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https://www.readbyqxmd.com/read/28091557/the-same-oculomotor-vermal-purkinje-cells-encode-the-different-kinematics-of-saccades-and-of-smooth-pursuit-eye-movements
#1
Zongpeng Sun, Aleksandra Smilgin, Marc Junker, Peter W Dicke, Peter Thier
Saccades and smooth pursuit eye movements (SPEM) are two types of goal-directed eye movements whose kinematics differ profoundly, a fact that may have contributed to the notion that the underlying cerebellar substrates are separated. However, it is suggested that some Purkinje cells (PCs) in the oculomotor vermis (OMV) of monkey cerebellum may be involved in both saccades and SPEM, a puzzling finding in view of the different kinematic demands of the two types of eye movements. Such 'dual' OMV PCs might be oddities with little if any functional relevance...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28080114/oculomotor-and-linguistic-processing-effects-in-reading-dynamic-horizontally-scrolling-text
#2
Hannah Harvey, Hayward J Godwin, Gemma Fitzsimmons, Simon P Liversedge, Robin Walker
Two experiments are reported investigating oculomotor behavior and linguistic processing when reading dynamic horizontally scrolling text (compared to reading normal static text). Three factors known to modulate processing time in normal reading were investigated: Word length and word frequency were examined in Experiment 1, and target word predictability in Experiment 2. An analysis of global oculomotor behavior across the 2 experiments showed that participants made fewer and longer fixations when reading scrolling text, with shorter progressive and regressive saccades between these fixations...
January 12, 2017: Journal of Experimental Psychology. Human Perception and Performance
https://www.readbyqxmd.com/read/28079062/does-retinal-configuration-make-the-head-and-eyes-of-foveate-birds-move
#3
Bret A Moore, Luke P Tyrrell, Diana Pita, Olaf R P Bininda-Emonds, Esteban Fernández-Juricic
Animals move their heads and eyes to compensate for movements of the body and background, search, fixate, and track objects visually. Avian saccadic head/eye movements have been shown to vary considerably between species. We tested the hypothesis that the configuration of the retina (i.e., changes in retinal ganglion cell density from the retinal periphery to the center of acute vision-fovea) would account for the inter-specific variation in avian head/eye movement behavior. We characterized retinal configuration, head movement rate, and degree of eye movement of 29 bird species with a single fovea, controlling for the effects of phylogenetic relatedness...
January 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28078573/setting-things-straight-a-comparison-of-measures-of-saccade-trajectory-deviation
#4
Luke Tudge, Eugene McSorley, Stephan A Brandt, Torsten Schubert
In eye movements, saccade trajectory deviation has often been used as a physiological operationalization of visual attention, distraction, or the visual system's prioritization of different sources of information. However, there are many ways to measure saccade trajectories and to quantify their deviation. This may lead to noncomparable results and poses the problem of choosing a method that will maximize statistical power. Using data from existing studies and from our own experiments, we used principal components analysis to carry out a systematic quantification of the relationships among eight different measures of saccade trajectory deviation and their power to detect the effects of experimental manipulations, as measured by standardized effect size...
January 11, 2017: Behavior Research Methods
https://www.readbyqxmd.com/read/28072701/pathophysiology-of-refractory-obsessive-compulsive-disorder-a-study-of-visual-search-combined-with-overactive-performance-monitoring
#5
Qingxiao Liu, Bo Tan, Jing Zhou, Zhong Zheng, Ling Li, Yanchun Yang
Based on both functional and structural studies of excessive activity, fronto-striatal-thalamic-cortical and cortico-striatal circuits have been hypothesized to underlie the pathophysiology of obsessive-compulsive disorder (OCD). However, the neurobiological underpinnings of OCD refractory to medication and therapy remain controversial. This study aimed to evaluate neuroanatomical abnormalities of the whole brain and to evaluate visual processing in patients with refractory OCD.This study was comprised of 2 experiments...
January 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28072451/the-impact-of-salience-and-visual-working-memory-on-the-monitoring-and-control-of-saccadic-behavior-an-eye-tracking-and-eeg-study
#6
Matthew D Weaver, Clayton Hickey, Wieske van Zoest
In a concurrent eye-tracking and EEG study, we investigated the impact of salience on the monitoring and control of eye movement behavior and the role of visual working memory (VWM) capacity in mediating this effect. Participants made eye movements to a unique line-segment target embedded in a search display also containing a unique distractor. Target and distractor salience was manipulated by varying degree of orientation offset from a homogenous background. VWM capacity was measured using a change-detection task...
January 10, 2017: Psychophysiology
https://www.readbyqxmd.com/read/28072041/interpersonal-threat-sensitivity-in-borderline-personality-disorder-an-eye-tracking-study
#7
Katja Bertsch, Marlene Krauch, Katharina Stopfer, Katrin Haeussler, C Herpertz, Matthias Gamer
Threat sensitivity is a prominent predictor of interpersonal dysfunctions in borderline personality disorder (BPD), leading to intense, aversive feelings of threat and eventually dysfunctional behaviors, such as aggression. In the present study, BPD patients and healthy volunteers classified angry, fearful, neutral, and happy faces presented for 150 ms or 5,000 ms to investigate initial saccades and facial scanning. Patients more often wrongly identified anger, responded slower to all faces, and made faster saccades towards the eyes of briefly presented neutral faces and slower saccades away from fearful eyes compared with healthy volunteers...
January 10, 2017: Journal of Personality Disorders
https://www.readbyqxmd.com/read/28070793/object-location-binding-across-a-saccade-a-retinotopic-spatial-congruency-bias
#8
Anna Shafer-Skelton, Colin N Kupitz, Julie D Golomb
Despite frequent eye movements that rapidly shift the locations of objects on our retinas, our visual system creates a stable perception of the world. To do this, it must convert eye-centered (retinotopic) input to world-centered (spatiotopic) percepts. Moreover, for successful behavior we must also incorporate information about object features/identities during this updating - a fundamental challenge that remains to be understood. Here we adapted a recent behavioral paradigm, the "spatial congruency bias," to investigate object-location binding across an eye movement...
January 9, 2017: Attention, Perception & Psychophysics
https://www.readbyqxmd.com/read/28056653/a-statistical-physics-perspective-to-understand-social-visual-attention-in-autism-spectrum-disorder
#9
Alessio Liberati, Roberta Fadda, Giuseppe Doneddu, Sara Congiu, Marco A Javarone, Tricia Striano, Alessandro Chessa
This study investigated social visual attention in children with Autism Spectrum Disorder (ASD) and with typical development (TD) in the light of Brockmann and Geisel's model of visual attention. The probability distribution of gaze movements and clustering of gaze points, registered with eye-tracking technology, was studied during a free visual exploration of a gaze stimulus. A data-driven analysis of the distribution of eye movements was chosen to overcome any possible methodological problems related to the subjective expectations of the experimenters about the informative contents of the image in addition to a computational model to simulate group differences...
January 1, 2017: Perception
https://www.readbyqxmd.com/read/28044023/how-is-visual-salience-computed-in-the-brain-insights-from-behaviour-neurobiology-and-modelling
#10
REVIEW
Richard Veale, Ziad M Hafed, Masatoshi Yoshida
Inherent in visual scene analysis is a bottleneck associated with the need to sequentially sample locations with foveating eye movements. The concept of a 'saliency map' topographically encoding stimulus conspicuity over the visual scene has proven to be an efficient predictor of eye movements. Our work reviews insights into the neurobiological implementation of visual salience computation. We start by summarizing the role that different visual brain areas play in salience computation, whether at the level of feature analysis for bottom-up salience or at the level of goal-directed priority maps for output behaviour...
February 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28044017/cat-and-mouse-search-the-influence-of-scene-and-object-analysis-on-eye-movements-when-targets-change-locations-during-search
#11
Anne P Hillstrom, Joice D Segabinazi, Hayward J Godwin, Simon P Liversedge, Valerie Benson
We explored the influence of early scene analysis and visible object characteristics on eye movements when searching for objects in photographs of scenes. On each trial, participants were shown sequentially either a scene preview or a uniform grey screen (250 ms), a visual mask, the name of the target and the scene, now including the target at a likely location. During the participant's first saccade during search, the target location was changed to: (i) a different likely location, (ii) an unlikely but possible location or (iii) a very implausible location...
February 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28041794/invariant-temporal-dynamics-underlie-perceptual-stability-in-human-visual-cortex
#12
Ella Podvalny, Erin Yeagle, Pierre Mégevand, Nimrod Sarid, Michal Harel, Gal Chechik, Ashesh D Mehta, Rafael Malach
An inherent limitation of human visual system research stems from its reliance on highly controlled laboratory conditions. Visual processing in the real world differs substantially from such controlled conditions. In particular, during natural vision, we continuously sample the dynamic environment by variable eye movements that lead to inherent instability of the optical image. The neuronal mechanism by which human perception remains stable under these natural conditions remains unknown. Here, we examined a neural mechanism that may contribute to such stability, i...
December 28, 2016: Current Biology: CB
https://www.readbyqxmd.com/read/28039373/a-model-of-the-superior-colliculus-predicts-fixation-locations-during-scene-viewing-and-visual-search
#13
Hossein Adeli, Françoise Vitu, Gregory J Zelinsky
: Modern computational models of attention predict fixations using saliency maps and target maps, which prioritize locations for fixation based on feature contrast and target goals, respectively. But while many such models are biologically plausible, none have looked to the oculomotor system for design constraints or parameter specification. Conversely, while most models of saccade programming are tightly coupled to underlying neurophysiology, none have been tested using real-world stimuli and tasks...
December 30, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28031397/electrical-stimulation-of-superior-colliculus-affects-strabismus-angle-in-monkey-models-for-strabismus
#14
Suraj Upadhyaya, Hui Meng, Vallabh E Das
Disruption of binocular vision during the critical period for development leads to eye misalignment in humans and in monkey models. We have previously suggested that disruption within a vergence circuit could be the neural basis for strabismus. Electrical stimulation in the rostral superior colliculus (rSC) leads to vergence eye movements in normal monkeys. Therefore the purpose of this study was to investigate the effect of SC stimulation on eye misalignment in strabismic monkeys. Electrical stimulation was delivered to 51 sites in the intermediate and deep layers of the SC (400Hz, 0...
December 28, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28030516/scotoma-visibility-and-reading-rate-with-bilateral-central-scotomas
#15
Joshua D Pratt, Scott B Stevenson, Harold E Bedell
PURPOSE: In this experiment, we tested whether perceptually delineating the scotoma location and border with a gaze contingent polygon overlay improves reading speed and reading eye movements in patients with bilateral central scotomas. METHODS: Eight patients with age-related macular degeneration and bilateral central scotomas read aloud MNRead style sentences with their preferred eye. Eye movement signals from an EyeLink II eyetracker were used to create a gaze contingent display in which a polygon overlay delineating the area of the patient's scotoma was superimposed on the text during 18 of the 42 trials...
December 27, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
https://www.readbyqxmd.com/read/28027382/training-eye-movements-for-visual-search-in-individuals-with-macular-degeneration
#16
Christian P Janssen, Preeti Verghese
We report a method to train individuals with central field loss due to macular degeneration to improve the efficiency of visual search. Our method requires participants to make a same/different judgment on two simple silhouettes. One silhouette is presented in an area that falls within the binocular scotoma while they are fixating the center of the screen with their preferred retinal locus (PRL); the other silhouette is presented diametrically opposite within the intact visual field. Over the course of 480 trials (approximately 6 hr), we gradually reduced the amount of time that participants have to make a saccade and judge the similarity of stimuli...
December 1, 2016: Journal of Vision
https://www.readbyqxmd.com/read/28025052/holding-visual-attention-for-400millionyears-a-model-of-tectum-and-torus-longitudinalis-in-teleost-fishes
#17
David P M Northmore
Only ray-finned fishes possess a torus longitudinalis (TL), a paired, elongated body attached to the medial margins of the optic tectum. Its granule cells project large numbers of fine fibers running laterally over adjacent tectum, synapsing excitatorily on the spiny dendrites of pyramidal cells. Sustained TL activity is evoked visuotopically by dark stimuli; TL bursting is a corollary discharge of saccadic eye movements. To suggest a function for this ancient structure, neural network models were constructed to show that: (1) pyramidal cells could form an attentional locus, selecting one out of several moving objects to track, but rapid image shifts caused by saccades disrupt tracking; (2) TL could supply both the pre-saccade position of a locus, and the shift predicted from a saccade so as to prime pyramidal dendrites at the target location, ensuring the locus stays with the attended object; (3) that the specific pattern of synaptic connections required for such predictive priming could be learned by an unsupervised rule; (4) temporal and spatial filtering of visual pattern input to TL allows learning from a complex scene...
January 3, 2017: Vision Research
https://www.readbyqxmd.com/read/28024879/dynamic-representations-of-visual-space-for-perception-and-action
#18
REVIEW
W Pieter Medendorp, Anouk J de Brouwer, Jeroen B J Smeets
The division of labor in visual processing between two anatomically relatively separate cortical pathways, a ventral and a dorsal stream, has been hotly debated in the last decades. One influential model is the What & How pathway model, suggesting that the separation is along ventral perception versus dorsal action, although the degree of functional separation between the two streams is controversial. An implication of this model is that perception and memory-guided movements are highly sensitive to visual contextual illusions, whereas visually-guided movements are largely immune to them...
November 30, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/28018709/segmentation-guided-registration-of-wide-field-of-view-retinal-optical-coherence-tomography-volumes
#19
José Lezama, Dibyendu Mukherjee, Ryan P McNabb, Guillermo Sapiro, Anthony N Kuo, Sina Farsiu
Patient motion artifacts are often visible in densely sampled or large wide field-of-view (FOV) retinal optical coherence tomography (OCT) volumes. A popular strategy for reducing motion artifacts is to capture two orthogonally oriented volumetric scans. However, due to larger volume sizes, longer acquisition times, and corresponding larger motion artifacts, the registration of wide FOV scans remains a challenging problem. In particular, gaps in data acquisition due to eye motion, such as saccades, can be significant and their modeling becomes critical for successful registration...
December 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/28018166/motor-dysfunctions-and-neuropathology-in-mouse-models-of-spinocerebellar-ataxia-type-2-a-comprehensive-review
#20
REVIEW
João M Da Conceição Alves-Cruzeiro, Liliana Mendonça, Luís Pereira de Almeida, Clévio Nóbrega
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant ataxia caused by an expansion of CAG repeats in the exon 1 of the gene ATXN2, conferring a gain of toxic function that triggers the appearance of the disease phenotype. SCA2 is characterized by several symptoms including progressive gait ataxia and dysarthria, slow saccadic eye movements, sleep disturbances, cognitive impairments, and psychological dysfunctions such as insomnia and depression, among others. The available treatments rely on palliative care, which mitigate some of the major symptoms but ultimately fail to block the disease progression...
2016: Frontiers in Neuroscience
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