From Pigments to Perception

Two techniques were used to estimate the L/M cone ratio, best-fit linear sum of the L- and M-cone spectral sensitivities to heterochromatic flicker photometric spectral sensitivity and psychometric function shape for point source detection of lights of varying wavelength. Data from five color-normal observers run on both paradigms all are consistent with a preponderance of L-cones relative to M-cones though there are individual differences in the estimates of L/M cone ratio. The observers showed congruence in their individual results across technique. In a separate study, the perceptual consequences of individual variation in L/M cone populations were evaluated by looking for a relation between flicker photometric spectral sensitivity and the spectral locus of equilibrium yellow. No significant relation was found, suggesting that receptor populations do not play a major role in the normalization of the perceptual red/green opponent channel. ACKNOWLEDGEMENT Supported in part by USPH NEI grant EY00901. REFERENCES Adam, A. (1969) Foveal red-green ra. C10S c:,f normals, colorblinds and heterozygotes. Proceedings Tel-Hasrcomer Hospital (Tel-Aviv). 8: 2-6. Ahnelt, P. , H. Kolb and R. Pflug. (1987). Identification of a subtype of cone photoreceptor, likely to be blue sensitive, in the human retina. Journal of Compa:cative Neurology. 255: 18-34. Alpern, M. and E. Pugh. (1977). variation in the action spectrum of erythrolabe among deuteranopes. Journal of Physiology (London). 266: 613-646. Boynton, R. (1979). Human Color Vision. New York, Holt, Rinehart and Winston. Brindley, G. (1954) The summation areas of human colour-receptive mechanisms at increment threshold.

Klappentext

Proceedings of a NATO ARW on Advances in Understanding Visual Processes: Convergence of Neurophysiological and Psychological Evidence, held in Roros, Norway, August 6-10, 1990

Inhalt
Biophysics and Psychophysics of Photoreceptors.- Visual Pigments and Colour Vision in Primates.- The Cost of Trichromaticity for Spatial Vision.- Variability in Cone Populations and Implications.- Discussion: Biophysics and Psychophysics of Photoreceptor.- Transition from Photopic to Scotopic Light Assessments and Possible Underlying Processes.- Dual Rod Pathways.- Wavelength-Discrimination with Only Rods and Blue Cones.- Density of Bipolar Cells in the Macaque Monkey Retina.- Discussion: Rod Vision.- Parvocellular and Magnocellular Pathways and Psychophysics.- Which Cells Code for Color?.- Receptive Field Structure of P and M Cells in the Monkey Retina.- On the Relation between Cellular Sensitivity and Psychophysical Detection.- P and M Pathway Specialization in the Macaque.- The Color-Opponent and Broad-band Channels of the Primate Visual System.- Discussion: P- and M-Pathways I.- Temporal Characteristics of Colour Vision: VEP and Psychophysical Measurements.- The Contribution of Colour to Motion.- Functional Classification of Parallel Pathways.- The Responses of Macaque Retinal Ganglion Cells to Complex Temporal Waveforms.- Remote Surrounds and the Sensitivity of Primate P-Cells.- On Neurophysiological Correlates of Simultaneous Colour and Brightness Contrast as Demonstrated in P-LGN-Cells of the Macaque.- Development of Infant Contrast Sensitivity and Acuity for Coloured Patterns.- Psychophysical Evidence of two Gradients of Neural Sampling in Peripheral Vision.- Discussion: P- and M-Pathways II.- Visual Evoked Potentials.- On the Nature of Visual Evoked Potentials, Unit Responses and Psychophysics.- Localization of the Electromagnetic Sources of the Pattern Onset Response in Man.- Discussion: Evoked Potentials.- Cortical Processing and Psychophysical Measurement.-Probing the Primate Visual Cortex: Pathways and Perspectives.- Lateral Interactions in Visual Cortex.- The Perceptual Significance of Cortical Organization.- Orientation and Spatial Frequency Selectivity: Properties and Modular Organization.- Orientation and Color Columns in Monkey Striate Cortex.- Discussion: Cortical Processing.- Psychophysical Studies and Post-Receptoral Processes.- Visual Photometry: Relating Psychophysics to some Aspects of Neurophysiology.- Sensory and Perceptual Processes in Seeing Brightness and Lightness.- Assimilation Versus Contrast.- On Achromatic Colors.- Color Opponency from Eye to Brain.- Chromatic Mechanisms beyond Linear Opponency.- Discussion: Psychophysics and Post-Receptoral Processes I.- Adaptation Mechanisms in Color and Brightness.- Testing the Contrast Explanation of Color Constancy.- Adaptation and Color Discrimination.- Studies on Colour Constancy in Man Using a Checkerboard - Mondrian.- Discussion: Post-Receptoral Processes II.- Models, Neural Processes and Psychophysics.- Origin of Perceptually Measured Phase Shifts in the Visual System.- Psychophysical Correlates of Parvo Channel Function.- On the Physiological Basis of Higher Colour Metrics.- Neural Decoding.- Effects of Phase Shifts between Cone Inputs on Responses of Chromatically Opponent Cells.- Different Neural Codes for Spatial Frequency and Contrast.- Displacement Estimation, Stereo Matching and 'Object' Recognition: A Computer Simulation Approach Working with Real World Imagery.- Scaling and Thresholds of Color and Light Described by an Opponent Model of Color Vision Based on Psychophysical Data.- Discussion: Models and Neural Nets.- General Discussion.- Participants.