On inhibition between spatial frequency channels: adaptation to complex gratings.

Previous studies have shown that adapting to a complex grating may produce little rise in the contrast threshold of a test grating whose spatial frequency matches one of the higher harmonics of the adapting pattern. The present study shows that adaptation may be strong if the adapting component of a complex grating appears visible as a separate grating. The adapting component could be made to appear as a separate grating by suff icient ly separating the spatial frequencies of the components, or by dr i f t ing the components relative to each other, or by substituting a jittering, noisy component for the stationary component. Under these conditions, the visible component produced strong adaptation. Inhibi t ion between mechanisms tuned to different spatial frequencies does not readily account for our data. An alternate model wi th lateral inhibi t ion between spatially adjacent mechanisms is in agreement with known results.