Abstract

The dopamine (DA) system has been implicated in the mediation of cost/benefit evaluations involved in the intertemporal choices between immediate and delayed rewards. This involvement was further investigated in two studies of normal participants that had to decide between a smaller immediate and a larger delayed reward in a series of 27 decisions. In study 1 the dopamine D2/D3 receptor agonist pramipexole or placebo were administered in a double-blind cross-over protocol prior to the decisions. In study 2 the same experiment was conducted in two groups of normal participants that were homozygous for either the 7 repeat or the 4 repeat variant of the exon III polymorphism of the Dopamine D4 receptor gene. Dopaminergic involvement is highlighted by the results.