Cortical neural activities associated with binocular rivalry: an EEG-fMRI integrative study.

Binocular rivalry occurs over time when each eye is simultaneously presented with different visual stimuli. We have addressed which brain regions are and the mechanisms involved in binocular rivalry using EEG and fMRI measurements of cortical activities during observations of competitive (rivalry) and cooperative (fusion) drifting vertical gratings. By applying an EEG-fMRI integrative method, we analyzed the time courses of multiple cortical sources of event-related potentials obtained under rivalry or fusion conditions. We detected significant cortical activities at bilateral MT+/V5 and the right prefrontal eye field in the rivalry condition; however, this may not reflect intrinsic alternation in binocular rivalry. Our findings suggest that novel integrative methods are necessary to investigate the distributed cortical network associated with binocular rivalry, through analysis of multiple cortical sources of event-related desynchronization and/or synchronization in certain frequency bands.