Phase diagrams of sparsely connected networks of excitatory and inhibitory spiking neurons

The dynamics of networks of sparsely connected excitatory and inhibitory integrate-and-fire neurons is studied analytically. The 'phase diagrams' of such systems include: synchronous states in which neurons fire regularly; Asynchronous states with stationary global activity and very irregular individual cell activity; synchronous states in which the global activity oscillates but individual cells fire irregularly, typically at frequencies lower than the global oscillation frequency. The network can switch between these states, provided the external frequency, or the balance between excitation and inhibition, is varied. (C) 2000 Published by Elsevier Science B.V. All rights reserved.