Loss of adaptability of horizontal optokinetic response eye movements in mGluR1 knockout mice

Shutoh, Fumihiro; Katoh, Akira; Kitazawa, Hiromasa; Aiba, Atsu; Itohara, Shigeyoshi; Nagao, Soichi

doi:10.1016/s0168-0102(01)00308-x

Cited by 34 publications

(26 citation statements)

References 20 publications

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“…Alternatively, one can follow the procedure of the current study, making use of R P0 , the distance of the pupil centroid to the actual center of corneal curvature (Stahl, 2004a). In studies that do neither (e.g., (Shutoh, et al, 2002)) gain values could be over-or underestimated, depending on the selected R P and the elevation of the eye determined by the pitch of the head. For example, if one were to estimate R P from a postmortem cross section through the equator of the eye (e.g., (Remtulla and Hallett, 1985)), R P would equal R P0 .…”

Section: Practical Implications Of Results For Studies Of Eye Movemenmentioning

confidence: 99%

Eye orientation during static tilts and its relationship to spontaneous head pitch in the laboratory mouse

Oommen

Stahl

2008

Brain Research

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Both eye position and head orientation are influenced by the macular (otolith) organs, via the tilt maculo-ocular reflex (tiltMOR) and the vestibulo-collic reflexes, respectively. The mechanisms that control head position also influence the rest position of the eye, because head orientation influences eye position through the tiltMOR. Despite the increasing popularity of mice for studies of vestibular and ocular motor functions, relatively little is known in this species about tiltMOR, spontaneous orientation of the head, and their interrelationship. We used 2D video oculography to determine in C57BL/6 mice the absolute horizontal and vertical positions of the eyes over body orientations spanning 360° about the pitch and roll axes. We also determined head pitch during ambulation in the same animals. Eye elevation varied approximately sinusoidally as functions of pitch or roll angle. Over the central ±30° of pitch, sensitivity and gain in the light were 31.7°/g and 0.53, respectively. The corresponding values for roll were 31.5°/g and 0.52. Absolute positions adopted in light and darkness differed only slightly. During ambulation, mice carried the lambda-bregma plane at a downward pitch of 29°, corresponding to a horizontal eye position of 64° and a vertical eye position of 22°. The vertical position is near the center of the range of eye movements produced by the pitch tiltMOR. The results indicate the tiltMOR is robust in this species, and favor standardizing pitch orientation across laboratories. The robust tiltMOR also has significant methodological implications for the practice of pupil-tracking video oculography in this species.

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Section: Practical Implications Of Results For Studies Of Eye Movemenmentioning

confidence: 99%

Eye orientation during static tilts and its relationship to spontaneous head pitch in the laboratory mouse

Oommen

Stahl

2008

Brain Research

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“…Studies of several lines of mutant mice that lack pf-Pk LTD have provided evidence for a role of pf-Pk LTD, not just in eyeblink conditioning, but also OKR adaptation, motor learning in the VOR, and the rotorod task (Chen et al, 1996;Kishimoto et al, 2001;Shutoh et al, 2002;Koekkoek et al, 2003;Katoh et al, 2005). However, enhanced pf-Pk LTD would not necessarily enhance performance on these tasks.…”

Section: Inhibitory and Excitatory Signaling In Cerebellar Circuitsmentioning

confidence: 99%

Impaired Motor Learning in the Vestibulo-Ocular Reflex in Mice with Multiple Climbing Fiber Input to Cerebellar Purkinje Cells

Kimpo

Raymond²

2007

J. Neurosci.

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A unique feature of the cerebellar architecture is that Purkinje cells in the cerebellar cortex each receive input from a single climbing fiber. In mice deficient in the ␥ isoform of protein kinase C (PKC␥ Ϫ/Ϫ mice), this normal architecture is disrupted so that individual Purkinje cells receive input from multiple climbing fibers. These mice have no other known abnormalities in the cerebellar circuit. Here, we show that PKC␥ Ϫ/Ϫ mice are profoundly impaired in vestibulo-ocular reflex (VOR) motor learning. The PKC␥ Ϫ/Ϫ mice exhibited no adaptive increases or decreases in VOR gain at training frequencies of 2 or 0.5 Hz. This impairment was present across a broad range of peak retinal slip speeds during training. We compare the results for VOR motor learning with previous studies of the performance of PKC␥ Ϫ/Ϫ mice on other cerebellum-dependent learning tasks. Together, the results suggest that single climbing fiber innervation of Purkinje cells is critical for some, but not all, forms of cerebellum-dependent learning, and this may depend on the region of the cerebellum involved, the organization of the relevant neural circuits downstream of the cerebellar cortex, as well as the timing requirements of the learning task.

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“…In the case of the mouse, transgenic strains are also available, including many neurotransmitter receptor, metabolic and ion channel mutants, and one strain in which floccular Purkinje cell terminals are fluorescent (Sekirnjak et al 2003). Transgenics have already provided invaluable information regarding cellular mechanisms for motor learning (de Zeeuw et al 1998;Shutoh et al 2002).…”

Section: Comparison Of Model Species and Future Directionsmentioning

confidence: 99%

Learning in a Simple Motor System

Broussard¹,

Kassardjian²

2004

Learn. Mem.

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Motor learning is a very basic, essential form of learning that appears to share common mechanisms across different motor systems. We evaluate and compare a few conceptual models for learning in a relatively simple neural system, the vestibulo-ocular reflex (VOR) of vertebrates. We also compare the different animal models that have been used to study the VOR. In the VOR, a sensory signal from the semicircular canals is transformed into a motor signal that moves the eyes. The VOR can modify the transformation under the guidance of vision. The changes are persistent and share some characteristics with other types of associative learning. The cerebellar cortex is directly linked to the VOR reflex circuitry in a partnership that is present in all vertebrates, and which is necessary for motor learning. Early theories of Marr, Albus, and Ito, in which motor memories are stored solely in the cerebellar cortex, have not explained the bulk of the experimental data. Many studies appear to indicate a site of learning in the vestibular nuclei, and the most successful models have incorporated long-term memory storage in both the cerebellar cortex and the brainstem. Plausible cellular mechanisms for learning have been identified in both structures. We propose that short-term motor memory is initially stored in the cerebellar cortex, and that during consolidation of the motor memory the locus of storage shifts to include a brainstem site. We present experimental results that support our hypothesis.In many situations, inaccurate movements are worse than useless. If the movement is slow, errors can be corrected online by visual or other sensory feedback. However, rapid movements must be intrinsically accurate. This could be accomplished by hard-wiring an accurate movement, which has the obvious disadvantage that the movement cannot be readjusted for changes in downstream motor centers or (in the case of a reflex) for changes in sensory sensitivity. A better solution is to calibrate the movement by trial and error, that is, by motor learning. For our purposes, motor learning is defined as the process by which we acquire precise, coordinated movements, like those that are required in order to run, serve a tennis ball, and type accurately. Because accurate movements are necessary whenever predators must be avoided or prey captured, we can speculate that motor learning may have been one of the earliest types of associative learning to evolve. It has been demonstrated in the ventral nerve cord of insects (Horridge 1962) and is probably universal in freely-moving animals. Furthermore, because its substrate can be relatively simple and well understood, there is a real possibility of understanding motor learning both on the molecular level and on the level of brain circuitry.Motor learning is classified as procedural learning. Errors are monitored and used to guide adaptive changes without conscious awareness. Instead of learning a concept, the subject learns an accurate and appropriate motor response. Distinctions have also been made b...

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Loss of adaptability of horizontal optokinetic response eye movements in mGluR1 knockout mice

Cited by 34 publications

References 20 publications

Eye orientation during static tilts and its relationship to spontaneous head pitch in the laboratory mouse

Eye orientation during static tilts and its relationship to spontaneous head pitch in the laboratory mouse

Impaired Motor Learning in the Vestibulo-Ocular Reflex in Mice with Multiple Climbing Fiber Input to Cerebellar Purkinje Cells

Learning in a Simple Motor System

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