Motion dazzle: a locust's eye view

Motion dazzle describes high-contrast patterns (e.g. zigzags on snakes, dazzle paint on World War I ships) that do not conceal an object, but inhibit an observer’s perception of its motion. However, there is limited evidence for this phenomenon. Locusts have a pair of descending contralateral movement detector (DCMD) neurons which respond to predator-like looming objects, and trigger escape responses. Within the network providing input to a DCMD, separate channels are excited when moving edges cause areas of the visual field to brighten or darken respectively, and these stimuli interact antagonistically. When a looming square has an upper half and lower half that are both darker than background, it elicits a stronger DCMD response than the upper half does alone. However, when a looming square has a darker-than-background upper half and a brighter-than-background lower half, it elicits a weaker DCMD response than its upper half does alone. This effect allows high-contrast patterns to wea...