Brodsky's atavistic model is based on the idea that monocular OKN asymmetry reflects a phylogenetically ancient subcortical system seen in laterally eyed animals.
According to this model, the subcortical system is essentially a vestibular-driven system supplemented by the OKN at low frequencies.
Infants born with absent cerebral function do not exhibit any OKN.
OKN was first described in 1823 by Purkinje (1) as a response by spectators to a moving cavalry parade.
The natural (and evolutionary) OKN stimulus is the retinal image motion caused by self-motion.
All vertebrates with ocular motility (and many non-vertebrates) demonstrate an optokinetic response, (3) but there are two types of OKN: delayed OKN (OKNd) (also known as slow, slow build-up or indirect OKN), and early OKN (OKNe) (also known as fast, fast buildup or direct OKN).