An analysis was carried out on spontaneous multiple-unit activity recorded through one chronically implanted electrode in the auditory cortex of awake cats. Statistical relations between the neurons were evaluated by crossinterval histograms of two cells. After determination of the pattern of background interaction between three neighboring units, a cat was stimulated with clicks or electrical shocks triggered by spontaneous spikes of the selected neuron, which is considered a variant of cellular operant conditioning. Shock was applied to muscles of the eyelid or ear. Rhythmical and random stimulations with cliks were used in control experiment. A neuronal microsystem is supposed to be an elementary cell network, which allows detection of new qualitative properties of cortical activity. At the level of such a micronet it is possible to describe the specificity of systemic neuronal activity in adaptive reactions. The analysis of crossinterval histograms reveals diverse participation in network function of neurons, differing in amplitudes of spikes. Two neuronal mechanisms of learning are suggested.
