Synaptic interactions in cortical circuits involve strong recurrent excitation between nearby neurons and lateral inhibition that is more widely spread. This architecture is commonly thought to promote a winner-takeall competition, in which a small fraction of neuronal responses is selected for further processing. Here I report that such a competition is remarkably sensitive to the timing of neuronal action potentials. This is shown using simulations of model neurons and synaptic connections representing a patch of cortical tissue. In the simulations, uncorrelated discharge among neuronal units results in patterns of response dominance and suppression, that is, in a winner-take-all competition. Synchronization of firing, however, prevents such competition. These results demonstrate a novel property of recurrent cortical-like circuits, suggesting that the temporal patterning of cortical activity may play an important part in selection among stimuli competing for the control of attention and motor action.

Since it has been suggested that the brain binds its fragmentary representations of perceptual events via phase-locking of stimulated neural oscillators, it is important to determine how extended synchronization can occur in a clustered organization of cells possessing a distribution of firing rates. To answer that question, we establish the basic conditions for the existence of a binding mechanism based on synchronized oscillations. In addition, we present a simple hierarchical architecture of feedback units that not only induces robust phase-locking within and segregation between perceptual groups, but also serves as a generic binding machine.