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 d...

<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>

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.

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	<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 ...

Our technology automates a complicated behavioral analysis that can save time and serve as a springboard for many different types of studies. With our technique, the task and the reward are the same thing. There's no disconnect between performing a vague task, possibly incorrectly, and receiving a reward.Animal models provide an opportunity for testing approaches to augment recovery after a neurological injury. For example, in my lab we test approaches to augment recovery post-stroke, since there is an urgent need to develop innovative new approaches to post-stroke rehabilitation. In addition to stroke, our auto-trainer could be useful for studying motor learning before injury, as well as in models of Parkinson's, Alzheimer's, or traumatic brain injury.When a mouse reaches it's goal weight, start a training session by placing a 45 milligram pellet on the pellet surface directly in front of the slot, and allow the mouse to retrieve the pellet. When the mouse associates an open slot with being fed, use a pair of tweezers to hold a pellet in the same position that the mouse has retrieved the pellets previously. As the mouse begins to bite for the pellet, pull the pellet away approximately half a centimeter, such that the pellet is out of reach of the mouth.When the mouse extends a paw through the slot, reinforce the behavior by allowing the mouse to eat the pellet. While not instrumental to experimentation, record whether the left or right paw is preferred. As the mouse associates extending a paw with eating a pellet, further reinforce the behavior by withholding the pellet in response to attempts to retrieve the pellet with the mouth and tongue.Take care to stop your mice from successfully getting a pellet without using a paw, or they will learn bad habits that are hard to unlearn. Finalize the introduction of the desired paw-reaching behavior by placing the 45-milligram pellet just under one centimeter from the outer edge of the cage gate, such that the left or right-most point of the pellet is tangent to a line extending straight out from the edge of the cage gate slot. Then allow the mouse to attempt to retrieve the pellet, being vigilant to remove the pellet and prevent it's consumption if the mouse should attempt retrieval by some other method than paw extension.Before beginning the training session, click the Run arrow in the LabVIEW Interface of the auto-trainer and note the bait pellet sensor reading, both with and without a pellet in place. Click Stop to stop the test run and change the bait pellet sensor target to a value between those two readings. Place the modified mouse cage on the auto-trainer and affix the cage gate.Then align the pellet to the edge of the slot as in the manual procedure, and open a new training session in the LabVIEW Interface. Input the information as required to record data about the training session and click the Mouse ID field to enter the file name of each training session. Click the Total Pellets to Dispense During Routine field to control how many pellets are dispensed for a single experiment.Click the Pause After Pellet Number field to set a five second pause after the indicated pellet is removed from the diving board, and 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. Set the auto-trainer to manually record the distance at which the pellet is placed in the Reach Distance field, and click the Folder to Contain Logs field to select the file location to save the collected data. Once the information fields have been filled out, click Run 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.Once the software is set up, place the home cage of the mouse to be tested on the pedestal and click Run to allow the mouse to investigate the slot and it's new unfamiliar surroundings. Mice trained with the auto-trainer learned the prehension task and exhibit a clear increase in motor skill. This increase in skill is similar to that observed where the animal is trained manually without the use of the auto-trainer.Make sure to make the mice use their paws. If you let them think you're just letting them have food, they won't reach for you. An injury can be induced to any part of the motor pathway to determine what effects the lesion has on motor performance, and how to encourage recovery from said lesion.

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

Research

JoVE Journal

Behavior

5.5K vues.  Johns Hopkins University. Notre technologie automatise une analyse comportementale compliquée qui peut gagner du temps et servir de tremplin à de nombreux types d’études. Avec notre technique, la tâche et la récompense sont la même chose. Il n’y a pas de décalage entre l’exécution d’une tâche vague, peut-être incorrectement, et la réception d’une récompense.Les modèles animaux offrent l’occasion de tester des approches pour augmenter la récupération après une blessure neurologique. P...

Vidéo: 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 ...

Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with schizophrenia who are at familial high risk (FHR) may show similar cognitive and emotional changes. However, the neurological changes underlying the emergence of these symptoms remain unclear. This study sought to identify differences in frontal, striatal, and limbic regions in children and adolescents with FHR using functional magnetic resonance imaging. Groups of 21 children and adolescents at FHR and 21 healthy controls completed an emotional oddball task that relied on selective attention and the suppression of task-irrelevant emotional information. The standard oddball task was modified to include aversive and neutral distractors in order to examine potential group differences in both emotional and executive processing. This task was designed specifically to allow for children and adolescents to complete by keeping the difficulty and emotional image content age-appropriate. Furthermore, we demonstrate a technique for suitable fMRI registration for children and adolescent participants. This paradigm may also be applied in future studies to measure changes in neural activity in other populations with hypothesized developmental changes in executive and emotional processing.

This paper describes how to use the emotional oddball task and fMRI to measure brain activation in children and adolescents at familial high risk for schizophrenia (FHR).&#160;FMRI was used to measure differences in fronto-striato-limbic regions during an emotional oddball task. Children with FHR exhibited abnormal functional activation during adolescence.

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with ...

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 ...

Measuring Delay Discounting in Humans Using an Adjusting Amount Task

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. Delay discounting tasks are used to identify indifference points, which reflect equal preference for two dichotomous reward alternatives differing in both delay and magnitude. Indifference points are key to assessing the shape of a delay-discounting gradient because they allow us to isolate the effect of delay on value. For example, if at a 1 week delay and a maximum of $1,000, the indifference point is at $700 we know that, for that participant, a 1-week delay corresponds to a 30% reduction in value. This video outlines an adjusting amount delay-discounting task that identifies indifference points relatively quickly and is inexpensive and easy to administer. Once data have been collected, non-linear regression techniques are typically used to generate discounting curves. The steepness of the discounting curve reflects the degree of impulsive choice of a group or individual. These techniques have been used with a wide range of commodities and have identified populations that are relatively impulsive. For example, people with substance abuse problems discount delayed rewards more steeply than control participants. Although degree of discounting varies as a function of the commodity examined, discounting of one commodity correlates with discounting of other commodities, which suggests that discounting may be a persistent pattern of behavior1.

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. We outline a computer-based delay discounting task that is easy to implement and allows for the quantification of the degree of delay discounting in human participants.

Delay discounting refers to a decline in the value of a reward when it is delayed relative to when it is immediately available. Delay discounting tasks ...

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 ...