Spontaneous Recovery and Dishabituation of Ethanol-Reinforced Responding in Alcohol-Preferring Rats

• Published in: Experimental and clinical psychopharmacology 2006-11, Vol.14 (4), p.471-482
• Main Authors: Murphy, Eric S, McSweeney, Frances K, Kowal, Benjamin P, McDonald, Jennifer, Wiediger, Roberta V
• Format: Article
• Language: English
• Subjects: Alcohol Drinking - genetics; Alcohol Drinking - psychology; Animal; Animals; Central Nervous System Depressants - pharmacology; Conditioning; Conditioning, Operant - drug effects; Ethanol; Ethanol - pharmacology; Generalization (Psychology) - drug effects; Habituation; Male; Rats; Rats, Wistar; Reinforcement (Psychology); Spontaneous Recovery (Learning); Sucrose - pharmacology
• ISSN: 1064-1297; 1936-2293
• DOI: 10.1037/1064-1297.14.4.471

This study examined whether habituation, a decrease in responsiveness to a repeatedly presented stimulus, occurs to ethanol reinforcers in alcohol-preferring (P) rats. Three fundamental properties of habituation were evaluated: generality, spontaneous recovery, and dishabituation. In each experiment, P rats' lever pressing was reinforced by 10% ethanol on a variable-interval 15-s schedule during 50-min sessions. Experiment 1 evaluated the generality of habituation to repeatedly presented stimuli by using ethanol and water reinforcers. Rates of responding were higher for ethanol than they were for water. Additionally, the within-session patterns of responding differed for each reinforcer, suggesting that the pattern of responding was specific to the exact nature of the repeatedly presented reinforcer. Experiment 2 examined spontaneous recovery, an increase in responsiveness to a habituated stimulus when that stimulus is not presented for a time, by separating experimental sessions by 5 min, 2 hr, or 24 hr. Early-session rates of responding during Session 2 were slower than the corresponding rates during Session 1 when sessions were separated by 5 min or 2 hr. Response rates and within-session patterns of responding during Sessions 1 and 2 were similar when sessions were separated by 24 hr. Experiment 3 tested for dishabituation, a restoration of responsiveness following the presentation of an extraneous stimulus, by presenting a tone or a light 24 min and 55 s into the session. Rates of responding temporarily increased after the tone was presented. The results of these experiments support the idea that habituation contributes to the regulation of ethanol consumption.