Video-oculography in Mice

Abstract

Eye movements are very important in order to track an object or to stabilize an image on the retina during movement. Animals without a fovea, such as the mouse, have a limited capacity to lock their eyes onto a target. In contrast to these target directed eye movements, compensatory ocular eye movements are easily elicited in afoveate animals 1,2,3,4 . Compensatory ocular movements are generated by processing vestibular and optokinetic information into a command signal that will drive the eye muscles. The processing of the vestibular and optokinetic information can be investigated separately and together, allowing the specification of a deficit in the oculomotor system. The oculomotor system can be tested by evoking an optokinetic reflex (OKR), vestibulo-ocular reflex (VOR) or a visually-enhanced vestibulo-ocular reflex (VVOR). The OKR is a reflex movement that compensates for "full-field" image movements on the retina, whereas the VOR is a reflex eye movement that compensates head movements. The VVOR is a reflex eye movement that uses both vestibular as well as optokinetic information to make the appropriate compensation. The cerebellum monitors and is able to adjust these compensatory eye movements. Therefore, oculography is a very powerful tool to investigate brain-behavior relationship under normal as well as under pathological conditions (f.e. of vestibular, ocular and/or cerebellar origin).Testing the oculomotor system, as a behavioral paradigm, is interesting for several reasons. First, the oculomotor system is a well understood neural system 5 . Second, the oculomotor system is relative simple 6 ; the amount of possible eye movement is limited by its ball-in-socket architecture ("single joint") and the three pairs of extra-ocular muscles 7 . Third, the behavioral output and sensory input can easily be measured, which makes this a highly accessible system for quantitative analysis 8 . Many behavioral tests lack this high level of quantitative power. And finally, both performance as well as plasticity of the oculomotor system can be tested, allowing research on learning and memory processes 9 .Genetically modified mice are nowadays widely available and they form an important source for the exploration of brain functions at various levels 10 . In addition, they can be used as models to mimic human diseases. Applying oculography on normal, pharmacologically-treated or genetically modified mice is a powerful research tool to explore the underlying physiology of motor behaviors under normal and pathological conditions. Here, we describe how to measure video-oculography in mice 8 .

Motor Learning Requires Purkinje Cell Synaptic Potentiation through Activation of AMPA-Receptor Subunit GluA3

“…Mice were prepared for chronic experiments (de Jeu and De Zeeuw, 2012). Eye orientation was measured using video pupil tracking (Pulnix TM-6710CL).…”

Effects of high intensity noise on the vestibular system in rats

“…The tracked pupil and the CR recorded in the extreme positions of the camera rotation were used to calculate the radius of rotation of the pupil. Angular position of the eye was calculated using the methods described by De Jeu and De Zeeuw (2012). Following the calibration, a series of rotational and translational accelerations were delivered.…”

Dissociation of locomotor and cerebellar deficits in a murine Angelman syndrome model

“…Compensatory eye movements were recorded as described before (28). In short, mice were anesthetized, and an immobilizing construction containing 2 attached nuts (3 mm each) was placed on the frontal and parietal bones using OptiBond primer and adhesive (Kerr) and Charisma (Heraeus Kulzer).…”

“…The contribution of the visual and vestibular reflex pathways can be separately quantified by providing either visual stimulation (only the screen is rotating) to trigger an optokinetic reflex (OKR) or vestibular stimulation (only the mouse is rotating) to elicit a vestibulo-ocular reflex (VOR) (for a visual explanation of these compensatory eye movement paradigms, see the cartoon in Figure 2 and ref. 28). To investigate whether AS mice showed abnormalities in gross cerebellar function, we first measured baseline OKR and VOR performance during sinusoidal visual or turntable stimulation.…”