The auto-training device was constructed by Jason Dunthorn, Uri Tasch, and Dan Tasch at Step Analysis, LLC, with design input support and instructions provided by Robert Hubbard, Richard O&#39;Brien, and Steven Zeiler.
Teresa Duarte of the Champalimaud Centre for the Unknown provided valuable insight and ideas about describing and categorizing mouse reaching actions.

All methods described here have been approved by the ACUC (Animal Care and Use Committee) of the Johns Hopkins University.
1. Preparing mouse cages for use
<ol>
	<li>Create a slotted opening with dimensions of 0.8 cm width and 7 cm height from the base at the front end of each cage, as illustrated in Figure 1. This slot serves as the opening through which the animal will reach. 
	NOTE: The auto-trainer was designed for the use with the standard mouse cage dimensions (as shown in Figure 1) supplied by most animal research supply vendors. Further, the auto-trainer will easily support other cage-types.</li>
	<li>Inside each individual cage, add a platform adjacent to the slot to allow the mice to stand and reach the presented pellets. Ensure that the platform is located above the cage litter floor, approximately 3 cm in height. Use Petri dishes affixed with superglue and capped by a metal sheet approximately 10 cm x 15 cm, however, any flat surface large enough for a mouse to stand on to reach from will suffice.</li>
	<li>Create a vertical notch through the middle of the front of the cage measuring 0.8 cm across and 7 cm high that will allow a mouse to reach his paw out of the cage.</li>
	<li>From a thin sheet of metal, (approximately 2 mm thick) cut a cage gate into rectangles measuring 5 cm x 10 cm to serve as a uniform opening through which the animal is to reach. 
	NOTE: Mice may chew on plastic cages which would change the size of the opening. The mouse will reach through this 0.8 cm slot when the metallic cage gate is placed over the cage&#39;s slotted opening during testing using tape, maintaining the effective width of the slot between cages.</li>
	<li>Cover each cage&#39;s slot with tape when its mouse is not being tested to prevent litter from being expelled from the cage.</li>
</ol>
2. Introducing mice to the reaching motion
<ol>
	<li>Record each mouse&#39;s starting weight and calculate 85% of that value to find their goal weight, rounding up to 20 g if the result is less. Give them a feeding regime to bring them to and then maintain this goal weight.
	<ol>
		<li>Give each mouse 2.5 g of pellets the first day and note any change in their weight 24 h later. 
		NOTE: Weigh the mice once per day and expect a weight drop of 0.25-1 g per day.</li>
		<li>Change each mouse&#39;s daily feed as required, based on this initial change and ongoing changes in each mouse&#39;s weight, in order to induce gradual weight loss (less than 0.8 g lost per day) and then maintain the resulting goal weight. Vary between three to six 500 mg pellets (1.5 to 3.0 g) per day to be effective. 
		NOTE: Mice remain on this diet to maintain their goal weight throughout the protocol.</li>
	</ol>
	</li>
	<li>When a mouse has reached its goal weight, introduce each mouse to the concept of coming up to the gated slot for a supplementary food pellet. Start a training session by placing a 45 mg pellet on the pellet surface, directly in front of the slot, and allow each mouse to retrieve it. Most mice will take to this feeding arrangement within 1-2 days.</li>
	<li>Once the mouse associates an open slot with being fed, encourage them to reach with a paw, rather than the mouth. 
	NOTE: This is the most complex step, taking 1-2 days, and instilling counterproductive behavior in mice by mistake is very easy; please refer to the discussion section for further information and advice.
	<ol>
		<li>Using a pair of tweezers, hold a pellet in the same position the mouse has retrieved pellets previously. As the mouse begins to bite for the pellet, pull it away approximately half a centimeter such that the pellet is out of reach of its mouth. 
		NOTE: A mouse at its goal weight will attempt to retrieve the out-of-reach pellet. Whenever the mouse extends a paw through the slot, reinforce that behavior by allowing it to eat the pellet. Some mice may exhibit a preference for one paw over the other when extending for food.</li>
		<li>While not instrumental to experimentation, record whether the left or right paw is preferred. This may potentially allow for higher overall success rates in the behavioral assay; alternatively, eliminate a variable by forcing each mouse to reach with the same paw. 
		NOTE: Better results are obtained if mice use their preferred paw.</li>
		<li>As each mouse associates extending a paw with eating a pellet, further reinforce that behavior by withholding the pellet in response to attempts to retrieve the pellet with the mouth and tongue. Mice will start to comply with this arrangement over 2 to 3 days.</li>
		<li>Finalize the introduction of the desired paw reaching behavior by placing the 45 mg pellet just under 1 cm from the outer edge of the cage gate, such that the leftmost or rightmost point of the pellet (whether it is to the right or left of the cage slot from the investigator&#39;s perspective, respectively) is tangent to a line extending straight out from the edge of the cage gate&#39;s slot. Allow the mouse to attempt to retrieve the pellet, being vigilant to remove the pellet and prevent its consumption if the mouse should attempt by some other method than paw extension. 
		NOTE: When a mouse consistently extends a paw to grab at and is able to touch the provided pellet, it is ready for testing using the auto-trainer described below and associated behavioral assay. The time from na&#239;ve introductions to being prepared will vary between mice; if there are stragglers that take more than two weeks to understand, they should be excluded from the data set.</li>
	</ol>
	</li>
</ol>
3. Using the auto-trainer
NOTE: Please see Figure 1-3 and the discussion section for a full description of the hardware, software, and the physical actions of the auto-trainer.
<ol>
	<li>Prepare for the training session.
	<ol>
		<li>Calibrate the bait pellet sensor. Click the Run arrow in the LabVIEW interface and note the bait pellet sensor reading both with and without a pellet in place. Click the Stop button to stop this test run and change the bait pellet sensor target to a value between those two readings (Figure 3 and Table 2). Most lighting conditions provide a reading between 1 and 4.</li>
		<li>Place the modified mouse cage on the auto-trainer (Figure 2). Affix the cage gate ( Figure 1) and align the pellet to the edge of the slot as in the manual procedure.</li>
	</ol>
	</li>
	<li>Run the mouse&#39;s training session using the LabVIEW interface.
	<ol>
		<li>Input information as required to record data about the training session (Figure 3 and Table 2).
		<ol>
			<li>Click the Mouse ID field and type the filename of each training session using the computer&#39;s keyboard.</li>
			<li>Click the Total Pellets to Dispense During Routine field to control how many pellets are dispensed for a single experiment (usually 20 - 30). To do so, click the up and down arrows or input the number using the computer&#39;s keyboard.</li>
			<li>Click the Pause After Pellet Number field to set a 5 s pause after the indicated pellet is removed from the diving board. To do so, click the up and down arrows or input the number using the computer&#39;s keyboard.</li>
			<li>Click the Pause Length field to set a pause in between the time a pellet is removed from the diving board and the time a new pellet is dispensed. To do so, click the up and down arrows or input the number using the computer&#39;s keyboard 
			NOTE: Usually 1 s is an appropriate pause time. If the mice are anxious after each pellet is dispensed, it is advisable to increase the pause length using the Pause Length field to 5 s.</li>
			<li>Manually record the distance at which the pellet is placed in the Reach Distance field. To do so, click the up and down arrows or input the number using the computer&#39;s keyboard 
			NOTE: The Size of the Acceleration and Time Arrays is exposed for debugging purposes and may be ignored.</li>
			<li>Click the Folder to Contain Logs field to select the file location to save the collected data.</li>
			<li>Once the information fields have been filled out, click the Run button to begin the training session. The auto-trainer will dispense individual pellets and track whether they fall through the funnel until the total number of pellets has been dispensed, and the last pellet has either been retrieved or dropped by the mouse. The program will stop automatically at this point. If necessary, it can also be stopped prematurely by clicking on the Stop button.</li>
		</ol>
		</li>
		<li>Once the software is set up, place the home-cage of the mouse to be tested on the pedestal and observe the mouse so that you might gauge whether the mouse has indeed learned to attempt the required novel reaching behavior. After clicking the Run button, allow the mouse to investigate the slot and its new, unfamiliar surroundings. 
		NOTE: Similar to when introducing mice to the concept of reaching, expect some mice to be more compliant than others. Mice that have grasped the concept should try to reach within 5-10 min and will associate the movement of the auto-trainer with the presented pellet, as when they associate an uncovered slot with food in the initial stages of this protocol.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+endpoint,+descriptive,+and+kinematic+comparison+of+skilled+reaching+in+mice+(mus+musculus)+with+rats+(rattus+norvegicus).">An endpoint, descriptive, and kinematic comparison of skilled reaching in mice (mus musculus) with rats (rattus norvegicus).</a> Behavior Brain Research. 78, 101-111 (1996).</li><li>Farr, T. D., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+and+qualitative+impairments+in+skilled+reaching+in+the+mouse+(mus+musculus)+after+a+focal+motor+cortex+stroke.">Quantitative and qualitative impairments in skilled reaching in the mouse (mus musculus) after a focal motor cortex stroke.</a> Stroke. 33, 1869-1875 (2002).</li><li>Zeiler, S. R., Krakauer, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+interaction+between+training+and+plasticity+in+the+poststroke+brain.">The interaction between training and plasticity in the poststroke brain.</a> Current Opinion in Neurology. 26, 609-616 (2013).</li><li>Klein, A., Sacrey, L. A., Whishaw, I. Q., Dunnett, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+rodent+skilled+reaching+as+a+translational+model+for+investigating+brain+damage+and+disease.">The use of rodent skilled reaching as a translational model for investigating brain damage and disease.</a> Neuroscience and Biobehavioral Reviews. 36, 1030-1042 (2012).</li><li>Zeiler, S. R., 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=Medial+premotor+cortex+shows+a+reduction+in+inhibitory+markers+and+mediates+recovery+in+a+mouse+model+of+focal+stroke.">Medial premotor cortex shows a reduction in inhibitory markers and mediates recovery in a mouse model of focal stroke.</a> Stroke. 44, 483-489 (2013).</li><li>Becker, A. M., Meyers, E., Sloan, A., Rennaker, R., Kilgard, M., Goldberg, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+automated+task+for+the+training+and+assessment+of+distal+forelimb+function+in+a+mouse+model+of+ischemic+stroke.">An automated task for the training and assessment of distal forelimb function in a mouse model of ischemic stroke.</a> Journal of Neuroscience Methods. 258, 16-23 (2016).</li><li>Bruinsma, B., 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=An+automated+home-cage-based+5-choice+serial+reaction+time+task+for+rapid+assessment+of+attention+and+impulsivity+in+rats.">An automated home-cage-based 5-choice serial reaction time task for rapid assessment of attention and impulsivity in rats.</a> Psychopharmacology. , 1-12 (2019).</li><li>Francis, N. A., Kanold, P. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+operant+conditioning+in+the+mouse+home+cage.">Automated operant conditioning in the mouse home cage.</a> Frontiers in Neural Circuits. 11 (10), (2017).</li><li>Balcombe, J. P., Barnard, N. D., Sandusky, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+routines+cause+animal+stress.">Laboratory routines cause animal stress.</a> Contemporary Topics in Laboratory Animal Science. 43, 42-51 (2004).</li><li>Fenrich, K. K., 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=Improved+single+pellet+grasping+using+automated+ad+libitum+full-time+training+robot.">Improved single pellet grasping using automated ad libitum full-time training robot.</a> Behavior Brain Research. 281, 137-148 (2015).</li><li>Ng, K. L., 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=Fluoxetine+maintains+a+state+of+heightened+responsiveness+to+motor+training+early+after+stroke+in+a+mouse+model.">Fluoxetine maintains a state of heightened responsiveness to motor training early after stroke in a mouse model.</a> Stroke. 46 (10), 2951-2960 (2015).</li><li>Whishaw, I. Q., Suchowersky, O., Davis, L., Sarna, J., Metz, G. A., Pellis, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impairment+of+pronation,+supination,+and+body+co-ordination+in+reach-to-grasp+tasks+in+human+parkinson's+disease+(pd)+reveals+homology+to+deficits+in+animal+models.">Impairment of pronation, supination, and body co-ordination in reach-to-grasp tasks in human parkinson's disease (pd) reveals homology to deficits in animal models.</a> Behavior Brain Research. 133, 165-176 (2002).</li><li>Dobrossy, M. D., Dunnett, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+environment+and+experience+on+neural+grafts.">The influence of environment and experience on neural grafts.</a> Nature Review Neuroscience. 2, 871-879 (2001).</li><li>Alaverdashvili, M., Foroud, A., Lim, D. H., Whishaw, I. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&amp;#34;Learned+baduse&amp;#34;+limits+recovery+of+skilled+reaching+for+food+after+forelimb+motor+cortex+stroke+in+rats:+A+new+analysis+of+the+effect+of+gestures+on+success.">&amp;#34;Learned baduse&amp;#34; limits recovery of skilled reaching for food after forelimb motor cortex stroke in rats: A new analysis of the effect of gestures on success.</a> Behavior Brain Research. 188, 281-290 (2008).</li></ol>

Dan Tasch and Uri Tasch of Step Analysis, LLC have manufactured auto-trainer device with payment from Richard J. O'Brien and Steven R. Zeiler.

Our auto-trainer evaluates forelimb reach-to-grasp (prehension) in an automated manner. To achieve this endpoint, many of the parameters designed for the mouse prehension task, including pellet placement, pellet size, and training criteria, have been iterated over several years and adapted from prior protocols2,5,6. The advancement here is the automation of the task using a robot that allows home-cage housing. Home-cage housing ...

Methods to experimentally test a motor skill pre- and post- neurological injury as well as modulate the timing, amount, and type of motor training are important to translational research. Over the last decade, mice, because of the attendant ease of genetic manipulation, have become a popular model system in which to elucidate the mechanisms of motor learning pre- and post- injury. However, behavioral assays in mice have not been optimized in the same way that such assays have been for other mammals (especially rats). Further, there are important differences between the behavior of a mouse and a rat that strongly suggest training the two species in different manners1,2.
Skilled prehensile movements use a hand/paw to place food in the mouth, to manipulate an object, or to use a tool. Indeed, reaching to grasp various objects in daily life is a fundamental function of upper limbs and the reach-to-eat act is a form of prehension that many mammals use. Many of the genetic, physiological, and anatomic changes underpinning prehensile skill acquisition have been well defined in the field3. In translating preclinical findings to clinical outcomes, one needs a relevant test that is efficient and reproducible. Studies of rodent and human reaching demonstrate that prehension behavior is similar in humans and in animals4. Accordingly, these similarities suggest that prehension testing can serve as a translational model for investigating motor learning as well as impairments and treatments of human disease. Therefore, evaluating prehension in mice can offer a powerful tool in translational research studying both health and disease states4.
Unfortunately, the prehension task in mice, even for a small-scale laboratory setting, can be laborious and time consuming. To alleviate this problem, we describe here an automated version of the prehension task. The described task requires mice to extend a single paw through the mouse's home cage frontal slot, pronate the extended paw, grasp the food pellet reward, and pull the pellet back to the cage interior for consumption. The resulting data is presented as either a prehension success or failure. This automation successfully records the data and reduces the burden and time with which researchers must engage the task.

<table border="0" cellpadding="0" cellspacing="0" style="width:1319px;" width="1318">
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:318px;">ABS Filament</td>
			<td style="width:242px;">Custom 3D Printed</td>
			<td style="width:166px;">N/A</td>
			<td style="width:595px;">utilized for pellet holder, frame, arm and funnel</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">ABS Sheet</td>
			<td>McMaster-Carr</td>
			<td>8586K581</td>
			<td>3/8&#34; thickness; used for platform compononents, positioning stand guides and base</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Adruino Mini</td>
			<td>Adruino</td>
			<td>A000087</td>
			<td>nano version also compatiable as well as other similar microcontrollers</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Bench-Top Adjustable-Height Positioning Stand</td>
			<td>McMaster-Carr</td>
			<td>9967T43</td>
			<td>35 lbs. load capacity</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Clear Acrylic Round Tube</td>
			<td>McMaster-Carr</td>
			<td>8532K14</td>
			<td>ID 3/8&#34;</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Low-Carbon&#160;Steel Wire</td>
			<td>McMaster-Carr</td>
			<td>8855K14</td>
			<td>0.148&#34;&#160;diameter</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Pellet Dispenser</td>
			<td>Lafayette Instrument: Neuroscience</td>
			<td>80209-45</td>
			<td>with 45 mg interchangeable pellet size wheel and optional stand</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Photointerrupter Breakout Board&#160;</td>
			<td>SparkFun</td>
			<td>BOB-09322 ROHS</td>
			<td>designed for Sharp GP1A57HRJ00F</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Reflective Object Sensor</td>
			<td>Fairchild Semiconductor</td>
			<td>QRD1113</td>
			<td>phototransistor output</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Servo Motor</td>
			<td>SparkFun</td>
			<td>S8213</td>
			<td>generic metal gear (micro size)</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Transmissive Photointerrupter</td>
			<td>Sharp</td>
			<td>GP1A57HRJ00F</td>
			<td>gap: 10 mm, slit: 1.8 mm</td>
		</tr>
	</tbody>
</table>

evaluating skilled prehension in mice using an auto-trainer

We describe a method to introduce na&#239;ve mice to a novel prehension (reach-to-grasp) task. Mice are housed singly in cages with a frontal slot that permits the mouse to reach out of its cage and retrieve food pellets. Minimal food restriction is employed to encourage the mice to perform the food retrieval from the slot. As the mice begin to associate coming to the slot for food, the pellets are manually pulled away to stimulate extension and pronation of their paw to grasp and retrieve the pellet through the frontal slot. When the mice begin to reach for the pellets as they arrive at the slot, the behavioral assay can be performed by measuring the rate at which they successfully grasp and retrieve the desired pellet. They are then introduced to an auto-trainer that automates both the process of providing food pellets for the mouse to grasp, and the recording of successful and failed reaching and grasping attempts. This allows for the collection of reaching data for multiple mice with minimal effort, to be used in experimental analysis as appropriate.

In general, it is recommended that each training session consist of about 20-30 trials, which may be set by the user, run automatically by the auto-trainer and saved into a single log file per session and mouse. Each trial can be run consecutively, right after the other, with 2-5 s of pause. Mice trained on the auto-trainer exhibit an increase in skill over 10 training sessions.
To compare the utility of the auto-trainer to manu...

Watch this Scientific Journal Video about Evaluating Skilled Prehension in Mice Using an Auto-Trainer at JoVE.com

Evaluating Skilled Prehension in Mice Using an Auto-Trainer

Method to assess the impact of training on motor skills is a useful tool. Unfortunately, most behavioral assessments can be labor intensive and/or expensive.We describe here a robotic method of assessing prehension (reach-to-grasp) skill in mice.

We describe a method to introduce na&#239;ve mice to a novel prehension (reach-to-grasp) task. Mice are housed singly in cages with a frontal slot that ...

evaluating-skilled-prehension-in-mice-using-an-auto-trainer

Research

JoVE Journal

Behavior

5.6K Views.  Johns Hopkins University. Method to assess the impact of training on motor skills is a useful tool. Unfortunately, most behavioral assessments can be labor intensive and/or expensive.We describe here a robotic method of assessing prehension (reach-to-grasp) skill in mice. 

Video: Evaluating Skilled Prehension in Mice Using an Auto-Trainer

Nest Building as an Indicator of Health and Welfare in Laboratory Mice

The minimization and alleviation of suffering has moral and scientific implications. In order to mitigate this negative experience one must be able to identify when an animal is actually in distress. Pain, illness, or distress cannot be managed if unrecognized. Evaluation of pain or illness typically involves the measurement of physiologic and behavioral indicators which are either invasive or not suitable for large scale assessment. The observation of nesting behavior shows promise as the basis of a species appropriate cage-side assessment tool for recognizing distress in mice. Here we demonstrate the utility of nest building behavior in laboratory mice as an ethologically relevant indicator of welfare. The methods presented can be successfully used to identify thermal stressors, aggressive cages, sickness, and pain. Observation of nest building behavior in mouse colonies provides a refinement to health and well-being assessment on a day to day basis.

We demonstrate the utility of nest building behavior in laboratory mice as an indicator of welfare. Nest scoring is a sensitive technique that is altered by temperature, illness, and aggression. The time to integrate into nest test (TINT) is a simple cage-side assessment that can detect postoperative pain.

The minimization and alleviation of  suffering has moral and scientific implications. In order to mitigate this  negative experience one must be able to ...

The Modified Hole Board - Measuring Behavior, Cognition and Social Interaction in Mice and Rats

This protocol describes the modified hole board (mHB), which combines features from a traditional hole board and open field and is designed to measure multiple dimensions of unconditioned behavior in small laboratory mammals (e.g., mice, rats, tree shrews and small primates). This paradigm is a valuable alternative for the use of a behavioral test battery, since a broad behavioral spectrum of an animal&#8217;s behavioral profile can be investigated in one single test.
The apparatus consists of a box, representing the &#8216;protected&#8217; area, separated from a group compartment. A board, on which small cylinders are staggered in three lines, is placed in the center of the box, representing the &#8216;unprotected&#8217; area of the set-up. The cognitive abilities of the animals can be measured by baiting some cylinders on the board and measuring the working and reference memory. Other unconditioned behavior, such as activity-related-, anxiety-related- and social behavior, can be observed using this paradigm. Behavioral flexibility and the ability to habituate to a novel environment can additionally be observed by subjecting the animals to multiple trials in the mHB, revealing insight into the animals&#8217; adaptive capacities.
Due to testing order effects in a behavioral test battery, na&#239;ve animals should be used for each individual experiment. By testing multiple behavioral dimensions in a single paradigm and thereby circumventing this issue, the number of experimental animals used is reduced. Furthermore, by avoiding social isolation during testing and without the need to food deprive the animals, the mHB represents a behavioral test system, inducing if any, very low amount of stress.

This protocol describes the modified hole board, which is a behavioral test set-up that comprises the characteristics of an open field and a traditional hole board. This set-up enables the differential analysis of unconditioned behavior of small laboratory mammals as well as the analysis of cognitive abilities.

This protocol describes the modified hole board (mHB), which combines features from a traditional hole board and open field and is designed to measure ...

A Protocol for Housing Mice in an Enriched Environment

Environmental enrichment (EE) is a housing environment for mice that boosts mental and physical health compared to standard laboratory housing. Our recent studies demonstrate that environmental enrichment decreases adiposity, increases energy expenditure, resists diet induced obesity, and causes cancer remission and inhibition in mice. EE typically consists of larger living space, a variety of &#8216;toys&#8217; to interact with, running wheels, and can include a number of other novel environmental changes. All of this fosters a more complex social engagement, cognitive and physical stimulations. Importantly, the toy location and type of toy is changed regularly, which encourages the mice to adapt to a frequently changing and novel environment. Many variables can be manipulated in EE to promote health effects in mice. Thus these approaches are difficult to control and must be properly managed to successfully replicate the associated phenotypes. Therefore, the goal of this video is to demonstrate how EE is properly set up and maintained to assure a complex, challenging, and controlled environment so that other researchers can easily reproduce the protective effects of EE against obesity and cancer.

Environmental enrichment for mice requires a complex and challenging setup, as well as comprehensive husbandry and handling techniques to assure robust metabolic and anti-cancer effects in the mice. This protocol provides detailed procedures to reproduce the above mentioned effects in mice.

Environmental enrichment (EE) is a housing environment for mice that boosts mental and physical health compared to standard laboratory housing. Our recent ...

Quantifying Social Motivation in Mice Using Operant Conditioning

In this protocol, social motivation is measured in mice through a pair of operant conditioning paradigms. To conduct the experiments, two-chambered shuttle boxes were equipped with two operant levers (left and right) and a food receptacle in one chamber, which was then divided from the second chamber by an automated guillotine door covered by a wire grid. Different stimulus mice, rotated across testing days, served as a social stimulus behind the wire grid, and were only visible following the opening of the guillotine door. Test mice were trained to lever press in order to open the door and gain access to the stimulus partner for 15 sec. The number of lever presses required to obtain the social reward progressively increased on a fixed schedule of 3. Testing sessions ended after test mice stopped lever pressing for 5 consecutive minutes. The last reinforced ratio or breakpoint can be used as a quantitative measure of social motivation. For the second paradigm, test mice were trained to discriminate between left and right lever presses in order to obtain either a food reward or the social reward. Mice were rewarded for every 3 presses of each respective lever. The number of food and social rewards can be compared as a measurement of the value placed upon each reward. The ratio of each reward type can also be compared between mouse strains and the change in this ratio can be monitored within testing sessions to measure satiation with a given reward type. Both of these operant conditioning paradigms are highly useful for the quantification of social motivation in mouse models of autism and other disorders of social behavior.

This article describes a new protocol for the quantitative measurement of social motivation in mice using operant conditioning for a social reward. The protocol is useful for the measurement of social motivation in mouse models of autism and other disorders of social behavior.

In this protocol, social motivation is measured in mice through a pair of operant conditioning paradigms. To conduct the experiments, two-chambered ...

Acquisition of a High-precision Skilled Forelimb Reaching Task in Rats

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor learning and execution is of critical importance in order to understand the principles and processes that underlie motor function. Here we present a paradigm to study movement acquisition within a daily session of training (within-session) representing the fast learning component and primary acquisition as well as skilled motor learning over several training sessions (between-session) representing the slow learning component and consolidation of the learned task. This behavioral paradigm increases the degree of difficulty and complexity of the motor skill task due to two features: First, the animal realigns its body prior to each pellet retrieval forcing renewed orientation and preventing movement execution from the same angle. Second, pellets are grasped from a vertical post that matches the diameter of the pellet and is placed in front of the cage. This requires a precise grasp for successful pellet retrieval and thus prevents simple pulling of the pellet towards the animal. In combination with novel genetics, imaging and electrophysiological technologies, this behavioral method will aid to understand the morphological, anatomical and molecular underpinnings of motor learning and memory.

A paradigm is presented to analyze the acquisition of a high-precision skilled forelimb reaching task in rats.

Movements are the main measurable output of central nervous system function. Developing behavioral paradigms that allow detailed analysis of motor ...

Determining Ultrasonic Vocalization Preferences in Mice using a Two-choice Playback Test

Mice emit ultrasonic vocalizations (USVs) during a variety of conditions, such as pup isolation and adult social interactions. These USVs differ with age, sex, condition, and genetic background of the emitting animal. Although many studies have characterized these differences, whether receiver mice can discriminate among objectively different USVs and show preferences for particular sound traits remains to be elucidated. To determine whether mice can discriminate between different characteristics of USVs, a playback experiment was developed recently, in which preference responses of mice to two different USVs could be evaluated in the form of a place preference.
First, USVs from mice were recorded. Then, the recorded USVs were edited, trimmed accordingly, and exported as stereophonic sound files. Next, the USV amplitudes generated by the two ultrasound emitters used in the experiment were adjusted to the same sound pressure level. Nanocrystalline silicon thermo-acoustic emitters were used to play the USVs back. Finally, to investigate the preference of subject mice to selected USVs, pairs of two differing USV signals were played back simultaneously in a two-choice test box. By repeatedly entering a defined zone near an ultrasound emitter and searching the wire mesh in front of the emitter, the mouse reveals its preference for one sound over another. This model allows comparing the attractiveness of the various features of mouse USVs, in various contexts.

Ultrasonic vocalizations (USVs) in mice differ depending on age, sex, condition, and genetic background. Using two ultrasound emitters broadcasting simultaneously in different locations, this two-choice test can evaluate murine recognition and preference responses to different characteristics of USVs.

Mice emit ultrasonic vocalizations (USVs) during a variety of conditions, such as pup isolation and adult social interactions. These USVs differ with age, ...

An Operant Intra-/Extra-dimensional Set-shift Task for Mice

Alterations in executive control and cognitive flexibility, such as attentional set-shifting abilities, are core features of several neuropsychiatric diseases. The most widely used neuropsychological tests for the evaluation of attentional set-shifting in human subjects are the Wisconsin Card Sorting Test (WCST) and the CANTAB Intra-/Extra-dimensional set shift task (ID/ED). These tasks have proven clinical relevance and have been modified and successfully adapted for research in animal models. However, currently available tasks for rodents present several limitations, mainly due to their manual-based testing procedures, which are hampering translational advances in psychiatric medicine. To overcome these limitations and to better mimic the original version in primates, we present the development of a novel operant-based two-chamber ID/ED "Operon" task for rodents. We demonstrated the effectiveness of this novel task to measure different facets of cognitive flexibility in mice including attentional set formation and shifting, and reversal learning. Moreover, we show the high flexibility of this task in which three different perceptual dimensions can be manipulated with a high number of stimuli cues for each dimension. This novel ID/ED Operon task can be an effective preclinical tool for drug testing and/or large genetic screening relevant to the study of executive dysfunction and cognitive symptoms found in psychiatric disorders.

Attentional set-shifting cognitive abnormalities are a core feature of many psychiatric diseases. Here, we present the development of a novel automatic system for the effective study of attentional set-shifting abilities, executive functions and other cognitive abilities in mice with high translational validity to human studies.

Alterations in executive control and cognitive flexibility, such as attentional set-shifting abilities, are core features of several neuropsychiatric ...

Reinstatement of Drug-seeking in Mice Using the Conditioned Place Preference Paradigm

The present protocol describes the Conditioned Place Preference (CPP) as a model of relapse in drug addiction. In this model, animals are first trained to acquire a conditioned place preference in a drug-paired compartment, and after the post-conditioning test, they perform several sessions to extinguish the established preference. The CPP permits the evaluation of the conditioned rewarding effects of drugs related to environmental cues. Then, the extinguished CPP can be robustly reinstated by the non-contingent administration of a priming dose of the drug, and by exposure to stressful stimuli. Both methods will be explained here. When the animal reinitiates the behavioral response, a reinstatement of the conditioned reward is considered to have taken place.
The main advantages of this protocol are that it is non-invasive, inexpensive, and simple with good validity criteria. In addition, it allows the study of different environmental manipulations, such as stress or diet, which can modulate relapse into drug seeking behaviors. However, one limitation is that if the researcher aims to explore the motivation and primary reinforcing effects of the drug, it should be complemented with self-administration procedures, as they involve operant responses of animals.

This protocol describes the Conditioned Place Preference (CPP) as a model of relapse. This procedure permits the measurement of relapse in laboratory animals, considering the impact of drug-associated environmental cues as craving and relapse in abstaining addicts is currently the focus of drug-abuse treatment programs.

The present protocol describes the Conditioned Place Preference (CPP) as a model of relapse in drug addiction. In this model, animals are first trained to ...

Systematic Assessment of Well-Being in Mice for Procedures Using General Anesthesia

In keeping with the 3R Principle (Replacement, Reduction, Refinement) developed by Russel and Burch, scientific research should use alternatives to animal experimentation whenever possible. When there is no alternative to animal experimentation, the total number of laboratory animals used should be the minimum needed to obtain valuable data. Moreover, appropriate refinement measures should be applied to minimize pain, suffering, and distress accompanying the experimental procedure. The categories used to classify the degree of pain, suffering, and distress are non-recovery, mild, moderate, or severe (EU Directive 2010/63). To determine which categories apply in individual cases, it is crucial to use scientifically sound tools.
The well-being-assessment protocol presented here is designed for procedures during which general anesthesia is used. The protocol focuses on home cage activity, the Mouse Grimace Scale, and luxury behaviors such as burrowing and nest building behavior as indicators of well-being. It also uses the free exploratory paradigm for trait anxiety-related behavior. Fecal corticosterone metabolites as indicators of acute stress are measured over the 24-h post-anesthetic period.
The protocol provides scientifically solid information on the well-being of mice following general anesthesia. Due to its simplicity, the protocol can easily be adapted and integrated in a planned study. Although it does not provide a scale to classify distress in categories according to the EU Directive 2010/63, it can help researchers estimate the degree of severity of a procedure using scientifically sound data. It provides a way to improve the assessment of well-being in a scientific, animal-centered manner.

We developed a protocol to assess well-being in mice during procedures using general anesthesia. A series of behavioral parameters indicating levels of well-being as well as glucocorticoid metabolites were analyzed. The protocol can serve as a general aid to estimate the degree of severity in a scientific, animal-centered manner.

In keeping with the 3R Principle (Replacement, Reduction, Refinement) developed by Russel and Burch, scientific research should use alternatives to animal ...

Evaluating the Anti-depression Effect of Xiaoyaosan on Chronically-stressed Mice

In addition to the standardized use of antidepressant medications and psychotherapy, the usage of traditional Chinese medicine has lead to an overall improvement of patients with major depressive disorder (MDD). Therefore, the purpose of this study was to establish the mouse depressive model, observe the behavior changes associated with chronic unpredictable mild stress (CUMS), and then evaluate the anti-depression effect of Xiaoyaosan. Mice were randomly divided into four groups: a control group, a model group, a treatment group with Xiaoyaosan, and a treatment group with fluoxetine. All mice were individually kept in cages, and depression was induced in the mice by exposing them to several designed manipulations of CUMS for 21 days, as described in the protocol. Mice in the control group and model group received 0.5 mL of distilled water, while mice in the treatment groups received either Xiaoyaosan (0.25 g/kg/day) or fluoxetine (2.6 mg/kg/day). The drugs used in the study were given intragastrically daily during the entire three weeks. To estimate the depressive-like behaviors, a series of parameters including the coat state, body weight, open field test score, and sucrose preference test score were recorded. Data analysis showed that behaviors of model mice were significantly changed compared to behaviors of mice in the control group, which were improved by the treatment of Xiaoyaosan and fluoxetine. The current findings demonstrated the anti-depression effects of Xiaoyaosan on the behaviors of CUMS-induced mice and revealed that compounds from the Xiaoyaosan prescription may be worthwhile for treating depression, considering their beneficial effects on depressive-like behaviors.

Here, we present a protocol to establish the mouse depressive model, observe the behavior changes associated with chronic unpredictable mild stress (CUMS), and evaluate the anti-depression effect of Xiaoyaosan.

In addition to the standardized use of antidepressant medications and psychotherapy, the usage of traditional Chinese medicine has lead to an overall ...