In normal vision, the inputs from the two eyes are inte(cid:173) grated into a single percept. When dissimilar images are presented to the two eyes, however, perceptual integra(cid:173) tion gives way to alternation between monocular inputs, a phenomenon called binocular rivalry. Although recent evidence indicates that binocular rivalry involves a mod(cid:173) ulation of neuronal responses in extrastriate cortex, the basic mechanisms responsible for differential processing of con:6.icting and congruent stimuli remain unclear. Using a neural network that models the mammalian early visual system, I demonstrate here that the desynchronized fir(cid:173) ing of cortical-like neurons that first receive inputs from the two eyes results in rivalrous activity patterns at later stages in the visual pathway. By contrast, synchronization of firing among these cells prevents such competition. The temporal coordination of cortical activity and its effects on neural competition emerge naturally from the network connectivity and from its dynamics. These results suggest that input-related differences in relative spike timing at an early stage of visual processing may give rise to the phenomena both of perceptual integration and rivalry in binocular vision.