None of us would get on a plane that had its parts changed in mid-air, says Eve Marder, who has spent her career probing a very specific cluster of crustacean nerve cells. Yet we are all walking around undergoing a constant turnover of cellular parts, and so are the lobsters and crabs Marder studies.

Optical imaging neural activity in flies as they use a flight simulator can help us understand how the brain codes navigation.

In addition to encoding self location, brain cells in the rat hippocampus act like a GPS that encodes the location of other rats.