Changes in the rate-increasing effects of d-amphetamine and pentobarbital by response consequences

Publisher Website
Google Scholar
Abstract
Keypecking in one group of pigeons was maintained under schedules in which food was presented only when a specified number of responses was followed by a 30-s pause without a response. d-Amphetamine and pentobarbital increased low rates of responding (and, thus, decreased food presentation) only after initial injections or when, during drug sessions, responses during the 30-s period did not reset the period. When responses during the pause-interval postponed food delivery, the rate-increasing effects of both drugs diminished over succeeding administrations. Thus, immediate effects of response consequences were as influential as the actual presence of a drug in determining the reproducibility of the behavioral effects of that drug. In a second experiment, keypecking in another group of pigeons was maintained under a 10-min fixed-interval schedule of food presentation but suppressed by a 100-response fixed-ratio schedule of shock delivery (punishment). d-Amphetamine and pentobarbital increased low rates of punished responding when shock delivery was eliminated during drug sessions. Pentobarbital, but not d-amphetamine, also increased punished responding when shock delivery was present. Rate-increasing effects of these drugs were determined by not only predrug patterns of responding but also effects of reinforcers and punishers that occurred during exposure to the drug.

This publication has 15 references indexed in Scilit: