A new mini-feature from the MIT Technology Review: short digests to explain the significance of selected research. Scientists "found that a drug similar to ones used to treat Parkinson's disease can spur growth of new neurons in the substantia nigra, the brain area damaged in the disease. ... Current treatments for Parkinson's disease replace or mimic dopamine, an important signaling molecule in the brain. But those treatments lose their effectiveness over time; boosting the brain's ability to make more of the dopamine-producing cells could provide a more effective strategy. ... Ultimately, they hope to find compounds that will help replace cells lost in a range of neurodegenerative diseases, such as Alzheimer's and Huntington's."