Temporal shift of the position of the largest spectral peak in the anterior-posterior OIS periodograms and its dependence on stimulus amplitude. The frequency (A) and the period (B) of the largest spectral peak (average of 5 subjects) are plotted as a function of time since the stimulus onset. Two plots are shown, for 50 μm-amplitude and 400 μm-amplitude stimuli. With increasing stimulus duration, the peak frequency/period shifts across the power spectrum, at a rate dependent on the stimulus amplitude. C: Average magnitude of OIS in the segmented region as a function of time after stimulus onset. The dominance of lower spatial frequencies develops in time in parallel with an overall growth of the OIS response to the stimulus. D: The frequency of the largest spectral peak plotted as a function of the average magnitude of OIS in the sequential region. The relationship between the largest spectral peak and overall OIS magnitude varies depending on the stimulus amplitude.