Frequency Analyzers of the Human Visual Evoked Potential Using Dichoptic Stimuli of Short Interflash Interval and Varying Temporal Sequence.
ARMY MEDICAL RESEARCH LAB FORT KNOX KY
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Dichoptic stimuli coincident midpoints and 20 msec interflash interval of varying temporal relationships were presented to human subjects. Frequency, and subsequent discriminant analysis of the recorded visual evoked potential VEP, support several observations. It was possible to identify specific frequency components in the VEP records which discriminated between the temporal sequences. Based on the frequency content of the VEP records, the records were classified into the experimental groups by the computer. Best classification occurred for those conditions where the stimuli were temporally displaced by 20 msec, not where the stimuli midpoints were coincident. General relationships were observed for the 7.82 and 12.70 Hz components. When the stimuli were presented with coincident midpoints, temporal summation was observed, i.e., amplitude values were greater for this condition than when the stimuli were temporally displaced. When monoptic and dichoptic stimulation conditions were compared, the data suggested nonlinearity in the visual system. Asymmetry of frequency information in the VEP records was observed as a function of which eye received the long or short stimulus. Author
- Anatomy and Physiology