A taxonomy of different forms of visual motion detection and their underlying neural mechanisms.

A simple taxonomy of different forms of visual motion is presented to show that there may be a hierarchical system of processing of visual motion in the brain, and that this is first split into self-produced motion and object motion, and then further into various forms of animate and inanimate motion patterns. Further refinement results in specific mechanisms which stem from specific demands of an animal's life-style and ecological niche. Examples are presented of the underlying neural mechanisms for some of these different classes of visual motion processing, such as simple object motion, looming and time to collision, and stereopsis from the object motion processing subsystem. In contrast, other examples of the neural mechanisms from the self-produced motion system include simple canonical flow field analysis, translation and rotation for guiding action in 3D space, and motion parallax for depth perception. The taxonomy thus provides a framework that may guide future research on how the brain detects and processes other dynamic visual patterns.