Chromatic information processing in the foveal projection ( Area striata) of unanesthetized primate

Abstract

This investigation concerns the role of the foveal projection onto area striata in primates in the encoding of chromatic information as revealed by microelectrode recording in unanesthetized animals. The emphasis of the discussion is on the elaboration of a taxonomy of spectral response types found. In general, the experimental results obtained show two major sorts of responding: brightness and chromatic. One-half of the cells were “brightness cells” (those most sensitive to stimulus intensity and less concerned with wavelength). “Chromatic cells” (those showing responses that best correlate with wavelength and to a lesser extent with intensity) were of three major subcategories. “Pure hue” cells responding only to some narrow band of the spectrum. “Opponent color cells” responded by increasing their activity to part of the spectrum and decreasing activity for the rest of the spectrum when compared with resting levels in the dark. “Triphasic opponent color cells” were like opponent color cells except they responded by excitation, inhibition, excitation again (or the inverse pattern) in response to the spectrum. The complexity of chromatic response is believed to be related to the complexity of pattern responses, which was previously known to be related to anatomical location within the several layers of striate cortex.