Abstract

Spatial frequency adaptation was first believed to result from some form of neuronal fatigue. To test this we have reexamined the effects of spatial frequency adaptation on the contrast increment threshold function. Using 3.0 cpd adaptation and test stimuli, we have found that the power law exponent of the increment threshold function decreases from 0.62 before adaptation to 0.39 following spatial frequency adaptation. A re-analysis of data by Greenlee and Heitger¹ shows a similar decrease in the exponent. In a second experiment we examined the effect of test stimulus presentation time on spatial frequency adaptation. As expected, we found that thresholds were elevated by an average factor of 2.2 when test stimuli were presented for 500 msec. However, when a 30-msec presentation was used, the threshold elevation was reduced to only 1.2, just slightly above the pre-adapted threshold.

© 1991 Optical Society of America