PERCEPTUAL SPACE OF BRIGHTNESS IN CARP (C ARPIO-CYPRINUS L)

Brightness discrimination of black-white (in the range of 0,0082-0,214 W/m(2); CIE chromaticity coordinates X = 0,340, Y = 0,354) and red (i n the range of 0,0035-0,106 W/m(2); CIE chromaticity coordinates X = 0 ,641, Y = 0,342) stimuli was studied using choice conditioning paradig m in two carps. Confusion matrices for black-white and red stimuli sep arately were constructed from probabilities of instrumental responses (catching of a bead) to conditioned and differential stimuli in sequen tial six series in which one of ten intensities used in the experiment served as a conditioned stimulus. Confusion matrices were transformed into correlation matrices between the vectors which corresponded to t he applied stimuli. Principal component analysis revealed two-dimensio nal circular structure of carp's brightness perceptual space both for achromatic and for red stimuli. This space was principally similar to that in humans. Two eigenvectors which constitute two-dimensional Eucl idean space of brightness may be interpreted as bright and dark neuron al channels.