Evidence of structure and persistence in motivational attraction to serial Pavlovian cues

Abstract

Sign-tracking is a form of autoshaping where animals develop conditioned responding directed toward stimuli predictive of an outcome even though the outcome is not contingent on the animal's behavior. Sign-tracking behaviors are thought to arise out of the attribution of incentive salience (i.e., motivational value) to reward-predictive cues. It is not known how incentive salience would be attributed to serially occurring cues, despite cues often occurring in a sequence in the real world as reward approaches. The experiments presented here demonstrate that reward-proximal cue responding is not altered by the presence of a distal reward cue (Experiment 1), and similarly that reward-distal cue responding which animals favor, is not altered by the presence of a reward-proximal cue (Experiment 2). Extinction of reward-proximal cues after training of the serial sequence leads to a generalized reduction in lever responding (Experiment 3). Together, we show that both Pavlovian serial lever cues acquire motivational value. These experiments also provide support to the notion that sign-tracking responses are insensitive to changes in outcome value, and that responding to serial cues creates a distinct context for outcome value.

Effects of Limited and Extended Pavlovian Training on Devaluation Sensitivity of Sign- and Goal-Tracking Rats

“…Using a within-subject satiety-induced outcome devaluation procedure, we replicated our previous findings that after limited Pavlovian training, GT rats are sensitive to outcome devaluation while ST rats are not (Nasser et al, 2015). This trackingspecific devaluation sensitivity has replicated across several studies, Pavlovian paradigms, and devaluation procedures (Nasser et al, 2015;Patitucci et al, 2016;Smedley and Smith, 2018). As GT rats increased lever-directed and decreased food cup-directed behaviors across extended training, we expected their behavior to become inflexible during outcome devaluation, similar to ST rats.…”

“…Sign-tracking in rats also predicts heightened drug relapse despite having to traverse an electrified barrier to seek and take drugs . We and others have shown that even prior to the drug experience, sign-trackers are inflexible, continuing to respond to cues when associated outcomes are devalued (Morrison et al, 2015;Nasser et al, 2015;Smedley and Smith, 2018). In contrast, goal-trackers flexibly adapt after outcome devaluation and are less susceptible to drug relapse when punishment is imposed Nasser et al, 2015).…”

“…The differences in sign-tracking devaluation sensitivity between studies may be due to differences in the amount of training prior to devaluation procedures. Insensitivity to devaluation has been observed in ST rats after limited training [<10 training sessions; (Morrison et al, 2015;Nasser et al, 2015)], and some studies using extended training prior to devaluation [ >10 training sessions; (Patitucci et al, 2016;Smedley and Smith, 2018)]. Yet other studies using extended training prior to devaluation report devaluation sensitivity of lever directed behaviors generally, and in ST rats specifically (Cleland and Davey, 1982;Derman et al, 2018).…”

Increased Goal Tracking in Adolescent Rats Is Goal-Directed and Not Habit-Like

“…In adult rats, sign-tracking behavior, compared with goal-tracking behavior, is relatively insensitive to reward devaluation, whether accomplished via pre-feeding (Patitucci et al, 2016;Conrad and Papini, 2018) or conditioned taste aversion (CTA; Morrison et al, 2015;Smedley and Smith, 2018; although devaluation can affect the approach to the cue under some circumstances: see Cleland and Davey, 1982;Derman et al, 2018). Because resistance to reward devaluation is one of the defining features of habitual actions (Balleine and O'Doherty, 2010), these findings imply that sign tracking is a habit-like behavior, although it is distinct from a classically defined habit because it arises from Pavlovian rather than instrumental contingencies (Dayan and Berridge, 2014).…”

Cannabinoid receptor-1 signaling contributions to sign-tracking and conditioned reinforcement in rats

“…Others have shown endocannabinoid attenuation of cortical glutamate release in the dorsal medial striatum mediates the transition between goal-directed and habitual behaviors, which are defined by their sensitivity to changes in outcome value (Gremel, Chancey et al 2016). Given the differential sensitivity of sign- and goal-trackers to changes in outcome value (Anselme, Robinson et al 2013, Ahrens, Singer et al 2015, Morrison, Bamkole et al 2015, Nasser, Chen et al 2015, Smedley and Smith 2018), this may be another viable target for exploring the contributions of CB1 signaling on sign- and goal-tracking behaviors. Notably, the motivational properties of natural rewards depend on endocannabinoid and opiate system interactions within mesocorticolimbic circuitry.…”