A novel test of visual learning in the rat: effects of 8 -OH-DPAT and WAY-100579.
The 5-HT(1A) agonist 8-OH-DPATand the 5-HT(3) antagonist WAY-100579 were tested in a novel computerized visual learning task. Since rats show substantial learning of new problems within each single session, drug effects on new learning could be compared within subjects. Both the reaction time (RT) and choice accuracy were measured. A dose of 0.3 mg/kg of 8-OH-DPAT lengthened the RTs while 0.1 mg/kg of 8-OH-DPAT and 0.1 mg/kg of WAY-100579 shortened the RTs. In the absence of drugs, accuracy was independent of the RT for RTs > 1.5 s. Therefore, in order to unconfound the drug effects on accuracy from motor effects, only responses with longer RTs were analysed. Both 0.3 and 0.1 mg/kg of 8-OH-DPAT and 0.1 mg/kg of WAY-100579 significantly impaired accuracy, though some learning was seen in all cases. These findings may have implications for animal models of Alzheimer's disease.
Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD.
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Cassaday
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Gaffan