healthy adults directly into motor neurons without going through a stem cell state. The technique makes it possible to study motor neurons of the human central nervous system in the lab. Unlike commonly studied mouse motor neurons, human motor neurons growing in the lab would be a new tool since researchers can't take samples of these neurons from living people but can easily take skin samples.

Scientists working to develop new treatments for neurodegenerative diseases have been stymied by the inability to grow human motor neurons in the lab. Motor neurons drive muscle contractions, and their damage underlies devastating diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy, both of which ultimately lead to paralysis and early death.