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Tomoo Hirano - One of the best experts on this subject based on the ideXlab platform.

  • occurrence of long term depression in the cerebellar flocculus during adaptation of Optokinetic Response
    eLife, 2018
    Co-Authors: Takuma Inoshita, Tomoo Hirano
    Abstract:

    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. OKR shows adaptive change during continuous Optokinetic stimulation, which is regulated by the cerebellar flocculus. After OKR adaptation, amplitudes of quantal excitatory postsynaptic currents at PF-PC synapses were decreased, and induction of LTD was suppressed in the flocculus. These results suggest that LTD occurs at PF-PC synapses during OKR adaptation.

  • differential regulations of vestibulo ocular reflex and Optokinetic Response by β and α2 adrenergic receptors in the cerebellar flocculus
    Scientific Reports, 2017
    Co-Authors: Ryo Wakita, Takuma Inoshita, Soshi Tanabe, Kazunari Tabei, Asako Funaki, Tomoo Hirano
    Abstract:

    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. Effects of application of β- or α2-adrenergic agonist or antagonist into the flocculus suggest that the β-adrenergic receptor activity maintains the VOR gain at high levels and contributes to adaptation of OKR, and that α2-adrenergic receptor counteracts the β-receptor activity in VOR and OKR control. We also examined effects of norepinephrine application, and the results suggest that norepinephrine regulates VOR and OKR through β-adrenergic receptor at low concentrations and through α2-receptor at high concentrations.

  • involvement of the cerebellar synaptic plasticity in adaptation of the vestibulo ocular reflex and Optokinetic Response
    Equilibrium Research, 2011
    Co-Authors: Tomoo Hirano
    Abstract:

    The vestibulo-ocular reflex (VOR) and Optokinetic Response (OKR) work cooperatively to compensate for the eye position during head movement. The floccular region of the cerebellar cortex regulates the amplitude and timing of these reflexes through the inhibitory synaptic outputs of Purkinje neurons. Both the VOR and OKR undergo adaptive changes, when the retinal slip causing the blur of visual image occurs continuously. Long-term depression (LTD), a type of plasticity at the synapses between parallel fibers and a Purkinje cell, in the flocculus, has been proposed to contribute to the adaptation of VOR and OKR. The progress in the study on cerebellar LTD has revealed numbers of molecules involved in LTD. Glutamate receptor-like molecule δ2 (GluD2) and delphilin are proteins specifically expressed at the postsynaptic membrane of Purkinje neurons and involved in LTD. GluD2 knockout mice show failure of LTD induction and impaired adaptation of VOR and OKR. On the other hand, delphilin knockout mice show facilitation of the LTD induction and the enhanced adaptation of OKR. These results suggest that the cerebellar LTD is involved in the adaptation of reflex eye movements. In addition, a delayed OKR is observed in the GluD2 knockout mice, which seems to be caused by the abnormal Purkinje neuron activities.

  • increased occurrence of climbing fiber inputs to the cerebellar flocculus in a mutant mouse is correlated with the timing delay of Optokinetic Response
    European Journal of Neuroscience, 2007
    Co-Authors: Takashi Yoshida, Kazuo Funabiki, Tomoo Hirano
    Abstract:

    The cerebellum plays an essential role in motor control, and its dysfunction may delay the onset of action and disrupt smooth and efficient movement. A Purkinje neuron (PN), the sole output cell type in the cerebellar cortex, receives two distinct types of excitatory synaptic inputs, numerous weak inputs from granule neurons (GNs) and occasional strong inputs from a climbing fiber (CF). The role of each input and the significance of low firing rate of CF have been studied. Here we show that the increased occurrence of CF inputs altered the firing pattern of a PN, which was correlated with timing of a reflex. We used the mutant mice deficient in the glutamate receptor delta2 subunit, a molecule related to ionotropic glutamate receptor specifically expressed at GN-PN synapses. The mutant mouse shows more frequent CF inputs and longer timing delay in Optokinetic Response (OKR), reflex eye movement that follows slow motion of a large visual field. A PN shows two types of action potentials: complex spikes (CS) induced by CF inputs; and simple spikes. They changed respective firing rates during sinusoidal Optokinetic stimulation, and the timing of each firing rate modulation was similar in wild-type and mutant mice. However, increased occurrence of CS in the mutant altered the total firing pattern of a PN in the flocculus, which was correlated with the timing delay of OKR. These results support the functional merit of low firing rate of CF in motor control.

  • dynamic properties interactions and adaptive modifications of vestibulo ocular reflex and Optokinetic Response in mice
    Neuroscience Research, 2001
    Co-Authors: M Iwashita, Ryota Kanai, Kazuo Funabiki, K Matsuda, Tomoo Hirano
    Abstract:

    Dynamic properties of horizontal vestibulo-ocular reflex (VOR) and Optokinetic Response (OKR) were studied in mice. The VOR was examined in the dark (VORD), in the light (VORL) and in the condition in which most of the visual field moves synchronously with the head motion (VORF). A mouse and/or a surrounding screen with vertical stripes was rotated sinusoidally, and the gain and phase of eye movements were measured in wide dynamic stimulation ranges. The working conditions of VOR and OKR were supplementary; OKR worked at low speeds of head turn and VOR at high speeds. Examination of VORL and VORF revealed non-linear interaction of VOR and OKR. The continuous sinusoidal head oscillation coupled with the in-phase or the out-of-phase oscillation of the surrounding screen, decreased or increased the VORD gain, and increased or decreased the VORD phase lead, respectively. Continuous oscillation of the surrounding screen increased the OKR gain and decreased the phase delay. These changes of VOR and OKR work to reduce the retinal slip. The present study provides fundamental information concerning the dynamic properties of VOR and OKR and the nature of their adaptive modifications in mice, which have been extensively used in genetic manipulation recently.

Stephan C.f. Neuhauss - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of Optokinetic Response in Zebrafish by Computer-Based Eye Tracking
    Methods in molecular biology (Clifton N.J.), 2012
    Co-Authors: Sabina P. Huber-reggi, Kaspar P. Mueller, Stephan C.f. Neuhauss
    Abstract:

    Large-field movements in the visual surround trigger spontaneous, compensatory eye movements known as Optokinetic Response (OKR) in all vertebrates. In zebrafish (Danio rerio) the OKR is well developed at 5 days post fertilization and can be used in the laboratory for screening of visual performance following genetic manipulations or pharmaceutical treatments. Several setups for measurement of the zebrafish OKR have been described. All of them are based on the presentation of moving gratings to the larva or to the adult fish. However, they differ in the way of presenting gratings and in the method of analysis. Here, we describe a detailed protocol for our newest software that enables computer-generation of the moving stripes and automatic tracking of eye movement. This protocol makes it possible to quantitatively measure OKR in both larvae and adult fishes in a fast and reliable way.

  • Quantitative measurements of the Optokinetic Response in adult fish.
    Journal of neuroscience methods, 2009
    Co-Authors: Kaspar P. Mueller, Stephan C.f. Neuhauss
    Abstract:

    Small teleost fish are increasingly used for studying the genetic basis of vision. In particular, zebrafish (Danio rerio) and medaka (Oryzias latipes) are commonly used vertebrate model organisms in developmental research, including research on the development of visual function. A multitude of behavior-based visual tests are established for larvae that have been successfully used to identify and characterize visual defects in genetically manipulated strains of these species. Testing the visual system of adult fish has proven to be more difficult for a number of reasons, including complications in restraining fish, or shoaling and dominance behavior interfering with visual behavior in population screening assays. In this paper, we present a simple and cost-effective method to quantitatively measure the Optokinetic Response (OKR) of individual adult zebrafish and medaka, which can be used to characterize visual capabilities of adult fish. This method can be applied to any fish species of similar size.

  • Computer-based analysis of the Optokinetic Response in zebrafish larvae.
    CSH protocols, 2008
    Co-Authors: Corinne Hodel, Stephan C.f. Neuhauss
    Abstract:

    Abstract INTRODUCTIONLarge movements in the visual field trigger stereotypic eye movements in vertebrates. This Optokinetic Response (OKR) is robust in zebrafish (Danio rerio) larvae older than 4 days post-fertilization (dpf), and is hence ideally suited for use in the evaluation of visual performance after genetic manipulations. This protocol describes a simple method by which a computer-generated visual stimulus is projected onto a screen and watched by immobilized larvae. The resulting eye movements are recorded and evaluated automatically, using a digital video camera and appropriate computer software. Depending on the sophistication of the software used, the evaluation can be performed in real time during the recording session, or by analyzing the recorded movie files off-line.

  • The Optokinetic Response in zebrafish and its applications.
    Frontiers in bioscience : a journal and virtual library, 2008
    Co-Authors: Ying-yu Huang, Stephan C.f. Neuhauss
    Abstract:

    The Optokinetic Response (OKR) is a stereotyped eye movement in Response to movement in he surround. The OKR serves to stabilize the visual image on the retina, and allows for high resolution vision. Due to its high selection value, all vertebrates display this basic behavior. Here, we review the properties of the OKR with a focus on the zebrafish, including methodological aspects of measuring eye movements in small larvae. The genetic amenabilities of the zebrafish model permit the use of this reflexive behavior in genetic screens. Such approaches have led to the isolation of mutant strains with specific defects in the visual pathway. In addition to the use of the OKR as a screening assay, mutations with characteristic abnormalities in the execution of this behavior will enable the analysis of sensory-motor control in great detail. A case in point is the belladonna mutation, where an axonal misrouting effect at the optic chiasm leads to a reversed OKR with a number of interesting properties.

  • Contrast Sensitivity, Spatial and Temporal Tuning of the Larval Zebrafish Optokinetic Response
    Investigative ophthalmology & visual science, 2005
    Co-Authors: Oliver Rinner, Jens M. Rick, Stephan C.f. Neuhauss
    Abstract:

    PURPOSE: To characterize the quantitative properties of the Optokinetic Response (OKR) in zebrafish larvae as a tool to test visual performance in genetically modified larvae. METHODS: Horizontal OKR was triggered in 5-day-old zebrafish larvae by stimulation with projected computer-generated gratings of varying contrast, angular velocity, temporal and spatial frequency, and brightness. Eye movements were analyzed by a custom-made eye tracker based on image analysis. RESULTS: The gain of the OKR slow phase was dependent on angular velocity, spatial frequency, and contrast of a moving grating, but largely independent on brightness. Eye velocity was a logarithmically linear function of grating contrast with a slope of approximately 0.8 per log unit contrast. CONCLUSIONS: The OKR of the larval zebrafish is not scaled for stimulus contrast and spatial frequency. These properties make the OKR a valuable tool to quantify behavioral visual performance such as visual acuity, contrast sensitivity, and light adaptation. This behavioral paradigm will be useful for analyzing visual performance in mutant and gene-knockdown larval zebrafish.

Soichi Nagao - One of the best experts on this subject based on the ideXlab platform.

  • Research Inhibition of Nitric Oxide Synthesis and Gene Knockout of Neuronal Nitric Oxide Synthase Impaired Adaptation of Mouse Optokinetic Response Eye Movements
    2016
    Co-Authors: Akira Katoh, Hiromasa Kitazawa, Shigeyoshi Itohara, Soichi Nagao
    Abstract:

    Nitric oxide (NO) plays a key role in synaptic transmission efficiency in the central nervous system. To gain an insight on the role of NO in cerebellar functions, we, here, measured the dynamics of the horizontal Optokinetic Response (HOKR) and vestibulo-ocular reflex (HVOR), and the adaptation of HOKR in mice locally injected with NG-monomethyl-L-arginine (L-NMMA) that inhibits NO synthesis and in mice devoid of neuronal nitric oxide synthase (nNOS). Local application of L-NMMA into the cerebellar flocculi induced no change in the dynamics of the HOKR but markedly depressed the adaptation of the HOKR induced by 1 hr of sustained screen oscillation. A slight difference was seen in the HOKR but not in the HVOR dynamics between nNOS−/− mutant and wild-type mice. One hour of sustained screen oscillation induced adaptation of the HOKR gains in wild-type mice but not in mutants. These observations suggest that NO is essential for the adaptation of the HOKR and that nNOS is the major enzyme for NO synthesis in the process. Nitric oxide (NO) plays a number of important roles as a biological messenger molecule. In the central nervous sys-tem, the importance of NO in neural plasticity has recently been recognized. In the cerebellum, conjunctive stimuli to parallel and climbing fibers evoke long-term depression (LTD) of synaptic transmission of parallel fiber–Purkinje cell synapses (Ito et al. 1982; Ekerot and Kano 1985). The role of NO in induction of cerebellar LTD was first suggested b

  • Loss of adaptability of horizontal Optokinetic Response eye movements in mGluR1 knockout mice.
    Neuroscience research, 2002
    Co-Authors: Fumihiro Shutoh, Akira Katoh, Hiromasa Kitazawa, Atsu Aiba, Shigeyoshi Itohara, Soichi Nagao
    Abstract:

    Abstract Metabotropic glutamate receptor subtype 1 (mGluR1) plays an essential role in the cerebellar long-term depression (LTD). We examined the dynamic characteristics and adaptability of horizontal vestibulo-ocular reflex (HVOR) and Optokinetic Response (HOKR) eye movements in mGluR1 knockout mice. A mild difference was seen in the HOKR/HVOR dynamics between the wild-type and mGluR1(−/−) mice. Exposure to 1 h of sustained screen oscillation, which induced HOKR adaptation in wild-type mice, induced no change in mutant mice. These results suggest that the mGluR1 plays an essential role in the adaptation of HOKR, and LTD underlies the adaptation of ocular reflexes.

  • Inhibition of Nitric Oxide Synthesis and Gene Knockout of Neuronal Nitric Oxide Synthase Impaired Adaptation of Mouse Optokinetic Response Eye Movements
    Learning & memory (Cold Spring Harbor N.Y.), 2000
    Co-Authors: Akira Katoh, Hiromasa Kitazawa, Shigeyoshi Itohara, Soichi Nagao
    Abstract:

    Nitric oxide (NO) plays a key role in synaptic transmission efficiency in the central nervous system. To gain an insight on the role of NO in cerebellar functions, we, here, measured the dynamics of the horizontal Optokinetic Response (HOKR) and vestibulo-ocular reflex (HVOR), and the adaptation of HOKR in mice locally injected with N(G)-monomethyl-L-arginine (L-NMMA) that inhibits NO synthesis and in mice devoid of neuronal nitric oxide synthase (nNOS). Local application of L-NMMA into the cerebellar flocculi induced no change in the dynamics of the HOKR but markedly depressed the adaptation of the HOKR induced by 1 hr of sustained screen oscillation. A slight difference was seen in the HOKR but not in the HVOR dynamics between nNOS(-/-) mutant and wild-type mice. One hour of sustained screen oscillation induced adaptation of the HOKR gains in wild-type mice but not in mutants. These observations suggest that NO is essential for the adaptation of the HOKR and that nNOS is the major enzyme for NO synthesis in the process.

  • Dynamic characteristics and adaptability of mouse vestibulo-ocular and Optokinetic Response eye movements and the role of the flocculo-olivary system revealed by chemical lesions
    Proceedings of the National Academy of Sciences of the United States of America, 1998
    Co-Authors: Akira Katoh, Hiromasa Kitazawa, Shigeyoshi Itohara, Soichi Nagao
    Abstract:

    The dynamic characteristics of reflex eye movements were measured in two strains of chronically prepared mice by using an infrared television camera system. The horizontal vestibulo-ocular reflex (HVOR) and horizontal Optokinetic Response (HOKR) were induced by sinusoidal oscillations of a turntable, in darkness, by 10° (peak to peak) at 0.11–0.50 Hz and of a checked-pattern screen, in light, by 5–20°at 0.11–0.17 Hz, respectively. The gains and phases of the HVOR and HOKR of the C57BL/6 mice were nearly equivalent to those of rabbits and rats, whereas the 129/Sv mice exhibited very low gains in the HVOR and moderate phase lags in the HOKR, suggesting an inherent sensory-motor anomaly. Adaptability of the HOKR was examined in C57BL/6 mice by sustained screen oscillation. When the screen was oscillated by 10° at 0.17 Hz, which induced sufficient retinal slips, the gain of the HOKR increased by 0.08 in 1 h on average, whereas the stimuli that induced relatively small or no retinal slips affected the gain very little. Lesions of the flocculi induced by local applications of 0.1% ibotenic acid and lesions of the inferior olivary nuclei induced by i.p. injection of 3-acetylpyridine in C57BL/6 mice little affected the dynamic characteristics of the HVOR and HOKR, but abolished the adaptation of the HOKR. These results indicate that the olivo-floccular system plays an essential role in the adaptive control of the ocular reflex in mice, as suggested in other animal species. The data presented provide the basis for analyzing the reflex eye movements of genetically engineered mice.

Lorenzo Canavese - One of the best experts on this subject based on the ideXlab platform.

  • The Optokinetic Response is effective to assess objective visual acuity in patients with cataract and age-related macular degeneration
    International Ophthalmology, 2019
    Co-Authors: Carlo Aleci, Gabriele Cossu, Elena Belcastro, Lorenzo Canavese
    Abstract:

    Purpose To estimate objective visual acuity in subjects suffering from cataract and age-related macular degeneration via the Optokinetic Response evoked by a non-conventional induction method ( oktotype ); in addition, to compare such objective outcome with the subjective acuity based on the ETDRS charts. Methods Patients were presented with 13 sequences of symbols arranged horizontally to form a serial pattern, moving from left to right at a constant rate. In each sequence, the size of the stimuli was reduced progressively, while the operator checked for the disappearance of the Optokinetic Response via a small video camera mounted on the test lens frame. The minimum angular size of the serial pattern able to evoke the Optokinetic Response (MAER) was referred to as the objective visual acuity of the subject. Results Correlation between logMAER and logMAR was significant in the cataract and macular degeneration group ( $$R_{\text{cat}}^{2}$$ R cat 2  = 0.70, p  

  • the Optokinetic Response is effective to assess objective visual acuity in patients with cataract and age related macular degeneration
    International Ophthalmology, 2019
    Co-Authors: Carlo Aleci, Gabriele Cossu, Elena Belcastro, Lorenzo Canavese
    Abstract:

    To estimate objective visual acuity in subjects suffering from cataract and age-related macular degeneration via the Optokinetic Response evoked by a non-conventional induction method (oktotype); in addition, to compare such objective outcome with the subjective acuity based on the ETDRS charts. Patients were presented with 13 sequences of symbols arranged horizontally to form a serial pattern, moving from left to right at a constant rate. In each sequence, the size of the stimuli was reduced progressively, while the operator checked for the disappearance of the Optokinetic Response via a small video camera mounted on the test lens frame. The minimum angular size of the serial pattern able to evoke the Optokinetic Response (MAER) was referred to as the objective visual acuity of the subject. Correlation between logMAER and logMAR was significant in the cataract and macular degeneration group ( $$R_{\text{cat}}^{2}$$  = 0.70, p < .0001; $$R_{\text{AMD}}^{2}$$  = 0.63, p < .0007). In the two samples, the correspondence between subjective and objective visual acuity (as, respectively, decimal units and arbitrary decimal units) was satisfactory (concordance correlation coefficient: cataract group = 0.91 and AMD group = 0.93). Test–retest reliability of the oktotype was good for the cataract group and moderate for the AMD sample (Κ 0.81 and 0.59, respectively). The oktotype seems a promising tool to objectively assess visual acuity in noncooperating subjects with cataract or macular degeneration. Further research on other clinical conditions is needed to clarify the suitability of the procedure in the clinical setting.

  • The Optokinetic Response is effective to assess objective visual acuity in patients with cataract and age-related macular degeneration.
    International ophthalmology, 2018
    Co-Authors: Carlo Aleci, Gabriele Cossu, Elena Belcastro, Lorenzo Canavese
    Abstract:

    To estimate objective visual acuity in subjects suffering from cataract and age-related macular degeneration via the Optokinetic Response evoked by a non-conventional induction method (oktotype); in addition, to compare such objective outcome with the subjective acuity based on the ETDRS charts. Patients were presented with 13 sequences of symbols arranged horizontally to form a serial pattern, moving from left to right at a constant rate. In each sequence, the size of the stimuli was reduced progressively, while the operator checked for the disappearance of the Optokinetic Response via a small video camera mounted on the test lens frame. The minimum angular size of the serial pattern able to evoke the Optokinetic Response (MAER) was referred to as the objective visual acuity of the subject. Correlation between logMAER and logMAR was significant in the cataract and macular degeneration group ( $$R_{\text{cat}}^{2}$$  = 0.70, p 

  • A novel and cheap method to correlate subjective and objective visual acuity by using the Optokinetic Response
    International ophthalmology, 2017
    Co-Authors: Carlo Aleci, Martina Scaparrotti, Sabrina Fulgori, Lorenzo Canavese
    Abstract:

    To describe a novel Optokinetic visual acuity estimator (Oktotype) and to report the preliminary results obtained in poorly and non-collaborative subjects. 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. In the preliminary phase, three contrast levels were tested, with white noise added to the first five sequences so as to normalize the overestimate found at the lower-half range of the acuity scale. Subsequently, the correspondence between subjective and objective visual acuity was compared in 10 poorly collaborative subjects, and the agreement between Optokinetic and Teller visual acuity was measured in six non-collaborative subjects. The best agreement is provided by the minimum contrast level (20%) (R 2 = 0.74). The correspondence between the two techniques is satisfying both in the normal and in the poorly collaborative sample (concordance correlation coefficient: 0.85 and 0.83, respectively). In the non-collaborative group, the concordance correlation coefficient between Teller acuity and OKVA ranged between 0.79 (test) and 0.85 (retest). Test–retest reliability was very good for the Oktotype (K: 0.82), and better than the Teller test (K = 0.71), even if it was lower compared to Snellen acuity (K = 0.95). The Oktotype seems promising to predict Snellen visual acuity in normal and poorly collaborative subjects.

Stephen M. Highstein - One of the best experts on this subject based on the ideXlab platform.

  • A dynamical model for the vertical vestibuloocular reflex and Optokinetic Response in primate.
    Neurocomputing, 2003
    Co-Authors: Yutaka Hirata, Ichiro Takeuchi, Stephen M. Highstein
    Abstract:

    The vestibuloocular reflex (VOR) in concert with the Optokinetic Response (OKR) stabilizes vision during head motion. The VOR system characteristics are both compensatory and adaptively self-calibrated. A model was constructed to aid in the understanding of the roles of the cerebellum and other neuronal sites in the performance and adaptation of the vertical VOR. The model structure was based upon the known neuroanatomy, and model parameters were estimated using experimental data. The model can reproduce and predict eye movements and cerebellar Purkinje cell firing patterns during VOR, OKR, and various visual-vestibular mismatch paradigms.

  • A dynamic model for the vertical vestibulo-ocular reflex and Optokinetic Response in primate, Neurocomputing 52–54
    2003
    Co-Authors: Yutaka Hirata, Ichiro Takeuchi, Stephen M. Highstein
    Abstract:

    ABSTRACT The vestibuloocular reflex (VOR) in concert with the Optokinetic Response (OKR) stabilizes vision during head motion. The VOR system characteristics are both compensatory and adaptively self-calibrated. A model was constructed to aid in the understanding of the roles of the cerebellum and other neuronal sites in the performance and adaptation of the vertical VOR. The model structure was based upon the known neuroanatomy, and model parameters were estimated using experimental data. The model can reproduce and predict eye movements and cerebellar Purkinje cell firing patterns during VOR, OKR, and various visual-vestibular mismatch paradigms