[Off-effect in visual cortex evoked potentials of humans under several conditions of photic stimulation].

Visually evoked potentials (EP) to light were recorded from the occipital cortical area under conditions of changes in stimulus duration and of different intensity of retinal illumination. The work was aimed at establishing the appearance and development of the EP off-effect in humans at these conditions of photic stimulations. This was necessitated by the large dispersion of data obtained in establishing the conditions of photic stimulation, which many authors consider essential for recording the off-effect. The off-effect was studied in greater detail also to elucidate its role in EP generation to a high-frequency photic stimulation. The data recorded are discussed and compared with those of other authors, obtained in studying electrical responses of the retina and the cerebral cortex.