When dissimilar images are simultaneously presented to the two eyes, perception will alternate such that, for a few seconds, one image is visible only to disappear for the next few seconds while the other image is perceived. What is so compelling about this visual phenomenon, known as binocular rivalry, is that fluctuations in visibility of the two images seem practically indistinguishable from physically alternating between the presentations of the two images; yet, both images are in fact continuously being presented to the observer. It is because of this unique dissociation between what is being presented and what is being perceived, that binocular rivalry has been extensively used as a tool for studying the neural mechanisms underlying consciousness and visual perception. Several theories exist regarding the neural bases of binocular rivalry and many of those suggest neural adaptation as a key component underlying alternations in perception. However, there is little behavioral and physiological evidence in support of the role of neural adaptation in binocular rivalry. Our objective is to determine whether neural activity evoked by stimuli undergoing binocular rivalry show evidence of neural adaptation, using neuroimaging and electroencephalography (EEG) techniques. Neuroimaging pilot data was collected at Department of Brain and Cognitive Sciences in Seoul National University and EEG data is being collected in the Department of Psychology at Vanderbilt University. There are no conclusive findings as of yet since the study is in its early stages. However, results from pilot data are promising and data collection is ongoing. The current study, if successful, would provide the most direct evidence to date for the role of adaptation in binocular rivalry. The outcome of this research will bear importantly on our current conception of the neural mechanisms underlying the perceptual phenomena of binocular rivalry; it will bring us closer to fully explaining the fluctuations in perceptual awareness that occur with binocular rivalry and possibly with other forms of bi-stable perception. Findings may also influence the way in which we use binocular rivalry as a tool in investigating the neural correlates of consciousness.
