Effect of image statistics on fixational eye movements

Abstract

Under natural viewing conditions, small movements of the eyes prevent the maintenance of a steady direction of gaze. It is unclear how the spatiotemporal content of the fixated scene has an impact on the properties of miniatures, fixational eye movements. We have investigated the characteristics of fixational eye movements recorded while human subjects are instructed to fixate natural statistics random textures (Motion Clouds) in which we manipulated the spatial frequency content. We used long presentations (5 sec) of Motion Clouds stimuli (Schrater et al. 2000) of varying spatial frequency bandwidths (Bsf) around different central spatial frequency (Sf0). We found that central spatial frequency has an effect upon microsaccadic eye movements. In particular, smaller saccadic amplitudes were associated with high spatial frequencies, and larger saccades with low spatial frequencies. Broadening the spatial frequency bandwidth also changed the distribution of microsaccade amplitudes. A lower spatial frequencies, larger Bsf resulted in a large reduction of microsaccades amplitude while fixation behavior for high spatial frequencies texture was not affected. Relationship between microsaccade rate and intersaccadic timing was also dependent upon Bsf. These results suggest that the spatial frequency content of the fixated images have a strong impact upon fixation instability. Paul R. Schrater, David C. Knill and Eero P. Simoncelli (2000) " Mechanisms of visual motion detection" Nature Neuroscience 3, 64 - 68. Meeting abstract presented at VSS 2012