Plasticity

1998 ◽  
Vol 79 (2) ◽  
pp. 704-715 ◽  
Author(s):  
Charles A. Scudder ◽  
Ekatherina Y. Batourina ◽  
George S. Tunder
Keyword(s):  
Relative Size ◽  
Neural Mechanisms ◽  
The Other ◽  
Rapid Adaptation ◽  
Adaptive Mechanisms ◽  
Saccade Size ◽  
Orbital Position ◽  
One Step ◽  
Induced Changes ◽  
Visual Error

Scudder, Charles A., Ekatherina Y. Batourina, and George S. Tunder. Comparison of two methods of producing adaptation of saccade size and implications for the site of plasticity. J. Neurophysiol. 79: 704–715, 1998. Saccade accuracy is known to be maintained by adaptive mechanisms that progressively reduce any visual error that consistently exists at the end of saccades. Experimentally, the visual error is induced using one of two paradigms. In the first, the horizontal and medial recti of trained monkeys are tenectomized and allowed to reattach so that both muscles are paretic. After patching the unoperated eye and forcing the monkey to use the “paretic eye,” saccades initially undershoot the intended target, but gradually increase in size until they almost acquire the target in one step. In the second, the target of a saccade is displaced in midsaccade so that the saccade cannot land on target. Again saccade size adapts until the target can be acquired in one step. Because adaptation with the latter paradigm is very rapid but adaptation using the former is slow, it has frequently been questioned whether or not the two forms of adaptation depend on the same neural mechanisms. We show that the rate of adaptation in both paradigms depends on the number of possible visual targets, so that when this variable is equated, adaptation occurs at similar rates in both paradigms. To demonstrate further similarities between the result of the two paradigms, an experiment using intrasaccadic displacements was conducted to show that rapid adaptation possesses the capacity to produce gain changes that vary with orbital position. The relative size of intrasaccadic displacements were graded with orbital position so as to mimic the position-dependent dysmetria initially produced by a single paretic extraocular muscle. Induced changes in saccade size paralleled the size of the displacements, being largest for saccades into one hemifield and being negligible for saccades into the other hemifield or in the opposite direction. Collectively, the data remove the rational for asserting that adaptation produced by the two paradigms depends on separate neural mechanisms. We argue that adaptation produced by both paradigms depends on the cerebellum.

scholarly journals Bilateral control of interceptive saccades: evidence from the ipsipulsion of vertical saccades after caudal fastigial inactivation

2021 ◽  
Author(s):  
Clara Bourrelly ◽  
Julie Quinet ◽  
Laurent Goffart
Keyword(s):  
Purkinje Cells ◽  
Visual Target ◽  
Strongly Correlated ◽  
Bilateral Control ◽  
Target Speed ◽  
Burst Neurons ◽  
Oculomotor Vermis ◽  
Vertical Saccades ◽  
Saccade Size ◽  
Saccade Velocity

The caudal fastigial nuclei (cFN) are the output nuclei by which the medio-posterior cerebellum influences the production of saccades toward a visual target. On the basis of the organization of their efferences to the premotor burst neurons and the bilateral control of saccades, the hypothesis was proposed that the same unbalanced activity accounts for the dysmetria of all saccades during cFN unilateral inactivation, regardless of whether the saccade is horizontal, oblique, or vertical. We further tested this hypothesis by studying, in two head-restrained macaques, the effects of unilaterally inactivating the caudal fastigial nucleus on saccades toward a target moving vertically with a constant, increasing or decreasing speed. After local muscimol injection, vertical saccades were deviated horizontally toward the injected side with a magnitude that increased with saccade size. The ipsipulsion indeed depended upon the tested target speed, but not its instantaneous value because it did not increase (decrease) when the target accelerated (decelerated). By subtracting the effect on contralesional horizontal saccades from the effect on ipsilesional ones, we found that the net bilateral effect on horizontal saccades was strongly correlated with the effect on vertical saccades. We explain how this correlation corroborates the bilateral hypothesis and provide arguments against the suggestion that instantaneous saccade velocity would somehow be "encoded" by the discharge of Purkinje cells in the oculomotor vermis.

Effects of Image Segmentation and Target Number on Visual Search: An Eye-Tracking Study

2018 ◽  
Vol 62 (1) ◽  
pp. 1987-1991
Author(s):  
Kaifeng Liu ◽  
Calvin Ka-lun Or
Keyword(s):  
Image Segmentation ◽  
Visual Search ◽  
Eye Tracking ◽  
Repeated Measures ◽  
Fixation Duration ◽  
Search Time ◽  
Search Performance ◽  
Target Number ◽  
Lower Accuracy ◽  
Time Accuracy

This is an eye-tracking study examining the effects of image segmentation and target number on visual search performance. A two-way repeated-measures computer-based visual search test was used for data collection. Thirty students participated in the test, in which they were asked to search for all of the Landolt Cs in 80 arrays of closed rings. The dependent variables were search time, accuracy, fixation count, and average fixation duration. Our principal findings were that some of the segmentation methods significantly improved accuracy, and reduced search time, fixation count, and average fixation duration, compared with the no-segmentation condition. Increased target number was found to be associated with longer search time, lower accuracy, more fixations, and longer average fixation duration. Our study indicates that although visual search tasks with multiple targets are relatively difficult, the visual search accuracy and efficiency can potentially be improved with the aid of image segmentation.

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