Rapid forgetting in aged rats.

The retention performance of young (3-6 months) and aged (24-26 months) Sprague-Dawley rats was evaluated on three separate experimental paradigms. The three paradigms were sequenced so that the first, spontaneous alternation, tested for retention performance of short-term memory; the second, step-down inhibitory (passive) avoidance, tested for long-term memory; while the third, a shock-motivated spatial reversal problem, tested for both short- and long-term memory. The results suggest that aged rats experience significantly more rapid forgetting in both short- and long-term memory systems.