Stumbled on this one while looking for something else.
For the first time, researchers have developed a way to view stem cells in the brains of living animals, including humans—a finding that allows scientists to follow the process neurogenesis (the birth of neurons).
The key ingredient in this process is a substance unique to immature cells that is neither found in mature neurons nor in glia, the brain's nonneuronal support cells.
They were able to determine the chemical makeup of each variety—and isolate the compound unique to stem cells—with nuclear magnetic resonance (NMR) spectroscopy. (NMR helps to determine a molecule's structure by measuring the magnetic properties of its subatomic particles.)