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.