Document Detail

Second-order stimuli do not always increase overall response rates in second-order schedules of reinforcement in the rat.
MedLine Citation:
PMID:  15083254     Owner:  NLM     Status:  MEDLINE    
RATIONALE: Second-order schedules of reinforcement have been used extensively to model reward-seeking and drug-seeking behaviour. Second-order stimuli within second-order schedules have been shown to enhance response rates during operant responding for natural reinforcers and drug reinforcers. This has led some to view second-order schedules of drug reinforcement as a model maintained of drug-seeking in addicts by drug-associated stimuli. However, the functional role of the second-order stimulus within second-order schedules is complex. OBJECTIVE: We investigated the role of second-order stimuli within a second-order schedule of reinforcement [FI 4 min (FR10: S)] maintained by sweetened water reinforcement. METHODS: Eight rats were trained to press a bar on a second-order schedule of reinforcement and tested in the presence and absence of the second-order stimulus. RESULTS: In contrast to most previous work, overall bar-pressing rates were significantly increased when the second-order stimulus was omitted (second-order stimulus omission: 0.17 Hz (+/-0.04, 95% CI); second-order stimulus present: 0.13 Hz (+/-0.04, 95% CI)). However, second-order stimuli also changed the pattern of responding whereby rats would make a bout of bar presses prior to the presentation of the second-order stimulus and then pause briefly after the second-order stimulus. In the absence of second-order stimuli, responding was uniformly high. Control measures, such as the ability of the second-order stimulus to evoke checking for the primary reinforcers, indicated that the second-order stimulus was associated with the primary reinforcer. CONCLUSIONS: These results demonstrated that although second-order stimuli maintained responding and caused the rat to check for primary reinforcement, overall response rates were increased when the second-order stimuli were omitted. This has implications for interpreting the results of studies where overall response rates within second-order schedules have been the only measure used to assess the effects of potential anti-addiction drugs. Future studies could be improved by performing a second-order stimulus omission test analysing both the overall response rates and the temporal organization of responding with respect to the second-order stimulus.
David I G Wilson; E M Bowman
Related Documents :
24327304 - N-doped graphene derived from biomass as a visible-light photocatalyst for hydrogen gen...
16812294 - Conditional acceleration and external disinhibition of operant lever pressing by prerew...
16811464 - The role of reinforcement in controlling sequential irt dependencies.
20600344 - Brief light as a practical aversive stimulus for the albino rat.
2033564 - Daily torpor in the djungarian hamster (phodopus sungorus): photoperiodic regulation, c...
25235934 - Medial olivocochlear efferent effects on auditory responses.
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-04-09
Journal Detail:
Title:  Psychopharmacology     Volume:  174     ISSN:  0033-3158     ISO Abbreviation:  Psychopharmacology (Berl.)     Publication Date:  2004 Jul 
Date Detail:
Created Date:  2004-07-14     Completed Date:  2004-12-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7608025     Medline TA:  Psychopharmacology (Berl)     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  430-7     Citation Subset:  IM    
School of Psychology, St Mary's College, University of St Andrews, South Street, St Andrews, Fife KY16 9JP, UK.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Analysis of Variance
Appetitive Behavior* / drug effects
Conditioning, Operant / drug effects,  physiology*
Extinction, Psychological
Reinforcement (Psychology)*
Reinforcement Schedule*
Sweetening Agents / pharmacology
Time Factors
Reg. No./Substance:
0/Sweetening Agents

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Effects of acute nicotine administration on behavioral inhibition in adolescents with attention-defi...
Next Document:  Combined treatment of quetiapine with haloperidol in animal models of antipsychotic effect and extra...