Increase of late MEG component by perceptual transition in binocular rivalry

Binocular rivalry is a phenomenon created by presenting similar but different images for both eyes simultaneously. Many previous studies have investigated various brain responses to binocular rivalry. However, the response of the perceptual transition in binocular rivalry has not yet been elucidated. The purpose of the present study was to measure the response of the perceptual transition in binocular rivalry by using motion rivalry stimuli with various motion angles. It is known that the perception of motion rivalry stimuli has two conditions depending on the angle between the two directions of motion. One is a rivalrous condition that causes binocular rivalry and perceptual transition, and the other is a fused condition that does not cause them. The visual evoked fields (VEFs) in five healthy subjects were recorded with a 440‐channel whole‐head magnetoencephalogram (MEG) system. We classified the trials as representing the rivalrous or fused conditions and calculated the time averages of root mean square (RMS) values at every 100 ms in each condition. The time averages of the RMS values of the rivalrous condition were significantly larger than those of the fused condition after 400 ms poststimulus. These results suggest that the perceptual transition in binocular rivalry increased the late MEG component. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 12– 19, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10076