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Carey D Balaban, Joseph M Furman
This study provides the first clear evidence that the generation of optokinetic nystagmus fast phases is a decision process that is influenced by performance of a concurrent disjunctive reaction time task (DRT). Ten subjects performed an auditory DRT during constant velocity optokinetic stimulation. Eye movements were measured in three dimensions with a magnetic search coil. Slow phase (SP) durations were defined as the interval between fast phases (FPs). There were three main findings. Firstly, human optokinetic nystagmus SP durations are consistent with a model of a Gaussian basic interval generator (a type of biological clock), such that FPs can be triggered randomly at the end of a clock cycle (mean duration: 200-250 ms); Kolmogorov-Smirnov tests could not reject the modeled cumulative distribution for any data trials...
October 19, 2016: Journal of Neurophysiology
Yuka Morita, Kuniyuki Takahashi, Shuji Izumi, Yamato Kubota, Shinsuke Ohshima, Arata Horii
OBJECTIVE: Otitis media (OM) with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (OMAAV) is a novel concept of ear disease that is characterized by progressive mixed or sensorineural hearing loss with occasional systemic involvement. Considering the accumulating knowledge about the characteristics of and treatment for auditory dysfunction in OMAAV, the objective of this study was to investigate the vestibular function and symptoms of patients with OMAAV. STUDY DESIGN: Retrospective chart review...
September 30, 2016: Otology & Neurotology
Bao-Hua Liu, Andrew D Huberman, Massimo Scanziani
The mammalian visual cortex massively innervates the brainstem, a phylogenetically older structure, via cortico-fugal axonal projections. Many cortico-fugal projections target brainstem nuclei that mediate innate motor behaviours, but the function of these projections remains poorly understood. A prime example of such behaviours is the optokinetic reflex (OKR), an innate eye movement mediated by the brainstem accessory optic system, that stabilizes images on the retina as the animal moves through the environment and is thus crucial for vision...
October 12, 2016: Nature
Hitomi Matsuno, Moeko Kudoh, Akiya Watakabe, Tetsuo Yamamori, Ryuichi Shigemoto, Soichi Nagao
Adaptations of vestibulo-ocular and optokinetic response eye movements have been studied as an experimental model of cerebellum-dependent motor learning. Several previous physiological and pharmacological studies have consistently suggested that the cerebellar flocculus (FL) Purkinje cells (P-cells) and the medial vestibular nucleus (MVN) neurons targeted by FL (FL-targeted MVN neurons) may respectively maintain the memory traces of short- and long-term adaptation. To study the basic structures of the FL-MVN synapses by light microscopy (LM) and electron microscopy (EM), we injected green florescence protein (GFP)-expressing lentivirus into FL to anterogradely label the FL P-cell axons in C57BL/6J mice...
2016: PloS One
Steven C Dakin, Philip R K Turnbull
Although the contrast sensitivity function (CSF) is a particularly useful way of characterising functional vision, its measurement relies on observers making reliable perceptual reports. Such procedures can be challenging when testing children. Here we describe a system for measuring the CSF using an automated analysis of optokinetic nystagmus (OKN); an involuntary oscillatory eye movement made in response to drifting stimuli, here spatial-frequency (SF) band-pass noise. Quantifying the strength of OKN in the stimulus direction allows us to estimate contrast sensitivity across a range of SFs...
October 4, 2016: Scientific Reports
Salma Jeribi, Abdelmoneem Yahia, Imen Achour, Bouthaina Hammemi, Abdelmoneem Ghorbel, Mohamed Habib Elleuch, Sameh Ghroubi
OBJECTIVE: To determine the effect of completing a vestibular rehabilitation treatment protocol on postural balance, dizziness and quality of life in patients with peripheral vertigo. MATERIAL/PATIENTS AND METHODS: A prospective study concerning patients with instability due to unilateral peripheral vestibular disorder. The patients were evaluated with a clinical examination and a test of static and dynamic balance on the Satel(®) platform in which length, mediolateral (LongX) and anterior-posterior deviations (long Y) were monitored...
September 2016: Annals of Physical and Rehabilitation Medicine
Clément Provost, Giulia Piccinini, Sophie Tasseel-Ponche, Pierre Lozeron, Bertrand Arnulf, Alain Yelnik
OBJECTIVE: As proposed after stroke, the study of reactions to a sensory stimulation allows to a better understanding of postural strategies. Below, we provide the analysis in chronic acquired demyelinating polyneuropathies (CADP). MATERIAL/PATIENTS AND METHODS: Prospective study of 25 healthy subjects (57±12years, 8M, 17F) and 25 CADP (66±14years, 20M, 5F) on stabilometric platform (Techno-Concept(®), France). Proprioception was disturbed by tendon vibration on Triceps Surae (TS) and Tibialis Anterior (TA)...
September 2016: Annals of Physical and Rehabilitation Medicine
Yasumitsu Takimoto, Takao Imai, Makoto Kondo, Yukiko Hanada, Atsuhiko Uno, Yusuke Ishida, Takefumi Kamakura, Tadashi Kitahara, Hidenori Inohara, Shoichi Shimada
Cisplatin is a chemotherapeutic agent commonly used for the treatment of solid tumors, and its side-effects include vestibulotoxicity. Previous studies have reported cisplatin-induced vestibulotoxicity in various animal models, but no study has investigated in vivo mouse vestibular dysfunction after cisplatin. The aim of this study was to investigate cisplatin-induced vestibulotoxicity in C57BL/6J mice. Vestibular function was assessed by recording the vestibulo-ocular reflex (VOR). This was done during sinusoidal rotations in the horizontal plane at three frequencies (0...
September 19, 2016: Toxicology Letters
A M Bronstein
This chapter provides an introduction to the topic of multisensory integration in balance control in, both, health and disease. One of the best-studied examples is that of visuo-vestibular interaction, which is the ability of the visual system to enhance or suppress the vestibulo-ocular reflex (VOR suppression). Of clinical relevance, examination of VOR suppression is clinically useful because only central, not peripheral, lesions impair VOR suppression. Visual, somatosensory (proprioceptive), and vestibular inputs interact strongly and continuously in the control of upright balance...
2016: Handbook of Clinical Neurology
Ian C Murray, Lorraine A Cameron, Alice D McTrusty, Antonios Perperidis, Harry M Brash, Brian W Fleck, Robert A Minns
PURPOSE: To evaluate feasibility, accuracy, and repeatability of suprathreshold Saccadic Vector Optokinetic Perimetry (SVOP) by comparison with Humphrey Field Analyzer (HFA) perimetry. METHODS: The subjects included children with suspected field defects (n = 10, age 5-15 years), adults with field defects (n = 33, age 39-78 years), healthy children (n = 12, age 6-14 years), and healthy adults (n = 30, age 16-61 years). The test protocol comprised repeat suprathreshold SVOP and HFA testing with the C-40 test pattern...
August 2016: Translational Vision Science & Technology
Benjamin Bakondi, Sergey Girman, Bin Lu, Shaomei Wang
: : We previously demonstrated that subretinal injection (SRI) of isogenic mesenchymal stem cells (MSCs) reduced the severity of retinal degeneration in Royal College of Surgeons rats in a focal manner. In contrast, intravenous MSC infusion (MSC(IV)) produced panoptic retinal rescue. By combining these treatments, we now show that MSC(IV) supplementation potentiates the MSC(SRI)-mediated rescue of photoreceptors and visual function. Electrophysiological recording from superior colliculi revealed 3...
September 9, 2016: Stem Cells Translational Medicine
Daniel San-Juan, Manuel Escanio Cortés, Martha Tena-Suck, Adolfo Josué Orozco Garduño, Jesús Alejandro López Pizano, Jonathan Villanueva Domínguez, Maricarmen Fernández Gónzalez-Aragón, Juan Luis Gómez-Amador
This paper reports the case of a patient with optic nerve schwannoma and the first use of neurophysiological intraoperative monitoring of visual evoked potentials during the removal of such tumor with no postoperative visual damage. Schwannomas are benign neoplasms of the peripheral nervous system arising from the neural crest-derived Schwann cells, these tumors are rarely located in the optic nerve and the treatment consists on surgical removal leading to high risk of damage to the visual pathway. Case report of a thirty-year-old woman with an optic nerve schwannoma...
September 1, 2016: Journal of Clinical Monitoring and Computing
Haitao Liu, Jie Tang, Yunpeng Du, Aicha Saadane, Deoye Tonade, Ivy Samuels, Alex Veenstra, Krzysztof Palczewski, Timothy S Kern
PURPOSE: Loss of photoreceptor cells is associated with retinal vascular degeneration in retinitis pigmentosa, whereas the presence of photoreceptor cells is implicated in vascular degeneration in diabetic retinopathy. To investigate how both the absence and presence of photoreceptors could damage the retinal vasculature, we compared two mouse models of photoreceptor degeneration (opsin-/- and RhoP23H/P23H ) and control C57Bl/5J mice, each with and without diabetes. METHODS: Retinal thickness, superoxide, expression of inflammatory proteins, ERG and optokinetic responses, leukocyte cytotoxicity, and capillary degeneration were evaluated at 1 to 10 months of age using published methods...
August 1, 2016: Investigative Ophthalmology & Visual Science
Amena W Smith, Baerbel Rohrer, Lee Wheless, Supriti Samantaray, Swapan K Ray, Jun Inoue, Mitsuyoshi Azuma, Naren L Banik
Optic neuritis (ON), inflammation of the optic nerve, is strongly associated with multiple sclerosis. ON pathology is characterized by attack of autoreactive T cells against optic nerve antigens, resulting in demyelination, death of retinal ganglion cells, and cumulative visual impairment. A model of experimental autoimmune encephalomyelitis (EAE) was utilized to study the onset and progression of ON and the neuroprotective efficacy of oral treatment with the calpain inhibitor SNJ 1945. EAE was actively induced in B10...
October 2016: Journal of Neurochemistry
Ma'ayan Semo, Nasrin Haamedi, Lara Stevanato, David Carter, Gary Brooke, Michael Young, Peter Coffey, John Sinden, Sara Patel, Anthony Vugler
PURPOSE: We assessed the long-term efficacy and safety of human retinal progenitor cells (hRPC) using established rodent models. METHODS: Efficacy of hRPC was tested initially in Royal College of Surgeons (RCS) dystrophic rats immunosuppressed with cyclosporine/dexamethasone. Due to adverse effects of dexamethasone, this drug was omitted from a subsequent dose-ranging study, where different hRPC doses were tested for their ability to preserve visual function (measured by optokinetic head tracking) and retinal structure in RCS rats at 3 to 6 months after grafting...
July 2016: Translational Vision Science & Technology
Isla M Williams, Peter Schofield, Neha Khade, Larry A Abel
Multiple sclerosis (MS) frequently causes impairment of cognitive function. We compared patients with MS with controls on divided visual attention tasks. The MS patients' and controls' stare optokinetic nystagmus (OKN) was recorded in response to a 24°/s full field stimulus. Suppression of the OKN response, judged by the gain, was measured during tasks dividing visual attention between the fixation target and a second stimulus, central or peripheral, static or dynamic. All participants completed the Audio Recorded Cognitive Screen...
July 27, 2016: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Q Arshad, Y Nigmatullina, R E Roberts, U Goga, M Pikovsky, S Khan, R Lobo, A-S Flury, V E Pettorossi, R Cohen-Kadosh, P A Malhotra, A M Bronstein
Although a direct relationship between numerical allocation and spatial attention has been proposed, recent research suggests that these processes are not directly coupled. In keeping with this, spatial attention shifts induced either via visual or vestibular motion can modulate numerical allocation in some circumstances but not in others. In addition to shifting spatial attention, visual or vestibular motion paradigms also (i) elicit compensatory eye movements which themselves can influence numerical processing and (ii) alter the perceptual state of 'self', inducing changes in bodily self-consciousness impacting upon cognitive mechanisms...
September 2016: European Journal of Neuroscience
Abu E Bashar, Andrew L Metcalfe, Ishaq A Viringipurampeer, Anat Yanai, Cheryl Y Gregory-Evans, Kevin Gregory-Evans
PURPOSE: X-linked retinoschisis (XLRS) is juvenile-onset macular degeneration caused by haploinsufficiency of the extracellular cell adhesion protein retinoschisin (RS1). RS1 mutations can lead to either a non-functional protein or the absence of protein secretion, and it has been established that extracellular deficiency of RS1 is the underlying cause of the phenotype. Therefore, we hypothesized that an ex vivo gene therapy strategy could be used to deliver sufficient extracellular RS1 to reverse the phenotype seen in XLRS...
2016: Molecular Vision
Nergiz Turgut, Marcela Miranda, Andreas Kastrup, Paul Eling, Helmut Hildebrandt
Visuospatial neglect is a disabling syndrome resulting in impaired activities of daily living and in longer durations of inpatient rehabilitation. Effective interventions to remediate neglect are still needed. The combination of tDCS and an optokinetic task might qualify as a treatment method. A total of 32 post-acute patients with left (n = 20) or right-sided neglect were allotted to an intervention or a control group (both groups n = 16). The intervention group received eight sessions of 1.5-2.0 mA parietal transcranial direct current stimulation (tDCS) during the performance of an optokinetic task distributed over two weeks...
July 5, 2016: Neuropsychological Rehabilitation
Tafadzwa M Sibindi, Peter J Holland, Jos N van der Geest, Opher Donchin, Maarten A Frens
PURPOSE: Compensatory eye movements (CEM) maintain a stable image on the retina by minimizing retinal slip. The optokinetic reflex (OKR) and vestibulo-ocular reflex (VOR) compensate for low and high velocity stimuli, respectively. The OKR system is known to be highly nonlinear. The VOR is generally modeled as a linear system and assumed to satisfy the superposition and homogeneity principles. To probe CEM violation of the superposition principle, we recorded eye movement responses in C57BL/6 mice to sum of sine (SoS) stimulation, a combination of multiple nonharmonic inputs...
July 1, 2016: Investigative Ophthalmology & Visual Science
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