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https://www.readbyqxmd.com/read/29042258/an-open-source-method-to-analyze-optokinetic-reflex-responses-in-larval-zebrafish
#1
Seth D Scheetz, Enhua Shao, Yangzhong Zhou, Clinton L Cario, Qing Bai, Edward A Burton
BACKGROUND: Optokinetic reflex (OKR) responses provide a convenient means to evaluate oculomotor, integrative and afferent visual function in larval zebrafish models, which are commonly used to elucidate molecular mechanisms underlying development, disease and repair of the vertebrate nervous system. NEW METHOD: We developed an open-source MATLAB-based solution for automated quantitative analysis of OKR responses in larval zebrafish. The package includes applications to: (i) generate sinusoidally-transformed animated grating patterns suitable for projection onto a cylindrical screen to elicit the OKR; (ii) determine and record the angular orientations of the eyes in each frame of a video recording showing the OKR response; and (iii) analyze angular orientation data from the tracking program to yield a set of parameters that quantify essential elements of the OKR...
October 14, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29038003/hemin-supports-the-survival-of-photoreceptors-injured-by-n-methyl-n-nitrosourea-the-contributory-role-of-neuroglobin-in-photoreceptor-degeneration
#2
Ye Tao, Zhao Ma, Bei Liu, Wei Fang, Limin Qin, Yi Fei Huang, Lu Wang, Yanling Gao
Retina is a critical component of the central nerve system that is responsible for the conversion of light stimulus into electrical spikes. Retinitis pigmentosa (RP) comprises a heterogeneous group of inherited retinal dystrophies leading to blindness. We examined retinal neuroglobin (Ngb) expression in a pharmacologically induced RP animal model, the N-Methyl-N-nitrosourea (MNU) administered mice. The retinal Ngb expression in MNU administered mice attenuated following a time dependent manner, suggesting Ngb was involved in the photoreceptor degeneration...
October 13, 2017: Brain Research
https://www.readbyqxmd.com/read/28978733/head-movements-quadruple-the-range-of-speeds-encoded-by-the-insect-motion-vision-system-in-hawkmoths
#3
Shane P Windsor, Graham K Taylor
Flying insects use compensatory head movements to stabilize gaze. Like other optokinetic responses, these movements can reduce image displacement, motion and misalignment, and simplify the optic flow field. Because gaze is imperfectly stabilized in insects, we hypothesized that compensatory head movements serve to extend the range of velocities of self-motion that the visual system encodes. We tested this by measuring head movements in hawkmoths Hyles lineata responding to full-field visual stimuli of differing oscillation amplitudes, oscillation frequencies and spatial frequencies...
October 11, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28978580/use-of-optokinetics-based-okcsib-protocol-in-restoring-mobility-in-primary-progressive-ms
#4
Benjamin Chitambira, Ciara McConaghy
The case is of a mid-40s patient who developed progressive muscle weakness and loss of mobility over 6 weeks due to primary progressive multiple sclerosis. 2.5 days before admission, she became bed bound with weakness of 1/5 on the Oxford scale. She normally rested for a couple of days after similar periods of worsening symptoms and then got back on her feet although with worse balance. She was treated with optokinetic chart stimulation and sensory interaction for balance (OKCSIB) protocol. Within 2 days of intervention, she was mobile with a delta frame and supervision of one...
October 4, 2017: BMJ Case Reports
https://www.readbyqxmd.com/read/28929264/a-novel-and-cheap-method-to-correlate-subjective-and-objective-visual-acuity-by-using-the-optokinetic-response
#5
Carlo Aleci, Martina Scaparrotti, Sabrina Fulgori, Lorenzo Canavese
PURPOSE: To describe a novel optokinetic visual acuity estimator (Oktotype) and to report the preliminary results obtained in poorly and non-collaborative subjects. METHODS: Eleven series of symbols arranged horizontally and moving from left to right at a constant rate were displayed. In each sequence, the size of the stimuli was reduced logarithmically. By using this paradigm, the objective visual acuity was computed in 26 normal subjects as the minimum size of the symbols able to evoke the optokinetic response...
September 19, 2017: International Ophthalmology
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/28900183/a-brain-derived-neurotrophic-factor-mimetic-is-sufficient-to-restore-cone-photoreceptor-visual-function-in-an-inherited-blindness-model
#8
Conor Daly, Lisa Shine, Theresa Heffernan, Sudhakar Deeti, Alison L Reynolds, John J O'Connor, Eugène T Dillon, David J Duffy, Walter Kolch, Gerard Cagney, Breandán N Kennedy
Controversially, histone deacetylase inhibitors (HDACi) are in clinical trial for the treatment of inherited retinal degeneration. Utilizing the zebrafish dye (ucd6) model, we determined if treatment with HDACi can rescue cone photoreceptor-mediated visual function. dye exhibit defective visual behaviour and retinal morphology including ciliary marginal zone (CMZ) cell death and decreased photoreceptor outer segment (OS) length, as well as gross morphological defects including hypopigmentation and pericardial oedema...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28892180/long-term-exposure-to-bisphenol-s-damages-the-visual-system-and-reduces-the-tracking-capability-of-male-zebrafish-danio-rerio
#9
Wenmin Liu, Xiaona Zhang, Penghao Wei, Hua Tian, Wei Wang, Shaoguo Ru
Bisphenol S (BPS) is widely detected in aquatic environments and in human bodies. BPS has reproductive and thyroid disrupting effects, but its effect on the visual system remains unknown. In the present study, zebrafish embryos were exposed to BPS at concentrations of 1, 10, 100 and 1000 μg l(-1) until 120 days post-fertilization in a semistatic system, and the effect of BPS on the visual behavior was examined using the optokinetic response and the optomotor response tests in male zebrafish. The retinal histology, mRNA expression of photoreceptor opsin genes (zfrho, zfblue, zfgr1, zfred and zfuv) and apoptosis-related genes (bax and bcl-2) were also assessed...
September 11, 2017: Journal of Applied Toxicology: JAT
https://www.readbyqxmd.com/read/28891332/subretinal-delivery-of-erythropoietin-alleviates-the-n-methyl-n-nitrosourea-induced-photoreceptor-degeneration-and-visual-functional-impairments-an-in-vivo-and-ex-vivo-study
#10
Ye Tao, Yue Wang, Zhao Ma, Liqiang Wang, Limin Qin, Lu Wang, Yi Fei Huang, Shizhong Zhang
Retinitis pigmentosa (RP) is a heterogeneous group hereditary retinal disease that is characterized by photoreceptor degeneration. The present study sought to explore the therapeutic effects of erythropoietin (EPO) on the N-methyl-N-nitrosourea (MNU)-induced photoreceptor degeneration. The MNU-administered mouse or normal control received a subretinal injection of EPO (at the dose of 10U). Twenty-four hours after EPO injection, the retinal EPO levels of experimental animals were quantified. Subsequently, the experimental animals were subjected to optokinetic tests, ERG examination, SD-OCT examination, histology assessment, and immunohistochemistry evaluation...
November 2017: Drug Delivery
https://www.readbyqxmd.com/read/28878733/clinical-approach-to-supranuclear-brainstem-saccadic-gaze-palsies
#11
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/28864240/global-motion-perception-is-associated-with-motor-function-in-2-year-old-children
#12
Benjamin Thompson, Christopher J D McKinlay, Arijit Chakraborty, Nicola S Anstice, Robert J Jacobs, Nabin Paudel, Tzu-Ying Yu, Judith M Ansell, Trecia A Wouldes, Jane E Harding
The dorsal visual processing stream that includes V1, motion sensitive area V5 and the posterior parietal lobe, supports visually guided motor function. Two recent studies have reported associations between global motion perception, a behavioural measure of processing in V5, and motor function in pre-school and school aged children. This indicates a relationship between visual and motor development and also supports the use of global motion perception to assess overall dorsal stream function in studies of human neurodevelopment...
September 29, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28861030/coding-of-velocity-storage-in-the-vestibular-nuclei
#13
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/28846696/the-hypnotic-state-and-eye-movements-less-there-than-meets-the-eye
#14
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/28813718/transgenic-mice-over-expressing-rbp4-have-rbp4-dependent-and-light-independent-retinal-degeneration
#15
Mei Du, Eric Phelps, Michael J Balangue, Aaron Dockins, Gennadiy Moiseyev, Younghwa Shin, Shelley Kane, Laura Otalora, Jian-Xing Ma, Rafal Farjo, Krysten M Farjo
Purpose: Transgenic mice overexpressing serum retinol-binding protein (RBP4-Tg) develop progressive retinal degeneration, characterized by microglia activation, yet the precise mechanisms underlying retinal degeneration are unclear. Previous studies showed RBP4-Tg mice have normal ocular retinoid levels, suggesting that degeneration is independent of the retinoid visual cycle or light exposure. The present study addresses whether retinal degeneration is light-dependent and RBP4-dependent by testing the effects of dark-rearing and pharmacological lowering of serum RBP4 levels, respectively...
August 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28790966/randomized-controlled-study-of-a-remote-flipped-classroom-neuro-otology-curriculum
#16
Frederick Robert Carrick, Mahera Abdulrahman, Ahmed Hankir, Maksim Zayaruzny, Kinda Najem, Palita Lungchukiet, Roger A Edwards
CONTEXT: Medical Education can be delivered in the traditional classroom or via novel technology including an online classroom. OBJECTIVE: To test the hypothesis that learning in an online classroom would result in similar outcomes as learning in the traditional classroom when using a flipped classroom pedagogy. DESIGN: Randomized controlled trial. A total of 274 subjects enrolled in a Neuro-otology training program for non-Neuro-otologists of 25 h held over a 3-day period...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28783558/rod-and-frame-test-and-posture-under-optokinetic-stimulation-used-to-explore-two-complementary-aspects-of-the-visual-influence-in-postural-control-after-stroke
#17
Sophie Tasseel-Ponche, Hélène Le Liepvre, Florence Colle, Cédric Andriantsifanetra, Pierre-Paul Vidal, Isabelle Véronique Bonan, Alain-Pierre Yelnik
BACKGROUND: Balance rehabilitation should consider individual comportments according to visual input (VI). Indeed, visual dependence (VD), defined as the predominance given to the VI whatever the circumstances, frequent after stroke it could disturb balance. Because the term VD is a bit restrictive and cannot be deduced from clinical tests, the term visual sensitivity (VS) is preferred here. HYPOTHESIS: VI could have different influence depending on the task for a given individual...
October 2017: Gait & Posture
https://www.readbyqxmd.com/read/28742631/vestibular-function-in-adults-with-epilepsy-of-unknown-etiology
#18
Sherifa A Hamed, Amal M Tohamy, Amira M Oseilly
OBJECTIVE: This study aimed to evaluate vestibular function in adults with chronic epilepsy of unknown etiology in the inter-ictal period. BACKGROUND: Epilepsy is a chronic medical disorder. Life-long therapy may be required in one-third of patients. Epilepsy is associated with comorbid somatic conditions which impairs patients' quality of life. METHODS: This cross-sectional study included 28 with generalized tonic clonic (GTC) convulsions and 14 and 3 with temporal (TLE) and frontal lobe (FLE) epilepsies with secondary generalization (all were on regular carbamazepine therapy) and 40 healthy control subjects...
September 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28733210/threat-effects-on-human-oculo-motor-function
#19
E N Naranjo, T W Cleworth, J H J Allum, J T Inglis, J Lea, B D Westerberg, M G Carpenter
Neuro-anatomical evidence supports the potential for threat-related factors, such as fear, anxiety and vigilance, to influence brainstem motor nuclei controlling eye movements, as well as the vestibular nuclei. However, little is known about how threat influences human ocular responses, such as eye saccades (ES), smooth pursuit eye tracking (SP), and optokinetic nystagmus (OKN), and whether these responses can be facilitated above normal baseline levels with a natural source of threat. This study was designed to examine the effects of height-induced postural threat on the gain of ES, SP and OKN responses in humans...
July 18, 2017: Neuroscience
https://www.readbyqxmd.com/read/28717219/versatile-functional-roles-of-horizontal-cells-in-the-retinal-circuit
#20
Taro Chaya, Akihiro Matsumoto, Yuko Sugita, Satoshi Watanabe, Ryusuke Kuwahara, Masao Tachibana, Takahisa Furukawa
In the retinal circuit, environmental light signals are converted into electrical signals that can be decoded properly by the brain. At the first synapse of the visual system, information flow from photoreceptors to bipolar cells is modulated by horizontal cells (HCs), however, their functional contribution to retinal output and individual visual function is not fully understood. In the current study, we investigated functional roles for HCs in retinal ganglion cell (RGC) response properties and optokinetic responses by establishing a HC-depleted mouse line...
July 17, 2017: Scientific Reports
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