Abstract
Motion After Effects (MAE) is a phenomenon that a stationary object seems to move in the opposite direction after observing the one-side movement for a while. MAE has been used to isolate neural activity related to the processing of motion perception in human. It has been reported that direction-specific activity can be detected from the steady-state visual evoked potential (SSVEP) (Ales & Norcia, 2008, Momose et al , 2014). Here we used the method, and investigated the effect of motion velocity on direction specific response in SSVEP. Four healthy university students (two males, 22.25±0.43 years old) with normal vision participated in the experiment. Stimulus was vertical sinusoidal grating of 2 c/deg. Test stimulus was 12 sec oscillating grating (4, 9, or 18 Hz) that presented immediately after the adaptor of 25.6 sec drifting grating (2, 4.5 or 9 deg/s). EEG was recorded during the test stimulus using a 64-channel Geodesic Sensor Net with 0.1-50Hz filtering. Fourier analysis was used to extract 1F and 2F responses. The phase of 1F responses depended on direction of adaptor agreeing with the previous studies. The brain area shown the MAE direction specific responses was dependent on the velocity of the adaptor.
