||Independent orientation-selective mechanisms for the cardinal directions of colour space.
Simultaneous, oppositely tilted aftereffects were obtained for pairs of equiluminant gratings (e.g., magenta/cyan vs purple/greenish-yellow) and pairs of equiluminant and luminant gratings (e.g., magenta/cyan vs dark-grey/light-grey) that were presented to 3 observers. Maximum aftereffects occurred for gratings whose colors were modulated along the principle axes of the colorspace described by J. Krauskopf et al (see record 1983-07196-001): an axis of short-wavelength cone activation (B-cone axis), the difference between long- and medium-wavelength cone activation (R - G cone axis), and an axis of a contrast ratio of long-, medium-, and short-wavelength cone activation (R + G + B cone axis). Results indicate that selectivity for orientation occurs independently in at least 2 chromatic channels and 1 achromatic channel. (PsycINFO Database Record (c) 2007 APA, all rights reserved)