The Form of a Conditioned Stimulus Can Influence the Degree to Which It Acquires Incentive Motivational Properties

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.

Isolating the incentive salience of reward-associated stimuli: value, choice, and persistence

“…Like others (Holland 1977;Cleland and Davey 1983;Holland et al 2014;Meyer et al 2014) the present results demonstrate clearly that different conditioned stimuli can preferentially elicit sign-and goal-tracking, and these stimuli can be differentially attributed with incentive salience or value. However, the current within-subject method is a departure from the predominant method used to study sign-and goal-tracking behavior in the past.…”

“…Furthermore, Meyer et al (2014) demonstrated that a reward-predictive tone that elicits goal-tracking behavior maintains the same amount of conditioned reinforcement in animals prescreened as sign-trackers or goal-trackers, while the lever stimulus associated with sign-tracking was the most robust conditioned reinforcer. Importantly, Meyer et al (2014) also demonstrated that the conditioned reinforcement maintained by the tone in sign-and goal-trackers was equivalent to that maintained by a lever in animals prescreened as goal-trackers. Collectively, these results indicate that a tone associated with goal-tracking and a lever associated with goal-tracking are of equivalent value, maintaining identical conditioned reinforcement regardless of whether an animal is labeled as a sign-tracker or goal-tracker.…”

“…Interestingly, there is also a large literature demonstrating that pairing different stimuli (e.g., levers or tones) with reward can differentially induce signand goal-tracking. For example, pairing a tone with food results in primarily goal-tracking behavior (Holland 1977;Harrison 1979;Cleland and Davey 1983;Holland et al 2014;Meyer et al 2014). Furthermore, Meyer et al (2014) demonstrated that a reward-predictive tone that elicits goal-tracking behavior maintains the same amount of conditioned reinforcement in animals prescreened as sign-trackers or goal-trackers, while the lever stimulus associated with sign-tracking was the most robust conditioned reinforcer.…”

“…For example, pairing a tone with food results in primarily goal-tracking behavior (Holland 1977;Harrison 1979;Cleland and Davey 1983;Holland et al 2014;Meyer et al 2014). Furthermore, Meyer et al (2014) demonstrated that a reward-predictive tone that elicits goal-tracking behavior maintains the same amount of conditioned reinforcement in animals prescreened as sign-trackers or goal-trackers, while the lever stimulus associated with sign-tracking was the most robust conditioned reinforcer. Importantly, Meyer et al (2014) also demonstrated that the conditioned reinforcement maintained by the tone in sign-and goal-trackers was equivalent to that maintained by a lever in animals prescreened as goal-trackers.…”

A Cocaine Context Renews Drug Seeking Preferentially in a Subset of Individuals

“…Taken together, these results suggest GTs more readily rely on contextual cues, and STs on discrete or punctate cues, irrespective of extinction training or the motivational valence or associative nature (instrumental or Pavlovian) of the setting. However, it remains to be determined exactly what psychological propensities give rise to such variation in the ability of various classes of environmental stimuli to gain control over motivated behavior (see also Meyer et al, 2014). Although we have emphasized a motivational interpretation here, we readily acknowledge there are a number of other interacting processes that could contribute to such variation, from visuospatial (Hickey et al, 2010;Hickey and van Zoest, 2012) to attentional processes, to variation in the content of learning (Clark et al, 2012).…”