We would like to thank Professor Olena Severynovska, Anastasia Halinska and Maryna Kuscheriava of the Department of Physiology, Faculty of Biology, Ecology, and Medicine, as well as Oles Honchar of Dnipro University, Dnipro, Ukraine, for their help in analyzing video recordings of the social organization test.

The experiments were conducted in accordance with recommendations of the Declarations of Helsinki and Tokyo and the Guidelines for the Use of Experimental Animals of the European Community. The experiments were approved by the Animal Care Committee of Ben-Gurion University of the Negev. The authorization code for this experiment was IL-55-8-12.
1. Rat preparation
<ol>
	<li>Obtain approval for experiments from Institutional Animal Care and Use Committee (IACUC).</li>
	<li>Select adult Sprague Dawley rats. Exclude animals that exhibit abnormal physical traits, such as seizures or other motor deficits. 
	NOTE: For this protocol, we used adult male rats, weighing 300&#8722;350 g, aged 4-8 months old. Female rats may be used as well.</li>
	<li>Maintain rats at room temperature (22 &#176;C &#177; 1 &#176;C), with 12 h light and 12 h dark cycles. Provide rat chow and water ad libitum. House 3 rats per cage. 
	&#8203;NOTE: All rats housed in the same cage must be in the same experimental group.</li>
	<li>Randomly place 120 rats into one of three experimental groups. Use Group 1 (n=60) w as a control group. Induce the experimental group, Group 2 (n=30), with stressors as detailed below. Induce Group 3, the experimental group with treatment (n=30), with anhedonia and subsequently administer antidepressant treatment. The timeline for the experimental protocol can be found in Figure 1.</li>
	<li>Mark rats with colored pens at the beginning of the experiment to allow for individual identification.</li>
	<li>Perform all experiments between 6:00 a.m. and 12:00 p.m.</li>
	<li>Weigh rats daily throughout procedure for possible weight loss. Weight loss above 20% will exclude rats from the study. See section 3.1.3.</li>
</ol>
2. Induction of anhedonia in rats
<ol>
	<li>Chronic Unpredictable Stress model
	<ol>
		<li>Induce rats from the experimental group and the experimental group with treatment with features of a depressive-like state by the Chronic Unpredictable Stress model, as previously detailed23.</li>
	</ol>
	</li>
	<li>Chronic Unpredictable Stress model
	<ol>
		<li>Induce rats from the two experimental groups with depressive-like behaviors by the Chronic Unpredictable Stress model, as previously detailed23. 
		NOTE: Rats are exposed to 2 of the 7 stressors daily in a random order; one in the daytime and the second at night for 5 weeks24,25.</li>
		<li>Introduce the following stressors in random order:
		<ol>
			<li>House rats with 6 animals per cage instead of 3 for 18 h.</li>
			<li>Tilt cage placement 45&#176; along the vertical axis for 3 h.</li>
			<li>Deprive animals of food for 18 h.</li>
			<li>Deprive animals of water for 18 h and then introduce an empty water bottle.</li>
			<li>Maintain a soiled cage for 8 h with 300 mL of water spilled in the bedding.</li>
			<li>Keep continuous lighting and reverse the light/dark cycle for 48 h per week.</li>
			<li>Heat the environment to 40 &#176;C for 5 min.</li>
		</ol>
		</li>
		<li>Confirm the development of anhedonia, one of the features of a depression-like state, by performing a sucrose preference test. See section 4.</li>
	</ol>
	</li>
	<li>Anti-depression therapy
	<ol>
		<li>Administer 20 mg/kg imipramine hydrochloride (tricyclic antidepressant) intraperitoneally once per day for 3 weeks to rats from the experimental group26,27,28. 
		&#8203;NOTE: A sub-group (n=3 in each set of rats) of the experimental group is administered 0.9% saline (placebo) intraperitoneally once per day for the 3-week duration, at the same volume as the antidepressant treatment group.</li>
	</ol>
	</li>
</ol>
3. The social organization test (complex diving-for-food task)
NOTE: The experimental apparatus was described in previous studies9,29,30 with minor modifications. All parts of the apparatus should be composed of transparent plexiglass.
<ol>
	<li>Prepare apparatus and acclimate rats.
	<ol>
		<li>Connect two cages (50 cm x 50 cm x 50 cm) to an aquarium (130 cm x 35 cm x 50 cm) via tunnels (45 cm x 15 cm x 15 cm) (Figure 2). Ensure that there is no access from one cage to another without diving into the aquarium25. Maintain water temperature at 25 &#176;C.</li>
		<li>Place tubes with food pellets (one food pellet in each tube) at one end of the aquarium. 
		NOTE: A reduction in the accessibility of food pellets in the cage of departure should gradually encourage the rat, who would otherwise develop a habit of stealing, to dive to reach the food.</li>
		<li>On day 1 of the experiment, introduce each group of 6 rats to experimental apparatus without water for 3-hour sessions. Return rats to standard cage after session.
		<ol>
			<li>Restrict rat food access to the 3-hour sessions, with no other access to food during the rest of the day.</li>
			<li>Remove rats that lost more than 20% of their baseline weight from the experiment together with their social group, and give ad libitum food and water.</li>
			<li>Manually towel dry rats or provide access to a heat source until dry and before placing them back in their regular housing to avoid hypothermia.</li>
			<li>Repeat these sessions for days 2-3. 
			NOTE: Video record rats in the apparatus continuously for 3-hour sessions. Ensure that the camera is set to high definition (720p) and the auto-focus is turned off.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform diving-for-food task
	<ol>
		<li>On days 4-17, add water progressively until maximum water level is reached, as described previously4. On days 17-21, maintain maximum water level.</li>
		<li>Observe rats diving for pellet access.</li>
		<li>Record the following parameters for each rat:
		<ol>
			<li>Assess frequency of entry into the tunnel.</li>
			<li>Count each attempt to dive for food. 
			NOTE: The travel from cage to aquarium back to a cage should not exceed 5-6 seconds, which will ensure that the pellet remains edible.</li>
			<li>Assess the number of times that food is obtained by attack between rats that do swim for food and rats that do not.</li>
			<li>Record the number of times food is carried by a rat who swims.</li>
			<li>Record the time that rats spent in separate cages compared to time spent in the original cage. 
			&#8203;NOTE: All the data was obtained by continuous visual observation.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
4. Assessment of anhedonia: The sucrose preference test
<ol>
	<li>Assess anhedonia by the sucrose preference test with minor modification, as previously described23,25,31,32,33. Perform this test on days -6, 0, 35, 41, 62 and 68 of the procedure (see Figure 1 for protocol timeline).
	<ol>
		<li>Allow rats to consume sucrose solution for 24 h by free access to the two bottles in each cage, containing 100 mL of sucrose solution (1%, w/v).</li>
		<li>After 24 h, replace one of the bottles with water for an additional 24 h.</li>
		<li>Deprive rats of water for 12 hours34.</li>
		<li>Give rats both bottles (one with water and one with sucrose). After 4 h, record the volume of both the consumed sucrose solution and water.</li>
		<li>Calculate sucrose preference as sucrose preference (%) = sucrose consumption (mL)/(sucrose consumption (mL) + water consumption (mL)) &#215; 100%. 
		&#8203;NOTE: When utilizing the Chronic Unpredictable Stress model in conjunction with a social organization test, we recommend not only recording the mean sucrose and water consumption, but also to note changes in behavior of each individual rat. This will allow for a more specific understanding of behavioral changes within the individual instead of within the group when confronted with a hierarchical model such as the diving-for-food task.</li>
	</ol>
	</li>
</ol>
5. Statistical analysis
<ol>
	<li>Determine comparisons between groups using the Kruskal-Wallis followed by Mann-Whitney for nonparametric data or a one-way analysis of variance (ANOVA) followed by Bonferroni&#39;s post hoc test or the Student&#39;s t-test for parametric data. 
	NOTE: Results are considered statistically significant when p &#60; 0.05, and highly significant when p &#60; 0.01.</li>
</ol>

The authors have nothing to disclose.

Social hierarchies determine the behavior of many species, including humans, and are often defined by relationships based on aggression and submission. These relationships often depend on environmental factors in additional to social structures35. Social formations based on dominance and submission are multifaceted36,37. Among humans, aggression is described as consisting of behaviors ranging from non-physical bullying to war and violence<...

Rats are highly social animals, making them an ideal model for understanding social behavior and how it relates to decision making. Rats divide themselves into hierarchical groups based on dominant and submissive relationships. Rats can be trained for tasks that express cooperation, risk management, deceptive behavior, and behaviors that change depending on the decisions of other rats1,2. Studies with rat models expressing these behaviors prove helpful in understanding social structure and its relationship to decision making with relevance for human psychology.
As a necessary resource, access to food is a major reason for social organization among rats3.&#160;Na&#239;ve rats have been observed engaging in social interaction and differentiation in situations where access to food was limited1,2,4,5,6,7,8. In one study, adult rats were required to cross a tunnel underwater to access the food and then bring the food back through the tunnel to the cage9. Individual rats within each group were able to be categorized according to their method of obtaining food. Two behavioral profiles have emerged: the first are the &#34;carriers&#34;, who dive down and swim underwater to the feeder, obtain a pellet, and hold the pellet in its mouth as they swim back to the cage. The second group are the &#34;non-carriers&#34;, who do not dive and obtain food only by stealing from the carriers. In groups of six rats, approximately one-half were carriers and the other half were not9. All of the rats were observed to be carriers when they were trained individually in the diving apparatus10.
Similar animal behavioral tasks involve competition for food or space and have been employed with chickens11, rodents12,13,14,15, and pigs16. In the tube test, two mice are sent through a narrow tube from opposite ends, with one mouse necessarily ceding right of way to the other. This test assists in measuring social dominance17,18,19. A behavioral test referred to as the warm spot test has mice compete for a position in a small warm spot in an otherwise cold cage19,20.
A subsequent diving-for-food task that is more complex allows carrier rats to have access to a second cage, away from non-carriers, where they could consume their food separately4. In this protocol, we present a diving-for-food task&#160;as an alternative model for social hierarchy and behavior in rats. This diving-for-food task provides a method for rats to avoid the social groups of the main cage and therefore escape aggression and the social interactions of other rats. This task introduces the option of avoidant social behavior in rats that can elucidate our understanding of social aggression.
Social functioning, which describes the ability to engage in normal social roles, can be affected by conditions such as depression3. Depressed individuals often struggle with unemployment, have few social contacts, and scarcely engage in leisure activities3. Effective treatment of depression is often measured by improvement in social and interpersonal function21. Antidepressant treatments, however, vary in their efficacy in treating impairments in social functioning related to depression3.
In this methodology, we induced a depressive-like condition in rats through the Chronic Stress test and evaluated the rats&#39; level of anhedonia, one of the features of a depression-like state, with a sucrose preference test. Anhedonic rats, as well as anhedonic rats who were administered anti-depressants, were monitored through the diving-for-food task in comparison to a control group.
The previously-mentioned diving-for-food tasks resemble food competition tests that often use only one pair of animals or one dichotomy as a point of comparison, such as carriers and non-carriers and a single analysis that compares submission to dominance15,17,22. Our method defines more complex interactions between rats through divisions into multiple types of behavior, including: carriers and non-carriers, those who fight for food and those who do not, and rats who share food or go to separate cages. We believe that this protocol is the only type that uses a hierarchy to assess a complex structure of social interaction in a group of animals, rather than in pairs. It will be helpful for studies that test dominance based on food preference, as well as studies that aim to clarify more hierarchical relationships that are not limited to a dominant-submissive model.
In this protocol, we describe in detail the complex diving-for-food task to investigate social organization and interactions in rats with changes in individual behavior, particularly after the development of anhedonia. This animal model may also be utilized to study other psychiatric conditions associated with changes in social behavior and hierarchy.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alcohol</td>
			<td>Pharmacy</td>
			<td></td>
			<td>99% pharmaceutical alcohol diluted to 5% and used for cleaning the open field test box before the introduction of each rat</td>
		</tr>
		<tr>
			<td>Bottles</td>
			<td>Techniplast</td>
			<td>ACBT0262SU</td>
			<td>150 mL bottles filled with 100 mL of water and 100 mL of 1% (w/v) sucrose solution</td>
		</tr>
		<tr>
			<td>Equipment for Diving for Food Task (Plexiglas)</td>
			<td>self made in Ben Gurion University of Negev</td>
			<td></td>
			<td>Two cages (50 x 50 x 50 cm) to an aquarium (130 x 35 x 50 cm) via tunnels</td>
		</tr>
		<tr>
			<td>Imipramine hydrochloride</td>
			<td>SIGMA</td>
			<td>Lot# SLBB9914V</td>
			<td>(Tricyclic antidepressant) 20 mg/kg intraperitoneally once per day for 3 weeks</td>
		</tr>
		<tr>
			<td>Purina Chow</td>
			<td>Purina</td>
			<td>5001</td>
			<td>Rodent laboratory chow given to rats, mice and hamster is a life-cycle nutrition that has been used in biomedical researc for over 5</td>
		</tr>
		<tr>
			<td>Rat Cages</td>
			<td>Techniplast</td>
			<td>2000P</td>
			<td>Conventional housing for rodents. Was used for housing rats throughout the experiment</td>
		</tr>
		<tr>
			<td>Video Camera</td>
			<td>Canon</td>
			<td></td>
			<td>Digital video camera for high definition recording of rat behavior under plus maze test</td>
		</tr>
	</tbody>
</table>

a complex diving-for-food task to investigate social organization and interactions in rats

For many species, where status is a vital motivator that can affect health, social hierarchies influence behavior. Social hierarchies that include dominant-submissive relationships are common in both animal and human societies. These relationships can be affected by interactions with others and with their environment, making them difficult to analyze in a controlled study. Rather than a simple dominance hierarchy, this formation has a complicated presentation that allows rats to avoid aggression. Status can be stagnant or mutable, and results in complex societal stratifications. Here we describe a complex diving-for-food task to investigate rodent social hierarchy and behavioral interactions. This animal model may allow us to assess the relationship between a wide range of mental illnesses and social organization, as well as to study the effectiveness of therapy on social dysfunction.

Body weight changes 
A one-way ANOVA did not show any differences in changes in body weight between experimental groups for the 21 days of the diving-for-food task. From days 2 to 21, there were changes in body weight for all 3 groups (p&#60;0.01, Table 1).
Sucrose preference test 
At the start of the experiment (day 0), there was no difference in the percent of sucrose preference between the experimental group of rats induced with a...

Watch this Scientific Journal Video about A Complex Diving-For-Food Task to Investigate Social Organization and Interactions in Rats at JoVE.com

A Complex Diving-For-Food Task to Investigate Social Organization and Interactions in Rats

This protocol describes a method of examining social hierarchy in a rat model. Rats perform a complex diving-for-food task in which they form a distinct hierarchy according to their willingness to dive underwater and swim to obtain a food pellet. This method is used to understand decision making and social relationships among highly social animals in small groups.

For many species, where status is a vital motivator that can affect health, social hierarchies influence behavior. Social hierarchies that include ...

a-complex-diving-for-food-task-to-investigate-social-organization

Research

JoVE Journal

Behavior

3.9K Views.  Mayo Clinic. This protocol describes a method of examining social hierarchy in a rat model. Rats perform a complex diving-for-food task in which they form a distinct hierarchy according to their willingness to dive underwater and swim to obtain a food pellet. This method is used to understand decision making and social relationships among highly social animals in small groups. 

Video: A Complex Diving-For-Food Task to Investigate Social Organization and Interactions in Rats

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals and humans. However, many animal models of depression were developed in males and are not applicable or effective in studies of postpartum females. Recent studies have reported significant effects of chronic social stress during lactation, an ethologically relevant and effective stressor, on maternal behavior, growth, and behavioral neuroendocrinology. This manuscript will describe this chronic social stress paradigm using repeated exposure of a lactating dam to a novel male intruder, and the assessment of the behavioral, physiological, and neuroendocrine effects of this model. Chronic social stress (CSS) is a valuable model for studying the effects of stress on the behavior and physiology of the dam as well as her offspring and future generations. The exposure of pups to CSS can also be used as an early life stress that has long term effects on behavior, physiology, and neuroendocrinology.

This article describes the use of chronic resident intruder social stress as an ethologically relevant paradigm to model postpartum depression and anxiety in lactating rodents.

Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals ...

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 ...

Moderate Prenatal Alcohol Exposure and Quantification of Social Behavior in Adult Rats

Alterations in social behavior are among the major negative consequences observed in children with Fetal Alcohol Spectrum Disorders (FASDs). Several independent laboratories have demonstrated robust alterations in the social behavior of rodents exposed to alcohol during brain development across a wide range of exposure durations, timing, doses, and ages at the time of behavioral quantification. Prior work from this laboratory has identified reliable alterations in specific forms of social interaction following moderate prenatal alcohol exposure (PAE) in the rat that persist well into adulthood, including increased wrestling and decreased investigation. These behavioral alterations have been useful in identifying neural circuits altered by moderate PAE1, and may hold importance for progressing toward a more complete understanding of the neural bases of PAE-related alterations in social behavior. This paper describes procedures for performing moderate PAE in which rat dams voluntarily consume ethanol or saccharin (control) throughout gestation, and measurement of social behaviors in adult offspring.

The goal of the protocol presented here is to describe procedures to expose rats to moderate levels of alcohol during prenatal brain development and to quantify resulting alterations in social behavior during adulthood.

Alterations in social behavior are among the major negative consequences observed in children with Fetal Alcohol Spectrum Disorders (FASDs). Several ...

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 ...

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 ...

The Social Dimension of Stress: Experimental Manipulations of Social Support and Social Identity in the Trier Social Stress Test

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations supportive behavior of other people as well as positive social relationships can act as powerful resources to cope with stress. In order to study the interplay between these variables, this protocol describes two effective experimental manipulations of social relationships and supportive behavior in the laboratory. In the present article, these two manipulations are implemented in the Trier Social Stress Test (TSST)&#8212;a standard stress induction paradigm in which participants are subjected to a simulated job interview. More precisely, we propose (a) a manipulation of the relationship between different protagonists in the TSST by making a shared social identity salient and (b) a manipulation of the behavior of the TSST-selection committee, which acts either supportively or unsupportively. These two experimental manipulations are designed in a modular fashion and can be applied independently of each other but can also be combined. Moreover, these two manipulations can also be integrated into other stress protocols and into other standardized social interactions such as trust games, negotiation tasks, or other group tasks.

Previous research on the social dimension of stress has focused on two important variables: social identity and social support. This protocol introduces an effective experimental manipulation of these two social variables and describes their implementation in a standard stress induction paradigm (Trier Social Stress Test).

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations ...

A Method for Evaluating the Reinforcing Properties of Ethanol in Rats without Water Deprivation, Saccharin Fading or Extended Access Training

Operant oral self-administration methods are commonly used to study the reinforcing properties of ethanol in animals. However, the standard methods require saccharin/sucrose fading, water deprivation and/or extended training to initiate operant responding in rats. This paper describes a novel and efficient method to quickly initiate operant responding for ethanol that is convenient for experimenters and does not require water deprivation or saccharin/sucrose fading, thus eliminating the potential confound of using sweeteners in ethanol operant self-administration studies. With this method, Wistar rats typically acquire and maintain self-administration of a 20% ethanol solution in less than two weeks of training. Furthermore, blood ethanol concentrations and rewards are positively correlated for a 30 min self-administration session. Moreover, naltrexone, an FDA-approved medication for alcohol dependence that has been shown to suppress ethanol self-administration in rodents, dose-dependently decreases alcohol intake and motivation to consume alcohol for rats self-administering 20% ethanol, thus validating the use of this new method to study the reinforcing properties of alcohol in rats.

This protocol describes a novel and efficient method to quickly initiate operant responding for ethanol in rats that, contrary to standard methods, does not require water deprivation or saccharin/sucrose fading to initiate responding.

Operant oral self-administration methods are commonly used to study the reinforcing properties of ethanol in animals. However, the standard methods ...

The Deese-Roediger-McDermott (DRM) Task: A Simple Cognitive Paradigm to Investigate False Memories in the Laboratory

The Deese,&#160;Roediger and McDermott&#160;(DRM) task is a false memory paradigm in which subjects are presented with lists of semantically related words (e.g., nurse, hospital, etc.) at encoding. After a delay, subjects are asked to recall or recognize these words. In the recognition memory version of the task, subjects are asked whether they remember previously presented words, as well as related (but never presented) critical lure words (&#39;doctor&#39;). Typically, the critical word is recognized with high probability and confidence. This false memory effect has been robustly demonstrated across short (e.g., immediate, 20 min) and long (e.g., 1, 7, 60 d) delays between encoding and memory testing. A strength of using this task to study false memory is its simplicity and short duration. If encoding and retrieval components of the task occur in the same session, the entire task can take as little as 2 - 30 min. However, although the DRM task is widely considered a &#39;false memory&#39; paradigm, some researchers consider DRM illusions to be based on the activation of semantic memory networks in the brain, and argue that such semantic gist-based false memory errors may actually be useful in some scenarios (e.g., remembering the forest for the trees; remembering that a word list was about &#34;doctors&#34;, even though the actual word &#34;doctor&#34; was never presented for study). Remembering the gist of experience (instead of or along with individual details) is arguably an adaptive process and this task has provided a great deal of knowledge about the constructive, adaptive nature of memory. Therefore, researchers should use caution when discussing the overall reach and implications of their experiments when using this task to study &#39;false memory&#39;, as DRM memory errors may not adequately reflect false memories in the real world, such as false memory in eyewitness testimony, or false memories of sexual abuse.

The Deese-Roediger-McDermott DRM Task: A Simple Cognitive Paradigm to Investigate False Memories in the Laboratory

Here we present the Deese,&#160;Roediger and McDermott&#160;(DRM) task, a tool to study false memories in the laboratory. Subjects study lists of semantically related words (e.g.,&#160;nurse, sick, etc.), and later falsely remember an unstudied word (doctor) that represents the gist, or theme, of the word list.

The Deese,&#160;Roediger and McDermott&#160;(DRM) task is a false memory paradigm in which subjects are presented with lists of semantically related words ...

The Knob Supination Task: A Semi-automated Method for Assessing Forelimb Function in Rats

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity largely use video analysis of reaching or food manipulation. While these tasks are easy to implement and are robust across disease models, they are subjective and laborious for the experimenter. Automating traditional tasks or creating new automated tasks can make the tasks more efficient, objective, and quantitative. Since rats are less dexterous than primates, central nervous system (CNS) injury produces more subtle deficits in dexterity, however, supination is highly affected in rodents and crucial to hand function in primates. Therefore, we designed a semi-automated task that measures forelimb supination in rats. Rats are trained to reach and grasp a knob-shaped manipulandum and turn the manipulandum in supination to receive a reward. Rats can acquire the skill within 20 &plusmn; 5 days. While the early part of training is highly supervised, much of the training is done without direct supervision. The task reliably and reproducibly captures subtle deficits after injury and shows functional recovery that accurately reflects clinical recovery curves. Analysis of data is performed by specialized software through a graphical user interface that is designed to be intuitive. We also give solutions to common problems encountered during training, and show that minor corrections to behavior early in training produce reliable acquisition of supination. Thus, the knob supination task provides efficient and quantitative evaluation of a critical movement for dexterity in rats.

This manuscript describes a semi-automated task that quantifies supination in rats. Rats reach, grasp, and supinate a spherical manipulandum. The rat is rewarded with a pellet if the turn angle exceeds a criterion set by the user. This task increases throughput, sensitivity to injury, and objectivity compared to traditional tasks.

Tasks that accurately measure dexterity in animal models are critical to understand hand function. Current rat behavioral tasks that measure dexterity ...

A Visual Guide for Studying Behavioral Defenses to Pathogen Attacks in Leaf-Cutting Ants

The complex lifestyle, evolutionary history of advanced cooperation, and disease defenses of leaf-cutting ants are well studied. Although numerous studies have described the behaviors connected with disease defense, and the associated use of chemicals and antimicrobials, no common visual reference has been made. The main aim of this study was to record short clips of behaviors involved in disease defense, both prophylactically and directly targeted towards an antagonist of the colony following infection. To do so we used an infection experiment, with sub-colonies of the leaf-cutting ant species Acromyrmex echinatior, and the most significant known pathogenic threat to the ants&#39; fungal crop (Leucoagaricus gongylophorus), a specialized pathogenic fungus in the genus Escovopsis. We filmed and compared infected and uninfected colonies, at both early and more advanced stages of infection. We quantified key defensive behaviors across treatments and show that the behavioral response to pathogen attack likely varies between different castes of worker ants, and between early and late detection of a threat. Based on these recordings we have made a library of behavioral clips, accompanied by definitions of the main individual defensive behaviors. We anticipate that such a guide can provide a common frame of reference for other researchers working in this field, to recognize and study these behaviors, and also provide greater scope for comparing different studies to ultimately help better understand the role these behaviors play in disease defense.

We present a visual guide to disease defense behaviors in leaf-cutting ants, with individual clips and accompanying definitions, illustrated in an experimental infection scenario. Our main aim is to help other researchers recognize key defensive behaviors and to provide a common understanding for future research in this field.

The complex lifestyle, evolutionary history of advanced cooperation, and disease defenses of leaf-cutting ants are well studied. Although numerous studies ...