THE CHOLINERGIC AGENT PHYSOSTIGMINE ENHANCES SHORT-TERM-MEMORY-BASED PERFORMANCE IN THE DEVELOPING RAT

There are age-related differences in the rat's short-term memory processes. Rats 24-25 days old are 90% correct when the delay interval separating the forced run and choice run of a trial is either 10 or 30 s, but they perform at chance when the delay interval is 60 s. In contrast, the choice performance of 30-day-old rats remains constant across all delay intervals. It is reported that the cholinergic agent physostigmine dramatically improved the short-term-memory-based performance of rats 24-25 days old such that they displayed no loss in choice accuracy even when the delay interval was 60 s. No such enhanced performance was seen in rats treated with neostigmine, a peripherally acting anticholinesterase. The results support the hypothesis that postnatal maturational differences in central cholinergic systems may contribute to age-related differences in short-term memory.