Cognitive skills such as learning and memory diminish with age in everyone, and the drop-off is steepest in Alzheimer's disease. Texas scientists seeking a way to prevent this decline reported exciting results this week with a drug that has Polynesian roots. The researchers added rapamycin to the diet of healthy mice throughout the rodents' life span. Rapamycin, a bacterial product first isolated from soil on Easter Island, enhanced learning and memory in young mice and improved these faculties in old mice, the study showed.