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https://www.readbyqxmd.com/read/28922090/microsaccades-and-interest-areas-during-free-viewing-sport-task
#1
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/28913514/the-incidence-of-needle-stick-and-sharp-injuries-and-their-associations-with-visual-function-among-hospital-nurses
#2
Mohammad Ghasemi, Mehdi Khabazkhoob, Hassan Hashemi, Abbasali Yekta, Payam Nabovati
PURPOSE: To determine the one-year incidence of needle stick and sharp injuries (NSIs and SIs) and their associations with visual function among Iranian nurses. METHODS: In this cross-sectional study, 278 nurses working at one hospital were selected through stratified random sampling. After applying the exclusion criteria, the final analysis was performed on the data of 267 nurses. The data of occupational injuries were collected through a researcher-administered questionnaire...
September 2017: Journal of Current Ophthalmology
https://www.readbyqxmd.com/read/28912699/effects-of-scene-properties-and-emotional-valence-on-brain-activations-a-fixation-related-fmri-study
#3
Michał Kuniecki, Kinga B Wołoszyn, Aleksandra Domagalik, Joanna Pilarczyk
Temporal and spatial characteristics of fixations are affected by image properties, including high-level scene characteristics, such as object-background composition, and low-level physical characteristics, such as image clarity. The influence of these factors is modulated by the emotional content of an image. Here, we aimed to establish whether brain correlates of fixations reflect these modulatory effects. To this end, we simultaneously scanned participants and measured their eye movements, while presenting negative and neutral images in various image clarity conditions, with controlled object-background composition...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28904108/comparison-of-three-models-of-saccade-disconjugacy-in-strabismus
#4
Mark M G Walton, Michael J Mustari
In pattern strabismus the horizontal and vertical misalignments vary with eye position along the orthogonal axis. The disorder is typically described in terms of overaction or underaction of oblique muscles. Recent behavioral studies in humans and monkeys, however, have reported that such actions are insufficient to fully explain the patterns of directional and amplitude disconjugacy of saccades. There is mounting evidence that the oculomotor abnormalities associated with strabismus are at least partially attributable to neurophysiological abnormalities...
September 13, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28904104/the-superior-colliculus-and-the-steering-of-saccades-toward-a-moving-visual-target
#5
Laurent Goffart, Aaron Lee Cecala, Neeraj J Gandhi
Following the suggestion that a command encoding the current target location feeds the oculomotor system during interceptive saccades, we tested the involvement of the deep superior colliculus (dSC). Extracellular activity of 52 saccade-related neurons was recorded in three monkeys while they generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward a fixated target (inward) with a constant speed (20°/s). Vertical and horizontal motions were tested when possible...
September 13, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28900577/comparison-of-threshold-saccadic-vector-optokinetic-perimetry-svop-and-standard-automated-perimetry-sap-in-glaucoma-part-ii-patterns-of-visual-field-loss-and-acceptability
#6
Alice D McTrusty, Lorraine A Cameron, Antonios Perperidis, Harry M Brash, Andrew J Tatham, Pankaj K Agarwal, Ian C Murray, Brian W Fleck, Robert A Minns
PURPOSE: We compared patterns of visual field loss detected by standard automated perimetry (SAP) to saccadic vector optokinetic perimetry (SVOP) and examined patient perceptions of each test. METHODS: A cross-sectional study was done of 58 healthy subjects and 103 with glaucoma who were tested using SAP and two versions of SVOP (v1 and v2). Visual fields from both devices were categorized by masked graders as: 0, normal; 1, paracentral defect; 2, nasal step; 3, arcuate defect; 4, altitudinal; 5, biarcuate; and 6, end-stage field loss...
September 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28900576/comparison-of-saccadic-vector-optokinetic-perimetry-and-standard-automated-perimetry-in-glaucoma-part-i-threshold-values-and-repeatability
#7
Ian C Murray, Antonios Perperidis, Lorraine A Cameron, Alice D McTrusty, Harry M Brash, Andrew J Tatham, Pankaj K Agarwal, Brian W Fleck, Robert A Minns
PURPOSE: We evaluated threshold saccadic vector optokinetic perimetry (SVOP) and compared results to standard automated perimetry (SAP). METHODS: A cross-sectional study was done including 162 subjects (103 with glaucoma and 59 healthy subjects) recruited at a university hospital. All subjects underwent SAP and threshold SVOP. SVOP uses an eye tracker to monitor eye movement responses to stimuli and determines if stimuli have been perceived based on the vector of the gaze response...
September 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28900172/cultural-and-developmental-influences-on-overt-visual-attention-to-videos
#8
Omid Kardan, Laura Shneidman, Sheila Krogh-Jespersen, Suzanne Gaskins, Marc G Berman, Amanda Woodward
Top-down influences on observers' overt attention and how they interact with the features of the visual environment have been extensively investigated, but the cultural and developmental aspects of these modulations have been understudied. In this study we investigated these effects for US and Yucatec Mayan infants, children, and adults. Mayan and US participants viewed videos of two actors performing daily Mayan and US tasks in the foreground and the background while their eyes were tracked. Our region of interest analysis showed that viewers from the US looked significantly less at the foreground activity and spent more time attending to the 'contextual' information (static background) compared to Mayans...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28891467/removal-of-inhibition-uncovers-latent-movement-potential-during-preparation
#9
Uday K Jagadisan, Neeraj J Gandhi
The motor system prepares for movements well in advance of their execution. In the gaze control system, the dynamics of preparatory neural activity have been well described by stochastic accumulation-to-threshold models. However, it is unclear whether this activity has features indicative of a hidden movement command. We explicitly tested whether preparatory neural activity in premotor neurons of the primate superior colliculus has "motor potential". We removed downstream inhibition on the saccadic system using the trigeminal blink reflex, triggering saccades at earlier-than-normal latencies...
September 11, 2017: ELife
https://www.readbyqxmd.com/read/28890683/rapid-processing-of-a-global-feature-in-the-on-visual-pathways-of-behaving-monkeys
#10
Jun Huang, Yan Yang, Ke Zhou, Xudong Zhao, Quan Zhou, Hong Zhu, Yingshan Yang, Chunming Zhang, Yifeng Zhou, Wu Zhou
Visual objects are recognized by their features. Whereas, some features are based on simple components (i.e., local features, such as orientation of line segments), some features are based on the whole object (i.e., global features, such as an object having a hole in it). Over the past five decades, behavioral, physiological, anatomical, and computational studies have established a general model of vision, which starts from extracting local features in the lower visual pathways followed by a feature integration process that extracts global features in the higher visual pathways...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28879396/vestibulo-ocular-reflex-deficits-with-medial-longitudinal-fasciculus-lesions
#11
Swee T Aw, Luke Chen, Michael J Todd, Michael H Barnett, G Michael Halmagyi
The medial longitudinal fasciculus (MLF) is the final common pathway for all conjugate adducting horizontal eye movements, as well as for the vertical-torsional vestibulo-ocular reflex (VOR). MLF lesion causes adduction paresis of ipsilesional (adducting) eye with dissociated nystagmus of contralesional (abducting) eye-the well-known clinical syndrome of internuclear ophthalmoplegia (INO). We measured the VOR stimulation and also any catch-up saccades, from individual semicircular canal (SCC) evoked by the head impulse test (HIT), using head and binocular 3-dimensional scleral search coils in 27 multiple sclerosis (MS) patients, 8 with unilateral, 19 with bilateral INO...
September 6, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28878733/clinical-approach-to-supranuclear-brainstem-saccadic-gaze-palsies
#12
REVIEW
Alexandra Lloyd-Smith Sequeira, John-Ross Rizzo, Janet C Rucker
Failure of brainstem supranuclear centers for saccadic eye movements results in the clinical presence of a brainstem-mediated supranuclear saccadic gaze palsy (SGP), which is manifested as slowing of saccades with or without range of motion limitation of eye movements and as loss of quick phases of optokinetic nystagmus. Limitation in the range of motion of eye movements is typically worse with saccades than with smooth pursuit and is overcome with vestibular-ocular reflexive eye movements. The differential diagnosis of SGPs is broad, although acute-onset SGP is most often from brainstem infarction and chronic vertical SGP is most commonly caused by the neurodegenerative condition progressive supranuclear palsy...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28870284/microsaccadic-sampling-of-moving-image-information-provides-drosophila-hyperacute-vision
#13
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/28868046/a-novel-saccadic-strategy-revealed-by-suppression-head-impulse-testing-of-patients-with-bilateral-vestibular-loss
#14
Catherine de Waele, Qiwen Shen, Christophe Magnani, Ian S Curthoys
OBJECTIVE: We examined the eye movement response patterns of a group of patients with bilateral vestibular loss (BVL) during suppression head impulse testing. Some showed a new saccadic strategy that may have potential for explaining how patients use saccades to recover from vestibular loss. METHODS: Eight patients with severe BVL [vestibulo-ocular reflex (VOR) gains less than 0.35 and absent otolithic function] were tested. All patients were given the Dizziness Handicap Inventory and questioned about oscillopsia during abrupt head movements...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28861030/coding-of-velocity-storage-in-the-vestibular-nuclei
#15
Sergei B Yakushin, Theodore Raphan, Bernard Cohen
Semicircular canal afferents sense angular acceleration and output angular velocity with a short time constant of ≈4.5 s. This output is prolonged by a central integrative network, velocity storage that lengthens the time constants of eye velocity. This mechanism utilizes canal, otolith, and visual (optokinetic) information to align the axis of eye velocity toward the spatial vertical when head orientation is off-vertical axis. Previous studies indicated that vestibular-only (VO) and vestibular-pause-saccade (VPS) neurons located in the medial and superior vestibular nucleus could code all aspects of velocity storage...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28853331/the-effects-of-varying-levels-of-hemispheric-activation-on-episodic-memory
#16
Stephen Prunier, Stephen Christman, John Jasper
Bilateral saccadic eye movements enhance episodic memory retrieval; however, this usually only occurs for consistent-handed, not inconsistent-handed, individuals. It was hypothesized that inconsistent-handers begin closer to the peak of a Yerkes-Dodson-type inverted-U curve and increasing activation pushes them along the curve eventually decreasing performance, while consistent-handers start at a lower baseline and therefore increasing activation increases their performance. The current study tested this hypothesis by using hand clenching (grip strength) to increase activation at 5 different levels for both consistent- and inconsistent-handers...
August 30, 2017: Laterality
https://www.readbyqxmd.com/read/28852092/change-in-sensitivity-to-visual-error-in-superior-colliculus-during-saccade-adaptation
#17
Yoshiko Kojima, Robijanto Soetedjo
Saccadic eye movements provide a valuable model to study the brain mechanisms underlying motor learning. If a target is displaced surreptitiously while a saccade is underway, the saccade appears to be in error. If the error persists gradual neuronal adjustments cause the eye movement again to land near the target. This saccade adaptation typically follows an exponential time course, i.e., adaptation speed slows as adaptation progresses, indicating that the sensitivity to error decreases during adaptation. Previous studies suggested that the superior colliculus (SC) sends error signals to drive saccade adaptation...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28851914/simulated-forward-and-backward-self-motion-based-on-realistic-parameters-causes-motion-induced-blindness
#18
Victoria Thomas, Matthew Davidson, Parisa Zakavi, Naotsugu Tsuchiya, Jeroen van Boxtel
Motion Induced Blindness (MIB) is a well-established visual phenomenon whereby highly salient targets disappear when viewed against a moving background mask. No research has yet explored whether contracting and expanding optic flow can also trigger target disappearance. We explored MIB using mask speeds corresponding to driving at 35, 50, 65 and 80 km/h in simulated forward (expansion) and backward (contraction) motion as well as 2-D radial movement, random, and static mask motion types. Participants (n = 18) viewed MIB targets against masks with different movement types, speed, and target locations...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28846696/the-hypnotic-state-and-eye-movements-less-there-than-meets-the-eye
#19
Etzel Cardeña, Barbara Nordhjem, David Marcusson-Clavertz, Kenneth Holmqvist
Responsiveness to hypnotic procedures has been related to unusual eye behaviors for centuries. Kallio and collaborators claimed recently that they had found a reliable index for "the hypnotic state" through eye-tracking methods. Whether or not hypnotic responding involves a special state of consciousness has been part of a contentious debate in the field, so the potential validity of their claim would constitute a landmark. However, their conclusion was based on 1 highly hypnotizable individual compared with 14 controls who were not measured on hypnotizability...
2017: PloS One
https://www.readbyqxmd.com/read/28845923/clinical-rating-scale-for-pantothenate-kinase-associated-neurodegeneration-a-pilot-study
#20
Alejandra Darling, Cristina Tello, María Josep Martí, Cristina Garrido, Sergio Aguilera-Albesa, Miguel Tomás Vila, Itziar Gastón, Marcos Madruga, Luis González Gutiérrez, Julio Ramos Lizana, Montserrat Pujol, Tania Gavilán Iglesias, Kylee Tustin, Jean Pierre Lin, Giovanna Zorzi, Nardo Nardocci, Loreto Martorell, Gustavo Lorenzo Sanz, Fuencisla Gutiérrez, Pedro J García, Lidia Vela, Carlos Hernández Lahoz, Juan Darío Ortigoza Escobar, Laura Martí Sánchez, Fradique Moreira, Miguel Coelho, Leonor Correia Guedes, Ana Castro Caldas, Joaquim Ferreira, Paula Pires, Cristina Costa, Paulo Rego, Marina Magalhães, María Stamelou, Daniel Cuadras Pallejà, Carmen Rodríguez-Blazquez, Pablo Martínez-Martín, Vincenzo Lupo, Leonidas Stefanis, Roser Pons, Carmen Espinós, Teresa Temudo, Belén Pérez Dueñas
BACKGROUND: Pantothenate kinase-associated neurodegeneration is a progressive neurological disorder occurring in both childhood and adulthood. The objective of this study was to design and pilot-test a disease-specific clinical rating scale for the assessment of patients with pantothenate kinase-associated neurodegeneration. METHODS: In this international cross-sectional study, patients were examined at the referral centers following a standardized protocol. The motor examination was filmed, allowing 3 independent specialists in movement disorders to analyze 28 patients for interrater reliability assessment...
August 28, 2017: Movement Disorders: Official Journal of the Movement Disorder Society
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