Naturalistic path integration of desert ants on an air-cushioned lightweight spherical treadmill.

Air-cushioned spheres are widely used as treadmills to study behavioural and neurophysiological questions in numerous species. We describe an improved spherical treadmill design that reliably registers the path and walking behaviour of an animal walking on top of the sphere. The simple and robust set-up consists of a very light hollowed styrofoam ball supported by an air stream in a hollow half sphere and can be used indoors and outdoors.

Odometry for ground moving agents by optic flow recorded with optical mouse chips.

Optical mouse chips-equipped with adequate lenses-can serve as small, light, precise, fast, and cheap motion sensors monitoring optic flow induced by self motion of an agent in a contrasted environment. We present a device that extracts self motion parameters exclusively from flow in eight mouse sensors. Four pairs of sensors with opposite azimuth are mounted on a sensor head, each individual sensor looking down with -45° elevation.