Differential acquisition of a "working memory" task by the Roman strains of rats.

Twenty-eight male rats of the Roman strains-fourteen RHA (Roman High Avoidance) and fourteen RLA (Roman Low Avoidance)-were submitted to a positively reinforced task, the delayed reinforced alternation test (DRA), in a T-maze. Performances of RLA rats were significantly better than those of RHA; RLA rats also had higher VTE (vicarious trial and error) and spontaneous alternation (SA) scores. These data confirm the fact that RLA may acquire positively reinforced learning as rapidly, or even more rapidly, than RHA rats, and that the differences in active avoidance behavior between these strains depend more on differential freezing behavior than on learning and memory capacities. Since the delayed reinforced alternation is considered as a working memory test, our results suggest that the Roman strains could be used as a genetic model for the neurobiological study of this form of memory.