Adam Cole/NPR

A screen presents the winners of the Nobel Prize in Medicine, U.S.-British scientist John O'Keefe and Norwegian husband and wife Edvard Moser and May-Britt Moser, for their discoveries of cells that constitute a positioning system in the brain. TT News Agency/Reuters/Landov hide caption

toggle caption TT News Agency/Reuters/Landov

Molecular biologist Randy Sheckman, who shared the 2013 Nobel Prize in physiology or medicine, acknowledges applause after receiving his prize during the ceremony in Stockholm last December. Pascal Le Segretain/Getty Images hide caption

toggle caption Pascal Le Segretain/Getty Images

Shinya Yamanaka from Kyoto University was named the winner of the Nobel Prize in Physiology or Medicine for discovering how mature, adult cells can be reprogrammed into immature stem cells. Shizuo Kambayashi/Associated Press hide caption

toggle caption Shizuo Kambayashi/Associated Press