VISUAL AND SPATIAL TRIALS PAIRED IN A NEW BEHAVIORAL-PROCEDURE - EFFECTS OF BENACTYZINE

A paired discrimination (PD) task in which visual and spatial discrimi nation trials were combined is offered as a method for the evaluation of drug effects on various behavioral parameters. Acquisition of the P D task is characterized by six different parameters simultaneously rec orded each session. Analysis of memory requirements suggest that intac t reference memory is involved in the performance of both types of tri als while working memory is involved only in the performance of the sp atial trial. Benactyzine (1-4 mg/kg), an anticholinergic drug, was tes ted for its effects on visual and spatial tasks presented either separ ately or in the PD combination. Benactyzine-induced mydriasis was also determined for its possible role in photophobic-induced errors. Benac tyzine was found to differentially increase the number of errors perfo rmed during the spatial but not during the visual trials. The data are in accord with earlier finding of specific cholinergic involvement in working memory processes. Thus, low doses of benactyzine, and the PD task, can prove useful in the cognitive analysis of cholinergic hypofu nction and its reversal by memory-enhancing drugs.