This work was funded by the University of Michigan Department Of Psychiatry (U032826; JDM), the National Institute on Drug Abuse (NIDA; K08 DA037912-01; JDM) and the Department of Defense (DoD) National Defense Science and Engineering Graduate (NDSEG) Fellowship (CJF).

All procedures have been approved by the University Committee on the Use and Care of Animals (UCUCA; University of Michigan, Ann Arbor, MI).
1. Equipment and Software
<ol>
	<li>Obtain commercial operant chambers and devices. See Materials Table.</li>
	<li>Conduct training in rat operant conditioning chambers (24.1 cm width &#215; 20.5 cm depth x 29.2 cm height), situated in sound-attenuating cabinets with ventilation fans to provide ambient noise.</li>
	<li>Equip each chamber wi...

<ol>
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J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+individual+variation+in+the+propensity+to+attribute+incentive+salience+to+reward+cues.">Quantifying individual variation in the propensity to attribute incentive salience to reward cues.</a> PloS One. 7 (6), e38987 (2012).</li><li>Yager, L. M., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+classically+conditioned+cocaine+cue+acquires+greater+control+over+motivated+behavior+in+rats+prone+to+attribute+incentive+salience+to+a+food+cue.">A classically conditioned cocaine cue acquires greater control over motivated behavior in rats prone to attribute incentive salience to a food cue.</a> Psychopharmacology (Berl). 226 (2), 217-228 (2013).</li><li>Yager, L. M., Pitchers, K. K., Flagel, S. B., Robinson, T. 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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+variation+in+the+motivational+properties+of+cocaine.">Individual variation in the motivational properties of cocaine.</a> Neuropsychopharmacology. 36 (8), 1668-1676 (2011).</li><li>Saunders, B. T., Yager, L. M., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cue-evoked+cocaine+'craving':+role+of+dopamine+in+the+accumbens+core.">Cue-evoked cocaine 'craving': role of dopamine in the accumbens core.</a> J Neurosci. 33 (35), 13989-14000 (2013).</li><li>Kearns, D. N., Gomez-Serrano, M. A., Weiss, S. J., Riley, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+Lewis+and+Fischer+rat+strains+on+autoshaping+(sign-tracking),+discrimination+reversal+learning+and+negative+auto-maintenance.">A comparison of Lewis and Fischer rat strains on autoshaping (sign-tracking), discrimination reversal learning and negative auto-maintenance.</a> Behav Brain Res. 169 (2), 193-200 (2006).</li><li>Fitzpatrick, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+the+form+of+Pavlovian+conditioned+approach+behavior+among+outbred+male+Sprague-Dawley+rats+from+different+vendors+and+colonies:+sign-tracking+vs.+goal-tracking.">Variation in the form of Pavlovian conditioned approach behavior among outbred male Sprague-Dawley rats from different vendors and colonies: sign-tracking vs. goal-tracking.</a> PloS One. 8 (10), e75042 (2013).</li><li>Anderson, R. I., Spear, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autoshaping+in+adolescence+enhances+sign-tracking+behavior+in+adulthood:+impact+on+ethanol+consumption.">Autoshaping in adolescence enhances sign-tracking behavior in adulthood: impact on ethanol consumption.</a> Pharmacol Biochem Behav. 98 (2), 250-260 (2011).</li><li>Pitchers, K. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+variation+in+the+propensity+to+attribute+incentive+salience+to+a+food+cue:+Influence+of+sex.">Individual variation in the propensity to attribute incentive salience to a food cue: Influence of sex.</a> Behav Brain Res. 278, 462-469 (2015).</li><li>Anderson, R. I., Bush, P. C., Spear, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+manipulations+alter+age+differences+in+attribution+of+incentive+salience+to+reward-paired+cues.">Environmental manipulations alter age differences in attribution of incentive salience to reward-paired cues.</a> Behav Brain Res. 257, 83-89 (2013).</li><li>Beckmann, J. S., Bardo, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+enrichment+reduces+attribution+of+incentive+salience+to+a+food-associated+stimulus.">Environmental enrichment reduces attribution of incentive salience to a food-associated stimulus.</a> Behav Brain Res. 226 (1), 331-334 (2012).</li><li>Burns, M., Domjan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topography+of+spatially+directed+conditioned+responding:+effects+of+context+and+trial+duration.">Topography of spatially directed conditioned responding: effects of context and trial duration.</a> J Exp Psychol Anim Behav Process. 27 (3), 269-278 (2001).</li><li>Christie, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+contiguity+facilitates+Pavlovian+conditioning.">Spatial contiguity facilitates Pavlovian conditioning.</a> Psychon Bull Rev. 3 (3), 357-359 (1996).</li><li>Meyer, P. J., Cogan, E. S., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+form+of+a+conditioned+stimulus+can+influence+the+degree+to+which+it+acquires+incentive+motivational+properties.">The form of a conditioned stimulus can influence the degree to which it acquires incentive motivational properties.</a> PloS One. 9 (6), e98163 (2014).</li><li>Beckmann, J. S., Chow, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolating+the+incentive+salience+of+reward-associated+stimuli:+value,+choice,+and+persistence.">Isolating the incentive salience of reward-associated stimuli: value, choice, and persistence.</a> Learn Mem. 22 (2), 116-127 (2015).</li><li>Flagel, S. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+selective+role+for+dopamine+in+stimulus-reward+learning.">A selective role for dopamine in stimulus-reward learning.</a> Nature. 469 (7328), 53-57 (2011).</li><li>Saunders, B. T., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+dopamine+in+the+accumbens+core+in+the+expression+of+Pavlovian-conditioned+responses.">The role of dopamine in the accumbens core in the expression of Pavlovian-conditioned responses.</a> Eur J Neurosci. 36 (4), 2521-2532 (2012).</li><li>Clark, J. J., Collins, A. L., Sanford, C. A., Phillips, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+encoding+of+Pavlovian+incentive+stimuli+diminishes+with+extended+training.">Dopamine encoding of Pavlovian incentive stimuli diminishes with extended training.</a> J Neurosci. 33 (8), 3526-3532 (2013).</li><li>Anselme, P., Robinson, M. J., Berridge, K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reward+uncertainty+enhances+incentive+salience+attribution+as+sign-tracking.">Reward uncertainty enhances incentive salience attribution as sign-tracking.</a> Behav Brain Res. 238, 53-61 (2013).</li><li>Robinson, M. J., Anselme, P., Fischer, A. M., Berridge, K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Initial+uncertainty+in+Pavlovian+reward+prediction+persistently+elevates+incentive+salience+and+extends+sign-tracking+to+normally+unattractive+cues.">Initial uncertainty in Pavlovian reward prediction persistently elevates incentive salience and extends sign-tracking to normally unattractive cues.</a> Behav Brain Res. 266, 119-130 (2014).</li><li>Gallistel, C. R., Gibbon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time,+rate,+and+conditioning.">Time, rate, and conditioning.</a> Psychol Rev. 107 (2), 289-344 (2000).</li><li>Morrow, J. D., Maren, S., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+variation+in+the+propensity+to+attribute+incentive+salience+to+an+appetitive+cue+predicts+the+propensity+to+attribute+motivational+salience+to+an+aversive+cue.">Individual variation in the propensity to attribute incentive salience to an appetitive cue predicts the propensity to attribute motivational salience to an aversive cue.</a> Behav Brain Res. 220 (1), 238-243 (2011).</li><li>Morrow, J. D., Saunders, B. T., Maren, S., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sign-tracking+to+an+appetitive+cue+predicts+incubation+of+conditioned+fear+in+rats.">Sign-tracking to an appetitive cue predicts incubation of conditioned fear in rats.</a> Behav Brain Res. 276, 59-66 (2015).</li><li>Saunders, B. T., O'Donnell, E. G., Aurbach, E. L., Robinson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cocaine+context+renews+drug+seeking+preferentially+in+a+subset+of+individuals.">A cocaine context renews drug seeking preferentially in a subset of individuals.</a> Neuropsychopharmacology. 39 (12), 2816-2823 (2014).</li></ol>

PCA training can be used to determine individual variation in the tendency to attribute incentive salience to conditioned cues, which has been argued to be an important component of addiction vulnerability. For example, it has previously been demonstrated that STs attribute incentive salience to both food and drug cues6, and both food- and drug-related cues activate similar brain regions within an amygdalo-striatal-thalamic circuit in STs7. Moreover, STs are more impulsive8, vulnerable to...

The transition of drug use to addiction involves complex interactions between Pavlovian and instrumental learning1,2. During drug-taking and drug-seeking behaviors, actions and outcomes are learned through instrumental processes; however, relationships between stimuli (e.g., drug-related cues) and rewards are also learned through Pavlovian processes. Pavlovian cues acquire predictive value, but they can also acquire incentive motivational value3, whereby they become attractive, desirable, and capable of promoting and maintaining reward-seeking behavior4.
Many procedures investigating reward learning in animals, however, do not permit the disentanglement of predictive versus incentive motivational learning. In drug self-administration procedures, for example, both instrumental and Pavlovian contingencies are typically employed, such that rats learn to perform an action (e.g., nose-poking, lever-pressing, etc.) in order to receive an outcome (i.e., intravenous drug infusion). The rewarding outcome is also paired with Pavlovian stimuli (e.g., illumination of a nose-poke port, cue light presentation, sound of the infusion pump, interoceptive feeling of fluid delivery into the bloodstream, etc.). It is often unclear in these procedures whether cues are supporting goal-directed actions simply because of their predictive relationship with the reward, or whether cues have acquired incentive motivational properties of their own.
In order to experimentally isolate the incentive motivational value from the predictive value of Pavlovian stimuli, our laboratory uses a Pavlovian conditioned approach (PCA) procedure in order to identify rats that attribute incentive salience to reward-related cues. During a training session, a conditioned stimulus (CS; e.g., a lever) response-independently predicts the delivery of an unconditioned stimulus (US; e.g., a food pellet). Over the course of multiple training sessions, three phenotypes develop: sign-tracking (CS-directed conditioned response [CR]), goal-tracking (US-directed CR), and an intermediate response (both CRs). For goal-trackers (GTs), the CS is utilized as a predictor of reward delivery; however, for sign-trackers (STs), the CS is attributed with incentive salience, becoming attractive and desirable. In this review, we outline the equipment, setup, and data processing necessary to perform a PCA procedure. In addition, we provide representative results of PCA training, outline important experimental considerations, and discuss the putative utility of PCA procedures in investigating addiction and other neuropsychiatric disorders.

<table>
	<tbody>
		<tr>
			<td>Standard Modular Operant Test Chamber with Modified Top for Rat</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-008CT</td>
			<td>Top has access slot for drug delivery leashes or other harness systems; comes with ENV-008CTC (Cover Insert) for access slot</td>
		</tr>
		<tr>
			<td>Expanded PVC Sound Attenuating Cubicle</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-022V</td>
			<td></td>
		</tr>
		<tr>
			<td>PCI Operating Package for up to Sixteen Chambers</td>
			<td>Med Associates, Inc.</td>
			<td>MED-SYST-16</td>
			<td>Based on the number of operant chambers, MED-SYST-8 (PCI Operating Package for up to Eight Chambers) is also available</td>
		</tr>
		<tr>
			<td>SmartCtrl</td>
			<td>Med Associates, Inc.</td>
			<td>DIG-716P2</td>
			<td></td>
		</tr>
		<tr>
			<td>Universal Cable, 25&#8242; (7.6 m)</td>
			<td>Med Associates, Inc.</td>
			<td>SG-210CB</td>
			<td>Based on individual needs, SG-210CB-50 (Universal Cable, 50&#8242; [15.2 m]) is also available</td>
		</tr>
		<tr>
			<td>18&#8243; (45.7 cm) 3-Pin Mini-Molex</td>
			<td>Med Associates, Inc.</td>
			<td>SG-216A</td>
			<td>Based on individual needs, SG-216A-2 (2&#8242; [61.0 cm] 3-Pin Mini-Molex) is also available</td>
		</tr>
		<tr>
			<td>Power Cable, 25&#8242; (7.6 m)&#160;</td>
			<td>Med Associates, Inc.</td>
			<td>SG-210CP-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless Steel Grid Floor for Rat</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-005</td>
			<td>Based on preference, ENV-005A (Stainless Steel Grid Floor for Mouse) is also available&#160;</td>
		</tr>
		<tr>
			<td>Reusable Waste Pan</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-007-P3</td>
			<td></td>
		</tr>
		<tr>
			<td>Filler Panel Package for Standard Modular Test Chamber</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-008-FP</td>
			<td></td>
		</tr>
		<tr>
			<td>Modular Pellet Dispenser for Rat, 45mg</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-203M-45</td>
			<td></td>
		</tr>
		<tr>
			<td>Pellet Receptacle, Trough Type</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-200R2M</td>
			<td>Based on preference, ENV-200R1M (Pellet Receptable, Cup Type) is also available&#160;</td>
		</tr>
		<tr>
			<td>Retractable Lever</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-112CM</td>
			<td>Calibrated to 25 g; needs to be adjusted to 10 g before Pavlovian conditioned approach training</td>
		</tr>
		<tr>
			<td>Retractable Lever Cue Light</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-112CML</td>
			<td></td>
		</tr>
		<tr>
			<td>House Light for Rat</td>
			<td>Med Associates, Inc.</td>
			<td>ENV-215M</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mA Replacement Bulbs, Pack of 10</td>
			<td>Med Associates, Inc.</td>
			<td>SG-800R</td>
			<td>Red-colored; for use with ENV-215M (House Light for Rat)</td>
		</tr>
		<tr>
			<td>Pellets, 45 mg, Primate Purified Diet, Banana Flavor</td>
			<td>Bio-Serv</td>
			<td>F0059</td>
			<td>50,000/box&#160;</td>
		</tr>
	</tbody>
</table>

pavlovian conditioned approach training in rats

Cues that are contingently paired with unconditioned, rewarding stimuli can acquire rewarding properties themselves through a process known as the attribution of incentive salience, or the transformation of neutral stimuli into attractive, &#34;wanted&#39; stimuli capable of motivating behavior. Pavlovian conditioned approach (PCA) develops after the response-independent presentation of a conditioned stimulus (CS; e.g., a lever) that predicts the delivery of an unconditioned stimulus (US; e.g., a food pellet) and can be used to measure incentive salience. During training, three patterns of conditioned responses (CRs) can develop: sign-tracking behavior (CS-directed CR), goal-tracking behavior (US-directed CR), and an intermediate response (both CRs). Sign-trackers attribute incentive salience to reward-related cues and are more vulnerable to cue-induced reinstatement of drug-seeking as well as other addiction-related behaviors, making PCA a potentially valuable procedure for studying addiction vulnerability. Here, we describe materials and methods used to elicit PCA behavior from rats as well as analyze and interpret PCA behavior in individual experiments.

We have found that 5-7 daily sessions of PCA training is sufficient to phenotype rats as STs, GTs, and intermediate responders (IRs), although rats can be trained further based on the needs of a particular laboratory or experiment. Phenotyping is based on PCA index scores, which are calculated by averaging the response bias, latency score, and probability difference of individual sessions as previously described in the protocol. Phenotypes are determined by averaging the PCA index scores ...

Watch this Scientific Journal Video about Pavlovian Conditioned Approach Training in Rats at JoVE.com

Pavlovian Conditioned Approach Training in Rats

Here, we present a protocol to elicit Pavlovian conditioned approach behavior in rats. This procedure can be used to measure individual differences in the tendency to approach and attribute incentive salience to reward-related cues and investigate addiction vulnerability.

Cues that are contingently paired with unconditioned, rewarding stimuli can acquire rewarding properties themselves through a process known as the ...

The overall goal of this procedure is to elicit Pavlovian conditioned approach behavior in rats. This procedure can help answer key questions in the field of behavioral neuroscience, such as why some individuals can resist the temptation to pursue reward cues while others cannot. The main advantage of this procedure is that it allows us to measure the incentive motivational value of cues separately from their predictive value.Demonstrating this procedure will be Christopher Fitzpatrick, a neuroscience graduate student from my laboratory. This protocol utilizes commercial operant conditioning chambers in sound-attenuating cabinets with ventilation fans to provide ambient noise. Within each chamber, equip a pellet magazine with an infrared sensor for head entries.Position it in the front wall of each chamber, three centimeters above the floor, and attach a dispenser to deliver 45-milligram banana-flavored food pellets. Next, in a counterbalanced manner, position a retractable lever about 2.5 centimeters to either side of the receptacle and about 3 centimeters above the floor. The lever should have an LED cue light to make it more attractive.To calibrate the lever, place a 10-gram weight on it and adjust the calibration screw until the weight pushes the lever down. Then, attach a red light to the roof of the chamber above the receptacle. This will increase the conspicuousness of the illuminated lever.This completes the chamber preparations. Order adult male Sprague Dawley rats that are between 250 and 300 grams, and pair-house them on arrival. Leave the rats undisturbed for at least two days in the housing colony to acclimate.The colony should be maintained on a 12-hour light-dark cycle, and the rats should have ad libitum access to food and water. After an initial acclimation period, handle each rat for at least one minute per day, for a couple of days. On the two days before pre-training, give each rat 15 banana-flavored pellets daily.Divide these pellets evenly on separate sides of the home cage. For this protocol, create a pre-training program. The programming is done in MEDState Notation.The manual is available online. Write a program to deliver 50 food pellets on a variable-time 30-second schedule five minutes after the start of the program. The interval is on average 30 seconds but varies randomly between zero and 60 seconds.During this time, the red house light should be on, but the retractable lever should remain retracted for the duration of the program. Do the pre-training during the light cycle the day before PCA training. Place each rat into an operant chamber.Close and latch the chamber door. Close the sound-attenuating cabinet door, and immediately run the program. As soon as the program is completed, remove the rats from the chambers.Record the number of pellets consumed. Any rats that do not consume all of the pellets should be excluded from further testing. In the software, write a training program to run 25 trials over about 40 minutes, beginning one minute after the start of the program.During each trial, have the lever illuminate and extend into the chamber for eight seconds. The interior red light is always on. When the lever retracts, have one food pellet dispense independently of the rat's response.Separate each trial on a variable-time 90-second schedule. The interval is on average 90 seconds but varies randomly between 30 and 150 seconds. Run the PCA program just as the pre-training was run.After removing the rats, record the number of pellets consumed, and exclude rats that do not consume all of the pellets. Now, using data collected by the program, calculate the PCA index scores. Male rats underwent five PCA training sessions, during which the number, latency, and probability of magazine entries and lever presses were recorded.For each daily PCA training session, PCA index scores were calculated from these variables. The PCA index scores from the last two training sessions were used to categorize the rats as sign trackers, goal trackers, or as having an intermediate phenotype. Sign trackers primarily approached and directed their behavior toward the reward-related lever cue.On the PCA index, their scores ranged from 5 to 1. In contrast, goal trackers primarily approached and directed their behavior toward the source of reward delivery, the pellet magazine. On the PCA index, their scores ranged from 5 to 1.The intermediate phenotype does not bias either behavior. After watching this video, you should have a good understanding of how to elicit Pavlovian conditioned approach in rats.

pavlovian-conditioned-approach-training-in-rats

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JoVE Journal

Behavior

10.8K 조회수.  University of Michigan. The overall goal of this procedure is to elicit Pavlovian conditioned approach behavior in rats. This procedure can help answer key questions in the field of behavioral neuroscience, such as why some individuals can resist the temptation to pursue reward cues while others cannot. The main advantage of this procedure is that it allows us to measure the incentive motivational value of cues separately from their predictive value.Demonstrating this procedure will be Christopher Fitzpatrick...