Name: assessment of mouse judgment bias through an olfactory digging task
Uploaded: 2022-03-04T14:00:00
Description: Watch this Scientific Journal Video about Assessment of Mouse Judgment Bias through an Olfactory Digging Task at JoVE.com

The authors are grateful to Miguel Ayala, Lindsey Kitchenham, Dr. Michelle Edwards, Sylvia Lam and Stephanie Dejardin for their contributions to the Reseasco et al.19 validation work which this protocol is based on. We would also like to thank the mice and our wonderful animal care technicians, Michaela Randall and Michelle Cieplak.

Experiments were approved by the University of Guelph&#39;s Animal Care Committee (AUP #3700), conducted in compliance with Canadian Council on Animal Care guidelines, and reported in accordance with ARRIVE (Animal Research: Reporting of In Vivo Experiments)20 requirements.
1. Experiment preparation
<ol>
	<li>Experimental design (see Table 1). 
	NOTE: This behavioral test is a scent-based Go/Go digging task, in which mic...

<ol>
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The scent-based digging protocol and results outlined here demonstrate the ability of this novel JB task to detect changes in mouse affective state. The task thus presents a valuable tool for diverse fields of research. Similar to any JB task, to assess animal affect it is critical that animals first learn to discriminate between cues (step 4.7.3) and that the ambiguous stimulus is interpreted as intermediate (step 5.3). Though simple, meeting these requirements can be challenging, particularly in laboratory mice for whi...

Measuring affectively modulated judgment bias (henceforth JB) has proven to be a useful tool for studying the emotional states of animals. This innovative approach borrows from human psychology since humans experiencing positive or negative affective states (emotions and longer-term moods) reliably demonstrate differences in the way they process information1,2,3. For example, humans experiencing anxiety or depression might interpret neutral facial expressions as negative, or neutral sentences as threatening4,5. It is likely that these biases have an adaptive value and are therefore conserved across species6,7. Researchers aiming to assess animal affect have cleverly taken advantage of this phenomenon, operationalizing optimism as the increased expectation of reward in response to neutral or ambiguous cues, and pessimism as the increased expectation of punishment or reward absence8,9. Thus, in an experimental setting, optimistic and pessimistic responses to ambiguous stimuli can be interpreted as indicators of positive and negative affect, respectively10,11.
Compared to other indicators of animal affect, JB tasks have the potential to be particularly valuable tools since they are capable of detecting both the valence and intensity of affective states10,11. The ability of JB tasks to detect positive states (e.g., Rygula et al.12) is especially useful since most indicators of animal affect are limited to the detection of negative states13. During JB tasks, animals are typically trained to respond to a positive discriminative cue predicting reward (e.g., high-frequency tone) and a negative discriminative cue predicting punishment (e.g.,&#160;low-frequency tone), before being presented with an ambiguous cue (e.g., intermediate tone)8. If in response to ambiguous cues an animal &#39;optimistically&#39; performs the trained response for the positive cue (as if expecting reward), this indicates a positive judgment bias. Alternatively, if animals demonstrate the negative trained response to avoid punishment, this is indicative of &#39;pessimism&#39; or negative judgment bias.
Since the development of the first successful JB task for animals by Harding and colleagues8, several JB tasks have been developed for a wide range of species across diverse research fields7. But despite their increasing popularity, animal JB tasks are often labor-intensive. Moreover, perhaps because they are methodologically different from the human tasks that inspired them, they sometimes produce null or counterintuitive results14 and commonly yield only small treatment effect sizes15. As a result, JB tasks can be challenging to develop and implement. In fact, for laboratory mice, the most widely used vertebrates in research16,17 and a species heavily relied upon to model affective disorders18, only one JB task has been successfully validated as sensitive to changes in affective state19 despite many attempts over the past decade (see supplementary material of Resasco et al.19&#160;for a summary). This article describes the recently validated murine JB task, detailing its biologically relevant design, and highlighting the ways that this humane task can be applied to test important hypotheses relevant to mouse affect. Overall, the protocol can be implemented to investigate the affective effects of any variable of interest on JB in mice. This would include categorical treatment variables as described here (drug or disease effects, environmental conditions, genetic background, etc.), or relationships with continuous variables (physiological changes, home cage behaviors, etc.).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Absolute ethanol</td>
			<td>Commercial alcohol</td>
			<td>P016EAAN</td>
			<td>Dilute to 70% with distilled water, for cleaning</td>
		</tr>
		<tr>
			<td>Centrifuge tubes</td>
			<td>Fischer</td>
			<td>55395</td>
			<td>15 mL tubes used to dilute essences here. However, size may be selected based on total volume required for sample size</td>
		</tr>
		<tr>
			<td>Cheerios (original)</td>
			<td>Cheerios</td>
			<td>N/A</td>
			<td>Commercially available. Used as reward to train animals to enter annex cage for handling</td>
		</tr>
		<tr>
			<td>Corncob bedding</td>
			<td>Envigo</td>
			<td>7092</td>
			<td>Teklad 1/8 corncob bedding used in digging pots and animal cages</td>
		</tr>
		<tr>
			<td>Cotton pads</td>
			<td>Equate</td>
			<td>N/A</td>
			<td>Commercially available. Modified in lab to fit within tissue cassettes for scent dispensing</td>
		</tr>
		<tr>
			<td>Digging pots</td>
			<td>Rubbermaid</td>
			<td>N/A</td>
			<td>Commercially available. Containers were modified to fit the apparatus in the lab</td>
		</tr>
		<tr>
			<td>Dried, sweetened banana chips</td>
			<td>Stock and Barrel</td>
			<td>N/A</td>
			<td>Commercially available. High value reward in JB task</td>
		</tr>
		<tr>
			<td>JB apparatus</td>
			<td></td>
			<td>N/A</td>
			<td>The apparatus was made in the lab</td>
		</tr>
		<tr>
			<td>JWatcher event recording software</td>
			<td>Animal Behavior Laboratory, Macquarie University</td>
			<td>Version 1.0</td>
			<td>Freely available for download online. Used to score digging behavior during JB task</td>
		</tr>
		<tr>
			<td>Mint extract</td>
			<td>Fleibor</td>
			<td>N/A</td>
			<td>Commercially &#34;Menta (Soluci&#243;n)&#34;. Discriminative stimulus odor</td>
		</tr>
		<tr>
			<td>Rodent Diet</td>
			<td>Envigo</td>
			<td>2914</td>
			<td>Teklad global 14% protein rodent maintenance diets. Low value reward in JB task and regular diet in home cage</td>
		</tr>
		<tr>
			<td>SAS statistical software</td>
			<td>SAS</td>
			<td>Version 9.4</td>
			<td>Other comparable software programs (e.g. R) are also appropriate</td>
		</tr>
		<tr>
			<td>Vanilla extract</td>
			<td>Fleibor</td>
			<td></td>
			<td>Commercially available &#34;Vainilla (Soluci&#243;n)&#34;. Discriminative stimulus odor</td>
		</tr>
		<tr>
			<td>Video camera</td>
			<td>Sony</td>
			<td>DCR-SX22</td>
			<td>Sony handycam.</td>
		</tr>
	</tbody>
</table>

assessment of mouse judgment bias through an olfactory digging task

Judgment biases (JB) are differences in the way that individuals in positive and negative affective/emotional states interpret ambiguous information. This phenomenon has long been observed in humans, with individuals in positive states responding to ambiguity 'optimistically' and those in negative states instead showing 'pessimism'. Researchers aiming to assess animal affect have taken advantage of these differential responses, developing tasks to assess judgment bias as an indicator of affective state. These tasks are becoming increasingly popular across diverse species and fields of research. However, for laboratory mice, the most widely used vertebrates in research and a species heavily relied upon to model affective disorders, only one JB task has been successfully validated as sensitive to changes in affective state. Here, we provide a detailed description of this novel murine JB task, and evidence of its sensitivity to mouse affect. Though refinements are still necessary, assessment of mouse JB opens the door for answering both practical questions regarding mouse welfare, and fundamental questions about the impact of affective state in translational research.

Results presented here reflect relevant findings from Experiment 1 of Resasco et al.19. Subjects in this experiment were 18 female C57BL/6NCrl (&#39;C57&#39;) and 18 Balb/cAnNCrl (&#39;Balb&#39;) mice. Animals arrived at the facility at 3-4 weeks of age and were randomly assigned to environmentally enriched or conventional housing treatments (EH or CH, respectively) in mixed strain quartets25. Each cage contained one C57 and one Balb, in addition to two DBA/2NCrl mice being...

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Assessment of Mouse Judgment Bias through an Olfactory Digging Task

This article provides a detailed description of a novel mouse judgment bias protocol. Evidence of this olfactory digging task's sensitivity to affective state is also demonstrated and its utility across diverse research fields is discussed.

Judgment biases (JB) are differences in the way that individuals in positive and negative affective/emotional states interpret ambiguous information. This ...

This is the first ever mouse judgment bias task to be validated as sensitive to changes in affective state, in other words, mood or emotion. It can be used to investigate the effects of any variable on mouse affect. This protocol uses an ethological design, making it easy for mice to learn, and it's also welfare friendly, since the task avoids the use of punishment or negative reinforcement.This task can assess the impact of husbandry or experimental procedures on mouse affective states, making it valuable across diverse fields, like animal welfare research or modeling human affective disorders. Assuming researchers are already comfortable with non-aversive handling methods, our main advice is to use pilots before training to identify appropriate odor mixtures, in other words, the ones that mice treat as ambiguous. This behavioral test is a scent-based go-go digging task in which a mouse must dig for high-or low-value food rewards.The experimental apparatus comprises a rectangular arena with two arms. One arm is always centered and marked with either the positive or negative discriminative stimulus odor, and the other arm is always unscented. Digging pots include an accessible and an inaccessible compartment separated by a perforated plastic barrier.Both pots in the apparatus always contain the high-and low-value food, but treats are made accessible depending on the arm and trial type. During positive training trials, the mouse can choose to explore and dig in the scented arm, which contains a pot marked with a positive discriminative stimulus odor and a buried high-value food reward. The mouse can also choose to dig in the unscented arm, which is marked with distilled water and contains a low-value food reward.During negative training trials, The mouse can again choose between the scented arm, which now contains a pot marked with the negative discriminative stimulus odor and no accessible food reward, or the unscented arm, which is again marked with distilled water and contains a low-value food reward. Then, mice are tested in positive and negative un-reinforced trials, where no food rewards are available, and those who have learned the task will undergo an un-reinforced ambiguous trial. In the ambiguous trial, the scented arm contains a pot marked with a mixture of the positive and negative discriminative stimulus odor cues, making the ambiguous odor, while the unscented arm is marked with only distilled water, as always.Mice reveal their judgment biases in this ambiguous trial. For experimental preparation, using a one-milliliter syringe or micropipette, add mint and vanilla extract into labeled centrifuge tubes. Dilute the extracts 1:4 with distilled water and mix by inverting several times.Make these daily and repeatedly invert before use to ensure that the mixtures are fresh and consistent. For the ambiguous odor mixture, after the mint and vanilla essences have been diluted, add equal volumes to a centrifuge tube to make a 1:1 mixture of the diluted essences. Next, during the reinforced trials, for the positive discriminative stimulus odor pot, place one piece of chow in the inaccessible compartment and bury one piece of banana chip in the accessible area of the pot.For the negative discriminative stimulus odor pot, place one piece of chow and one piece of banana chip in the inaccessible compartment. Then, fill the pot with three centimeters of corn cob bedding. No food rewards will be available in the accessible area of this pot.For unscented pots, place one piece of banana chip in the inaccessible compartment and bury one piece of chow in the accessible area of the pot. During all un-reinforced trial tests, place one piece of chow and one piece of banana chip in the inaccessible compartment. Then, fill the pot with three centimeters of corn cob bedding.No food rewards will be available in the accessible area of this pot. After filling the pots, use a syringe or micropipette to draw 100 microliters of the appropriate odor mixture or distilled water and inject it directly on top of the corn cob in a circular motion. Next, to prepare scent dispensers, place one cotton pad piece in the base of the tissue cassette.Then, using a one-milliliter syringe or micropipette, draw 100 microliters of the appropriate odor mixture or distilled water and inject it onto the cotton piece. Cover the tissue cassette with its lid to enclose the scented cotton and create a scent dispenser. Place the digging pots at the end of the arms of the arena and the scent dispensers at the beginning of each arm.Insert the removable door immediately before the cassette slots to block entry to the arena arms and create the start compartment. Perform all training and testing sessions under red light during the dark and active phase of the mouse. Fast the mouse for one hour in their cage before each training or testing session by removing food from the hopper.On day one of digging training, place the food rewards on top of the three-centimeter corn cob bedding instead of burying them underneath. Progressively bury the rewards deeper under the corn cob over the following four days until they're located at the bottom of the three-centimeter bedding by day five. To start training trials, move the mouse from the transport cage to the start compartment of the arena.Remove the start door, immediately lower the plexiglass lid over the arena, and start the five-minute trial timer. Then, record latency to dig as the time at which the first occurrence of digging is observed and latency to eat as the time at which the first occurrence of eating is observed. For discrimination training, conduct one positive reinforced trial followed by one negative reinforced trial on days one to five.On days 6 to 10, pseudo-randomize the order of trials so that each mouse undergoes two positive and two negative trials per day. In the testing phase, conduct one positive or negative un-reinforced test trial for each mouse daily until the learning criteria are met. Each day, perform one positive and one negative reinforced trial in a randomized order before the video-recorded test trial, and another positive and negative reinforced trial after the test trial.Ensure that the positive and negative test trials are conducted in alternating order across days. To perform a video-recorded un-reinforced test trial, move the mouse from the transport cage to the start compartment of the arena. Then, set up a video camera on a tripod so that both pots at the end of the arms are in view and start recording.Ensure to record the cue card with the mouse blind code and the trial type during video scoring. Remove the start door, immediately lower the plexiglass lid over the arena, and start the two-minute trial timer. After testing, return the mouse to its transport cage.Score the positive and negative test trial videos on the day of testing to assess whether the mice have met the learning criteria. Ensure same day video scoring, since animals who meet learning criteria will undergo ambiguous tests the following day. Using event recording software or a stopwatch, let the researcher who is blind to treatment record each mouse's latency to dig and digging duration in each pot during the first minute of positive and negative test trials.Record latency to dig as the time at which the first occurrence of digging is observed, and digging duration as the total time a mouse spends digging. Compare digging duration in the scented pot between positive and negative trials to determine whether mice can discriminate the task. Learning criteria are met if digging duration in the positive discriminative stimulus odor pot is at least double that for the negative discriminative stimulus odor pot during the first minute of testing.For mice that have met the learning criteria, test responses to the ambiguous odor mixture. Perform one positive and one negative reinforced trial in a randomized order. Then, perform one video-recorded test trial using the ambiguous odor mixture.For data analysis, plot the least-squared means of latency in each trial type to confirm that the ambiguous cue presented was interpreted as intermediate. While assessing judgment bias in both the one and two minutes of testing, the trial type by positive discriminative stimulus-odor interaction was significant. This reveals that mice with mint as their positive discriminative stimulus unexpectedly interpreted the ambiguous odor mixtures as positive, while mice with vanilla as their positive discriminative stimulus treated the same ambiguous odor mixtures as intermediate.This finding indicated that only mice with vanilla as their positive discriminative stimulus met the technical requirement for treating the scent mixture as intermediate between the positive and negative discriminative stimulus. Thus, mice with mint as their positive discriminative stimulus were excluded from subsequent judgment bias analyses. Within mice with vanilla as their positive discriminative stimulus, housing influenced the digging latencies, with conventionally housed animals being slower to dig in ambiguous trials than environmentally enriched mice, but not for positive or negative trials.These pessimistic interpretations of ambiguous cues by conventionally housed mice reflect negative judgment biases indicative of negative affect. While performing this protocol, it's important that technical criterion are met. The mice should meet learning criterion showing they're able to discriminate between cues, and interpret the ambiguous cue as intermediate.The development of this new judgment bias task opens the door to test important hypotheses about mouse affective states with both animal welfare and clinical implications.

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Assessment of Sensorimotor Function in Mouse Models of Parkinson's Disease

Sensitive and reliable behavioral outcome measures are essential to the evaluation of potential therapeutic treatments in preclinical trials for many neurodegenerative diseases. In Parkinson's disease, sensorimotor tests sensitive to varying degrees of nigrostriatal dysfunction are fundamental for testing the efficacy of potential therapeutics. Reliable and quite elegant sensorimotor measures exist for rats, however many of these tests measure sensorimotor asymmetry within the rat and are not entirely suitable for the newer genetic mouse models of PD. We have put together a battery of sensorimotor tests inspired by the sensitive tests in rats and adapted for mice. The test battery highlighted in this study is chosen for a) its sensitivity in a wide variety of mouse models of PD, b) its ease in implementing into a study, and c) its low expense. These tests have proven useful in characterizing novel genetic mouse models of PD as well as in testing potential disease-modifying therapies.

Assessment of Sensorimotor Function in Mouse Models of Parkinson&#039;s Disease

In Parkinson's disease and movement disorders in general, sensitive and reliable behavioral assays are essential for testing novel potential therapeutics. Here, we describe a manageable battery of sensorimotor tests for mice that are sensitive to varying degrees of injury to the nigrostriatal system and useful for preclinical studies.

Sensitive and  reliable behavioral outcome measures are essential to the evaluation of  potential therapeutic treatments in preclinical trials for many  ...

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

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

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

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

The 5-Choice Serial Reaction Time Task: A Task of Attention and Impulse Control for Rodents

This protocol describes the 5-choice serial reaction time task, which is an operant based task used to study attention and impulse control in rodents. Test day challenges, modifications to the standard task, can be used to systematically tax the neural systems controlling either attention or impulse control. Importantly, these challenges have consistent effects on behavior across laboratories in intact animals and can reveal either enhancements or deficits in cognitive function that are not apparent when rats are only tested on the standard task. The variety of behavioral measures that are collected can be used to determine if other factors (i.e., sedation, motivation deficits, locomotor impairments) are contributing to changes in performance. The versatility of the 5CSRTT is further enhanced because it is amenable to combination with pharmacological, molecular, and genetic techniques.

This protocol describes the 5-choice serial reaction time task, which is an operant based task used to study attention and impulse control in rodents. Test day challenges, which are modifications of the standard task, increase flexibility of the task and can be combined with other manipulations to more fully characterize behavior.

This protocol describes the 5-choice serial reaction time task, which is an operant based task used to study attention and impulse control in rodents. ...

Behavioral Assessment of the Aging Mouse Vestibular System

Age related decline in balance performance is associated with deteriorating muscle strength, motor coordination and vestibular function. While a number of studies show changes in balance phenotype with age in rodents, very few isolate the vestibular contribution to balance under either normal conditions or during senescence. We use two standard behavioral tests to characterize the balance performance of mice at defined age points over the lifespan: the rotarod test and the inclined balance beam test. Importantly though, a custom built rotator is also used to stimulate the vestibular system of mice (without inducing overt signs of motion sickness). These two tests have been used to show that changes in vestibular mediated-balance performance are present over the murine lifespan. Preliminary results show that both the rotarod test and the modified balance beam test can be used to identify changes in balance performance during aging as an alternative to more difficult and invasive techniques such as vestibulo-ocular (VOR) measurements.

Motor control and balance performance are known to deteriorate with age. This paper presents a number of standard noninvasive behavioral tests with the addition of a simple rotary stimulus to challenge the vestibular system and show changes in balance performance in a murine model of aging.

Age related decline in balance performance is associated with deteriorating muscle strength, motor coordination and vestibular function. While a number of ...

Experimental Assessment of Mouse Sociability Using an Automated Image Processing Approach

Mouse is the preferred model organism for testing drugs designed to increase sociability. We present a method to quantify mouse sociability in which the test mouse is placed in a standardized apparatus and relevant behaviors are assessed in three different sessions (called session I, II, and III).
The apparatus has three compartments (see Figure 1), the left and right compartments contain an inverted cup which can house a mouse (called &#34;stimulus mouse&#34;).
In session I, the test mouse is placed in the cage and its mobility is characterized by the number of transitions made between compartments. In session II, a stimulus mouse is placed under one of the inverted cups and the sociability of the test mouse is quantified by the amounts of time it spends near the cup containing the enclosed stimulus mouse vs. the empty inverted cup. In session III, the inverted cups are removed and both mice interact freely. The sociability of the test mouse in session III is quantified by the number of social approaches it makes toward the stimulus mouse and by the number of times it avoids a social approach by the stimulus mouse.
The automated evaluation of the movie detects the nose of the test mouse, which allows the determination of all described sociability measures in session I and II (in session III, approaches are identified automatically but classified manually). To find the nose, the image of an empty cage is digitally subtracted from each frame of the movie and the resulting image is binarized to identify the mouse pixels. The mouse tail is automatically removed and the two most distant points of the remaining mouse are determined; these are close to nose and base of tail. By analyzing the motion of the mouse and using continuity arguments, the nose is identified.
<img alt="Figure 1" src="/files/ftp_upload/52508/52508fig1.jpg" /> 
Figure 1. Assessment of Sociability During 3 sessions. Session I (top): Acclimation of test mouse to the cage. Session II (middle): Test mouse moving freely in the cage while the stimulus mouse is enclosed in an inverted cup. Session III (bottom): Both test mouse and stimulus mouse are allowed to move freely and interact with each other.

This protocol describes a method to quantify mouse sociability. Mice are videotaped as they move and interact in a special cage. Movie processing allows for the automated quantification of sociability with excellent accuracy and reliability.

Mouse is the preferred model organism for testing drugs designed to increase sociability. We present a method to quantify mouse sociability in which the ...

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

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

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

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

Measuring Delay Discounting in Humans Using an Adjusting Amount Task

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

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

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

Determining Pain Detection and Tolerance Thresholds Using an Integrated, Multi-Modal Pain Task Battery

Human pain models are useful in the assessing the analgesic effect of drugs, providing information about a drug&#39;s pharmacology and identify potentially suitable therapeutic populations. The need to use a comprehensive battery of pain models is highlighted by studies whereby only a single pain model, thought to relate to the clinical situation, demonstrates lack of efficacy. No single experimental model can mimic the complex nature of clinical pain. The integrated, multi-modal pain task&#160;battery presented here encompasses the electrical stimulation task, pressure stimulation task, cold pressor task, the UVB inflammatory model which includes a thermal task and a paradigm for inhibitory conditioned pain modulation. These human pain models have been tested for predicative validity and reliability both in their own right and in combination, and can be used repeatedly, quickly, in short succession, with minimum burden for the subject and with a modest quantity of equipment. This allows a drug to be fully characterized and profiled for analgesic effect which is especially useful for drugs with a novel or untested mechanism of action.

Human pain models are valuable tools used to assess the analgesic potential of novel compounds and predict their clinical efficacy, especially when used in an integrated manner. Although implementation of these models is complex, with proper execution, the pain models described in this protocol can provide predictive and reliable results.

Human pain models are useful in the assessing the analgesic effect of drugs, providing information about a drug&#39;s pharmacology and identify ...

Task Interruption and Resumption Paradigm for Testing the Activation and Pursuit of an Abstract Thinking Goal

This protocol is based on the task interruption and resumption paradigm, the premise of which is that active goals lead to persistent behavior and thus a higher resumption rate after a period of delay or interruption. The task interruption and resumption protocol described in this research is tailored to test the activation of cognitive goals (e.g., a goal to think more abstractly). Cognitive goals may be pursued even during the interruption period; thus, to prevent this, the protocol involves cognitive distraction. The protocol consists of several stages. Specifically, the initial stage includes the goal activation process, where the treatment (versus control) condition receives a manipulation to activate the cognitive goal being tested by the researcher. In the next stage, participants are presented with the introduction of a task that is perceived to either satisfy or not satisfy the cognitive goal of interest. Importantly, this task is interrupted a few seconds after it begins. The task interruption forces a delay period and introduces a cognitive distraction to prevent the automatic pursuit and fulfillment of the cognitive goal. After the interruption period, participants are given a choice between resuming the interrupted task and abandoning the interrupted task to complete an alternative task instead. Among participants whose cognitive goals had been activated at the earlier stage, the task resumption rate should be higher if the task was perceived as an opportunity to satisfy (versus not satisfy) the goal. Such a finding would provide empirical evidence that the cognitive goal has been activated and pursued. In previous research, this protocol has been used to test whether causal uncertainty activates an abstract thinking goal. Adapting the protocol to test the activation of other cognitive goals is also discussed.

This protocol was designed to test the activation and pursuit of cognitive goals (e.g., an abstract thinking goal) using the task interruption and resumption paradigm. The protocol is suitable for cognitive goals that are automatically pursued once activated, as the distraction procedure prevents goal pursuit during the interruption period.

This protocol is based on the task interruption and resumption paradigm, the premise of which is that active goals lead to persistent behavior and thus a ...

Iterative Development of an Innovative Smartphone-Based Dietary Assessment Tool: Traqq

To collect dietary intake data in a fast and reliable manner, a flexible and innovative smartphone application (app) called Traqq was developed (iOS/Android). This app can be used as a food record and&#160;24-h recall (or shorter recall periods). Different sampling schemes can be created on either prespecified or random days/times within a predetermined period for both methods, with&#160;push notifications to urge the participants to register their food intake. In case of non-response, notifications are automatically rescheduled to ensure complete data collection. For use as a food record, respondents can access the app and log their food intake throughout the day. Food records close automatically at the end of the day; recalls close after submission of the consumed items. The recall as well as the food record module provide access to an extensive food list based on the Dutch food composition database (FCDB), which can be accustomed to fit different research purposes. When selecting a food item, respondents are simultaneously prompted to insert portion size, i.e., in household measures (e.g., cups, spoons, glasses), standard portion sizes (e.g., small, medium, large), or weight in grams, and eating occasion/time of consumption. Portion size options can be adjusted, e.g., only entry in grams in case of a weighed food record or time of consumption instead of eating occasion). The app also includes a My Dishes function, which allows the respondent to create their own recipes or product combinations (e.g., a daily breakfast) and only report the total quantity consumed. Subsequently, the app accounts for yield and retention factors. The data are stored on a secure server. If desired, additional questions, i.e., in general or those related to specific food items or eating occasions can be incorporated. This paper describes the development of the system (app and backend), including expert evaluations and usability testing.

This article describes the protocol for the development of an innovative smartphone-based dietary assessment application Traqq, including expert evaluations and usability testing.