HUMANS, animals and some mobile robots use visual motion cues for object detection and
navigation in structured surroundings 1–4. Motion is commonly sensed by large arrays of
small field movement detectors, each preferring motion in a particular direction 5, 6. Self-
motion generates distinct'optic flow fields' in the eyes that depend on the type and direction
of the momentary locomotion (rotation, translation) 7. To investigate how the optic flow is
processed at the neuronal level, we recorded intracellularly from identified interneurons in …