Purchase this article with an account.
Doris I. Braun, Lars Pracejus, Karl R. Gegenfurtner; Smooth pursuit eye movements in response to the motion after effect. Journal of Vision 2004;4(8):114. doi: https://doi.org/10.1167/4.8.114.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We studied the relationship between pursuit eye movements and the perception of motion. Motion can be perceived even when there is no stimulus translating on the retina. One such situation is the motion after effect (MAE). After prolonged exposure to a stimulus moving in one direction, a subsequently presented stationary grating is perceived to be moving in the opposite direction. We used a nulling paradigm to measure the magnitude of the MAE. A moving sinewave grating of 0.25 cycle per degree, 8 degree per second, and 40 per cent contrast was presented for 30 seconds. The subjects were instructed to keep their eyes on a central fixation spot. The moving adapting grating was followed by a test grating that was either stationary or would slowly move in the adapting or the opposite direction. At the same time eye movements were monitored during the adapting and the testing phase. At the end of the trial, the subject had to give a rating whether the grating was stationary, moving in the adapting direction, or in the opposite direction. Typically, a stationary test grating was perceived to be moving in the direction opposite to the adapting direction. The test grating was perceived to be stationary when it moved in the adapting direction at a speed of about 0.5 degree per second. At the same physical speed of the test grating, the average eye movement speed at the start of the testing phase was 0, despite the retinal motion signal. For physically stationary test gratings, which were most often perceived to be moving in the opposite direction, smooth pursuit eye movements were observed that coincided with the percept. We conclude that smooth pursuit eye movements are possible without retinal image motion. Smooth pursuit and perception seem to share the same neural pathways for the analysis of motion.
This PDF is available to Subscribers Only