Name: investigating migraine-like behavior using light aversion in mice
Uploaded: 2021-08-11T15:00:00
Description: Watch this Scientific Journal Video about Investigating Migraine-Like Behavior Using Light Aversion in Mice at JoVE.com

This work was supported by grants from the NIH NS R01 NS075599 and&#160;RF1 NS113839. The contents do not represent the views of VA or the United States Government.

Animal procedures were approved by the University of Iowa Animal Care and Use Committee and performed in compliance with the standards set by the National Institutes of Health.
1. Light/dark assay
<ol>
	<li>Light/dark chamber apparatus (see Table of Materials) setup. All the equipment in this section is commercially available.
	<ol>
		<li>On a shelf, place the sound-attenuating cubicle (interior: 59.7 x 38 x 35.6 cm in W x H x D) containing a pull-out drawer for easy access ...

The light/dark assay is widely used to assess anxiety-like behavior12. The assay relies on the innate aversion of mice to light and their drive to explore when placed into a novel environment (light zone). However, as we report here, this assay can also be used to assess light-aversive behavior as well.
It is critical to consider the number and necessity of pre-exposures prior to testing. This depends on the mouse strain or model. For example, in our light/dark assay pr...

Migraine is a prevalent neurological disease, affecting approximately 17% of Americans1 and is the second leading cause of disability globally2,3. Patients experience headache that lasts 4-72 hours accompanied with at least one of the following symptoms: nausea and/or vomiting, or photophobia and phonophobia4. Recent advances in the development of calcitonin gene-related peptide (CGRP) antibodies that are now FDA approved have begun a new era for migraine treatment5,6,7. These antibodies block either CGRP or its receptor and prevent migraine symptoms in approximately 50% of migraine patients7. Within the past year, two small-molecule antagonists of the CGRP receptor have also been FDA approved for abortive treatment of migraine, and two more are in the pipeline8. Despite this therapeutic progress, mechanisms by which migraine attacks occur still remain elusive. For example, the sites of CGRP action are not known. The efficacy of therapeutic antibodies that do not appreciably cross the blood-brain barrier suggests that CGRP acts at peripheral sites, such as the meninges and/or trigeminal ganglia. However, we cannot rule out central actions at circumventricular organs, which lack a blood-brain barrier9. At least for photophobia, we think this is less likely given our results with light aversion using transgenic nestin/hRAMP1 mice in which hRAMP1 is overexpressed in the nervous tissue10. Understanding mechanisms of migraine pathophysiology will provide new avenues to the development of migraine therapeutics.
Preclinical animal models are critical to understanding disease mechanisms and the development of new drugs. However, migraine assessment in animals is challenging since animals cannot verbally report their sensations of pain. Given the fact that 80-90% of migraine patients exhibit photophobia11, light aversion is considered to be an indicator of migraine in animal models. This led to the need to develop an assay to assess light aversion in mice.
The light/dark assay contains a light zone and a dark zone. It is widely used for measuring anxiety in mice based on their spontaneous exploration of novel environments that is countered by their innate aversion to light12. Some studies set 1/3 of the chamber as the dark zone, while others set 1/2 of the chamber as the dark zone. The former setting is often used to detect anxiety13. While we initially chose equally sized light/dark chambers, we have not compared the two relative sizes. We can comment that the overall size of both chambers is not a major factor since the initial testing box14 was considerably larger than the subsequent apparatus15, yet results were essentially the same.
Two critical modifications to this light/dark assay to assess light aversion were: the testing condition and the light intensity (Figure 1). First, mice are pre-exposed to the light/dark chamber to reduce exploratory drive16 (Figure 1A). The necessity and times of pre-exposures depend on mouse strains and models. Wildtype C57BL/6J mice usually require two pre-exposures10, while only one pre-exposure for CD1 mice is sufficient17. In this manner, light-aversive behavior can be unmasked in these two mouse strains. Second, the chamber lighting has been adapted to include an adjustable range of light intensities from dim (55 lux) to bright (27,000 lux) where 55 lux is comparable to a dark overcast day, and 27,000 lux is comparable to a bright sunny day in the shade10. We have found that the required light intensity varies with the strain and genetic model. For this reason, individuals should first assess the minimum light intensity for their experimental paradigm.
Even with these modifications to the assay, which can reveal a light-aversive phenotype, it is necessary to test anxiety-like behavior to distinguish between light aversion due to light alone versus due to anxiety. The open field assay is a traditional way to measure anxiety based on the spontaneous exploration of novel environments. It differs from the light/dark assay in that the exploratory drive is countered by the innate aversion to unprotected open spaces. Both the center and edges of the chamber are in the light, so the open field assay is a light-independent anxiety assay. Thus, the combination of the light/dark and open field assays enables us to distinguish between light aversion due to an avoidance of light versus an overall increase in anxiety.
CGRP is a multifunctional neuropeptide that regulates vasodilation, nociception, and inflammation18. It is widely expressed in the peripheral and central nervous systems. It plays an important role in migraine pathophysiology18. However, the mechanism underlying CGRP action in migraine is unclear. By utilizing the light/dark and open field assays with this modified test paradigm, we were able to identify light-aversive behavior in mice following peripheral10,16 (Figure 2) and central14,15,16,19 CGRP administration. In addition to neuropeptides, the identification of brain regions involved in light aversion is also important in understanding migraine pathophysiology. The posterior thalamic nuclei are an integrative brain region for pain and light processing19, and the thalamus is activated during migraine20. Thus, we targeted posterior thalamic nuclei by injecting adeno-associated virus (AAV) containing channelrhodopsin-2 (ChR2) or eYFP into this region. By combining this optogenetic approach with these two assays, we demonstrated that optical stimulation of ChR2-expressing neurons in the posterior thalamic nuclei induced light aversion19 (Figure 3). In this experiment, given the dramatic effect on the evoked light aversion in these optogenetically manipulated mice, pre-exposures to the chamber were skipped.

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			<td>Activity monitor</td>
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			<td>Customized acrylic shelf</td>
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			<td>For adjusting the height of the LED panel</td>
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			<td>Dark box insert</td>
			<td>Med Assoc. Inc</td>
			<td>ENV-511</td>
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			<td>DC power supply</td>
			<td>Med Assoc. Inc</td>
			<td>SG-500T</td>
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			<td>DC regulated power supply</td>
			<td>Med Assoc. Inc</td>
			<td>SG-506</td>
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			<td>Fiber-optic cannula</td>
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			<td>MFC_200/ 240-0.22_4.5mm_ZF1.25_FLT</td>
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			<td>Germicidal disposable wipes</td>
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			<td>Connecting to LED panel</td>
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			<td>IR controller power cable</td>
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			<td>Modified LED light panel</td>
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			<td>Seamless open field chamber</td>
			<td>Med Assoc. Inc</td>
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			<td>Sound-attenuating cubicle</td>
			<td>Med Assoc. Inc</td>
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			<td>Stand and clamp</td>
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			<td>Three 16-beam IR arrays</td>
			<td>Med Assoc. Inc</td>
			<td>ENV-256</td>
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investigating migraine-like behavior using light aversion in mice

Migraine is a complex neurological disorder characterized by headache and sensory abnormalities, such as hypersensitivity to light, observed as photophobia. Whilst it is impossible to confirm that a mouse is experiencing migraine, light aversion can be used as a behavioral surrogate for the migraine symptom of photophobia. To test for light aversion, we utilize the light/dark assay to measure the time mice freely choose to spend in either a light or dark environment. The assay has been refined by introducing two critical modifications: pre-exposures to the chamber prior to running the test procedure and adjustable chamber lighting, permitting the use of a range of light intensities from 55 lux to 27,000 lux. Because the choice to spend more time in the dark is also indicative of anxiety, we also utilize a light-independent anxiety test, the open field assay, to distinguish anxiety from light-aversive behavior. Here, we describe a modified test paradigm for the light/dark and open field assays. The application of these assays is described for intraperitoneal injection of calcitonin gene-related peptide (CGRP) in two mouse strains and for optogenetic brain stimulation studies.

This behavioral test paradigm is designed to test light-aversive behavior. It can be performed using both na&#239;ve wildtype mice and optogenetic mice to investigate light aversion in real time during the stimulation of a targeted neuronal population.
This procedure has been used to study the effect of peripheral CGRP treatment in CD1 and C57BL/6J mice10,16 and optical stimulation of neurons in the posterior thalamic nuclei in C57BL/6...

Watch this Scientific Journal Video about Investigating Migraine-Like Behavior Using Light Aversion in Mice at JoVE.com

Investigating Migraine-Like Behavior Using Light Aversion in Mice

Rodents are not able to report migraine symptoms. Here, we describe a manageable test paradigm (light/dark and open field assays) to measure light aversion, one of the most common and bothersome symptoms in patients with migraines.

Migraine is a complex neurological disorder characterized by headache and sensory abnormalities, such as hypersensitivity to light, observed as ...

This method provides a preclinical behavioral surrogate for photophobia, which is a chief complaint of migraine patients. The main advantage of this technique is that the detection is automatic thus very convenient. Also, light aversion and anxiety can be distinguished by conducting these tests.On day one, turn the light/dark assay apparatus on. Set the light intensity to 27, 000 lux. Put the dark insert into light/dark chamber.Open the tracking software and set up a new protocol. In the new protocol setting, set the duration to 30 minutes. In the new analysis setting, set data bins by duration to 300 seconds.In the new zone setting, choose predefined zones. Choose two, and then horizontal. Check if the chamber is divided into two equal sized zones horizontally for recording.Prior to the testing, habituate the mice to the testing room for one hour, keeping the room light on so as not to disturb the mouses circadian rhythm. Ensure all the equipment for the light/dark assay is turned on allowing the mice to fully acclimate to the testing room environment. Select acquire data, enter the mouse IDs and start the protocol.Pull the drawer outside of the sound attenuating cubicle to access the light/dark chamber and the dark insert. Gently place a mouse in the light zone of the chamber and push the drawer inside the cubicle. Ensure that the software detects the mouse immediately and begins to record activity.Wait for the recording to automatically stop after 30 minutes. Return the mouse to its home cage. Clean the chamber and dark insert using alcohol odor germicidal disposable wipes to eradicate any olfactory cues left by the previous mouse.On day four, repeat all the steps that were performed on day one. On day seven, repeat the steps performed on day one, but only until the habituation of the mice. After the habituation, administer the mice with CGRP intraperitoneal.Then return mice to their home cages. After 30 minutes, resume the protocol and run the mouse in the light/dark chamber as mentioned earlier. Clean the chamber and dark insert as described previously.On day 10, repeat all the steps performed on day one. Turn the apparatus on and set the light intensity to 27, 000 lux. Open the tracking software and set up a new protocol as demonstrated previously.In the new zone settings, choose one followed by center. Set the periphery as 3.97 centimeters and the center as 19.05 by 19.05 centimeters. Habituate the mice to the testing room as demonstrated previously.Administer the mice with CGRP intraperitoneal. Return the mice to their home cages. After 30 minutes, start the protocol.Pull the pullout drawer outside of the sound attenuating cubicle and gently place a mouse in the middle of the open field chamber. Push the drawer inside of the cubicle. Track the behavior of the mouse for 30 minutes, then return mice to their home cages.Clean the apparatus as demonstrated previously. Results revealed that intraperitoneal injection of CGRP significantly decreased the duration of time spent in the light zone in the light/dark assay in CD1 and C57 black 6J mice, but did not affect the time mice spent in the center in the open field assay in CD1 and C57 black 6J mice. Treatment with CGRP also increased the amount of time mice rested in the dark zone, but not in the light zone in both CD1 and C57 black 6J mice.The optical stimulation of neurons in the posterior thalamic nuclei, led to a corresponding decrease in the duration mice spent in the light zone in the light/dark assay in channelrhodopsin-2 injected mice compared to control virus injected mice. An increase in the resting time in the dark zone but not in the light zone was also observed in the case of the channelrhodopsin-2 injected mice, as compared to the control virus injected mice. It's important to remember that when putting the mouse into the light/dark chamber, the mouse should be handled gently to avoid as much stress as possible.This technique will pave the way to explore mechanisms underlying migraine and other photophobia related disorders, and test the preclinical efficacy for potential therapeutics.

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Behavior

Contextual and Cued Fear Conditioning Test Using a Video Analyzing System in Mice

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association between environmental cues and aversive experiences. In this test, mice are placed into a conditioning chamber and are given parings of a conditioned stimulus (an auditory cue) and an aversive unconditioned stimulus (an electric footshock). After a delay time, the mice are exposed to the same conditioning chamber and a differently shaped chamber with presentation of the auditory cue. Freezing behavior during the test is measured as an index of fear memory. To analyze the behavior automatically, we have developed a video analyzing system using the ImageFZ application software program, which is available as a free download at http://www.mouse-phenotype.org/. Here, to show the details of our protocol, we demonstrate our procedure for the contextual and cued fear conditioning test in C57BL/6J mice using the ImageFZ system. In addition, we validated our protocol and the video analyzing system performance by comparing freezing time measured by the ImageFZ system or a photobeam-based computer measurement system with that scored by a human observer. As shown in our representative results, the data obtained by ImageFZ were similar to those analyzed by a human observer, indicating that the behavioral analysis using the ImageFZ system is highly reliable. The present movie article provides detailed information regarding the test procedures and will promote understanding of the experimental situation.

This article presents a protocol for a contextual and cued fear conditioning test using a video analyzing system to assess fear learning and memory in mice.

The contextual and cued fear conditioning test is one of the behavioral tests that assesses the ability of mice to learn and remember an association ...

Investigating the Effects of Antipsychotics and Schizotypy on the N400 Using Event-Related Potentials and Semantic Categorization

Within the field of cognitive neuroscience, functional magnetic resonance imaging (fMRI) is a popular method of visualizing brain function. This is in part because of its excellent spatial resolution, which allows researchers to identify brain areas associated with specific cognitive processes. However, in the quest to localize brain functions, it is relevant to note that many cognitive, sensory, and motor processes have temporal distinctions that are imperative to capture, an aspect that is left unfulfilled by fMRI&#8217;s suboptimal temporal resolution. To better understand cognitive processes, it is thus advantageous to utilize event-related potential (ERP) recording as a method of gathering information about the brain. Some of its advantages include its fantastic temporal resolution, which gives researchers the ability to follow the activity of the brain down to the millisecond. It also directly indexes both excitatory and inhibitory post-synaptic potentials by which most brain computations are performed. This sits in contrast to fMRI, which captures an index of metabolic activity. Further, the non-invasive ERP method does not require a contrast condition: raw ERPs can be examined for just one experimental condition, a distinction from fMRI where control conditions must be subtracted from the experimental condition, leading to uncertainty in associating observations with experimental or contrast conditions. While it is limited by its poor spatial and subcortical activity resolution, ERP recordings&#8217; utility, relative cost-effectiveness, and associated advantages offer strong rationale for its use in cognitive neuroscience to track rapid temporal changes in neural activity. In an effort to foster increase in its use as a research imaging method, and to ensure proper and accurate data collection, the present article will outline &#8211; in the framework of a paradigm using semantic categorization to examine the effects of antipsychotics and schizotypy on the N400 &#8211; the procedure and key aspects associated with ERP data acquisition.

Using event-related EEG potentials (ERPs), we investigate the effects of antipsychotic medications on abnormal semantic brain activations in healthy individuals with schizotypal traits. We use ERPs to track distinct changes in brain activity, shedding insight into the cognitive processes associated with semantic categorization.

Within the field of cognitive neuroscience, functional magnetic resonance imaging (fMRI) is a popular method of visualizing brain function. This is in ...

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 ...

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 ...

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, ...

The Rodent Psychomotor Vigilance Test (rPVT): A Method for Assessing Neurobehavioral Performance in Rats and Mice

The human Psychomotor Vigilance Test (PVT) is a widely used procedure for measuring changes in fatigue and sustained attention. The present article describes a rodent version of the PVT&#8212;termed the &#34;rPVT&#34;&#8212;that measures similar aspects of attention (i.e., performance accuracy, motor speed, premature responding, and lapses in attention). Data are presented that demonstrate both the short- and long-term usefulness of the rPVT when employed with laboratory rats. Rats easily learn the rPVT, and learning to perform the basic procedure takes less than two weeks of training. Once acquired, rat performances in the rPVT show a high degree of similarity to these same performance measures in the human PVT, including similarities in, lapses in attention, reaction times, vigilance decrements across session time (i.e., the human &#34;time-on-task&#34; effects), and the response-stimulus interval (RSI) effect described for humans. Thus the rPVT can be an extremely valuable tool for assessing the effects of a wide range of variables on sustained attention quite similar to human PVT performances, and thus can be useful for developing novel treatments for neurobehavioral dysfunctions.

The Rodent Psychomotor Vigilance Test rPVT: A Method for Assessing Neurobehavioral Performance in Rats and Mice

A rat version of the human Psychomotor Vigilance Test (PVT) is described that measures aspects of attention similar to those measured with the human PVT, including aspects of human vigilance such as performance accuracy, motor speed, premature responding, and lapses in attention.

The human Psychomotor Vigilance Test (PVT) is a widely used procedure for measuring changes in fatigue and sustained attention. The present article ...

A Method for Investigating Change Blindness in Pigeons (Columba Livia)

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. While many laboratory procedures have been developed that produce change blindness in humans, the flicker paradigm has emerged as a particularly effective method. In the flicker paradigm, two visual displays are presented in alternation with one another. If successive displays are separated by a short inter-stimulus interval (ISI), change detection is impaired. The simplicity of the procedure and the clear, performance-based operational definition of change blindness make the flicker paradigm well-suited to comparative research using nonhuman animals. Indeed, a variant has been developed that can be implemented in operant chambers to study change blindness in pigeons. Results indicate that pigeons, like humans, are worse at detecting the location of a change if two consecutive displays are separated in time by a blank ISI. Furthermore, pigeons&#39; change detection is consistent with an active, location-by-location search process that requires selective attention. The flicker task thus has the potential to contribute to investigations of the dynamics of pigeons&#39; selective spatial attention in comparison to humans. It also illustrates that the phenomenon of change blindness is not exclusive to humans&#39; visual perception, but may instead be a general consequence of selective attention. Finally, while the useful aspects of attention are widely appreciated and understood, it is also important to acknowledge that they may be accompanied by specific imperfections such as change blindness, and that these imperfections have consequences across a wide range of contexts.

A Method for Investigating Change Blindness in Pigeons Columba Livia

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. This protocol describes a variation on the flicker paradigm for investigating change blindness that is appropriate and effective for research with pigeons.

Change blindness is a phenomenon of visual attention, whereby changes to a visual display go unnoticed under certain specific circumstances. While many ...

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 ...

A Behavioral Assay for Investigating the Role of Spatial Memory During Instinctive Defense in Mice

Evolution has selected a repertoire of defensive behaviors that are essential for survival across all animal species. These behaviors are often stereotyped actions elicited in response to innately aversive sensory stimuli, but their success requires enough flexibility for adapting to different spatial environments, which can change rapidly. Here, we describe a behavioral assay to evaluate the influence of learned spatial knowledge on defensive behaviors in mice. We have adapted the widely used Barnes maze spatial memory assay to investigate how mice navigate to a shelter during escape responses to innately aversive sensory stimuli in a novel environment, and how they adapt to acute changes in the environment. This new assay is an ethological paradigm that does not require training and exploits the natural exploration patterns and navigation strategies in mice. We propose that the set of protocols described here are a powerful means of studying goal-directed behaviors and stimulus-triggered navigation, which should be of interest to both the fields of instinctive behaviors and spatial memory.

This protocol describes a behavioral assay, based on the Barnes maze test, to study how instinctive defensive actions are modified by the knowledge of spatial environment.

Evolution has selected a repertoire of defensive behaviors that are essential for survival across all animal species. These behaviors are often ...

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 ...