Russell De Valois was born on December 14, 1926 in Ames, IA, to missionary parents with whom he spent much of his early years in India. In 1947, he received a degree in zoology and physiology at Oberlin College in Ohio and in 1948 an MA degree in psychology. At Oberlin, he also was a player and for a year the coach of the soccer team. He moved on to the University of Michigan where, in 1952, he received his Ph.D. degree in physiological psychology. De Valois obtained a Fulbright scholarship and as a result spent time at Freiburg University in Germany. There he met a group of postdoctoral fellows working in the laboratory of the neurophysiologist Richard Jung (1911–1986) on the visual cortex of cats, inspiring in him his lifelong interest in the neurophysiology of vision. He encountered a paper proposing that activities in the lateral geniculate nuclei of the brain might be the biological basis for Helmholtz’ theory of color vision. When returning to the USA, he was offered a position at the newly installed Kresge Institute of Ophthalmology at the University of Michigan in Ann Arbor. After five years, he moved to Indiana University where he remained until 1968. There, together with students like I. Abramov and G. Jacobs, he worked on a neural version of the opponent processing model of color vision. From Ann Arbor De Valois transferred to the Department of Psychology of the University of California, Berkley, teaching and conducting research until his death as the result of a car accident on September 20, 2003. One of his partners in research was his wife Karen K. De Valois, with whom he cooperated on several research papers and the book “Spatial vision” (1988). De Valois described his major interest as “the physiological and anatomical organization underlying visual perception” [1].
94.1 A Multi-stage Color Vision Model
Like D.H. Hubel and T.N. Wiesel, De Valois was one of the pioneers of establishing relationships between neurobiological activities related to vision in the brain and the corresponding visual experiences in consciousness. Publications on the subject began in 1958, with a 1960 article titled “Color vision mechanisms in the monkey” [2]. In the mid-later 60 s, the activities in the lateral geniculate nuclei became the focus of investigation. In the 1970s, De Valois and his team investigated the response of single cells in regard to wavelength, saturation, and intensity discrimination. The question of the representation of spatial vision in the brain resulted in joint research between De Valois and his wife Karen and the joint publication of a book on the subject [3]. In the early 1990s, the couple became interested in the question of how to model the classical findings of Hering and Helmholtz with activities beginning in the retina and proceeding in the brain. The effort resulted in the joint 1993 article “A multi-stage color vision model” [4]. The model was built on the earlier ideas of D. Jameson and L.M. Hurvich who in 1955 had proposed a two-stage model [5]. The De Valois realized that the responses of opponent-color cells in the lateral geniculate nuclei were not in agreement with implicit perceptual performance and developed a more complicated four-stage model in general agreement with then current neurophysiological findings. The first stage is represented by absorption of light in the three cone types. The second stage is based on activities in the post-receptoral cells in the eye, with two possible alternative versions. The third stage is the basis of perceptual opponency. Figure 94.1 shows the spectral response curves of the third stage with the crossovers of the response functions being in good agreement with average perceived unique hues. The fourth stage involves what the authors defined as color-selective complex cells, presumed cells that fire in response to activation of the system at particular wavelength ranges. In addition, they proposed two achromatic systems: one active in the magnocellular and the other in the parvocellular pathways in the brain.
Fig. 94.1
Response functions of the De Valois third-stage cone-based model of color perception [4]
It is evident that the De Valois model of color perception is very complex and included much information available at the time about activity of the visual system. At the same time, it was somewhat controversial for a number of reasons. More than 20 years later, it appears that the activities in the brain related to color perception are even more complex than assumed by the De Valois and a broadly supported model is still in development.
