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Chromatic adaptation in red-green cone-opponent retinal ganglion cells of the macaque.

Lee BB, Smith VC, Pokorny J, Sun H

State University of New York, State College of Optometry, 33 W42nd Street, New York, NY, USA; Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.

The degree of chromatic adaptation of midget ganglion cells of the parvocellular (PC) pathway was studied by measuring long- (L) to middle-wavelength (M) cone weighting at different mean chromaticities in the mid-photopic range. Cone weighting was measured using a protocol involving changing the relative phase of modulated lights, which provided an estimate independent of the level of maintained activity. The degree of adaptation at 2500td was found to be less than complete (i.e., sub-Weberian), with the M- and L-cone contributions having slopes averaging 0.89 rather than 1.0. This is broadly consistent with the degree of light adaptation present in this cell class. The changes in maintained activity following a step change in chromaticity took tens of seconds to return toward a baseline level, but changes in cone weighting appeared much faster.

Published 18 February 2008 in Vision Res.
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