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Neurodegenerative disorders devastate the brain, but doctors hope one day to replace lost cells

By Ferris Jabr

BRAIN GROWTH: To replace brain cells lost to neurodegenerative disorders such as Parkinson's disease, some researchers are experimenting with grafts of fetal brain tissue and injections of young neurons grown from stem cells in the lab. Image: Bryan Christie

Inside the human brain, branching neurons grow beside, around and on top of one another like trees in a dense forest. Scientists used to think that any neurons that wilted and died from injury or disease were gone forever because the brain had no way to replace those cells. By the 1990s, however, most neuroscientists had accepted that the adult brain cultivates small gardens of stem cells that can turn into mature neurons.

This article was originally published with the title Replanting the Brain's Forest.

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