The spatial frequencies of two gratings can be discriminated when they differ by about 5%. This discrimination threshold was found to be remarkably independent of interstimulus interval in a temporal two-alternative forced-choice procedure. Discrimination threshold between parallel gratings did not change over a 50:1 range of interstimulus intervals between 0.4 and 20 sec; spatial-frequency information is stored with at least 5% precision without appreciable decay up to 20 sec at least. Spatial-frequency discrimination between orthogonal gratings was the same as spatial-frequency discrimination between parallel gratings and did not change over the 25:1 range of interstimulus intervals investigated (0.4 to 10 sec). It is suggested that, after being encoded to a high degree of precision by a size-opponent mechanism that is tuned to orientation, spatial-frequency information is stored in a form that is independent of orientation.
© 1985 Optical Society of AmericaFull Article | PDF Article
OSA Recommended Articles
J. Opt. Soc. Am. A 2(7) 1153-1159 (1985)
D. Regan and K. I. Beverley
J. Opt. Soc. Am. A 2(2) 147-155 (1985)
Arthur Bradley, Bernt C. Skottun, Izumi Ohzawa, Gary Sclar, and Ralph D. Freeman
J. Opt. Soc. Am. A 2(9) 1607-1610 (1985)