Abstract
Purpose: A strong interocular suppression occur when counter-rich patterns continuously flash to one eye [Tsuchiya N., & Koch, C. (2005) Nature Neuroscience, 8 (8), 1096–1101]. This is called the continuous flash suppression. Here, we examined which aspects of these patterns are important for the continuous flash suppression. Methods: Observers viewed dichoptic images through a mirror stereo scope. Gabor patterns were presented as targets to one eye. Spatially filtered fractal noise patterns or checker board patterns were presented to the other eye with a flickering rate of 0 (no flicker) or 10 Hz. We measured contrast discrimination thresholds for targets across a range of monocular pedestal contrasts, with and without the dichoptic stimuli. Results and Discussion: Flicker by itself was not very effective in dichoptic suppression, neither were the low spatial frequency components of our fractal noise. The high spatial frequency components contributed the major suppressive effect even though its lowest component was at least 2 octaves from the signal frequency. To test for the importance of phase alignments at high frequencies we compared phase-aligned and phase-scrambled high-pass checkerboards and show the former to be more effective. These results suggest that phase alignment of the high spatial frequency components is critical for the continuous flash suppression. This research is funded by the Canadian Institutes of Health Research (MOP 53346 to RFH).
This research is funded by the Canadian Institutes of Health Research (CIHR MOP-10818 awarded to RFH).