Abstract
[Purpose] We identified two types of motion detectors previously with a motion adaptation technique: one is sensitive to low spatial and high temporal frequencies and the other is sensitive to high spatial and low temporal frequencies (VSS 06). After the exposure to overlapped sinusoidal gratings with different spatial frequencies moving in the opposite directions, motion aftereffect of the high spatial frequency grating was seen with a static test (high spatial frequency superiority) while that of the low spatial frequency was seen with a flicker test. To investigate contribution of each type of motion detectors to global motion, we compared MAEs between global and local motion.
[Experiment] We measured MAE duration of rotation and expansion using four gabor patches arranged circularly. Each patch had two sinusoidal components with different spatial frequencies, which moved in the opposite directions at 5 Hz. The contrast of each grating was set to 30 times of each threshold. The spatial frequency of the gratings was 0.53 c/deg and 2.13 c/deg. After 20 s of adaptation, the observer judged the duration and the direction of MAE in the static or the flicker (4 Hz) stimulus of the same gabor patche(s).
[Results] The static test showed high spatial frequency superiority of MAE whereas the flicker test showed low spatial frequency superiority for the global motion as did for the single gabor motion. The duration of static MAE was longer for the global motion than that for the single gabor motion whereas flicker MAE showed similar duration for both types of stimuli.
[Discussion] The results suggest that the output from the motion detector that is sensitive to high spatial and low temporal frequencies is integrated for global motion perception while that of the motion detector sensitive to low spatial and high temporal frequencies is not.
MESSC GASR(B) 18330153-2006