Emergence of horizontal cells receptive fields spectral properties by de-correlation of cones spectral response functions

Receptor fields of primary neurons, cones and rods perceive the light stimulus in a retina of vertebrates. The curves of the spectral response functions of the carp cones superimpose practically the majority of a range of visible light, though each type has characteristic maximas. Spectral sensitivity of cones intersects considerably. Therefore electrical responses of cones in any spectral area correlate. We now report vectorial calculation of spectral response functions, which are orthogonal to each other, thus have no correlation. To calculate them we use standard recurrent orthogonalization procedure (by Gram-Schmidt) applied to cones spectral response functions. The result functions have opponent spectral structure and coincide to the spectral response functions of horizontal cells. These spectrally independent functions preserve themselves in the neuronal hierarchy and probably form a part of orthogonal basis (colour feature space) for colour vision at least in lower vertebrates