I. Kovacs, T. V. Papathomas, A. Feher: When the brain changes its mind: Interocular grouping during binocular rivalry, Society for Neuroscience, Abstracts, 22(1):271, 1996.
The prevalent view of binocular rivalry holds that it results from reciprocal inhibition among monocular neurons. However, there is recent evidence that binocularly driven cells in V4 and MT reflect perceptual alternations in their firing pattern (Leopold and Logothetis, Nature 1996, 379:549-552), suggesting that there is more to binocular rivalry than mere eye-competition. We have developed a method to study interocular interactions during rivalry. Conventional rivalry-inducing stimuli are dissimilar image pairs that are each coherent in their global structure (such as gratings of orthogonal orientations, or blobs of opposite colors). We replace these by complementary patchworks of intermingled rivalrous images(see figure below). Can the brain unscramble the pieces of the patchwork arriving from different eyes to obtain a global percept? Percepts with conventional, globally coherent image-pairs (e.g., a monkey face vs. a jungle scene) are compared to those obtained with the patchwork image pairs (spatially complementing pieces of the monkey and the jungle in each image). We found that interocular grouping of image components occurs across extended images (15degs x 15degs in all tested conditions (color defined, orientation defined, natural, and moving natural images), implying that binocular rivalry goes beyond interocular suppression and follows more complex rules of perceptual organization. We suggest that interocular grouping is mediated by extremely interactive feedforward-feedback connections involving a large part of the cortical architecture.
Supported by the J. S. McDonnell Foundation 9560.