[Effect of early visual deprivation on the recovery cycle of evoked potentials to photic stimuli in the rabbit cortex].

The influence of visual deprivation on the recovery cycle of the primary positive component (P1) of the visual evoked potential under conditions of dark or light adaptation was studied on eight adult unanaesthetized rabbits raised in darkness. The EP recovery cycle of visually deprived animals, studied in conditions of dark adaption, reveals a significant shortening (as compared with normal) of the initial depression period of testing responses. At the same time a significant lengthening of the facilitation phase and a sharp exaltation of the testing responses is observed. Unlike the norm, transition from dark- to light-adaptation of the deprived animals does not bring about any essential changes in the recovery cycle. An assumption is made that visual deprivation leads to a reduced effectiveness of the processes of successive inhibition. It is also assumed that enhanced excitabilty of a part of the cortical elements, apparently in the system of recurrent excitation, is likely to be one of the consequences of deprivation.