Effects of d-amphetamine on behavior maintained by signaled and unsignaled delays to reinforcement.
Four pigeons responded under a progressive-delay procedure. In a signaled-delay condition, a chained variable interval (VI) 30-s progressive time (PT) 4-s schedule was arranged; in an unsignaled-delay condition, a tandem VI 30-s PT 4-s schedule was arranged. Two pigeons experienced a signaled-unsignaled-signaled sequence; whereas, two pigeons experienced an unsignaled-signaled-unsignaled sequence. Effects of saline and d-amphetamine were determined under each condition. At intermediate doses (1.0 and 1.78m/kg) delay functions were shallower, area under the curve was increased, and, when possible, break points were increased compared to saline; these effects were not systematically related to signaling conditions. These effects on control by delay often were accompanied by decreased response rates at 0s. These results suggest that stimulus conditions associated with the delay may not play a crucial role in effects of d-amphetamine and other stimulants on behavior controlled by reinforcement delay.
Thomas
Lee D
LD
University of North Carolina Wilmington, Wilmington, NC 28403, USA.
Hughes
Christine E
CE
Pitts
Raymond C
RC
D000818:Animals; D019540:Area Under Curve; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D003463:Cues; D003627:Data Interpretation, Statistical; D003913:Dextroamphetamine / Q000494:pharmacology*; D008297:Male; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine