Color properties of movement detectors in the Carassius gibelio (Bloch, 1782) tectum opticum studied by selective stimulation of different cone types

Abstract

and takes part in orienting responses revealed in rapid eye, head, and/or body movemements. This function can proceed without taking into account information about color, and the superior colliculus in mammals is color-blind (Michael, 1973). In the frog, the system carrying chromatic information also originates as a channel separate from the tectal pathway, providing the main information needed for the frog’s reactions to moving objects (Maximov et al., 1985). Color blindness of movement detectors projecting to the fish tectum was proved in color-matching experiments for both orientation-selective (Maximova, 1999) and direction-selective (Maximova et al., 2005) units. Recent experiments using selective stimulation of different cone types revealed new features of these projections. The color vision of Prussian carp (Carassius gibelio Bloch, 1782) adults is determined by three types of cones: long-wavelength (L), middle-wavelength (M), and short-wavelength (�), con taining three A2-based visual pigments that absorb maximally at about 622, 545, and 434 nm, respectively (Maximova et al., 2005). Color opponent cells were presented at different levels of the fish visual system, and single-unit extracellular recordings from the C. gibelio tectum opticum were made in order to examine the possible role of action potential timing in coding chromatic stimuli.