Differential involvement of dopamine receptor subtypes in the acquisition of Pavlovian sign-tracking and goal-tracking responses.

ABSTRACT: RATIONALE:Previous work has identified that different forms of Pavlovian conditioned approach, sign-tracking and goal-tracking, are governed by distinct neurochemical mechanisms when compared in animals predisposed to learning one form vs. the other. OBJECTIVES:The present study aimed to investigate whether these are also neurochemically distinct processes in a population of animals capable of developing either response when this is manipulated via the use of distinct conditioned stimuli (CS). METHODS:Rats were trained on one of two Pavlovian conditioning procedures in which the CS was either a lever, which elicits sign-tracking, or an auditory click, which elicits goal-tracking. The differential involvement of dopamine D1- and D2-receptors (D1R; D2R) in the acquisition of approach types was investigated via systemic administration of antagonists selective to one or both receptor subtypes during Pavlovian training. RESULTS:Results indicate that dopaminergic signalling is important for the acquisition of both sign-tracking and goal-tracking responses. However, whilst development of sign-tracking to a lever depends on activity at both D1R and D2R, development of goal-tracking in response to a click was shown to depend only on activity at D1R. CONCLUSIONS:We suggest that the importance of D1R activity in both sign- and goal-tracking acquisition reflects a general role in learning Pavlovian associations, which aligns with data implicating dopamine in prediction error processes. In contrast, the selective involvement of D2R activity in sign-tracking acquisition may reflect its importance in motivational processes such as incentive salience attribution.

SUBMITTER: Roughley S 

PROVIDER: S-EPMC6602989 | biostudies-literature |

REPOSITORIES: biostudies-literature