EFFECTS OF DRUGS OF ABUSE AND SCOPOLAMINE ON MEMORY IN RATS - DELAYEDSPATIAL ALTERNATION AND MATCHING TO POSITION

Drugs of abuse produce amnestic effects in humans and laboratory anima ls in a variety of tasks. Generally, only a few compounds have been ex amined in any particular procedure. It was the goal of the present stu dies to examine drugs of abuse of different pharmacological classes in rats responding under two behavioral schedules historically employed as experimental models of memory: spatial alternation and matching to position. One group of rats responded under a single-response spatial- alternation baseline with a 10-s delay and another group responded und er a matching-to-position baseline with delay values of 3, 10 and 30 s . Performance under the spatial-alternation baseline was characterized by low variability and >90% accuracy. Under the matching-to position baseline, saline control percent accuracy was >95% at 3 a, >85% at 10 s and >70% at 30 s. Under spa tial alternation cocaine, d-amphetamine, pentobarbital, diazepam, phencyclidine, scopolamine and methscopolami ne produced significant (P<0.05) effects on accuracy, whereas only coc aine, d-amphetamine, pentobarbital and phencyclidine disrupted accurac y under the matching-to-position baseline. These results suggest that spatial alternation may be a more sensitive baseline for determining d rug effects on working memory in the rat.