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https://www.readbyqxmd.com/read/28717219/versatile-functional-roles-of-horizontal-cells-in-the-retinal-circuit
#1
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
https://www.readbyqxmd.com/read/28667905/spatial-and-temporal-postural-analysis-in-children-born-prematurely
#2
REVIEW
Maria Pia Bucci, Margherita Tringali, Clémence Trousson, Isabelle Husson, Olivier Baud, Valerie Biran
The aim of this study was to compare postural stability in a group of preterm-born children aged 4-6 years old and in a group of age-matched full-term control children by exploring both spatial and temporal analysis of the Center of Pressure (CoP). Twenty-nine children born prematurely (mean age: 5.38±0.17) and twenty-nine age-matched full-term control children participated in this study. Postural control was tested on both a stable and an unstable platform (from Framiral(®)) in three different visual conditions: eyes open fixating a target, eyes closed, and with vision perturbed by optokinetic stimulation...
June 24, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28666279/sodium-iodate-produces-a-strain-dependent-retinal-oxidative-stress-response-measured-in-vivo-using-quest-mri
#3
Bruce A Berkowitz, Robert H Podolsky, Jacob Lenning, Nikita Khetarpal, Catherine Tran, Johnny Y Wu, Ali M Berri, Kristin Dernay, Fatema Shafie-Khorassani, Robin Roberts
Purpose: We identify noninvasive biomarkers that measure the severity of oxidative stress within retina layers in sodium iodate (SI)-atrophy vulnerable (C57BL/6 [B6]) and SI-atrophy resistant (129S6/SvEvTac [S6]) mice. Methods: At 24 hours after administering systemic SI to B6 and S6 mice we measured: (1) superoxide production in whole retina ex vivo, (2) excessive free radical production in vivo based on layer-specific 1/T1 values before and after α-lipoic acid (ALA) administration while the animal was inside the magnet (QUEnch-assiSTed MRI [QUEST MRI]), and (3) visual performance (optokinetic tracking) ± antioxidants; control mice were similarly assessed...
June 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28649766/inferior-olivary-projection-to-the-zebrin-ii-stripes-in-lobule-ixcd-of-the-pigeon-flocculus-a-retrograde-tracing-study
#4
Douglas R Wylie, Cristian Gutierrez-Ibanez, Jeremy R Corfield, Iulia Craciun, David J Graham, Peter L Hurd
Zebrin II (ZII; a.k.a. aldolase C) is expressed heterogeneously in Purkinje cells (PCs) such that there are sagittal stripes of high expression (ZII+) interdigitated with stripes of little or no expression (ZII-). The pigeon flocculus receives visual-optokinetic information and is important for generating compensatory eye movements. It consists of 4 sagittal zones based on PC complex spike activity (CSA) in response to rotational optokinetic stimuli. There are two zones where CSA responds best to rotation about the vertical axis (VA), interdigitated with two zones where CSA responds best to rotation about an horizontal axis (HA)...
June 26, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28646240/delineating-function-and-connectivity-of-optokinetic-hubs-in-the-cerebellum-and-the-brainstem
#5
Ria Maxine Ruehl, Carolin Hinkel, Thomas Bauermann, Peter Zu Eulenburg
Optokinetic eye movements are crucial for keeping a stable image on the retina during movements of the head. These eye movements can be differentiated into a cortically generated response (optokinetic look nystagmus) and the highly reflexive optokinetic stare nystagmus, which is controlled by circuits in the brainstem and cerebellum. The contributions of these infratentorial networks and their functional connectivity with the cortical eye fields are still poorly understood in humans. To map ocular motor centres in the cerebellum and brainstem, we studied stare nystagmus using small-field optokinetic stimuli in the horizontal and vertical directions in 22 healthy subjects...
June 23, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28639422/medaka-and-zebrafish-contactin1-mutants-as-a-model-for-understanding-neural-circuits-for-motor-coordination
#6
Miki Takeuchi, Chikako Inoue, Akiko Goshima, Yusuke Nagao, Koichi Shimizu, Hiroki Miyamoto, Takashi Shimizu, Hisashi Hashimoto, Shigenobu Yonemura, Atsuo Kawahara, Yutaka Hirata, Masayuki Yoshida, Masahiko Hibi
A spontaneous medaka ro mutant shows abnormal wobbling and rolling swimming behaviors. By positional cloning, we mapped the ro locus to a region containing the gene encoding Contactin1b (Cntn1b), which is an immunoglobulin (Ig)-superfamily domain-containing membrane-anchored protein. The ro mutant had a deletion in the cntn1b gene that introduced a premature stop codon. Furthermore, cntn1b mutants generated by the CRISPR/Cas9 system and trans-heterozygotes of the CRISPR mutant allele and ro had abnormal swimming behavior, indicating that the cntn1b gene was responsible for the ro-mutant phenotype...
June 22, 2017: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
https://www.readbyqxmd.com/read/28638085/differential-regulations-of-vestibulo-ocular-reflex-and-optokinetic-response-by-%C3%AE-and-%C3%AE-2-adrenergic-receptors-in-the-cerebellar-flocculus
#7
Ryo Wakita, Soshi Tanabe, Kazunari Tabei, Asako Funaki, Takuma Inoshita, Tomoo Hirano
Norepinephrine modulates synaptic plasticity in various brain regions and is implicated in memory formation, consolidation and retrieval. The cerebellum is involved in motor learning, and adaptations of the vestibulo-ocular reflex (VOR) and optokinetic response (OKR) have been studied as models of cerebellum-dependent motor learning. Previous studies showed the involvement of adrenergic systems in the regulation of VOR, OKR and cerebellar synaptic functions. Here, we show differential contributions of β- and α2-adrenergic receptors in the mouse cerebellar flocculus to VOR and OKR control...
June 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28632848/effect-of-gabapentin-memantine-on-the-infantile-nystagmus-syndrome-in-the-zebrafish-model-implications-for-the-therapy-of-ocular-motor-diseases
#8
Stefan Yu Bögli, Maresa Afthinos, Melody Ying-Yu Huang
Purpose: Infantile nystagmus syndrome (INS) is a disorder characterized by typical horizontal eye oscillations. Due to the uncertain etiology of INS, developing specific treatments remains difficult. Single reports demonstrated, on limited measures, alleviating effects of gabapentin and memantine. In the current study, we employed the zebrafish INS model belladonna (bel) to conduct an in-depth study of how gabapentin and memantine interventions alleviate INS signs, which may further restore visual conditions in affected subjects...
June 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28624217/efficacy-of-postnatal-in%C3%A2-vivo-nonsense-suppression-therapy-in-a-pax6-mouse-model-of-aniridia
#9
Xia Wang, Kevin Gregory-Evans, Kishor M Wasan, Olena Sivak, Xianghong Shan, Cheryl Y Gregory-Evans
Nonsense mutations leading to premature stop codons are common occurring in approximately 12% of all human genetic diseases. Thus, pharmacological nonsense mutation suppression strategies would be beneficial to a large number of patients if the drugs could be targeted to the affected tissues at the appropriate time. Here, we used nonsense suppression to manipulate Pax6 dosage at different developmental times in the eye of the small eye (Pax6(Sey/+); G194X) mouse model of aniridia. Efficacy was assessed by functional assays for visual capacity, including electroretinography and optokinetic tracking (OKT), in addition to histological and biochemical studies...
June 16, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28536868/caffeine-increases-the-velocity-of-rapid-eye-movements-in-unfatigued-humans
#10
Charlotte J W Connell, Benjamin Thompson, Jason Turuwhenua, Robert F Hess, Nicholas Gant
BACKGROUND: Caffeine is a widely used dietary stimulant that can reverse the effects of fatigue on cognitive, motor and oculomotor function. However, few studies have examined the effect of caffeine on the oculomotor system when homeostasis has not been disrupted by physical fatigue. This study examined the influence of a moderate dose of caffeine on oculomotor control and visual perception in participants who were not fatigued. METHODS: Within a placebo-controlled crossover design, 13 healthy adults ingested caffeine (5 mg·kg(-1) body mass) and were tested over 3 h...
August 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28512444/longitudinal-quantification-of-eye-movement-impairments-after-pontine-hemorrhage
#11
Melis Suner, Glen T Prusky, Jason B Carmel, N Jeremy Hill
INTRODUCTION: We report a case of hypertrophic olivary degeneration due to pontine hemorrhage. A 59-year-old male with untreated hypertension suffered a primary pontine hemorrhage, which caused horizontal eye-movement limitation. Progressive neurological deterioration with involuntary eye and palatal movements began months after hemorrhage. This was accompanied by magnetic resonance imaging evidence of hypertrophic olivary degeneration at 4.5 months. BACKGROUND: Primary pontine hemorrhage often leads to impairment of eye movements and diplopia...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28502398/correlations-between-individual-susceptibility-to-visually-induced-motion-sickness-and-decaying-time-constant-of-after-nystagmus
#12
Coco C T Guo, Daniel J Z Chen, Isabella Y Wei, Richard H Y So, Raymond T F Cheung
This study examines the correlations between optokinetic after-nystagmus (OKAN) parameters and individual susceptibility to visually induced motion sickness (VIMS). Twenty-seven participants were exposed to vertical black-and-white stripes drifting along the yaw axis at 60° per second for 30 min to collect individual VIMS data (Phase 1). Two weeks after the exposure, OKANs were measured (Phase 2). 19 out of 27 participants (i.e., 70%) exhibited consistent OKAN patterns. Significant correlations between the time constants of OKAN and levels of VIMS experienced by the same viewers were found...
September 2017: Applied Ergonomics
https://www.readbyqxmd.com/read/28491015/protocols-for-visually-guided-navigation-assessment-of-efficacy-of-retina-directed-cell-or-gene-therapy-in-canines
#13
Puya Aravand, Pavitra S Ramachandran, Ivan Schpylchak, Nicholas T Phelps, Sergei Nikonov, Jean Bennett
There has been marked progress in recent years in developing gene delivery approaches for the treatment of inherited blinding diseases. Many of the proof-of-concept studies have utilized rodent models of retinal degeneration. In those models, tests of visual function include a modified water maze swim test, optokinetic nystagmus, and light-dark activity assays. Test paradigms used in rodents can be difficult to replicate in large animals due to their size and awareness of non-visual aspects of the test system...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28487376/visual-and-ocular-motor-function-in-the-atypical-form-of-neurodegeneration-with-brain-iron-accumulation-type-i
#14
Joana Jesus-Ribeiro, Cláudia Farinha, Margarida Amorim, Anabela Matos, Aldina Reis, João Lemos, Miguel Castelo-Branco, Cristina Januário
BACKGROUND/AIMS: Neurodegeneration with brain iron accumulation (NBIA) type I is a rare disease that can be divided into a classical or atypical variant, according to age of onset and clinical pattern. Neuro-ophthalmological involvement has been documented in the classical variant but only anecdotically in the atypical variant. We sought to describe the visual and ocular motor function in patients with atypical form of NBIA type I. METHODS: Cross-sectional study, including patients with genetically confirmed NBIA type I and classified as atypical variant, who underwent ophthalmological examination with best corrected visual acuity (BCVA), optical coherence tomography (OCT), fundus autofluorescence (FAF), electroretinography (ERG), visual evoked potentials (VEP) and video-oculography...
May 9, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28483062/immunocytochemical-localization-of-cholinergic-amacrine-cells-in-the-bat-retina
#15
Eun-Bee Park, Ya-Nan Gu, Chang-Jin Jeon
The purpose of this study was to localize the cholinergic amacrine cells, one of the key elements of a functional retina, in the retina of a microbat, Rhinolophus ferrumequinum. The presence and localization of choline acetyltransferase-immunoreactive (ChAT-IR) cells in the microbat retina were investigated using immunocytochemistry, confocal microscopy, and quantitative analysis. These ChAT-IR cells were present in the ganglion cell layer (GCL) and inner part of the inner nuclear layer (INL), as previously reported in various animals...
May 5, 2017: Acta Histochemica
https://www.readbyqxmd.com/read/28463578/comparison-of-naso-temporal-asymmetry-during-monocular-smooth-pursuit-optokinetic-nystagmus-and-ocular-following-response-in-strabismic-monkeys
#16
Anand C Joshi, Mehmet N Agaoglu, Vallabh E Das
PURPOSE: Under monocular viewing conditions, humans and monkeys with infantile strabismus exhibit asymmetric naso-temporal (N-T) responses to motion stimuli. The goal of this study was to compare and contrast these N-T asymmetries during 3 visually mediated eye tracking tasks-optokinetic nystagmus (OKN), smooth pursuit (SP) response, and ocular following responses (OFR). METHODS: Two adult strabismic monkeys were tested under monocular viewing conditions during OKN, SP, or OFR stimulation...
May 2, 2017: Strabismus
https://www.readbyqxmd.com/read/28452866/effects-of-dopamine-and-norepinephrine-on-exercise-induced-oculomotor-fatigue
#17
Charlotte J W Connell, Benjamin Thompson, Jason Turuwhenua, Alexa Srzich, Nicholas Gant
INTRODUCTION: Fatigue-induced impairments in the control of eye movements are detectable via reduced eye movement velocity following a bout of prolonged, strenuous exercise. Slower eye movements caused by neural fatigue within the oculomotor system can be prevented by caffeine and upregulation of central catecholamines may be responsible for this effect. This study explored the individual contribution of dopamine and norepinephrine to fatigue-related impairments in oculomotor control...
April 28, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28446583/a-shared-neural-integrator-for-human-posture-control
#18
Stephanie E Haggerty, Amy R Wu, Kathleen H Sienko, Arthur D Kuo
Control of standing posture requires fusion of multiple inputs including visual, vestibular, somatosensory, and other sensors, each having distinct dynamics. The semicircular canals, for example, have a high-pass filter response to angular velocity, quickly sensing a step change in head rotational velocity followed by a decay. To stabilize gaze despite this decay, the central nervous system supplies a neural "velocity storage" integrator, a filter that extends the angular velocity signal. Similar filtering might contribute temporal dynamics to posture control, as suggested by some state estimation models...
April 26, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28424291/comparison-of-optomotor-and-optokinetic-reflexes-in-mice
#19
Friedrich Kretschmer, Momina Tariq, Walid Chatila, Beverly Wu, Tudor Constantin Badea
During animal locomotion or position adjustments, the visual system uses image stabilization reflexes to compensate for global shifts in the visual scene. These reflexes elicit compensatory head movements (optomotor response, OMR) in unrestrained animals or compensatory eye movements (optokinetic response, OKR) in head-fixed or unrestrained animals exposed to globally rotating striped patterns. In mice, OMR are relatively easy to observe and find broad use in the rapid evaluation of visual function. OKR determinations are more involved experimentally but yield more stereotypical, easily quantifiable results...
July 1, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28422363/the-occhiolino-occ-mutant-zebrafish-a-model-for-development-of-the-optical-function-in-the-biological-lens
#20
Masamoto Aose, Tor H Linbo, Owen Lawrence, Tadashi Senoo, David W Raible, John I Clark
BACKGROUND: Zebrafish visual function depends on quality optics. An F3 screen for developmental mutations in the Zebrafish nervous system was conducted in wild-type (wt) AB Zebrafish exposed to 3 mM of N-ethyl-N-nitrosourea (ENU). RESULTS: Mutant offspring, identified in an F3 screen, were characterized by a small pupil, resulting from retinal hypertrophy or hyperplasia and a small lens. Deficits in visual function made feeding difficult after hatching at approximately 5-6 days postfertilization (dpf)...
April 19, 2017: Developmental Dynamics: An Official Publication of the American Association of Anatomists
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