Some structural-functional relations in the analyzer's optic nucleus and adjacent associative fields were investigated comparing it with the cortical limbic area in the rabbit and cat. New approaches for the structural brain cortex analysis were applied: method of retrograde elective detection of cortical and subcortical neurons (with the body and dendritic processes) after surgical lesion of their axons in the cortical focus of destruction, field 17. This method demonstrated the presence, in the fields surrounding the cortical optic nucleus, of associative neurons mediating the modal signals into the nucleus of the optical analyzer, as well as some constructive details of the optical analyzer at the subcortical level. Comparing angioarchitectonics of the capillary network, indirect data were obtained on structural-functional specialization of the nucleus of the optical analyzer, that explains the meaning of mediating into it the optical signals which come to other cortical areas (from the zone of scattered elements).