Purchase this article with an account.
Sucharit Katyal, Shinho Cho, Stephen Engel, Sheng He; Neural signature of the initiation of binocular rivalry. Journal of Vision 2014;14(10):1238. doi: 10.1167/14.10.1238.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
When differing visual inputs reach the two eyes, the visual system in some cases integrates them into a fused percept, while in others produces rivalry, with only one perceived at a time. The process by which the visual system determines whether two images should be fused or should rival remains relatively unstudied. We investigated this process using SSVEP. It is known that when rivaling dichoptic stimuli are modulated at two different frequencies, f1 and f2, the SSVEP amplitudes reflect the rivalry alternations. Here we measure SSVEP with stimuli that were only slightly different between the two eyes to look for the presence of a neural signature that reflects a state in between fusion and rivalry. Two orthogonal square-wave gratings (±45°, f1=4.72 Hz, f2=8.5 Hz) were dichoptically presented to three subjects on an 85 Hz monitor. In one condition all gratings had contrast of 0.5, leading to binocular fusion. In three other conditions, the contrast of the 45° grating in one eye and the -45° grating in the other eye were reduced by 0.1, 0.2, or 0.4, which changed the percept from complete fusion to clear rivalry. Each condition was presented in three 50-sec blocks while SSVEP was recorded using a 64-channel EEG. For all four conditions significant SSVEP amplitudes were obtained over occipital electrodes at the fundamental frequencies f1and f2. For the 0.1% contrast-reduction condition there was a significant SSVEP amplitude at the beat frequency (f2– f1), which was greater than all other conditions. Perceptual reports showed that rivalry was completely absent in this condition. The enhanced beat frequency response is an identifiable neural signature for the state where the stimulation between the two eyes is non-identical, but rivalry has not yet begun. We speculate that this might be relevant to the neural processes responsible for the initiation of rivalry.
Meeting abstract presented at VSS 2014
This PDF is available to Subscribers Only