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The form of a conditioned stimulus can influence the degree to which it acquires incentive motivational properties.

Meyer PJ, Cogan ES, Robinson TE - PLoS ONE (2014)

Bottom Line: There is considerable individual variation in the extent to which food- and drug-associated cues (conditioned stimuli, CSs) acquire incentive salience, as indicated by whether they elicit approach towards them, and/or act as conditioned reinforcers.Even when presented in compound (a lever-tone CS), the two elements of the compound differentially acquired motivational properties.We conclude that variation in the to the ability of CSs to acquire incentive salience, and thus their ability to act as incentive stimuli capable of motivating behavior, is determined in part by properties of the CS itself.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
There is considerable individual variation in the extent to which food- and drug-associated cues (conditioned stimuli, CSs) acquire incentive salience, as indicated by whether they elicit approach towards them, and/or act as conditioned reinforcers. Here we asked whether this variation is influenced by properties of the CS itself. In rats, we assessed both the attractiveness and conditioned reinforcing properties of two CSs: a manipulable lever CS versus an auditory (tone) CS. There was considerable individual variation in the extent to which a lever CS acquired incentive motivational properties, as indicated by whether it became attractive (evoked a sign-tracking or goal-tracking conditioned response) or acted as a conditioned reinforcer. However, with a tone CS all rats learned a goal-tracking response, and the tone CS was an equally effective conditioned reinforcer in sign-trackers and goal-trackers. Even when presented in compound (a lever-tone CS), the two elements of the compound differentially acquired motivational properties. In contrast, amphetamine and stress potentiated the conditioned reinforcing properties of both visual and auditory CSs similarly in rats that primarily sign-tracked or goal-tracked. We conclude that variation in the to the ability of CSs to acquire incentive salience, and thus their ability to act as incentive stimuli capable of motivating behavior, is determined in part by properties of the CS itself.

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PCA behaviors using a compound CS.A) Sign-trackers (ST), goal-trackers (GTs), and intermediates (INs) were identified based on PCA using a compound tone/lever-cue. STs and GTs demonstrated either lever-directed (A) or goal-directed (B) behavior, respectively, during training.
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pone-0098163-g003: PCA behaviors using a compound CS.A) Sign-trackers (ST), goal-trackers (GTs), and intermediates (INs) were identified based on PCA using a compound tone/lever-cue. STs and GTs demonstrated either lever-directed (A) or goal-directed (B) behavior, respectively, during training.

Mentions: Of the 47 rats tested, 24 STs, 9 GTs, and 14 INs were identified, based on the PCA Index scores. During training with the compound lever/tone stimulus, individual differences in the form of the CR (ST vs. GT) emerged, as in experiment 1. With training, some rats (STs) learned to approach the lever, and others (GTs) the food magazine (Fig. 3; Fs (8, 176)>7.7; ps<0.001 for the Phenotype by Day interaction for both measures). While not an explicit goal of this experiment, the similar PCA scores (mean: 0.34, SEM: 0.08) compared to experiment 1 (mean: 0.23, SEM: 0.08) suggest that presenting the tone in compound with the lever did not significantly alter PCA behavior [t (1, 97) = 0.98, p>0.05]. This result would be expected if the tone CS and lever CS acquired incentive salience through separate mechanisms. Otherwise, the auditory component of the CS would be expected to promote more goal-tracking in rats that would otherwise be sign-tracking, thereby reducing the number of rats identified as STs.


The form of a conditioned stimulus can influence the degree to which it acquires incentive motivational properties.

Meyer PJ, Cogan ES, Robinson TE - PLoS ONE (2014)

PCA behaviors using a compound CS.A) Sign-trackers (ST), goal-trackers (GTs), and intermediates (INs) were identified based on PCA using a compound tone/lever-cue. STs and GTs demonstrated either lever-directed (A) or goal-directed (B) behavior, respectively, during training.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048203&req=5

pone-0098163-g003: PCA behaviors using a compound CS.A) Sign-trackers (ST), goal-trackers (GTs), and intermediates (INs) were identified based on PCA using a compound tone/lever-cue. STs and GTs demonstrated either lever-directed (A) or goal-directed (B) behavior, respectively, during training.
Mentions: Of the 47 rats tested, 24 STs, 9 GTs, and 14 INs were identified, based on the PCA Index scores. During training with the compound lever/tone stimulus, individual differences in the form of the CR (ST vs. GT) emerged, as in experiment 1. With training, some rats (STs) learned to approach the lever, and others (GTs) the food magazine (Fig. 3; Fs (8, 176)>7.7; ps<0.001 for the Phenotype by Day interaction for both measures). While not an explicit goal of this experiment, the similar PCA scores (mean: 0.34, SEM: 0.08) compared to experiment 1 (mean: 0.23, SEM: 0.08) suggest that presenting the tone in compound with the lever did not significantly alter PCA behavior [t (1, 97) = 0.98, p>0.05]. This result would be expected if the tone CS and lever CS acquired incentive salience through separate mechanisms. Otherwise, the auditory component of the CS would be expected to promote more goal-tracking in rats that would otherwise be sign-tracking, thereby reducing the number of rats identified as STs.

Bottom Line: There is considerable individual variation in the extent to which food- and drug-associated cues (conditioned stimuli, CSs) acquire incentive salience, as indicated by whether they elicit approach towards them, and/or act as conditioned reinforcers.Even when presented in compound (a lever-tone CS), the two elements of the compound differentially acquired motivational properties.We conclude that variation in the to the ability of CSs to acquire incentive salience, and thus their ability to act as incentive stimuli capable of motivating behavior, is determined in part by properties of the CS itself.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
There is considerable individual variation in the extent to which food- and drug-associated cues (conditioned stimuli, CSs) acquire incentive salience, as indicated by whether they elicit approach towards them, and/or act as conditioned reinforcers. Here we asked whether this variation is influenced by properties of the CS itself. In rats, we assessed both the attractiveness and conditioned reinforcing properties of two CSs: a manipulable lever CS versus an auditory (tone) CS. There was considerable individual variation in the extent to which a lever CS acquired incentive motivational properties, as indicated by whether it became attractive (evoked a sign-tracking or goal-tracking conditioned response) or acted as a conditioned reinforcer. However, with a tone CS all rats learned a goal-tracking response, and the tone CS was an equally effective conditioned reinforcer in sign-trackers and goal-trackers. Even when presented in compound (a lever-tone CS), the two elements of the compound differentially acquired motivational properties. In contrast, amphetamine and stress potentiated the conditioned reinforcing properties of both visual and auditory CSs similarly in rats that primarily sign-tracked or goal-tracked. We conclude that variation in the to the ability of CSs to acquire incentive salience, and thus their ability to act as incentive stimuli capable of motivating behavior, is determined in part by properties of the CS itself.

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