Neuroscience. Stem cells hear call of injured tissue.

In animal models, injected stem cells travel to tissue injured by stroke, Alzheimer's-like plaques, contusions, or spinal cord bruises, sometimes traversing long distances. Several teams reported these surprising results this month at the Society for Neuroscience annual meeting. No one knows exactly how stem cells detect these different kinds of damage, but researchers hope that the cells' migratory powers can be harnessed to either replace dead tissue or deliver therapeutics right where they're needed.