In this paper we have analyzed the role of extracellular tissue (ECT) for signal transfer and information processing in biological neural networks. It was shown that the ECT controls some electric parameters of immersed neural network which are traditionally considered to be an intrinsic property of neuron itself. For example, the diffusion of action potential quasi-wave along the axon membrane excites in surrounding ECT temporal potential distribution and currents which influence the synapses of vicinal neurons. We have claimed that just this so-called ephaptic coupling between neighboring neurons is responsible for information processing in living creatures. This idea, incompatible with classical perceptron model of neuron, is on the other hand in full accord with the fact that within the neuron soma were never identified organelles, having ability to process the information.
