DIFFERENTIAL-EFFECTS OF ANTICHOLINERGIC DRUGS ON PAIRED DISCRIMINATION PERFORMANCE

Working and reference memory processes were simultaneously evaluated d uring the performance of a paired discrimination (PD) task in which vi sual and spatial discrimination trials were combined within the same s ession. Atropine (1 and 5 mg/kg), scopolamine (0.02-0.20 mg/kg), benac tyzine (1-4 mg/kg), trihexyphenidyl (1-10 mg/kg), and aprophen (5-20 m g/kg) were all found to increase the number of errors performed by ove rtrained rats during the spatial but not during the visual trials. Alt hough all the anticholinergic drugs tested induced specific working me mory impairment at low doses, they differentially affected other, simu ltaneously recorded, behavioral parameters. Thus, while atropine affec ted most of the recorded parameters, aprophen induced only a mild effe ct. Benactyzine was found to have the most specific effect on working memory, with only minimal side effects, a combination that supports it s use as the preferred psychopharmacological model of working memory i mpairment.