Neural Mechanisms for Binocular Depth, Rivalry and Multistability

The purpose of this chapter is to present a review of recent functional neuroimaging (fMRI) studies of binocular vision, including binocular depth and rivalry, as well as a review of studies of perceptual multistability. As such, we will first emphasize the binocular aspects of binocular rivalry, while later emphasizing the rivalrous aspects. The interrelationship of binocular depth and rivalry, as well as multistability, will be described with reference to fMRI studies and single-unit recording studies in animals. These studies have provided provocative new evidence that the neural substrates for depth and rivalry, as well as other forms of multistability are remarkably similar. We will also describe our own research findings from two recent experiments, in which we performed (1) a direct comparison between binocular rivalry and depth, and (2) a direct comparison between binocular rivalry and monocular rivalry, a related form of bistability [1,2]. Our studies are unique in using both matched stimulation and comparable tasks, overcoming a limitation in the interpretation of many previous studies. As a result, these experiments are particularly relevant in delineating some of the global similarities and differences in the cortical networks activated in each of these different domains.