Background light and the contrast gain of primate P and M retinal ganglion cells

Rockefeller University, New York, NY 10021-6399.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 07/1988; 85(12):4534-7. DOI: 10.1073/pnas.85.12.4534
Source: PubMed


Retinal ganglion cells projecting to the monkey lateral geniculate nucleus fall into two classes: those projecting to the magnocellular layers of the nucleus (M cells) have a higher contrast gain to luminance patterns at photopic levels of retinal illumination than those projecting to the parvocellular layers (P cells). We report here that this difference in luminance contrast gain between M and P cells is maintained at low levels of mean retinal illumination. In fact, our results suggest that in the mesopic and scotopic ranges of mean illumination, the M-cell/magnocellular pathway is the predominant conveyor of information about spatial contrast to the visual cortex.

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Available from: Ehud Kaplan
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    • "It is thought the M pathway dominates detection of spatial patterns in the mesopic (rod-and cone-mediated) and scotopic (rod-dominated) ranges of retinal illumination. Purpura et al. (1988) used a primate model, to show that M cells, rather than P cells were sensitive to temporally modulated sine gratings at low spatial frequency (0.6e1.6 cpd) when the mean retinal illumination was lower than 0.43 td which is equivalent to the low mesopic range in humans. D'Zmura and Lennie (1986) using a technique to isolate rod and cone systems, found that over most of the mesopic range, the spatial contrast sensitivity of the cone system was lower than that of the rod system at low spatial frequencies (1e3 cpd). "
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