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Amphetamine decreases the expression and acquisition of appetitive conditioning but increases the acquisition of anticipatory responding over a trace intervalSchool of Psychology, University of Nottingham, University Park, Nottingham, UK
School of Psychology, University of Nottingham, University Park, Nottingham, UK
School of Psychology, University of Nottingham, University Park, Nottingham, UK, helen.cassaday{at}nottingham.ac.uk The effects of amphetamine on selective learning were tested in a trace conditioning procedure, in which the informativeness of the conditioned stimulus (CS) (noise) was manipulated through the introduction of a time interval before the delivery of the unconditioned stimulus (UCS) (food). The results showed that d-amphetamine (0.5 and 1.5 mg/kg) impaired both the expression (Experiment 1b) and acquisition (Experiment 2) of appetitive conditioning. This was true for both trace and contiguously conditioned groups. The effects of the 0.5 mg/kg dose of d-amphetamine were not attributable to general motor (measured pre-CS) or motivational (measured post-UCS) effects of the drug. Moreover, the same pattern of effects (impaired appetitive conditioning, irrespective of the trace interval between CS and UCS) was confirmed in drug-free extinction tests. By contrast to the general depression in the acquisition and expression of associative learning observed under amphetamine, the 0.5 mg/kg dose promoted the acquisition of anticipatory responses made later in the trace interval (in Experiment 2 but, again, not the expression of previous conditioning in Experiment 1b). This suggests a dissociable effect of low-dose d-amphetamine on learning about the temporal relationship between CS and UCS.
Key Words: amphetamine appetitive conditioning dopamine trace conditioning
Journal of Psychopharmacology, Vol. 18, No. 4,
516-526 (2004) This article has been cited by other articles:
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