Name: Implantation of a Head Bar on Top of the Mouse Skull
Uploaded: 2023-06-23T13:40:00
Description: Watch this Scientific Journal Video about Implantation of a Head Bar on Top of the Mouse Skull at JoVE.com

implantation of a head bar on top of the mouse skull

Bewertung optokinetischer Reflexantworten bei Mäusen: Ein neues hochpräzises Protokoll

In response to visual stimuli in the environment, our eyes move to shift our gaze, stabilize retinal images, track moving targets, or align the foveae of two eyes with targets located at different distances from the observer, which are vital to proper vision1,2. Oculomotor behaviors have been widely used as attractive models of sensorimotor integration to understand the neural circuits in health and disease, at least partly because of the simplicity of the oculomotor system3. Controlled by three pairs of extraocular muscles, the eye rotates in the socket primarily around three corresponding axes: elevation and depression along the transverse axis, adduction and abduction along the vertical axis, and intorsion and extorsion along the anteroposterior axis1,2. Such a simple system allows researchers to evaluate the oculomotor behaviors of mice easily and accurately in a lab environment.
One prime oculomotor behavior is the optokinetic reflex (OKR). This involuntary eye movement is triggered by slow drifts or slips of images on the retina and serves to stabilize retinal images as an animal&#39;s head or its surroundings move2,4. The OKR, as a behavioral paradigm, is interesting to researchers for several reasons. First, it can be stimulated reliably and quantified accurately5,6. Second, the procedures of quantifying this behavior are relatively simple and standardized and can be applied to evaluate the visual functions of a large cohort of animals7. Third, this innate behavior is highly plastic5,8,9. Its amplitude can be potentiated when repetitive retinal slips occur for a long time5,8,9, or when its working partner vestibular ocular reflex (VOR), another mechanism of stabilizing retinal images triggered by vestibular input2, is impaired5. These experimental paradigms of OKR potentiation empower researchers to unveil the circuit basis underlying oculomotor learning.
Two non-invasive methods have primarily been used to evaluate the OKR in previous studies: (1) video-oculography combined with a physical drum7,10,11,12,13 or (2) arbitrary determination of head turns combined with a virtual drum6,14,15,16. Although their applications have made fruitful discoveries in understanding the molecular and circuit mechanisms of oculomotor plasticity, these two methods each have some drawbacks which limit their powers in quantitatively examining the properties of the OKR. First, physical drums, with printed patterns of black and white stripes or dots, do not allow easy and quick changes of visual patterns, which largely restricts the measurement of the dependence of the OKR on certain visual features, such as spatial frequency, direction, and contrast of moving gratings8,17. Instead, tests of the selectivity of the OKR to these visual features can benefit from computerized visual stimulation, in which visual features can be conveniently modified from trial to trial. In this way, researchers can systematically examine the OKR behavior in the multi-dimensional visual parameter space. Moreover, the second method of the OKR assay reports only the thresholds of visual parameters that trigger discernible OKRs, but not the amplitudes of eye or head movements6, 14,15,16. The lack of quantitative power thus prevents analyzing the shape of tuning curves and the preferred visual features, or detecting subtle differences between individual mice in normal and pathological conditions. To overcome the above limitations, video-oculography and computerized virtual visual stimulation had been combined to assay the OKR behavior in recent studies5,17,18,19,20. However, these previously published studies did not provide enough technical details or step-by-step instructions, and consequently it is still challenging for researchers to establish such an OKR test for their own research.
Here, we present a protocol to precisely quantify the visual feature selectivity of OKR behavior under photopic or scotopic conditions with the combination of video-oculography and computerized virtual visual stimulation. Mice are head-fixed to avoid the eye movement evoked by vestibular stimulation. A high-speed camera is used to record the ocular movements from mice viewing moving gratings with changing visual parameters. The physical size of the eyeballs of individual mice is calibrated to ensure the accuracy of deriving the angle of eye movements21. This quantitative method allows comparing OKR behavior between animals of different ages or genetic backgrounds, or monitoring its change caused by pharmacological treatments or visual-motor learning.

Autor im Rampenlicht: Ein genauer und quantitativer Ansatz zur Untersuchung der visuellen Merkmalsselektivität des optokinetischen Reflexes bei Mäusen 

Quantifizierung der visuellen Merkmalsselektivität des optokinetischen Reflexes in Mäusen

We're interested in the capacity of retinal system in health and disease mouse model. Currently, we are using optokinetic reflex or OKR insured, which is our involuntary eye movement that serves to stabilize retinal images to understand how the retinal system contributes to the adaptive plasticity in retinal innate behaviors. OKR model studies have advanced our understanding of innate behavior plasticity by demonstrating that prolonged retinal stimulation or impaired by similar ocular reflex can increase the behavior amplitude.And by investigating the underlying molecular synaptic and secretory mechanisms. We combined video oculargraphy and computerized virtual visual stimulation to precisely quantify the OKR behavior invokes by truncating with freely changing parameters. This procedure is relatively simple and can be standardized to accommodate large scale studies.Our protocol accurately analyzes to include shapes and prefer visual features, detects subtle differences in normal and pathological conditions, and also can monitor changes in OKR due to pharmacological treatments or visual motor learning. The high precision and the quantitative power make it possible to compare repetitive OKR measurements of the same eyes in longitudinal studies and their different pharmacological treatments or under neurosurpreterations. It also provides opportunities to study the neurosurpres and the circuit mechanisms of OKR plasticity.

Watch this Scientific Journal Video about Implantation of a Head Bar on Top of the Mouse Skull at JoVE.com

Implantation of a Head Bar on Top of the Mouse Skull  

Implantation eines Kopfbügels auf den Mäuseschädel

Nachdem Sie die Maus betäubt haben, legen Sie sie auf ein Heizkissen, um ihre Körpertemperatur aufrechtzuerhalten. Tragen Sie eine Schicht Gleitmittel-Augensalbe auf beide Augen auf und decken Sie sie mit Alufolie ab, um sie vor leichter Beleuchtung zu schützen. Injizieren Sie dann Carprofen subkutan in einer Dosis von 20 Milligramm pro Kilogramm, um die Schmerzen zu lindern.Befeuchten Sie das Fell auf der Oberseite des Schädels mit 4%igem Chlorhexidingluconat und rasieren Sie den Bereich. Desinfizieren Sie die exponierte Kopfhaut zweimal mit 70%igem Isopropylalkohol und Chlorhexidinalkohol. Als nächstes injizieren Sie Bupivacain subkutan an der Inzisionsstelle.Entfernen Sie dann die Kopfhaut mit einer Schere, um die dorsale Oberfläche des Schädels freizulegen, einschließlich des hinteren Stirnbeins, des Scheitelbeins und des interparietalen Knochens. Tragen Sie mehrere Tropfen 1%iges Lidocain und einen bis 100.000 Adrenalin auf den freiliegenden Schädel auf, um lokale Schmerzen und Blutungen zu reduzieren. Dann kratzen Sie den Schädel mit einer Meyhoefer-Kürette ab, um die Faszie zu entfernen, und reinigen Sie ihn mit PBS.Blasen Sie vorsichtig Druckluft auf die Schädeloberfläche, bis die Feuchtigkeit verschwunden ist und der Knochen weißlich wird. Tragen Sie dann eine dünne Schicht Sekundenkleber auf die freiliegende Oberfläche des Schädels auf, einschließlich des Randes der abgeschnittenen Kopfhaut. Gefolgt von einer Schicht Acrylharz.Platzieren Sie nun eine Kopfstange aus Edelstahl entlang der Mittellinie auf dem Schädel. Und tragen Sie mehr Acrylharz auf, beginnend mit dem Rand der Kopfleiste, bis die Basis vollständig in das Acrylharz eingebettet ist. Warten Sie ca. 15 Minuten, bis das Acrylharz ausgehärtet ist.Subkutan injizieren Sie einen Milliliter Ringer-Milchlösung. Setzen Sie die Maus dann wieder in einen Käfig, der auf einem Heizkissen steht, bis das Tier vollständig mobil ist.

Research

JoVE Journal

Neuroscience

Implantation of a Head Bar on Top of the Mouse Skull

Quantification of Visual Feature Selectivity of the Optokinetic Reflex in Mice

The optokinetic reflex (OKR) is an essential innate eye movement that is triggered by the global motion of the visual environment and serves to stabilize ...