Effects of variable training, signaled and unsignaled delays, and d-amphetamine on delay-discounting functions.

摘要: One common procedure for obtaining delay-discounting functions consists of a choice between larger reinforcer that is presented after an increasing delay and smaller always immediately within session. Repeating the same context presentation (e.g. ascending order) in discrete-choice paradigm, however, may lead to perseverative response pattern when rats are used as subjects. The purpose this study was increase variability (i.e. descending delays) attempt reduce gain tighter control over by amount delay. For one group (n = 8), delays were differentially signaled flashing houselight 8) unsignaled. Effects signal d-amphetamine on evaluated both groups. Similar rates discounting area under curve (AUC) observed with presentations unsignaled reinforcement. Increasing order resulted differences during 0-s probe sessions. d-Amphetamine had little or no effect AUC at low doses, but decreased highest doses tested, is, 1.0 1.7 mg/kg. Some changes administration have been because disruption discrimination different food amounts.