COMPONENT ANALYSIS OF HUMAN AVERAGED EVOKED POTENTIALS - DICHOPTIC STIMULI USING DIFFERENT TARGET STRUCTURE

In dichoptic viewing conditions, human subjects were shown subjectively superposed targets for the left and right eye. The left eye saw a steadily illuminated field containing different amounts of structure, and the right eye saw repetitive light flashes of constant parameters. Averaged EEG evoked responses were recorded from occipito-parietal electrodes; means responses and their standard deviations were computed for each subject, weighted average responses were computed for the whole subject population. It was found that the RMS value of the evoked responses decreased monotonically with increase in target structure. An analysis of the average responses into Gaussian components showed that peak latencies and relative peak amplitudes did not change; i.e., that no change in shape of the responses of individual subjects, analysis applied responses of individual subjects, however, leads to the conclusion that shape changes do occur; but these changes are different from one subject to another and are not characteristic of the entire subject population. The reduction of the evoked responses was interpreted as a consequence of increased informational load upon the neural populations whose activity is synchronized by the flash stimulus to produce the evoked response. © 1968.