ABSTRACT
Tomita’s results of intracellular recording from three types of cones in the carp (Tomita, 1965) demonstrate overlapping characteristics with peaks in the short, middle, and long wavelengths (Fig. 8.1). The same characteristics are found in the goldfish, so it is possible to make a comparison between different data. The most important finding is the overlapping functions of blue, green, and red cones. The main task of this study was to find the neural basis for color vision. Having formulated (chaps. 9, 10) the concept of the spherical structure of color space and the concept of the excitation vector, and having identified, from multidimensional scaling, the characteristics of red-green, yellow-blue, and achromatic cells, the question now was whether it would prove possible to re-establish the spherical structure of color vision from the neural response characteristics of opponent cells of an animal having color vision. In order to check this, it was decided to study horizontal cells of fish because the cells participate very much in the integration of responses from the cones. The responses
of horizontal cells approximate the linear combination of the responses generated by different cones. The nonlinear transformation in the color analyzer is connected with the cone itself. When an electrical recording is made from the cone, a logarithmic function is already apparent. Thus, the potential of cones is linearly related to the next stage of the responses at the horizontal cells level.
