Visual evoked potential in man: early oscillatory potentials.

Short latency visual evoked oscillatory potentials to bright light stimulation were recorded from the scalp of 15 normal human adult subjects. The onset latencies of these potentials recorded over anterior frontal and posterior scalp regions were 9--17 msec and 13--24 msec, respectively. The frequency of the oscillations was about 100 c/sec. These potentials were widespread in their distribution over the scalp but were most prominent at midline and parasagittal recording locations. Like similar potentials recorded in animals, it seems that these potentials arise in both subcortical and cortical visual structures. The mechanism underlying the generation of these potentials and their possible functional significance are discussed.