Abstract
1. Photic driving of the EEG and the average evoked response to photicstimulation were studied on 42 normal subjects between the ages of 17 and57. Photic stimulation was applied during the period of suppressed EEG, while the subjects kept their eyes open.
2. Marked photic driving was observed in 15 subjects (35.7%). The frequencyresponse curve, showed two types of response pattern. The one was “sum-mation type” which showed the maximum amplitude at the stimulus frequencyof 7-8c/sec. The other was “non-summation type” which showed a gradualdecrease in parallel with frequency increase.
3. The frequency response of the average evoked response produced thesame course of events as that of photic driving.
4. The negative component of the evoked response with the peak latencyof 170 msec showed maximal percent recovery at 120-190 msec. interval ofpaired stimuli.
5. It was suggested that the most indispensable component of the evokedresponse was VII, one of the secondary response, for the generation of photicdriving in the eye-opened state.
