Figure 1

A. Phase space of the firing-rate dynamics. Dependence of the rate change dr/dt on the rate r (sketch). B. Firing-rate distribution in the self-sustained state (sketch). C. Dependence of the lifetime of self-sustained activity (color coded) on the level g of inhibition and the synaptic weight J in a random network of 100000 excitatory and 25000 inhibitory IaF neurons with 1% connectivity (simulation results).