Navigating space in the mammalian brain

How does the brain represent the world and allow spatial navigation? One mechanism is hippocampal place cells—neurons that fire according to where an animal is in its environment. Different place cells fire according to different locations, and together they are thought to provide a cognitive map that supports spatial navigation and memory (1). Place cells have been described in a range of mammalian species, including mice, bats, marmosets, and humans. However, most studies have used rats in small enclosures or mazes. Thus, it is unknown how such representations might underpin larger-scale, real-world navigation. On page 933 of this issue, Eliav et al. (2) show that in bats flying in a large (200-m-long) enclosure, most place cells fire in several different locations and with varying spatial scales. Such multiscale representations are likely the most efficient way for a finite number of neurons to encode large distances