Science 325, 210–213 (2009)

Researchers have uncovered a function of new neurons that are generated in the brains of adult mice.

The role of adult neurogenesis in a brain region called the hippocampus has been difficult to pin down because the effects seem to be subtle and it is technically tricky to selectively disrupt neuronal development in adult animals. Fred Gage of the Salk Institute for Biological Studies in La Jolla, California, Timothy Bussey at the University of Cambridge, UK, and their colleagues designed challenging tasks that required mice to distinguish between very similar surroundings.

Using two techniques to knock down neurogenesis, the authors discovered that although the new neurons were not necessary for easy navigational tasks, they were important for more complex ones. Notably, for remembering very small differences in the spatial arrangement of their environment.