G. S. Voronkov

Each vision field (VF) is known to be represented in the animal and human visual systems by the projection sequence - by the optic projection and by the follow-up projections, the layers of neural elements. These projections are topographically organized. Based on the analysis of published anatomical and physiological data, this article provides evidence that, in the sequence of topographic VF projections, the initial map-projection is replaced on its mirror map, and that the mechanisms providing this replacement are the retina inversion and the visual fiber crossings. Thus, it appears that the phenomena of retina inversion and visual fiber crossings, which was previously regarded as incomprehensible as to their destination and as not related to one another and to the topographic phenomenon, are actually related to the latter and united in a common destination - they form the topographic VF neural projections and the projection of the united vision field (UVF) as the non-mirror projections to their originals - VF and UVF. If these mechanisms were absent, the projections would be mirror to their originals as the optic projections are mirror ones to the originals - VF and UVF. This article discusses these results from the standpoint of the problem of cerebral representation (coding) of the visual information concerning the spatial coordinates of the visual world. The author has advanced his idea - why the brain needs the non-mirror topographic VF and UVF neural projections.