Pavlovian learning

Notwithstanding the above caveats, we favor the interpretation of the effects of neuroleptics in the paradigm of Ettenberg and colleagues as due to an impairment of Pavlovian incentive learning rather than of response reinforcement. These studies also indicate that, once acquired by Pavlovian learning, the expression of the incentive properties of stimuli are resistant to neuroleptics. 

According to Berridge (1996), Berridge and Robinson (1998) and Robinson and Berridge (1993), DA is involved in a mechanism of incentive salience attribution . By this mechanism, stimuli conditioned to a reward by DA-independent Pavlovian learning are imbued with response-eliciting (incentive) properties as a result of their conditioned... 

We discuss associative, Pavlovian learning between odours and food reward in Drosophila. We argue that flies (just like insects in general) posses a discrete side... 

Classical ( Pavlovian ) conditioning is a process whereby a subject learns the associative relationships between discrete elemental or configural stimuli, with... 

In classical Pavlovian fear conditioning, an initially neutral cue (conditioned stimulus, CS), through temporal pairing with an aversive unconditioned stimulus (US), acquires the abihty to ehcit a fear response in the absence of the US. This acquired abihty represents a type of associative learning and imphes that plasticity mechanisms underlying fear learning may be similar to those... 

Meneses A. Effects of the 5-HT7 receptor antagonists SB-269970 and DR 4004 in autoshaping Pavlovian/instrumental learning task. Behav Brain Res 2004 155 275-282. 

Impairment of performance and sensory-motor functions (4) Impairment of Pavlovian incentive learning. 

Impairment of Pavlovian incentive learning also provides an explanation for the observations of Ettenberg and collaborators. 

Place-conditioning by conventional rewards evidence for a role of dopamine in Pavlovian incentive learning... 

Summing up, impairment of DA transmission by DA receptor antagonists and in particular by D1 receptor antagonists impairs the acquisition of place preference conditioned by nondrug rewards (food, water, sucrose and sex). This effect is unrelated to an impairment of the hedonic impact of the rewards, consistent with other evidence, obtained from taste reactivity and consumption studies, that DA is not involved in stimulus-bound hedonia. Therefore, conditioned place-preference studies utilizing conventional rewards support a role of DA in Pavlovian incentive learning. 

Summing up, blockade of DA transmission impairs acquisition of place preference conditioned by appetitive as well as aversive drugs. In the case of psychostimulants this effect might be the result of a combination of an action on DA-dependent reward and on Pavlovian incentive learning. In the case of aversive drugs, which do not increase, or even decrease, DA transmission, an action on Pavlovian incentive learning is more likely. 

Recently, we have completed a series of studies comparing the effect of Pavlovian stimuli conditioned to morphine and food on DA relase in the NAc shell, NAc core and PFCX (Bassareo et al., in preparation). A more detailed account of these studies will be given in the Section Drug-induced stimulation of DA transmission and abnormal Pavlovian incentive learning. Here it will suffice to say that while drug-conditioned stimuli elicit a sustained release of DA in the NAc shell but not in the NAc core, food-conditioned stimuli release DA in the NAc core but not in the shell (Figs. 6-8). 

In principle it might be a Pavlovian habit related to the establishement of a direct association between a Pavlovian CS and an UR (see Cardinal et ah, 2004). Another possibility is that automatic responding is an instrumental habit related to learning of an instrumental stimulus-response (S-R) association. An instrumental habit is more likely to account for the relative flexibility of the behavior as indicated by the ability to rapidly switch to an explicit goal-oriented mode when the automatic responding is impaired. 

DOPAMINE AND THE ACQUISITION OF DRUG ADDICTION THE PAVLOVIAN INCENTIVE LEARNING HYPOTHESIS... 

Among existing theories the one that explicitly links the disturbance of motivation to the property of addictive drugs to stimulate DA transmission in the NAc, and in particular in the NAc shell, is the abnormal Pavlovian incentive learning hypothesis of drug... 

Bower G, Grusec T (1964) Effect of prior Pavlovian discrimination training upon learning an operant discrimination. J Exp Anal Behav 7 401 404. 

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