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https://www.readbyqxmd.com/read/29212065/development-of-the-visual-system-in-a-burrow-nesting-seabird-leach-s-storm-petrel
#1
Mindaugas Mitkus, Gabrielle A Nevitt, Almut Kelber
Little is known about the development of vision in wild birds. It is unknown, for example, whether the ability to see can be predicted by the level of prenatal growth or whether the eyes are open at hatching in a particular species. In this study, we investigated the growth of eyes, the formation of retinal ganglion cell topography, and the appearance of simple, visually guided behaviours in chicks of a small procellariiform seabird, Leach's storm petrel (Oceanodroma leucorhoa). This semi-precocial species, which has a well-developed sense of smell, nests in underground burrows where adults provision chicks for 6-8 weeks in the dark before fledging...
December 7, 2017: Brain, Behavior and Evolution
https://www.readbyqxmd.com/read/29190849/concussion-recovery-phase-affects-vestibular-and-oculomotor-symptom-provocation
#2
Kelly M Cheever, Jane McDevitt, Ryan Tierney, W Geoffrey Wright
Vestibular and oculomotor testing is emerging as a valuable assessment in sport-related concussion (SRC). However, their usefulness for tracking recovery and guiding return-to-play decisions remains unclear. Therefore the purpose of this study was to evaluate their clinical usefulness for tracking SRC recovery. Vestibular and oculomotor assessments were used to measure symptom provocation in an acute group (n=21) concussed≤10 days, prolonged symptoms group (n=10) concussed ≥16 days (median=84 days), healthy group (n=58) no concussions in >6 months...
November 30, 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/29179637/cone-dystrophy-and-ectopic-synaptogenesis-in-a-cacna1f-loss-of-function-model-of-congenital-stationary-night-blindness-csnb2a
#3
D M Waldner, N C Giraldo Sierra, S Bonfield, L Nguyen, I S Dimopoulos, Y Sauvé, W K Stell, N T Bech-Hansen
Congenital stationary night blindness 2A (CSNB2A) is an X-linked retinal disorder, characterized by phenotypically variable signs and symptoms of impaired vision. CSNB2A is due to mutations in CACNA1F, which codes for the pore-forming α1F subunit of a L-type voltage-gated calcium channel, Cav1.4. Mouse models of CSNB2A, used for characterizing the effects of various Cacna1f mutations, have revealed greater severity of defects than in human CSNB2A. Specifically, Cacna1f-knockout mice show an apparent lack of visual function, gradual retinal degeneration, and disruption of photoreceptor synaptic terminals...
November 28, 2017: Channels
https://www.readbyqxmd.com/read/29176570/population-scale-organization-of-cerebellar-granule-neuron-signaling-during-a-visuomotor-behavior
#4
Sherika J G Sylvester, Melanie M Lee, Alexandro D Ramirez, Sukbin Lim, Mark S Goldman, Emre R F Aksay
Granule cells at the input layer of the cerebellum comprise over half the neurons in the human brain and are thought to be critical for learning. However, little is known about granule neuron signaling at the population scale during behavior. We used calcium imaging in awake zebrafish during optokinetic behavior to record transgenically identified granule neurons throughout a cerebellar population. A significant fraction of the population was responsive at any given time. In contrast to core precerebellar populations, granule neuron responses were relatively heterogeneous, with variation in the degree of rectification and the balance of positive versus negative changes in activity...
November 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29157002/effects-of-circadian-clock-protein-per1b-on-zebrafish-visual-functions
#5
Ke Nie, Kun Wang, Deng-Feng Huang, Yu-Bin Huang, Wu Yin, Da-Long Ren, Han Wang, Bing Hu
The circadian clock is an endogenous and entrainable time-keeping mechanism with a period of approximately 24 h, operated by transcription/translation feedback loops composed of circadian clock genes and their proteins. The visual system displays robust circadian changes. Relatively little, however, is known about the mechanisms underlying visual circadian rhythmicity. Zebrafish period1b (per1b), as a canonical circadian clock gene, is involved in circadian regulation. Here, we observed that zebrafish per1b mutants exhibit visual defects including reduced behavioral contrast sensitivity and significant retinal dopaminergic deficiency...
November 20, 2017: Chronobiology International
https://www.readbyqxmd.com/read/29141881/it-s-not-all-black-and-white-visual-scene-parameters-influence-optokinetic-reflex-performance-in-xenopus-laevis-tadpoles
#6
Céline M Gravot, Alexander G Knorr, Stefan Glasauer, Hans Straka
The maintenance of visual acuity during active and passive body motion is ensured by gaze-stabilizing reflexes that aim at minimizing retinal image slip. For the optokinetic reflex (OKR), large-field visual motion of the surround forms the essential stimulus that activates eye movements. Properties of the moving visual world influence cognitive motion perception and the estimation of visual image velocity. Therefore, the performance of brainstem-mediated visuo-motor behaviors might also depend on image scene characteristics...
November 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/29120919/nystagmus
#7
Alexander A Tarnutzer, Dominik Straumann
PURPOSE OF REVIEW: The clinical and laboratory assessment of nystagmus in patients with neurologic disorders can provide crucial elements for a state-of-the-art differential diagnosis. An increasing number of publications in the fields of neuro-otology and neuro-ophthalmology have nystagmus in the center of interest, which makes frequent updates on the diagnostic and therapeutic relevance of these contributions indispensable. This review covers important clinical studies and studies in basic research relevant for the neurologist published from January 2016 to August 2017...
November 7, 2017: Current Opinion in Neurology
https://www.readbyqxmd.com/read/29110135/the-effect-of-visual-contrast-on-human-vestibulo-ocular-reflex-adaptation
#8
M Muntaseer Mahfuz, Michael C Schubert, Christopher J Todd, William V C Figtree, Serajul I Khan, Americo A Migliaccio
The vestibulo-ocular reflex (VOR) is the main retinal image stabilising mechanism during rapid head movement. When the VOR does not stabilise the world or target image on the retina, retinal image slip occurs generating an error signal that drives the VOR response to increase or decrease until image slip is minimised, i.e. VOR adaptation occurs. Visual target contrast affects the human smooth pursuit and optokinetic reflex responses. We sought to determine if contrast also affected VOR adaptation. We tested 12 normal subjects, each over 16 separate sessions...
November 6, 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/29060092/analysis-of-computerized-optokinetic-nystagmus-induction-and-effect-of-contrast-on-ocular-fatigue
#9
Ji Sung Kim, Changhoon Baek, Sunyoung Yoo, Jeong-Min Hwang, Jong Mo Seo
Optokinetic nystagmus (OKN) is useful in evaluating visual function objectively, and the classical black-and-white-striped OKN drum is being replaced by video or computer monitor. However, the examinee may feel fatigue during test because of high contrast of luminous pattern from monitor. This paper suggests a plan to reduce eye fatigue of participant by decreasing contrast of patterns without reducing OKN response. Alternating black and white stripes are shown on flat-panel liquid-crystal display monitor and moved horizontally to evoke OKN of the examinee, and the OKN wasW observed through electrooculography (EOG)...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29042258/an-open-source-method-to-analyze-optokinetic-reflex-responses-in-larval-zebrafish
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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