Bats’ mental compass

Most mammals can navigate complex environments thanks to an accurate neural representation of three-dimensional space involving the coordination of cells encoding space, distance, boundaries and head direction. Orientation via head-direction cells is a critical component of this navigation but little is known of the nature of this compass. In a study of freely moving Egyptian fruit bats, either in flight or crawling in search of food, Arseny Finkelstein et al. provide new insights into how the brain encodes its neural compass. Using neural recordings from the brain — specifically from the presubiculum — the authors identified neurons encoding the three Euler rotation angles of the head (azimuth, pitch and roll). Recordings from these head-direction cells revealed a toroidal model of spatial orientation mapped out by cells tuned to two circular variables — azimuth and pitch.