Color- and edge-sensitive channels in the human visual system: tuning for orientation

After subjects scanned red stripes tilted clockwise off vertical and green stripes tilted equally but counterclockwise, vertical test stripes appeared tilted counterclockwise when red but clockwise when green. As the angle between scanned and test stripes was increased from 0 degrees to 75 degrees , the magnitude of the tilt aftereffect rapidly increased to a peak between 10 degrees and 15 degrees and then dropped close to zero at about 40 degrees , a result consistent with narrowly tuned edge-sensitive channels.