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https://www.readbyqxmd.com/read/29648979/long-term-functional-and-structural-consequences-of-primary-blast-overpressure-to-the-eye
#1
Rachael Allen, Cara T Motz, Andrew Feola, Kyle Chesler, Raza Haider, Sringanesh Ramachandra Rao, Lara Skelton, Steven Fliesler, Machelle T Pardue
Acoustic blast overpressure (ABO) injury in military personnel and civilians is often accompanied by delayed visual deficits. However, most animal model studies dealing with blast-induced visual defects have focused on short-term (≤1 month) changes. Here, we evaluated long-term (≤8 months) retinal structure and function deficits in rats with ABO injury. Adult male Long Evans rats were subjected to ABO from a single blast (∼ 190 dB SPL, ∼ 63 kPa, @80 psi), generated by a shock tube device. Retinal function (electroretinography), visual function (optokinetic tracking), retinal thickness (spectral domain-optical coherence tomography), and spatial cognition/exploratory motor behavior (Y-maze) were measured at 2, 4, 6, and 8 months post-blast...
March 6, 2018: Journal of Neurotrauma
https://www.readbyqxmd.com/read/29593643/spontaneous-nystagmus-in-the-dark-in-an-infantile-nystagmus-patient-may-represent-negative-optokinetic-afternystagmus
#2
Ting-Feng Lin, Christina Gerth-Kahlert, James V M Hanson, Dominik Straumann, Melody Ying-Yu Huang
Abnormal projection of the optic nerves to the wrong cerebral hemisphere transforms the optokinetic system from its usual negative feedback loop to a positive feedback loop with characteristic ocular motor instabilities including directional reversal of the optokinetic nystagmus (OKN) and spontaneous nystagmus, which are common features of infantile nystagmus syndrome (INS). Visual input plays a critical role in INS linked to an underlying optic nerve misprojection such as that often seen in albinism. However, spontaneous nystagmus often continues in darkness, making the visual, sensory-driven etiology questionable...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29593513/zebrafish-lacking-circadian-gene-per2-exhibit-visual-function-deficiency
#3
Deng-Feng Huang, Ming-Yong Wang, Wu Yin, Yu-Qian Ma, Han Wang, Tian Xue, Da-Long Ren, Bing Hu
The retina has an intrinsic circadian clock, but the importance of this clock for vision is unknown. Zebrafish offer many advantages for studying vertebrate vision and circadian rhythm. Here, we explored the role of zebrafish per2 , a light-regulated gene, in visual behavior and the underlying mechanisms. We observed that per2 mutant zebrafish larvae showed decreased contrast sensitivity and visual acuity using optokinetic response (OKR) assays. Using a visual motor response (VMR) assay, we observed normal OFF responses but abnormal ON responses in mutant zebrafish larvae...
2018: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/29590622/lrit1-a-retinal-transmembrane-protein-regulates-selective-synapse-formation-in-cone-photoreceptor-cells-and-visual-acuity
#4
Akiko Ueno, Yoshihiro Omori, Yuko Sugita, Satoshi Watanabe, Taro Chaya, Takashi Kozuka, Tetsuo Kon, Satoyo Yoshida, Kenji Matsushita, Ryusuke Kuwahara, Naoko Kajimura, Yasushi Okada, Takahisa Furukawa
In the vertebrate retina, cone photoreceptors play crucial roles in photopic vision by transmitting light-evoked signals to ON- and/or OFF-bipolar cells. However, the mechanisms underlying selective synapse formation in the cone photoreceptor pathway remain poorly understood. Here, we found that Lrit1, a leucine-rich transmembrane protein, localizes to the photoreceptor synaptic terminal and regulates the synaptic connection between cone photoreceptors and cone ON-bipolar cells. Lrit1-deficient retinas exhibit an aberrant morphology of cone photoreceptor pedicles, as well as an impairment of signal transmission from cone photoreceptors to cone ON-bipolar cells...
March 27, 2018: Cell Reports
https://www.readbyqxmd.com/read/29582755/occurrence-of-long-term-depression-in-the-cerebellar-flocculus-during-adaptation-of-optokinetic-response
#5
Takuma Inoshita, Tomoo Hirano
Long-term depression (LTD) at parallel fiber (PF) to Purkinje cell (PC) synapses has been considered as a main cellular mechanism for motor learning. However, the necessity of LTD for motor learning was challenged by demonstration of normal motor learning in the LTD-defective animals. Here, we addressed possible involvement of LTD in motor learning by examining whether LTD occurs during motor learning in the wild-type mice. As a model of motor learning, adaptation of optokinetic response (OKR) was used. OKR is a type of reflex eye movement to suppress blur of visual image during animal motion...
March 27, 2018: ELife
https://www.readbyqxmd.com/read/29545576/age-related-changes-in-eye-brain-and-visuomotor-behavior-in-the-dba-2j-mouse-model-of-chronic-glaucoma
#6
Xiao-Ling Yang, Yolandi van der Merwe, Jeffrey Sims, Carlos Parra, Leon C Ho, Joel S Schuman, Gadi Wollstein, Kira L Lathrop, Kevin C Chan
Although elevated intraocular pressure (IOP) and age are major risk factors for glaucoma, their effects on glaucoma pathogenesis remain unclear. This study examined the onset and progression of glaucomatous changes to ocular anatomy and physiology, structural and physiological brain integrity, and visuomotor behavior in the DBA/2J mice via non-invasive tonometry, multi-parametric magnetic resonance imaging (MRI) and optokinetic assessments from 5 to 12 months of age. Using T2-weighted MRI, diffusion tensor MRI, and manganese-enhanced MRI, increasing IOP elevation at 9 and 12 months old coincided with anterior chamber deepening, altered fractional anisotropy and radial diffusivity of the optic nerve and optic tract, as well as reduced anterograde manganese transport along the visual pathway respectively in the DBA/2J mice...
March 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29518090/gait-phenotypes-in-paediatric-hereditary-spastic-paraplegia-revealed-by-dynamic-time-warping-analysis-and-random-forests
#7
Irene Pulido-Valdeolivas, David Gómez-Andrés, Juan Andrés Martín-Gonzalo, Irene Rodríguez-Andonaegui, Javier López-López, Samuel Ignacio Pascual-Pascual, Estrella Rausell
The Hereditary Spastic Paraplegias (HSP) are a group of heterogeneous disorders with a wide spectrum of underlying neural pathology, and hence HSP patients express a variety of gait abnormalities. Classification of these phenotypes may help in monitoring disease progression and personalizing therapies. This is currently managed by measuring values of some kinematic and spatio-temporal parameters at certain moments during the gait cycle, either in the doctor´s surgery room or after very precise measurements produced by instrumental gait analysis (IGA)...
2018: PloS One
https://www.readbyqxmd.com/read/29514678/early-alpha-lipoic-acid-therapy-protects-from-degeneration-of-the-inner-retinal-layers-and-vision-loss-in-an-experimental-autoimmune-encephalomyelitis-optic-neuritis-model
#8
Michael Dietrich, Niklas Helling, Alexander Hilla, Annemarie Heskamp, Andrea Issberner, Thomas Hildebrandt, Zippora Kohne, Patrick Küry, Carsten Berndt, Orhan Aktas, Dietmar Fischer, Hans-Peter Hartung, Philipp Albrecht
BACKGROUND: In multiple sclerosis (MS), neurodegeneration is the main reason for chronic disability. Alpha-lipoic acid (LA) is a naturally occurring antioxidant which has recently been demonstrated to reduce the rate of brain atrophy in progressive MS. However, it remains uncertain if it is also beneficial in the early, more inflammatory-driven phases. As clinical studies are costly and time consuming, optic neuritis (ON) is often used for investigating neuroprotective or regenerative therapeutics...
March 7, 2018: Journal of Neuroinflammation
https://www.readbyqxmd.com/read/29501085/vertical-nystagmus-associated-with-glutamic-acid-decarboxylase-antibodies-responding-to-cyclophosphamide
#9
José Fidel Baizabal-Carvallo, Marlene Alonso-Juarez
Several neurological disorders have been described in patients with autoimmunity associated with GAD antibodies. Among these disorders, nystagmus and oculomotor dysfunction are increasingly recognized, although they have been rarely reported isolated or as the main manifestation of anti-GAD autoimmunity. Moreover, therapeutic approaches for such patients are unclear. Here we present a 44-year-old man with disabling oscillopsia secondary to downbeat nystagmus, abnormal saccades, ocular pursuit and optokinetic nystagmus, as well as mild gait ataxia and cerebellar atrophy associated with high serum GAD antibodies with intrathecal secretion of such antibodies...
April 15, 2018: Journal of Neuroimmunology
https://www.readbyqxmd.com/read/29494741/sirt1-and-nrf2-gene-transfer-mediate-distinct-neuroprotective-effects-upon-retinal-ganglion-cell-survival-and-function-in-experimental-optic-neuritis
#10
Devin S McDougald, Kimberly E Dine, Alexandra U Zezulin, Jean Bennett, Kenneth S Shindler
Purpose: Optic neuritis is a condition defined by autoimmune-mediated demyelination of the optic nerve and death of retinal ganglion cells. SIRT1 and NRF2 stimulate anti-inflammatory mechanisms and have previously demonstrated therapeutic value in preclinical models of neurodegenerative disease. Here we investigated the neuroprotective potential of SIRT1 or NRF2 gene transfer using adeno-associated virus (AAV) vectors in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis...
March 1, 2018: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29481883/loss-of-gprc5b-impairs-synapse-formation-of-purkinje-cells-with-cerebellar-nuclear-neurons-and-disrupts-cerebellar-synaptic-plasticity-and-motor-learning
#11
Takamitsu Sano, Ayako Kohyama-Koganeya, Masami O Kinoshita, Tetsuya Tatsukawa, Chika Shimizu, Eriko Oshima, Kazuyuki Yamada, Tung Dinh Le, Takumi Akagi, Koujiro Tohyama, Soichi Nagao, Yoshio Hirabayashi
GPRC5B is a membrane glycoprotein robustly expressed in mouse cerebellar Purkinje cells (PCs). Its function is unknown. In Gprc5b-/- mice that lack GPRC5B, PCs develop distal axonal swellings in deep cerebellar nuclei (DCN). Numerous misshapen mitochondria, which generated excessive amounts of reactive oxygen species (ROS), accumulated in these distal axonal swellings. In primary cell cultures of Gprc5b-/- PCs, pharmacological reduction of ROS prevented the appearance of such swellings. To examine the physiological role of GPRC5B in PCs, we analyzed cerebellar synaptic transmission and cerebellum-dependent motor learning in Gprc5b-/- mice...
February 23, 2018: Neuroscience Research
https://www.readbyqxmd.com/read/29472888/the-effect-of-visual-stimuli-on-stability-and-complexity-of-postural-control
#12
Haizhen Luo, Xiaoyun Wang, Mengying Fan, Lingyun Deng, Chuyao Jian, Miaoluan Wei, Jie Luo
Visual input could benefit balance control or increase postural sway, and it is far from fully understanding the effect of visual stimuli on postural stability and its underlying mechanism. In this study, the effect of different visual inputs on stability and complexity of postural control was examined by analyzing the mean velocity (MV), SD, and fuzzy approximate entropy (fApEn) of the center of pressure (COP) signal during quiet upright standing. We designed five visual exposure conditions: eyes-closed, eyes-open (EO), and three virtual reality (VR) scenes (VR1-VR3)...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29460827/repeated-attacks-of-dizziness-caused-by-a-rare-mitochondrial-encephalomyopathy
#13
Teruo Toi, Yasuyuki Nomura, Akihiro Kishino, Shuntaro Shigihara, Takeshi Oshima, Harumi Ishikawa, Satoshi Kamei, Hidemi Miyazaki
Cases of dizziness caused by multiple sclerosis are commonly reported, but those caused by mitochondrial encephalomyopathy have been rarely reported. Particularly, the description of eye nystagmography (ENG) using caloric and optokinetic nystagmus tests has not been reported to date. We encountered the case of a 40-year-old woman with mitochondrial encephalomyopathy who visited us with the chief complaint of dizziness. At first, we considered multiple sclerosis based on the magnetic resonance imaging (MRI) findings and dizziness...
February 20, 2018: Journal of International Advanced Otology
https://www.readbyqxmd.com/read/29459843/hypothesis-the-vestibular-and-cerebellar-basis-of-the-mal-de-debarquement-syndrome
#14
Bernard Cohen, Sergei B Yakushin, Catherine Cho
The Mal de Debarquement syndrome (MdDS) generally follows sea voyages, but it can occur after turbulent flights or spontaneously. The primary features are objective or perceived continuous rocking, swaying, and/or bobbing at 0.2 Hz after sea voyages or 0.3 Hz after flights. The oscillations can continue for months or years and are immensely disturbing. Associated symptoms appear to be secondary to the incessant sensation of movement. We previously suggested that the illness can be attributed to maladaptation of the velocity storage integrator in the vestibular system, but the actual neural mechanisms driving the MdDS are unknown...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29458753/challenges-in-sleep-stage-r-scoring-in-patients-with-autosomal-dominant-spinocerebellar-ataxias-sca1-sca2-and-sca3-and-oculomotor-abnormalities-a-whole-night-polysomnographic-evaluation
#15
Doniparthi Venkata Seshagiri, Arun Sasidharan, Gulshan Kumar, Pramod Kumar Pal, Sanjeev Jain, Bindu M Kutty, Ravi Yadav
OBJECTIVES: Spinocerebellar ataxias are progressive neurodegenerative disorders characterized by progressive cerebellar features with additional neuro-axis involvement. Oculomotor abnormality is one of the most frequent manifestations. This study was done to assess the polysomnographic abnormalities in patients with Spinocerebellar ataxia (SCA1, SCA2 and SCA3) and also to evaluate whether oculomotor abnormalities interfere with sleep stage R scoring. METHODS: The study was carried out using 36 genetically positive SCA patients...
February 2018: Sleep Medicine
https://www.readbyqxmd.com/read/29410359/modulation-of-the-zebrafish-optokinetic-reflex-by-pharmacologic-agents-targeting-gabaa-receptors
#16
Enhua Shao, Seth D Scheetz, Wenting Xie, Edward A Burton
Optokinetic reflex (OKR) responses provide a convenient means to evaluate visual, integrative and oculomotor function in larval zebrafish. We measured multiple aspects of the OKR response in zebrafish exposed systemically to compounds altering signaling at GABAA receptors in order to derive quantitative concentration-response relationships. The GABAA antagonist picrotoxin caused concentration-dependent decreases in reflex gain, saccade velocity, saccade amplitude, interocular concordance and interocular gain...
February 2, 2018: Neuroscience Letters
https://www.readbyqxmd.com/read/29391484/a-highly-efficient-murine-model-of-experimental-myopia
#17
Xiaoyan Jiang, Toshihide Kurihara, Hiromitsu Kunimi, Maki Miyauchi, Shin-Ichi Ikeda, Kiwako Mori, Kinya Tsubota, Hidemasa Torii, Kazuo Tsubota
Despite the global pandemic of myopia, the precise molecular mechanism of the onset of myopia remains largely unknown. This is partially because of the lack of efficient murine myopic models that allow genetic manipulation at low cost. Here we report a highly practical and reproducible lens-induced myopia model by specially designed frames and lenses for mice. A lens power dependent myopic induction in mice was shown until minus 30 diopter lenses. The phenotype was significantly stronger than form-deprivation myopia...
February 1, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29346495/long-term-temporal-changes-in-structure-and-function-of-rat-visual-system-after-blast-exposure
#18
Daniel F Shedd, Nikolaus A Benko, Justin Jones, Brian E Zaugg, Robert L Peiffer, Brittany Coats
Purpose: We identify long-term ocular sequelae subsequent to experimental blast exposure. Methods: Male Long-Evans rats were exposed to 230 kPa side-on primary blast overpressure using a compressed air driven shock tube. Visual system function and structure were assessed for 8 weeks after exposure using optokinetic nystagmus and optical coherence tomography. Vitreous protein expression and histology (TUNEL, H&E) were performed at 1 day and 1, 4, and 8 weeks...
January 1, 2018: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29340763/the-retinal-projection-to-the-nucleus-lentiformis-mesencephali-in-zebra-finch-taeniopygia-guttata-and-anna-s-hummingbird-calypte-anna
#19
Cristian Gutierrez-Ibanez, Andrea H Gaede, Max R Dannish, Douglas L Altshuler, Douglas R Wylie
In birds, the nucleus of the basal optic root (nBOR) and the nucleus lentiformis mesencephali (LM) are retinal recipient nuclei involved in the analysis of optic flow and the generation of the optokinetic response. In both pigeons and chickens, retinal inputs to the nBOR arise from displaced ganglion cells (DGCs), which are found at the margin of the inner nuclear and inner plexiform layers. The LM receives afferents from retinal ganglion cells, but whether DGCs also project to LM is a matter of debate. Previous work in chickens had concluded that DGCs do not project to LM, but a recent study in pigeons found that both retinal ganglion cells and DGCs project to LM...
April 2018: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/29332093/structure-function-correlation-in-hemianopic-vision-loss-in-children-aged-3-6-years-using-oct-and-svop-and-comparison-with-adult-eyes
#20
Wadim Bowl, Robert Knobloch, Silke Schweinfurth, Kerstin Holve, Knut Stieger, Birgit Lorenz
PURPOSE: To correlate visual field assessment with saccadic vector optokinetic perimetry (SVOP) in children with ganglion cell loss due to anterior pathway pathologies resulting in hemianopic visual field defects measured with optical coherence tomography (OCT). METHODS: 5 young (aged 3-6 years) and 5 adult patients with hemianopia, 10 healthy preschoolers (mean age 4.4 years), and 10 healthy adults (mean age 25.3 years) were tested with SVOP and OCT (focusing on the ganglion cell layer, GCL+)...
January 13, 2018: Ophthalmic Research
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