Chlordiazepoxide and successive discrimination: different effects on acquisition and performance.
Benzodiazepines have been reported to increase low rates of responding during a stimulus correlated with non-reinforcement while leaving prestimulus rates unaffected (successive discrimination). However, the results have been obtained by superimposition of the drug upon a discrimination which was learned in the absence of drug. The observed effects may therefore have been due to the sudden change in drug state (state-dependency) rather than to a specific action of the drug. The present experiments found that chronic administration of chlordiazepoxide (5 mg/kg, IP) impaired acquisition but not performance of successive discrimination. Intermittent administration of chlordiazepoxide impaired discrimination by increasing low rates of responding during the stimulus signalling non-reinforcement. This effect was obtained with saline-drug but not drug-saline state changes (asymmetric state-dependency). A final experiment showed that chronic administration of the drug did reduce well-learned inhibition resulting from signalled shock. It was concluded that chlordiazepoxide has not only pure anxiolytic but also state-dependent effects and that if successive discrimination depends on conditioned frustration it does so only while the discrimination is being learned.
D000818:Animals; D002707:Chlordiazepoxide / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects*; D004192:Discrimination, Psychological / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule; D013997:Time Factors
D002707:Chlordiazepoxide