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EFFECTS OF COCAINE ON FIXED‐INTERVAL RESPONDING REINFORCED BY THE OPPORTUNITY TO RUN
Author(s) -
Belke Terry W.,
Dunbar Michelle J.
Publication year - 2001
Publication title -
journal of the experimental analysis of behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.75
H-Index - 61
eISSN - 1938-3711
pISSN - 0022-5002
DOI - 10.1901/jeab.2001.75-77
Subject(s) - reinforcement , psychology , stimulus (psychology) , food delivery , lever , stimulus control , wheel running , stimulation , audiology , developmental psychology , anesthesia , toxicology , medicine , zoology , social psychology , neuroscience , cognitive psychology , biology , physics , marketing , quantum mechanics , business , nicotine
Rate‐dependent drug effects have been observed for operant responding maintained by food, water, heat, light onset, electrical brain stimulation, shock‐stimulus termination, and shock presentation. The present study sought to determine if the effects of cocaine on lever pressing maintained by the opportunity to run could also be described as rate dependent. Seven male Wistar rats were trained to respond on levers for the opportunity to run in a wheel. The schedule of reinforcement was fixed‐interval 60 s, and the reinforcing consequence was the opportunity to run for 60 s. On this schedule, overall rates of responding were low, usually below six presses per minute, and pauses frequently exceeded the 60‐s interval. Despite these differences, an overall scalloped pattern of lever pressing was evident for each rat. Doses of 1, 2, 4, 8, and 16 mg/kg cocaine were administered 10 min prior to a session. Only at the 16 mg/kg dose did the responding of the majority of rats change in a manner suggestive of a rate‐dependent drug effect. Specifically, lower response rates at the beginning of the intervals increased and higher rates at the end of the intervals decreased, as indicated by the fact that slopes from the regression of drug rates on control rates decreased. These data provide tentative support for the generalization of rate‐dependent effects to operant responding maintained by wheel running. Differences in the baseline performance maintained by wheel running compared to those for food and water point to the need for further experimentation before this effect can be firmly established.