[Coordination of processes in the hierarchical structure of the visual analyzer].

The influence of prolonged light stimulation on different parts of the visual analyser was studied in cats. An immense complexity of the adaptation process has been revealed as manifested in a great number of varied parallel processes in the hierarchic structure of the analyser. It has been shown that adaptative reorganization in the distal parts of the retina is directed towards regulation of general sensitivity; in the optic tract and LGB -- towards diminishing dependence of cortical processes on the fluctuations of the illumination level; predominance of inhibitory processes in the cortex characterizes the increasing complexity of cortical processes. The preservation of high efficiency of the visual system in different conditions of background illumination is also due to reciprocal change in temporal characteristics of the on- and off-system and to the shift of the main mechanism of psychophysical reactions from the level of receptor -- horizontal cell to that of bipolars. The hypothesis is corroborated the reorganization of electrical activity expresses not only a change a sensitivity, but also adaptation to many parameters which characterize the transition from darkness to light.