Failure of rivalry at low contrast: evidence of a suprathreshold binocular summation process.
Presentation of different images to the two eyes normally results in a time-varying alternation between the two images (binocular rivalry). However, we find that when orthogonal gratings are viewed dichoptically at low contrast, a stable summation between the two images is perceived in the form of a dichoptic plaid. The range of perception of the dichoptic plaid depends on spatial frequency, contrast and luminance of the gratings. This phenomenon differs from the "false fusion", a fleeting summation of different images perceived only under very brief presentation of the stimuli. The observations suggest that there exists a neural process that performs a summation of dissimilar images, and that is distinct from the competitive process of suppression and binocular rivalry.
Liu
L
L
University of California, School of Optometry, Berkeley 94720.
Tyler
C W
CW
Schor
C M
CM
D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008027:Light; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010783:Photometry; D012684:Sensory Thresholds / Q000502:physiology; D013997:Time Factors; D015348:Vision, Binocular / Q000502:physiology*; D015349:Vision, Monocular / Q000502:physiology