Binocular rivalry and fusion under scotopic luminances.
A study is reported of human binocular rivalry and fusion over a range of luminances from scotopic to photopic. At scotopic light levels, rivalry alternations were very slow and complete. Suppression spread over much larger areas of the visual field than at photopic light levels. As luminances decreased from photopic to scotopic levels there was a rod-cone break for binocular rivalry. Mean suppression durations became abruptly greater as light levels dropped below those allowing the cones to be active. Horizontal disparities allowing fusion were 4 to 6 times greater at scotopic than at photopic light levels. Binocular vision at scotopic luminances was sluggish and of low resolution. It is as though connections to, and within, binocular vision are changed when light levels allow only rod input.
Cresap Neuroscience Laboratory, Northwestern University, Evanston, IL 60208.
R P
RP
O'Shea
R
R
Blake
J M
JM
Wolfe
D000328:Adult; D001288:Attention / Q000502:physiology; D003623:Dark Adaptation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology; D011601:Psychophysics; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D015357:Vision Disparity / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology