A brief view of known landmarks reorientates path integration in hamsters

In darkness, hamsters commute between their nest and a feeding site through path integration only, and therefore show cumulative errors in the return direction to the nest. We examined whether a brief presentation of familiar room cues could reset the path integrator. The hamsters could see the room cues either during, or at the end of, the outward journey to the food plac e, in a conflict situation where motion cues and visual information were se t at variance. In both conditions, the animals used mainly visual informati on to return home. Thus, hamsters can determine their azimuth, and possibly their location, through a visual fix, and can reset their path integrator through the fix. This allows them to update their position during further l ocomotion in the dark and thus to compute a correct homing vector with resp ect to a visually induced reference frame. Taking episodic positional fixes may greatly enhance the functional value of path integration.