With a little help, our brains can be trained to heal themselves. After a traumatic brain injury, some of your brain cells go into reset mode, reverting to a stem cell-like state. Using these "reset cells," a group of German researchers were able to coax the brains of injured mice to regrow neurons to replace damaged tissue (the images above are micrographs of the cells regrowing over time).

Though their methods are far from perfect, this breakthrough could help replace dead or damaged brain cells in people suffering from Alzheimer's as well as any type of injury. It's just a matter of extending the brain's natural self-healing powers.

According to an article in the Proceedings of the National Academies of Science today:

Magdalena Götz and colleagues found that cells called astrocytes expand and multiply after brain injury. The authors induced brain injury in mice, then observed as quiescent astrocytes activated themselves and became reactive, causing reactive gliosis, which is the universal cellular reaction to brain injury. The researchers found that the reactive astrocytes remained astrocytes in the cerebral cortex, whereas in a cell culture they could be coaxed to switch to different brain cell types, including neurons. These results identify astrocytes as a source of stem cells in the injury site and show that other types of brain cells do not have this potential. The authors conclude that the cells provide a promising cell type to initiate repair in humans after brain injury.