Scientists have discovered that a bacterial product first isolated from soil on Easter Island, or Rapa Nui, could help prevent diminishing cognitive skills, including memory retention.Rapamycin is an antifungal agent that has been administered to transplant patients to prevent organ rejection.However researchers at the School of Medicine at the University of Texas Health Science Center at San Antonio have found that older mice fed rapamycin displayed improved learning and memory skills.According to the researchers, the drug also lowered anxiety and depressive-like behaviour in the mice, factors that impair cognitive performance in humans.