1. An artificial asynchronous neural network system comprising a plurality of neurons each of which is operable to receive a respective input signal representing an input stimulus for the network, and to generate an output signal in response to receipt of such an input stimulus, the network system being operable to supply an output signal representing a spatio-temporal sequence of rhythmic electric pulses to an external system in response to receipt of such an input stimulus, wherein respective pairs of the multiple neurons are interconnected using mutually inhibitory links.