IRREGULAR SYNCHRONOUS ACTIVITY IN STOCHASTICALLY-COUPLED NETWORKS OF INTEGRATE-AND-FIRE NEURONS

We investigate the spatial and temporal aspects of firing patterns in a network of integrate-and-fire neurons arranged in a one-dimensional ring topology. The coupling is stochastic and shaped like a Mexican ha t with local excitation and lateral inhibition. With perfect precision in the couplings, the attractors of activity in the network occur at every position in the ring. Inhomogeneities in the coupling break the translational invariance of localized attractors and lead to synchroni zation within highly active as well as weakly active clusters. The int erspike interval variability is high, consistent with recent observati ons of spike time distributions in visual cortex. The robustness of ou r results is demonstrated with more realistic simulations on a network of McGregor neurons which model conductance changes and after-hyperpo larization potassium currents.