Name: reinstatement of drug-seeking in mice using the conditioned place preference paradigm
Uploaded: 2018-06-07T13:00:00
Description: Watch this Scientific Journal Video about Reinstatement of Drug-seeking in Mice Using the Conditioned Place Preference Paradigm at JoVE.com

Generalitat Valenciana, PROMETEOII / 2014/063; Ministry of Health, Social Services and Equality. Delegation of the Government for the National Plan on Drugs, Research Projects on Drug Dependencies, 2014I007; Ministry of Economy and Competitiveness (MINECO), Health Institute Carlos III, Network of Addictive Disorders (RTA) RD12 / 0028/0005 and RD16 / 0017/0007 and European Union, FEDER Funds &#34; una manera de hacer Europa&#34;, and PSI2014- 51847-R.

All procedures involving mice and their care complied with national, regional, and local laws and regulations, which are in accordance with Directive 2010/63/EU of the European Parliament and the council of September 22, 2010 on the protection of animals used for scientific purposes. The Animal Use and Care Committee of the University of Valencia approved the present protocol.
1. Materials and Set-up for Conditioned Place Preference:
<ol>
	<li>Handle mice 3 days prior to testing for 1 - 2 mi...

The key point of drug addiction research is the development of treatments that diminish craving and, consequently, reduce the vulnerability to relapse. Thanks to the reinstatement model of the CPP paradigm, it is possible to study the influence of different procedural and environmental factors that modulate relapse, which is a priority of future research. There are some important points to consider, as the CPP paradigm is a test that is highly sensitive to environmental factors.
Modifi...

The Conditioned Place Preference (CPP) paradigm offers a simple way of assessing the conditioned reward induced by diverse stimuli1,2, and has been used broadly to study the conditioned rewarding effects of addictive drugs3. It is based on Pavlovian conditioning, evaluating the motivational value of drug-associated environmental cues for maintaining addictive behavior4. In this model, environmental cues acquire secondary appetitive properties (conditioned rewarding effects) when paired with a primary reinforcer3. For example, an initially neutral place (such as the color of one compartment in the CPP cage) is paired with the specific effects of a drug of abuse during some conditioning sessions5, while another compartment is associated with the injection of a vehicle. Following conditioning, if the animal spends more time in the compartment previously associated with the drug, it is assumed that CPP has developed3. The establishment of the preference is achieved when the animal gives a positive value to the environmental cues linked to the drug, which is the primary reinforcer. Consequently, animals will perform behavioral drug-seeking responses in response to those contextual cues6. The CPP model permits the evaluation of the rewarding properties of subthreshold doses of the drug, showing whether animals in a specific condition (e.g., having suffered from social defeat previously) are more vulnerable and sensitive to doses that are not effective in naive animals7.
The CPP model has also been used to evaluate extinction/reinstatement as an animal model to study relapse3, which is the aim of the present protocol. There are three different phases: acquisition, extinction, and reinstatement (Figure 1). In the CPP reinstatement model, animals first acquire the CPP for a drug-paired compartment, and then they perform several extinction sessions. We define extinction as the moment in which the animal reduces its behavioral responses of approximation to a conditioned rewarding stimulus that has been removed (e.g., the drug)8. During the extinction sessions, animals explore the compartments in the absence of the drug, so that the acquired preference is gradually attenuated9. An important issue to consider is that the behavioral change that the animal exhibits during extinction (the progressive decrease in the time spent in the drug-paired compartment) can be due to new learning processes that compete with the previous learned response, or due to a decrease in the internal motivational state of the subject3. Finally, the reestablishment of the place preference through the context or drug cues would be our model of reinstatement1.
Administering a priming injection of the associated drug can reinstate the preference, which is considered a reestablishment of the approximation to the contextual cues. Drug priming reinstatement occurs due to the persistent memory of the pleasurable effects of the drug, which induced craving and motivates animals to seek the environmental cues related to reward.
Some advantages of the CPP reinstatement model are that the procedure is non-invasive (in contrast with self-administration, which requires surgery), inexpensive, and simple. In addition, this model has a good criterion validity, as it mimics well what occurs in humans10,11, inducing reinstatement with stimuli that induce relapse, such as re-exposure to the drug12,13 or stress14.
There are other techniques such as the extinction &#8211; reinstatement model of intravenous self-administration. Here, animals press a lever to self-administer the drug, which permits the evaluation of the operant response of the animal, compulsivity, and motivation14,15,16. The main advantage of the CPP over self-administration procedures is that CPP reinstatement is considered to reflect the reactivation of the incentive-motivational value of the context stimuli paired with the drug, consisting of the reappearance of the approach behavior to the context17. Moreover, non-drug stimuli, such as stress, can also induce reinstatement18,19. For example, one self-administration study described no effects on reinstatement of heroin intake in rats after a foot shock or restraint stress20. Authors discussed that it was unsuccessful because those stressors were tested outside the self-administration chamber in a different context. In contrast, when using the CPP model of reinstatement, there was a clear re-establishment of morphine-induced CPP after using the same stressors, and applied in a different context to that of the CPP and at different times (0 and 15 min after stress exposure)18.
Several studies in the literature have shown different ways of drug and stress-induced reinstatement. On the one hand, drug-induced reinstatement has been reported in rats and mice using morphine5,21,22,23, cocaine24,25, amphetamine26,27, ethanol28,29, and 3,4-Methylenedioxymethamphetamine (MDMA)30. On the other hand, exposure to stress may be a determining factor in vulnerability to drug abuse. Stress is known to increase the rewarding effects of drugs7,31,32 and their role in relapse is well established33,34. For example, defeat in social interactions with a conspecific reinstates morphine and cocaine CPP18,19. In addition, animals exposed to repeated social defeat are more vulnerable to the conditioned rewarding effects of subthreshold doses of cocaine, and reinstate the preference with very low doses of cocaine7.
Application of the CPP reinstatement model is a useful and sensitive way to evaluate vulnerability to relapse in animals, and permits the assessment of different subtle environmental manipulations, which are the main triggers that threaten human relapse, such as drug- or stress-induced reinstatement.

<table>
	<tbody>
		<tr>
			<td>MONPRE 2Z software</td>
			<td>CIBERTEC S.A., Spain</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Identical Plexiglas boxes with two equal sized compartments separated by a grey central area.</td>
			<td>CIBERTEC S.A., Spain</td>
			<td>N/A</td>
			<td>The compartments have different colored walls (black vs white) and distinct floor textures (fine grid in the black compartment and wide grid in the white one). All boxes are equipped with four infrared light beams in each compartment of the box and six in the central area which allow the recording of the position of the animal and its crossings from one compartment to the other.</td>
		</tr>
		<tr>
			<td>Cocaine hydrochloride</td>
			<td>Laboratorios Alcaliber S.A., Madrid, Spain</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Animals: mice of the OF1 outbred strain</td>
			<td>Charles River, Barcelona Spain</td>
			<td>N/A</td>
			<td>Male mice who arrive to the laboratory on PND 42 and on PND 60 perform the CPP test. These animals are specially indicated for social defeat and aggression models.</td>
		</tr>
		<tr>
			<td>Standard Diet- Teklad Global Diet 2014</td>
			<td>Supplied by Harlan Laboratories Models, S. L. (Barcelona, Spain)</td>
			<td></td>
			<td>13 kcal % fat, 67 kcal % carbohydrates and 20% kcal protein; 2.9 kcal/g</td>
		</tr>
		<tr>
			<td>High fat diet TD.06415</td>
			<td></td>
			<td></td>
			<td>45 kcal % fat, 36 kcal % carbohydrates and 19% kcal protein; 4.6 kcal/g</td>
		</tr>
	</tbody>
</table>

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.

Firstly, representative results from the priming- and stress-induced reinstatement are shown in Figure 7 using adult OF1 male mice.
The data in Figure 7a-b representing time spent in the drug-paired compartment(s) in the Pre- and Post-C test were analyzed with a repeated measures ANOVA with a within-subjects variable Days (comparing Pre-C and Post-C). T...

Watch this Scientific Journal Video about Reinstatement of Drug-seeking in Mice Using the Conditioned Place Preference Paradigm at JoVE.com

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

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 ...

The overall goal of this procedure is to evaluate reinstatement of drug-seeking behavior in laboratory animals considering the impact of the drug associated environmental cues and stress. This method can help answer key question in the drug addiction field, such as the role of different environmental manipulation that can modulate relapsing to drug-seeking. The main advantage of this technique is that the CPP reinstatement is considered to reflect the reactivation of the incentive motivational value of the context stimuli paired with the drug consistent in the reappearance of the approach behavior to the context.The implications of this technique extend toward the ethology of drug relapse, because it is a useful and sensitive way to assess different environmental manipulations, which are the main triggers of human relapse. New to this method will struggle because the reinstatement model is very sensitive to environmental change. Room and environment condition should stay constant during the procedure, especially with mates of the opposite sex, noises, or light conditions.Responses to the drug and stress-induced reinstatement is performed by different procedures that can affect the results. Especially for this reason, it is important to show social defeat as a determinant factor of reinstatement. To begin, handle mice for one to two minutes each three days prior to testing.Set up identical boxes, testing room, and cocaine solution, as directed in the written protocol. Every day, bring the mice to the testing room in their home cages. Allow the mice to sit undisturbed for 15 minutes, as the habituation period to all test-related noises and stimuli.Ensure the guillotine doors are removed from the cage, and begin setting up the computer. Enter the mouse's ID, and press the trial and start command. Then, place the mouse in the middle chamber of the box, and maintain minimal noise in the testing room.When the trial is complete, gather the mice back to their home cages, and save the data on the computer. Allow each mouse to access both compartments of the boxes for 15 minutes per day, for three consecutive days. On the third day, record the amount of time each mouse spends in each compartment.Next, assign half of the mice to receive the drug in one compartment and the other half in the other compartment. First, weigh the mice to determine the appropriate cocaine dosage. Then, prepare syringes with the appropriate dosage of cocaine or saline.Inject each mouse at a time intraperitoneally, and gently place it into its assigned compartment. After four hours, inject the cocaine dose, and confine the mouse to its drug-paired compartment for 30 minutes. Ensure that the guillotine doors separating the two compartments is closed.On the post-conditioning test day, bring the animals to the testing room, and allow them to habituate for 15 minutes. Remove the guillotine doors, separating the two compartments and set up the computer program. Enter the animal IDs and press the start command.Record the amount of time spent by the untreated mice in compartment of the box during the 15 minute observation period. When the observation period is over, gather the mice back into their home cages, and save the data on the computer. Each week, conduct an extinction session with all of the mice that have demonstrated a preference for the drug-paired compartment.First, remove the guillotine door from the box, and place the animal in the box for 15 minutes. When a whole group demonstrates no preference for the drug-paired compartment, repeat the test 24 hours later to confirm the extinction. For drug-induced reinstatement, bring the animals to a different room 24 hours after extinction has been confirmed.Then, inject them with half the previous dose of cocaine, and return them to their vivarium for 15 minutes. Next, take the mice into the testing room, and place them into the box for 15 minutes. Record the amount of time each mouse spends in each compartment, and save the data on the computer.To evaluate the effects of stress-induced reinstatement, take the mice to a different room 24 hours after extinction has been confirmed. Next, place an experimental mouse into a plastic cage with an aggressive opponent mouse for 10 minutes. After the antagonistic encounter, remove the experimental mice, and bring them to the testing room.Finally remove the guillotine door, and keep the mice in the box for 15 minutes. Regarding social stress, we should confirm that the animal has actually been defeated. A positive social encounter, that does not end in defeat shows protective effects, blocking the reinstatement of the place preference of cocaine.Using the CPP protocol, male mice in this study were subjected to varying environmental manipulations to measure relapse from cocaine. Priming induced reinstatement was subjected to subsequent decreasing priming doses until the priming dose was confirmed to be ineffective. As shown in this figure, priming with 12.5, 6.25, 3.125, and 1.56 milligrams per kilogram of cocaine had a significant effect on reinstatement.Mice were subjected to a social interaction, in which the experimental animals were defeated by an aggressive opponent to measure stress-induced reinstatement. Being exposed to an aggressive animal and defeated 15 minutes before the test led to reinstating previously extinguished preference. Mice that suffered repeated social defeat before the CPP procedure, demonstrated modified rewarding effects of subthreshold doses of cocaine.After the extinction of preference, socially defeated mice reinstated their preference with the priming dose of only 0.5 milligrams per kilogram of cocaine. It is important to remember that the key point of the crack addiction research is that the development of treatments that diminish craving and consequently reduce vulnerability to relapse. Other methods, like intravenous self-administration, can be performed in order to answer additional questions like compulsivity or motivation to obtain the drug.After this development, this technique paved the way for researchers in the field of the drug addiction to explore reinstatement into drug-seeking in mice. After watching this video, you should have a good understanding of how to induce relapse through different environment manipulations, such as context or drug cues, which re-establish the place preference.

reinstatement-drug-seeking-mice-using-conditioned-place-preference

Research

JoVE Journal

Behavior

The Crossmodal Congruency Task as a Means to Obtain an Objective Behavioral Measure in the Rubber Hand Illusion Paradigm

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden hand is touched. If the viewed and felt touches are given at the same time then this is sufficient to induce the compelling experience that the rubber hand is one's own hand. The RHI can be used to investigate exactly how the brain constructs distinct body representations for one's own body. Such representations are crucial for successful interactions with the external world. To obtain a subjective measure of the RHI, researchers typically ask participants to rate statements such as "I felt as if the rubber hand were my hand". Here we demonstrate how the crossmodal congruency task can be used to obtain an objective behavioral measure within this paradigm.
The variant of the crossmodal congruency task we employ involves the presentation of tactile targets and visual distractors. Targets and distractors are spatially congruent (i.e. same finger) on some trials and incongruent (i.e. different finger) on others. The difference in performance between incongruent and congruent trials - the crossmodal congruency effect (CCE) - indexes multisensory interactions. Importantly, the CCE is modulated both by viewing a hand as well as the synchrony of viewed and felt touch which are both crucial factors for the RHI.
The use of the crossmodal congruency task within the RHI paradigm has several advantages. It is a simple behavioral measure which can be repeated many times and which can be obtained during the illusion while participants view the artificial hand. Furthermore, this measure is not susceptible to observer and experimenter biases. The combination of the RHI paradigm with the crossmodal congruency task allows in particular for the investigation of multisensory processes which are critical for modulations of body representations as in the RHI.

We demonstrate how an objective measure can be employed in the widely employed rubber hand illusion paradigm. This measure is obtained by modifying the well-established crossmodal congruency task. This task allows the investigation of multisensory processes which are critical for modulations of body representations as in the rubber hand illusion.

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden ...

Stereotaxic Microinjection of Viral Vectors Expressing Cre Recombinase to Study the Role of Target Genes in Cocaine Conditioned Place Preference

Microinjecting recombinant adenoassociated viral (rAAV) vectors expressing Cre recombinase into distinct mouse brain regions to selectively knockout genes of interest allows for enhanced temporally- and regionally-specific control of gene deletion, compared to existing methods. While conditional deletion can also be achieved by mating mice that express Cre recombinase under the control of specific gene promoters with mice carrying a floxed gene, stereotaxic microinjection allows for targeting of discrete brain areas at experimenter-determined time points of interest. In the context of cocaine conditioned place preference, and other cocaine behavioral paradigms such as self-administration or psychomotor sensitization that can involve withdrawal, extinction and/or reinstatement phases, this technique is particularly useful in exploring the unique contribution of target genes to these distinct phases of behavioral models of cocaine-induced plasticity. Specifically, this technique allows for selective ablation of target genes during discrete phases of a behavior to test their contribution to the behavior across time. Ultimately, this understanding allows for more targeted therapeutics that are best able to address the most potent risk factors that present themselves during each phase of addictive behavior.

This article describes how to microinject viral vectors into mouse brain and then test in a conditioned place preference paradigm that includes an acquisition, extinction and reinstatement phase.

Microinjecting recombinant adenoassociated viral (rAAV) vectors expressing Cre recombinase into distinct mouse brain regions to selectively knockout genes ...

A Procedure to Observe Context-induced Renewal of Pavlovian-conditioned Alcohol-seeking Behavior in Rats

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate drug-seeking behavior and prompt relapse in abstinent drug users. We have developed a procedure to study the behavioral and neural processes that mediate the impact of context on alcohol-seeking behavior in rats. Following acclimation to the taste and pharmacological effects of 15% ethanol in the home cage, male Long-Evans rats receive Pavlovian discrimination training (PDT) in conditioning chambers. In each daily (Mon-Fri) PDT session, 16 trials each of two different 10 sec auditory conditioned stimuli occur. During one stimulus, the CS+, 0.2 ml of 15% ethanol is delivered into a fluid port for oral consumption. The second stimulus, the CS-, is not paired with ethanol. Across sessions, entries into the fluid port during the CS+ increase, whereas entries during the CS- stabilize at a lower level, indicating that a predictive association between the CS+ and ethanol is acquired. During PDT each chamber is equipped with a specific configuration of visual, olfactory and tactile contextual stimuli. Following PDT, extinction training is conducted in the same chamber that is now equipped with a different configuration of contextual stimuli. The CS+ and CS- are presented as before, but ethanol is withheld, which causes a gradual decline in port entries during the CS+. At test, rats are placed back into the PDT context and presented with the CS+ and CS- as before, but without ethanol. This manipulation triggers a robust and selective increase in the number of port entries made during the alcohol predictive CS+, with no change in responding during the CS-. This effect, referred to as context-induced renewal, illustrates the powerful capacity of contexts associated with alcohol consumption to stimulate alcohol-seeking behavior in response to Pavlovian alcohol cues.

A procedure to study the capacity of an alcohol associated environmental context to trigger the renewal of alcohol-seeking behavior in rats is described.

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate ...

Assessment of Cocaine-induced Behavioral Sensitization and Conditioned Place Preference in Mice

It is thought that rewarding experiences with drugs create strong contextual associations and encourage repeated intake. In turn, repeated exposures to drugs of abuse make lasting alterations in the brain function of vulnerable individuals, and these persistent alterations likely serve to maintain the maladaptive drug seeking and taking behaviors characteristic of addiction/dependence2. In rodents, reward experience and contextual associations are frequently measured using the conditioned place preference assay, or CPP, wherein preference for a previously drug-paired context is measured. Behavioral sensitization, on the other hand, is an increase in a drug-induced behavior that develops progressively over repeated exposures. Since sensitized behaviors can often be measured after several months of drug abstinence, depending on the dose and length of initial exposure, they are considered observable correlates of lasting drug-induced plasticity. Researchers have found these assays useful in determining the neurobiological substrates mediating aspects of addiction as well as assessing the potential of different interventions in disrupting these behaviors. This manuscript describes basic, effective protocols for mouse CPP and locomotor behavioral sensitization to cocaine.

This protocol is intended to enable researchers to conduct experiments designed to test these aspects of addiction using the conditioned place preference and locomotor behavioral sensitization assays.

It is thought that rewarding experiences with drugs create strong contextual associations and encourage repeated intake. In turn, repeated exposures to ...

Place and Response Learning in the Open-field Tower Maze

This protocol describes how the Open-field Tower Maze (OFTM) paradigm is used to study spatial learning in rodents. This maze is especially useful for examining how rats learn to use a place- or response-learning to successfully navigate in an open-field arena. Additionally, this protocol describes how the OFTM differs from other behavioral maze paradigms that are commonly used to study spatial learning in rodents. The OFTM described in this article was adapted from the one previously described by Cole, Clipperton, and Walt (2007). Specifically, the OFTM was created to test spatial learning in rodents without the experimenter having to consider how &#8220;stress&#8221; might play a role as a confounding variable. Experiments have shown that stress-alone can significantly affect cognitive function1. The representative results section contains data from an experiment that used the OFTM to examine the effects of estradiol treatment on place- and response-learning in adult female Sprague Dawley rats2. Future studies will be designed to examine the role of the hippocampus and striatum in place- and response-learning in the OFTM.

The Open-field Tower Maze (OFTM) is a maze created to study the behavioral and neural mechanisms of spatial learning (e.g., place- or response-learning) in rats. This maze is especially useful for experimenters who want to use a non-stressful maze paradigm to investigate spatial learning in their research.

This protocol describes how the Open-field Tower Maze (OFTM) paradigm is used to study spatial learning in rodents. This maze is especially useful for ...

Examining Recall Memory in Infancy and Early Childhood Using the Elicited Imitation Paradigm

The ability to recall the past allows us to report on details of previous experiences, from the everyday to the significant. Because recall memory is commonly assessed using verbal report paradigms in adults, studying the development of this ability in preverbal infants and children proved challenging. Over the past 30 years, researchers have developed a non-verbal means of assessing recall memory known as the elicited or deferred imitation paradigm. In one variant of the procedure, participants are presented with novel three-dimensional stimuli for a brief baseline period before a researcher demonstrates a series of actions that culminate in an end- or goal-state. The participant is allowed to imitate the demonstrated actions immediately, after a delay, or both. Recall performance is then compared to baseline or to performance on novel control sequences presented at the same session; memory can be assessed for the individual target actions and the order in which they were completed. This procedure is an accepted analogue to the verbal report techniques used with adults, and it has served to establish a solid foundation of the nature of recall memory in infancy and early childhood. In addition, the elicited or deferred imitation procedure has been modified and adapted to answer questions relevant to other aspects of cognitive functioning. The broad utility and application of imitation paradigms is discussed, along with limitations of the approach and directions for future research.

The elicited imitation procedure was established to examine the development of recall memory in infancy and early childhood. This procedure has been widely used to establish a solid foundation of the nature of recall memory in infancy and early childhood.

The ability to recall the past allows us to report on details of previous experiences, from the everyday to the significant. Because recall memory is ...

Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded via an eye tracker as the participant produces or comprehends a spoken language describing the concurrent visual world. This paradigm has high versatility, as it can be used in a wide range of populations, including those who cannot read and/or who cannot overtly give their behavioral responses, such as preliterate children, elderly adults, and patients. More importantly, the paradigm is extremely sensitive to fine grained manipulations of the speech signal, and it can be used to study the online processing of most topics in language comprehension at multiple levels, such as the fine grained acoustic phonetic features, the properties of words, and the linguistic structures. The protocol described in this article illustrates how a typical visual world eye tracking study is conducted, with an example showing how the online processing of some semantically complex statements can be explored with the visual world paradigm.

The visual world paradigm monitors participants' eye movements in the visual workspace as they are listening to or speaking a spoken language. This paradigm can be used to investigate the online processing of a wide range of psycholinguistic questions, including semantically complex statements, such as disjunctive statements.

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded ...

A Conditioned Place Preference Protocol for Measuring Incubation of Craving in Rats

A major cause of repeated relapses is a craving for the drug. Drug craving increases progressively during the abstinence period, a phenomenon termed incubation of drug craving. Here, we describe a morphine conditioned place preference (CPP) protocol for measuring the incubation of craving in rats. In this protocol, a CPP paradigm mainly employing somatosensory cues is used to establish a long-term reward memory of morphine. A three-chamber CPP box that differs in the texture of the chamber floor is constructed. First, the animals are tested for their baseline preference to the two side chambers for three consecutive days. Then, they are injected intraperitoneally with morphine/saline and put into their non-preferred/preferred chamber for 45 min. After 6 days of conditioning, their preference to the side chambers is tested for 15 min at different time points after the last conditioning session. With this paradigm, the reward memory of morphine could last for at least 18 days. To test whether the above-mentioned protocol can model increased craving, the number of entrances into the two side chambers are counted during the abstinence period. The results show that the entrances increased, suggesting that the CPP paradigm could mimic the incubation of craving. Future studies can employ this model to study neural mechanisms underlying long-term memory and incubation of craving.

Here, a morphine conditioned place preference (CPP) protocol is described to measure incubation of craving in rats.

A major cause of repeated relapses is a craving for the drug. Drug craving increases progressively during the abstinence period, a phenomenon termed ...

Using the Visual World Paradigm to Study Sentence Comprehension in Mandarin-Speaking Children with Autism

Sentence comprehension relies on the ability to rapidly integrate different types of linguistic and non-linguistic information. However, there is currently a paucity of research exploring how preschool children with autism understand sentences using different types of cues. The mechanisms underlying sentence comprehension remains largely unclear. The present study presents a protocol to examine the sentence comprehension abilities of preschool children with autism. More specifically, a visual world paradigm of eye-tracking is used to explore the moment-to-moment sentence comprehension in the children. The paradigm has multiple advantages. First, it is sensitive to the time course of sentence comprehension and thus can provide rich information about how sentence comprehension unfolds over time. Second, it requires minimal task and communication demands, so it is ideal for testing children with autism. To further minimize the computational burden of children, the present study measures eye movements that arise as automatic responses to linguistic input rather than measuring eye movements that accompany conscious responses to spoken instructions.

We present a protocol to examine the use of morphological cues during real-time sentence comprehension by children with autism.

Sentence comprehension relies on the ability to rapidly integrate different types of linguistic and non-linguistic information. However, there is ...

Exploring Infant Sensitivity to Visual Language using Eye Tracking and the Preferential Looking Paradigm

We discuss the use of the preferential looking paradigm in eye tracking studies in order to study how infants develop, understand, and attend to the world around them. Eye tracking is a safe and non-invasive way to collect gaze data from infants, and the preferential looking paradigm is simple to design and only requires the infant to be attending to the screen. By simultaneously showing two visual stimuli that differ in one dimension, we can assess whether infants show different looking behavior for either stimulus, thus demonstrating sensitivity to that difference. The challenges in such experimental approaches are that experiments must be kept brief (no more than 10 min) and be carefully controlled such that the two stimuli differ in only one way. The interpretation of null results must also be carefully considered. In this paper, we illustrate a successful example of an infant eye tracking study with a preferential looking paradigm to discover that 6-month-olds are sensitive to linguistic cues in a signed language despite having no prior exposure to signed language, suggesting that infants possess intrinsic or innate sensitivities to these cues.

Eye tracking studies using a preferential looking paradigm can be used to study infants&#39;&#160;emerging understanding of, and attention to, their external visual world.

We discuss the use of the preferential looking paradigm in eye tracking studies in order to study how infants develop, understand, and attend to the world ...