Visual stimulus-specific habituation of innate defensive behaviour in mice

Innate defensive responses such as freezing or escape are essential for animal survival. Mice show defensive behaviour to stimuli sweeping overhead, like a bird cruising the sky. Here, we found that mice reduced their defensive freezing after sessions with a stimulus passing overhead repeatedly. This habituation is stimulus-specific, as mice freeze again to a novel shape. This allows us to investigate the invariances in the mouse visual system. The mice generalize over retinotopic location and over size and shape, but distinguish objects when they differ in both size and shape. Innate visual defensive responses are thus strongly influenced by previous experience as mice learn to ignore specific stimuli. This form of learning occurs at the level of a location-independent representation.