Highly read on www.cell.com 22 May—21 June

A changing environment can affect the behaviour of stem cells in the brain, helping to decide whether they generate neurons or more stem cells.

Alex Dranovsky at Columbia University in New York and his colleagues labelled neural stem cells in a brain region called the hippocampus, which is involved in cognition, and traced their development. In mice kept in isolation, the cells were more likely to make new stem cells than neurons. But in mice housed in an 'enriched' environment for three months, 80% of the cells descended from the original population of labelled stem cells were neurons. The results suggest a new mechanism by which the brain adapts to different environments.

Neuron 70, 908–923 (2011)