Manipulating the revision of reward value during the intertrial interval increases sign tracking and dopamine release

Abstract

Recent computational models of sign tracking (ST) and goal tracking (GT) have accounted for observations that dopamine (DA) is not necessary for all forms of learning and have provided a set of predictions to further their validity. Among these, a central prediction is that manipulating the intertrial interval (ITI) during autoshaping should change the relative ST-GT proportion as well as DA phasic responses. Here, we tested these predictions and found that lengthening the ITI increased ST, i.e., behavioral engagement with conditioned stimuli (CS) and cue-induced phasic DA release. Importantly, DA release was also present at the time of reward delivery, even after learning, and DA release was correlated with time spent in the food cup during the ITI. During conditioning with shorter ITIs, GT was prominent (i.e., engagement with food cup), and DA release responded to the CS while being absent at the time of reward delivery after learning. Hence, shorter ITIs restored the classical DA reward prediction error (RPE) pattern. These results validate the computational hypotheses, opening new perspectives on the understanding of individual differences in Pavlovian conditioning and DA signaling.

Individual differences in the nature of conditioned behavior across a conditioned stimulus: Adaptation and application of a model.

“…The pattern of results was clear: Rats designated as sign-trackers were more likely to exhibit their bias to sign-track at the start of the CS, while rats designated as goal-trackers were more likely to exhibit their bias to goal-track toward the end of the CS. At no point during the 6 blocks of training did the pattern of results observed in the groups designated as sign-trackers and goal-trackers match that reported in Lee et al (2018). However, they did match closely those reported by Derman et al (2018), especially in the small subset of rats that engaged in both sign-tracking and goal-tracking.…”

“…The aims of the current analyses were twofold: To assess how sign-tracking and goaltracking vary across the duration of a CS (cf. Derman et al, 2018;Lee et al, 2018); and to determine whether a simple modification to HeiDI allows it to provide an account of such variation, which is routinely taken to reflect a process of timing (e.g., Gallistel & Gibbon, 2000; see also Savastano & Miller, 1998) or the discrimination of successive parts of a CS (e.g., Vogel et al, 2003). We examined the empirical issue using archival data from Iliescu et al (2018).…”

In Vitro and In Vivo Sequestration of Phencyclidine by Me4Cucurbit[8]uril

“…Mice were trained on a standard autoshaping task described previously (Lee et al, 2018). All behavioral procedures were conducted in a Med Associates test chamber equipped with a food cup, a retractable lever, and 4 floor IR photobeams.…”

Instrumental and Pavlovian Mechanisms in Alcohol Use Disorder

“…Dopamine has thus been posited a role in incentive salience attribution, not S-R learning itself [150]. A recent computational model has accounted for this individual variation in Pavlovian conditioned approach behavior and dopaminergic release patterns [151] and its predictions were supported experimentally [152]. This model accounts for the development of distinct CRs in rodents through a combination of a model-based and a featured-model-free system, a revised model-free system that uses factored representations [151,153,154].…”