On the principles of binocular interactions in the guinea pig visual cortex (Re: development of stereopsis mechanisms)

A novel approach to interactions between afferentation from the two eyes in the visual cortex of animals with poorly developed binocular vision is presented. Hypotheses are proposed concerning evolutionary succession between these interaction mechanisms and mechanisms of stereopsis. The proposed approach implies that the main function of interaction between afferentations from both eyes (in animals with primitive binocular visual functions, e.g., guinea pigs) is to create a continuous integrated visual field and to ensure adequate perception of visual information at the junction of both visual semifields. This is assumed to be achieved through the formation, in visual cortical neurons, of interocular receptive fields (RFs) within the area where right and left visual fields overlap. Such a mechanism secures uniformity of interactions across the whole visual field, uninterrupted tracing of an object which moves from one half of the visual field to another, etc. The results support the assumption that the decisive role in the formation of interocular RFs belongs to uncrossed optic tract fibers which provide information transmission to the cortex, avoiding unnecessary delays introduced by switching elements