DIFFERENCE OF SPATIAL-FREQUENCY SELECTIVITY BETWEEN STATIC AND FLICKER MOTION AFTEREFFECTS

The strength of motion aftereffect (MAE) was measured with the use of sinusoidal gratings of several spatial frequencies, to examine the spa tial frequency selectivity of two types of MAE. With ordinary static g rating as a test stimulus, to measure 'static MAE', the maximum aftere ffect for each adapting spatial frequency was obtained at the testing stimuli of the same spatial frequency, showing spatial frequency selec tivity. However, in the case when the sinusoidally flickering grating was used as a test stimulus, to measure 'flicker MAE', no spatial freq uency selectivity was observed. The two types of MAE were considered t o be based on different mechanisms. Static MAE is thought to depend on the spatiotemporal channel mechanism in the early processing stages, whereas flicker MAE might reflect higher-level processes which might o ccur at the extrastriate regions.