Rod temporal channels.
Mechanisms underlying rod temporal contrast sensitivity have been considered in terms of a fast retinal signal predominating at mesopic levels and a slower retinal signal predominating at scotopic levels. Here we use a small signal masking method, which has previously been used to delineate the cone-mediated cortical temporal channels, to investigate their rod-mediated cortical counterparts. The results suggest that there are three different rod-mediated cortical temporal channels, one which is lowpass and two which are bandpass. These mechanisms co-exist at all light levels and their relative sensitivity depend on the stimulus spatio-temporal frequency.
Hess
R F
RF
Department of Ophthalmology, McGill Vision Research, McGill University, Montreal, Canada. rhess@bradman.vision.mcgill.ca
Waugh
S J
SJ
Nordby
K
K
D003117:Color Vision Defects; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008297:Male; D010470:Perceptual Masking / Q000502:physiology; D011601:Psychophysics; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D013053:Spectrophotometry; D013997:Time Factors; D014793:Visual Cortex / Q000503:physiopathology; D014795:Visual Pathways