Sign-tracking (autoshaping) in rats: a comparison of cocaine and food as unconditioned stimuli.
A series of experiments was performed to determine whether sign-tracking would occur in rats with intravenous (i.v.) cocaine as the unconditioned stimulus. In Experiment 1, a retractable lever paired with food produced strong sign-tracking, but a lever paired with one of three doses of i.v. cocaine did not elicit any approach or contact behavior. Experiment 2 demonstrated that doses of cocaine that did not elicit sign-tracking would function as a positive reinforcer for a lever contact operant. In Experiment 3, an artificial consummatory response was added to make the cocaine reinforcement episode more behaviorally comparable to that occasioned by food. Although the rats readily performed this response when it was required to receive cocaine infusions, they still did not contact a lever that signaled the availability of these infusions. It appears that cocaine is different from other positive reinforcers (e.g., food, water, warmth, or intracranial stimulation) in that it will not produce sign-tracking in rats.
Kearns
David N
DN
Department of Psychology, American University, Washington, DC 20016, USA. dk0085a@american.edu
Weiss
Stanley J
SJ
D000821:Animal Feed; D000818:Animals; D001070:Appetitive Behavior; D001245:Association Learning; D001288:Attention; D003042:Cocaine / Q000494:pharmacology; D003214:Conditioning, Classical; D003259:Consummatory Behavior; D004305:Dose-Response Relationship, Drug; D007262:Infusions, Intravenous; D008297:Male; D009042:Motivation; D051381:Rats; D020318:Rats, Long-Evans; D012054:Reinforcement, Psychology; D012646:Self Administration
D003042:Cocaine