Intensity coding in primate visual system
- 1 February 1978
- journal article
- research article
- Published by Springer Nature in Experimental Brain Research
- Vol. 31 (2), 163-177
- https://doi.org/10.1007/bf00237597
Abstract
The pupil reflex and the discharge of LGN cells of the awake macaque were measured under stimulus conditions that yielded evidence for wide-range intensity coding in human psychophysical experiments. Ganzfeld flashes of white light were delivered under dark-adapted conditions to the surgically immobilized eye of the monkey while the other eye was observed in the infrared. Three-sec flashes elicited a consensual pupil reflex that was graded from −8 to 0 log Lamberts (L), indicating that the optic nerve fibers are capable of coding at least an 8 log-unit range of light intensity. In the physiological experiments, shorter flashes (0.1–0.5 sec) but otherwise identical conditions elicited monotonically graded responses from one type of LGN cell over the photopic range of −5 to 0 log L. Responses from other types of LGN cells were also graded over wide ranges but had different thresholds and, in some cases, nonmonotonic intensity-response functions. Latency of the excitatory LGN responses decreased with increasing intensity according to a power function with slope of −0.08. The pupil reflex and the LGN cell excitatory responses approximate power functions of light intensity with exponents of 0.22 and 0.14–0.29 respectively. The range of intensity coding found for single LGN cells is the widest yet reported for diffuse stimuli.This publication has 30 references indexed in Scilit:
- Reaction time as a measure of temporal summation at suprathreshold levelsVision Research, 1977
- Brightness sensation in a ganzfeldVision Research, 1976
- Possible neural basis of brighness magnitude estimationsBrain Research, 1975
- Visual sensitivity in the squirrel monkeyAmerican Journal of Physical Anthropology, 1973
- Maintained activity of lateral geniculate nucleus neurons as a function of background luminanceExperimental Neurology, 1972
- Monocular and Binocular Aftereffects of Chromatic AdaptationScience, 1967
- Effects of Adaptation on the Lateral Geniculate Response to Light Increment and Decrement*Journal of the Optical Society of America, 1965
- Brightness Function: Effects of Adaptation*Journal of the Optical Society of America, 1963
- VARIATION OF PUPIL SIZE WITH CHANGE IN THE ANGLE AT WHICH THE LIGHT STIMULUS STRIKES THE RETINABritish Journal of Ophthalmology, 1948
- Variation in the size of the cat's pupil as a function of stimulus brightness.Journal of Comparative Psychology, 1943