ABSTRACT
The predicted results of acute administration of the dopaminergic agonist methamphetamine (MAP) in the gap procedure, given the assumption that dopaminergic drugs affect solely the pacemaker level of the internal clock. The attentional resetting effect of MAP was eliminated in rats trained with a filled intertrial interval and tested with empty gaps, suggesting that the behavioral and pharmacological manipulations affect the stop-reset mechanism of interval timing by acting on the same processes. Assuming that dopaminergic agonists increase the perceived salience of interrupting events, one might expect the gap to affect timing more under the influence of MAP. In contrast to human studies of interval timing, studies of interval timing in rats and pigeons are typically conducted in single-task paradigms designed to explore the specifics of the time processor, but less apt to address the possible relation with general processing.
