Some neurons regenerate better than others.

Researchers led by Vincenzo De Paola at Imperial College London severed nerve cells in mouse brains, using lasers to minimize scarring and inflammation. The authors set glass panes into the skulls of the animals and monitored regrowth in more than 100 neurons for up to a year. More than half of the cut neurons from the deepest layer of the brain's cortex regrew, but only about one-fifth of those in its other layers did. Neurons in the brains of juvenile mice were also more likely to regrow than those in adult brains.

Regrowth depends, at least in part, on the neurons themselves and not just external factors such as neural-support cells, the authors say. They suggest that long-term imaging could be used to test potential neuron-repair strategies in the brains of living animals.

Nature Commun. 4, 2038 (2013)