Pattern Evoked Average EEG Potentials and Dichoptic Visual Percepts
Journal article

Pattern Evoked Average EEG Potentials and Dichoptic Visual Percepts

  • Lehmann, Dietrich Neurologische Universitätsklinik Zürich, Zürich, Switzerland, and Smith—Kettlewell Institute of Visual Sciences, San Francisco, Calif. 94115, USA
  • Koukkou, Martha Forschungsdirektion der Psychiatrischen Universitätsklinik Zürich, Zürich, Switzerland
  • Dittrich, Adolf Forschungsdirektion der Psychiatrischen Universitätsklinik Zürich, Zürich, Switzerland
  • 2016-6-25
Published in:
  • Perception. - SAGE Publications. - 1977, vol. 6, no. 1, p. 77-84
English Monocular xenon flashes were used to evoke average EEG potentials while blank, dot or grid targets were shown simultaneously in ten dichoptic stimulus conditions, either continuously illuminated (added to the flashes, or contraocularly), or presented only by the flashes. Mean evoked-EEG-potential waveforms over repeated conditions were computed from average evoked potentials (EPs) for each stimulus condition and each hemisphere. Correlation coefficients were computed between mean-EP waveforms of all stimulus conditions for each subject. Mean correlation coefficients over subjects were treated in a cluster analysis to diagnose conditions associated with similar EP waveforms. Data from the two hemispheres yielded identical cluster results. Presence or absence of continuous target illumination for the flashed eye was the most powerful descriptor. Next important was continuously visible structure (regardless whether seen by the flashed or the nonflashed eye) in conditions with continuous illumination seen by the flashed eye, and flashed structure in conditions without continuous illumination for the flashed eye. It was concluded that a visual percept which enters the processor as non-EP-evoking information nevertheless is reflected by the EP waveform. However, the waveforms are different if the flashes carry the perceptual information exclusively. More powerful than visual structure is the mode of flash presentation (with or without continuous target illumination) for the EP waveform.
Language
  • English
Open access status
closed
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Persistent URL
https://sonar.rero.ch/global/documents/103374
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