Unconditional discrimination as a paradigm for investigating visual processing in the avian brainstem.

Visual discrimination between colors and patterns was studied in telencephalectomized chicks of Japanese quail lines that were artificially selected for early approach preferences for particular colors and patterns. Since these preferences are not conditional on prior learning, they provide an effective experimental paradigm to study visual discrimination without reliance on acquired stimulus discrimination. The data indicate that the quail's brainstem-thalamus complex is sufficient for relatively fine discriminations between various colors and achromatic patterns.