The authors would like to acknowledge The Garnett Passe and Rodney Williams Memorial Foundation and the Bosch Institute Animal Behavioural Facility.

1. Animals
<ol>
	<li>Mice (C57/BL6) of ages 1, 9, and 13 months old were obtained from the Animal Resources Centre (Perth, Australia). These mice were housed in standard mouse cages in the Bosch Rodent Facility at the University of Sydney on a 12/12 hr light/dark cycle with access to food and water ad libitum. The procedures outlined below were approved by the University of Sydney Animal Ethics Committee.</li>
	<li>Bring mouse cages into the testing room prior to each test for 10 min to allow mice to acclimati...

<ol>
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V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Psychomotor+functions+in+developing+rats:+ontogenetic+approach+to+structure-function+relationships.">Psychomotor functions in developing rats: ontogenetic approach to structure-function relationships.</a> Neurosci. Biobehav. Rev. 19, 413-425 (1995).</li><li>Yu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+animal+model+for+motion+sickness+and+its+first+application+in+rodents.">A novel animal model for motion sickness and its first application in rodents.</a> Physiol. Behav. 92, 702-707 (2007).</li><li>Tung, V. 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The authors declare they have no competing financial interests.

Critical Steps within the Protocol
Previous work has shown that it is easy to overtrain mice on both the rotarod and balance beam apparatus and as a consequence, the acquisition of accurate measurements can be challenging15. For example, overtraining on the rotarod can lead to mice intentionally jumping off the dowels during both the acclimatization and trial periods, while overtraining on the balance beam can lead to more frequent stopping (exploratory behavior) and travelling in the ...

Our sense of balance is perhaps one of the most overlooked yet vital components of even the most basic motor activities including walking and turning. Balance is influenced by numerous factors including muscle strength, motor coordination and vestibular function, and it is only in the presence of vestibular neuropathies or during normal aging that the importance of a fully functioning balance system is appreciated. Disturbances to the vestibular system are often associated with experiences of vertigo or dizziness and disequilibrium resulting in an increased risk of falls and subsequent injuries1. This is particularly critical in older populations where falls are one of the leading causes of injury2.
Vestibular function tests are commonly based on the vestibular reflexes, in particular, the vestibulo-ocular (VOR) or the vestibulo-collic reflex (VCR). The VOR and VCR are essential for the stabilization of images on the retina and head position during movements of the head and body respectively. Commonly, VOR measurements require invasive implantation of search coils to measure eye movements or video tracking of eye movement3. This is challenging in mice due to the small nature of the mouse eye and the difficulty in detecting the pupil for video analysis3. As an alternative, the VCR has been used to measure stabilization of the head in response to body movements in mice without the need for invasive surgery4. Despite this, few studies focus specifically on how the vestibular system performs as a whole and more importantly how it changes during aging.
To assess overall balance performance simply and noninvasively we modified two commonly used behavioral tests. The rotarod and inclined balance beam tests assess different aspects of motor performance in rodents and in previous studies have been used in a test battery to acquire a complete profile of motor capability. This capability can be affected by disease or genetic modification, and is also sensitive to processes associated with normal development and aging5-7. Earlier work using the rotarod has shown that motor coordination in mice declines after 3 months of age8. In addition, rats show noticeable balance deficits with increasing age on the balance beam test9.
This paper describes the use of the rotarod and balance beam tests in conjunction with a vestibular stimulus in order to challenge the vestibular system and characterize the subsequent impact on balance performance in young and older mice. While the simple and noninvasive methods described are not designed as stand-alone measures of peripheral vestibular function, they do provide a useful and simple behavioral measure to compare cellular and subcellular changes at multiple stages of vestibular processing during normal aging in mice.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">Rotarod</td>
			<td style="width:71px;">IITC Life Science Inc.</td>
			<td style="width:119px;">#755</td>
			<td style="width:167px;">&#34;Rat dowels&#34; = 70 mm diameter. Do not allow ethanol contact perspex.</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:216px;">iPhone</td>
			<td style="width:71px;">Apple</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Can use any type of camera (e.g. Logitech webcam described above). Velcro fixed to the back surface for attachment to the the 3D articulated arm.</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:216px;">3D articulated arm</td>
			<td style="width:71px;">Fisso/Baitella</td>
			<td style="width:119px;">Classic 3300-28</td>
			<td style="width:167px;">Any type of stable vertical stand would be adequate. Velcro is fixed to the apical end of the arm for iPhone attachment.</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">Wooden walking beam: 1m long strip of smooth wood with a circular cross-section of 14 mm diameter</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">A range of diameters and cross section shapes can be used to suit experimental parameters</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Wooden goal box (130 x 140 x 220 mm) made from 11 mm thick boards</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="378">
			<td height="378" style="height:378px;width:216px;">Support stand made of 41 x 41 mm beams: 2 vertical beams 525 and 590 mm from ground at the start and goal ends respectively; 803 mm horizontal beam that runs along the ground directly under the walking beam; two 20 mm long beams act as &#34;feet&#34;, joining the horizontal and vertical beams at each end; a 21 x 21 x 36 mm block hewn at the apical end of the &#34;starting&#34; vertical beam; a 13 x 13 mm aperture cut out of the centre of this block, forming a tunnel which runs perpendicular to the walking beam.&#160;</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Brace all joins with small steel brackets.&#160;</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:216px;">Adjustible metal ring (13 mm wide)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Pass this through the aperture in the block, pass the starting end of the balance beam through this ring and tighten until the beam is firmly in place.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Black paint (water based)</td>
			<td style="width:71px;">Handycan</td>
			<td style="width:119px;">Acrylic Matt Black</td>
			<td style="width:167px;">2-3 coats for all wooden surfaces of the balance beam apparatus</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">Clear finish</td>
			<td style="width:71px;">Wattle Estapol</td>
			<td style="width:119px;">Polyurethane Matt</td>
			<td style="width:167px;">Single coat for all beams. Double coat for all other surfaces of the balance beam apparatus</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Foam, packaging material</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">To cushion any falls from the balance beam</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Electrical tape</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Fix webcam to roof.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">70% Ethanol, paper towels</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Clean beam and goal box between each animal.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Gauze pads/paper towels</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;">To line the floor of the goal box</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Mouse house (from home cage)</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
	</tbody>
</table>

behavioral assessment of the aging mouse vestibular system

Age related decline in balance performance is associated with deteriorating muscle strength, motor coordination and vestibular function. While a number of studies show changes in balance phenotype with age in rodents, very few isolate the vestibular contribution to balance under either normal conditions or during senescence. We use two standard behavioral tests to characterize the balance performance of mice at defined age points over the lifespan: the rotarod test and the inclined balance beam test. Importantly though, a custom built rotator is also used to stimulate the vestibular system of mice (without inducing overt signs of motion sickness). These two tests have been used to show that changes in vestibular mediated-balance performance are present over the murine lifespan. Preliminary results show that both the rotarod test and the modified balance beam test can be used to identify changes in balance performance during aging as an alternative to more difficult and invasive techniques such as vestibulo-ocular (VOR) measurements.

Rotarod
The motor performance of mice was described as the Time To Fall (TTF) recorded for each mouse over 8 trials. Using these measurements of TTF, training curves for each mouse can be plotted. Figure 2 shows examples of the motor performance of one 1 month-old mouse and one 9 month-old mouse over the course of 8 trials. These training curves show an increase in TTF during the first 3-5 trials followed by a subsequent plateau. Measurements of TTF recorded before the plateau we...

Watch this Scientific Journal Video about Behavioral Assessment of the Aging Mouse Vestibular System at JoVE.com

Behavioral Assessment of the Aging Mouse Vestibular System

Motor control and balance performance are known to deteriorate with age. This paper presents a number of standard noninvasive behavioral tests with the addition of a simple rotary stimulus to challenge the vestibular system and show changes in balance performance in a murine model of aging.

Age related decline in balance performance is associated with deteriorating muscle strength, motor coordination and vestibular function. While a number of ...

behavioral-assessment-of-the-aging-mouse-vestibular-system

Research

JoVE Journal

Behavior

16.7K vistas.  University of Sydney.  Control del motor y el rendimiento balanza se conocen a deteriorarse con la edad. Este artículo presenta una serie de pruebas de comportamiento no invasivas estándar con la adición de un estímulo rotatorio sencillo para desafiar al sistema y mostrar los cambios en el rendimiento vestibulares equilibrio en un modelo murino de envejecimiento. 