ABSTRACT
A great variety of animals, from man to the crab, respond to movements of the visual surround with following eye movements. In spite of the fact that this type of eye movement is found in quite primitive animals and must have developed early in evolution, the anatomical pathways that serve this reflex remain obscure. There are very few places in the primate brain, for example, where stimulation produces smooth movements (not counting the vestibuloocular pathways), there are no restricted locations where a lesion can abolish smooth movements, and no cells whose activity is principally related to optokinetic eye movements have been observed in the brain stems of alert animals. Consequently, very little is actually known about the neurophysiology and neuroanatomy of pursuit or following eye movements. We're not much better off when it comes to the descriptive physiology of these movements. In spite of many studies in man there are many areas left unexplored and there exist no theoretical models which can satisfactorily unite and explain what information we do have.
