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Stimulation of both operant and consummatory behavior following the cessation of amphetamine‐induced focused stereotypy
Author(s) -
Pinkston Jonathan W,
Vorontsova Elena,
Fowler Stephen C
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a782-a
Subject(s) - stereotypy , licking , operant conditioning , extinction (optical mineralogy) , psychology , amphetamine , reinforcement , stimulation , neuroscience , open field , developmental psychology , medicine , dopamine , biology , psychiatry , social psychology , paleontology
At doses above 2 mg/kg, amphetamine (AMP) elicits in rats robust stereotyped head movements. Little or no locomotion accompanies the expression of these stereotypies. Stereotypies may persist for as long as 2 hours and have been shown to compete with and suppress operant behavior. Our lab has recently investigated the interactions between operant behavior and AMP‐induced stereotypy in long observation sessions and has identified limits on the suppression of operant behavior. Specifically, Sprague‐Dawley rats responded on a multiple fixed‐ratio 20 extinction schedule in 4‐hr daily sessions. Each 20th response on the operandum provided brief access to water. Once day‐to‐day variance in responding minimized, 5 mg/kg AMP was administered i.p. every 4th session for 20 days. Observations of the saline vehicle were interposed between each test of AMP. The data showed that once AMP‐induced stereotypies subsided, a ‘rebound’ increase in operant responding was observed. The increase in operant rate was evident in both schedule components, though increases under extinction were modest. The rhythm of licking during consumption of reinforcers also was significantly increased once operant behavior resumed. The observation that both the operant and consummatory behavior were enhanced is interesting as the two responses are functionally distinct, and likely involve different brain pathways. Previous work has shown that AMP increases exploratory behavior and locomotion in open field paradigms. The present data extend previous findings to both operant and cosummatory behavior. Taken together, the results may reflect general performance enhancing effects of the drug. Supported by MH43429 and HD002528.