Abstract
This study investigated temporal dynamics of binocular rivalry (BR) in which the filled-in stimulus of the blind spot (BS) competed against the physical stimulus in the fellow eye (FE). Experiment 1 compared the strength of filled-in surface to physical surface during BR. Participants tracked the percept of the BS area during rivalry between the filled-in grating at the BS and the physical grating of the FE. The frequency of short dominance durations of the FE increased and the frequency of long dominance durations of the FE decreased as compared to when rivalry occurred outside the BS. In contrast, the dominance duration distribution of the BS eye was not significantly different across the conditions. These results suggest that the weak representation of the filled-in surface modulates dominance duration distribution of the FE, consistent with Levelt's 2nd proposition. Experiment 2 investigated whether perceptual travelling waves could pass through filled-in surface at the BS. The bar stimuli with clockwise or counterclockwise grating were separately presented to the BS of one eye and the corresponding region of the FE. Participants' task was to track the percept at the cued region which was located above or below the BS during rivalry. When the BS eye was suppressed, the high contrast trigger was given at the opposite side of the tracking region to evoke travelling waves. The event-related probability function of perceiving the BS eye stimulus showed a step-like function as compared to the condition without triggers, indicating travelling waves could pass over the filled-in surface of the BS. However, when we presented rival stimuli outside the BS with a gap that had the size of the BS, this trend was not observed. These results suggest that with the aid of filled-in surface travelling waves can pass over a relatively large region like the BS.
This research was supported by the Converging Research Center Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0029270).