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John Krauskopf
Higher-order mechanisms of color vision
My research is concerned with many aspects of vision. Much
of my early work involved physical measurement such as the recording
of eye movements and the determination of the optical properties
of the eye. I also studied the effects of eye movements on vision
by means of the stabilized image technique.
More recently, I have concentrated on problems of color vision
using both psychophysical and electrophysiological techniques.
I've been particularly interested in working out the nature of
the mechanisms signaling color at different levels in the visual
system. I've attacked this problem psychophysically by measuring
the selective effects of prior viewing of fluctuating light fields
on the detection of colored pulses. These experiments have demonstrated
the existence of mechanisms selectively responsive to variations
of light in a multiplicity of specific directions in color space.
Additional evidence for these "Higher-Order" mechanisms
has been obtained in experiments on the conditions resulting in
coherent motion of plaid patterns.
In related studies of the monkey lateral geniculate nucleus,
we have found single neurons with chromatic properties predicted
by the psychophysical experiments. These experiments are one of
the fruits of a long-term collaboration with Peter Lennie which
include a characterization of the chromatic properties of neurons
in the primary visual cortical area (V1).
My current work involves extending these approaches to higher
order color mechanisms. In terms of the electrophysiological experiments,
this means studying the responses in the primary visual cortical
areas and beyond. In psychophysical terms, it means studying the
nature of mechanisms underlying simultaneous color contrast and
other aspects of vision of complex arrays of light. I have been
interested in the question of whether the mechanisms which process
chromatic stimuli are less effective than those which process
luminance stimuli in providing information about spatial details
and in assessing motion.
I received my Ph.D. from the University of Texas in 1953. I
then spent two years in the U.S. Army working in a lab at Fort
Knox, Kentucky. There followed a postdoctoral fellowship with
Lorrin Riggs at Brown University, three years at Rutgers, and
four years at Walter Reed Army Institute of Research in Washington,
DC. After that, I spent 20 years as a memeber of the technical
staff in research at the AT&T
Bell Laboratories in Murray Hill, New Jersey. I have been at New
York University since the fall of 1986 as a research professor.
E-mail: jkr@cns.nyu.edu
Representative Publications
Krauskopf, J., Williams, D. R., and Heeley, D. W. (1982). The
cardinal directions of color space. Vision Research 22, 1123-1131.
Derrington, A. M., Krauskopf, J., and Lennie, P. (1984). Chromatic
mechanisms in lateral geniculate nucleus of macaque. Journal of
Physiology 357, 241-265.
Krauskopf, J., Williams, D. R., Mandler, M. B., and Brown,
A. M. (1986). Higher order color mechanisms. Vision Research 26,
23-32.
Krauskopf, J., and Zaidi, Q. (1986). Induced desensitization.
Vision Research 26, 759-762.
Krauskopf, J., Zaidi, Q., and Mandler, M. B. (1986). Mechanisms
of simultaneous color induction. Journal of the Optical Society
of America A 3, 1752-1757.
Lennie, P., Krauskopf, J., and Sclar, G. (1990). Chromatic
mechanisms in striate cortex of macaque. Journal of Neuroscience
10, 649-669.
Krauskopf, J., and Farell, B. (1990). The influence of chromatic
content on the perception of coherent motion. Nature 348, 328-331.
Krauskopf, J., and Farell, B. (1991). Vernier acuity: Effects
of chromatic content, blur and contrast. Vision Research 31, 735-749.
Krauskopf, J., and Gegenfurtner, K. R. (1992). Color discrimination
and adaptation. Vision Research 32, 2165-2175.
Krauskopf, J., Wu, H. W., and Farell, B. (1996). Coherence,
cardinal directions and higher-order mechanisms. Vision Research
36, 1235-1245.
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