Our purpose is to clarify cell-to-cell communications between neurons by constructing a spatial pattern of cell networks through manipulation of neurotransmission direction. To study this phenomenon, we have developed four techniques to make artificial neuronal networks; 1) an agarose-microprocessing technique to create artificial neuronal networks with actual neurons on a culture dish, 2) a cryopreservation technique of several types of primary neurons, 3) a non-invasive-cell-collecting technique from a group of primary cultured neurons using a low-adhesive micro-cup array, 4) a multi-electrode array system for continuous measurement of multi-point extracellular potential of neurons while simultaneously stimulating these cells. These techniques allow us to evaluate functions of single neuron, create artificial neuronal networks with neurotransmission manipulation constructed from particular cells, and evaluate electrophysiological function of artificial neuronal networks continuously. Moreover, these techniques allow us to evaluate interactions of neurons and glia within created neuronal networks. Then, we constructed artificial neuronal networks using rat hippocampal E18 neurons and characterized the electrophysiological features. Such artificial neuronal networks showed electrophysiological activities displaying various activity patterns. We intend to elucidate the operating principles of neuronal networks such as information processing and the mechanism of memory by investigating the hysteretic changes of individual neurons and neuronal plasticity at a neuronal network level.