Change in the activity of cortical neurons under the influence of biogenic amines.

Under the conditions of extracellular recording of action potentials, the influence of proposed neuromediators on the structure of background impulse activity of neurons of various regions of the cerebral cortex was studied. Computer analysis of the statistical parameters of impulse flows revealed the presence of a fundamental difference between the effects of neuromediators of cortical and subcortical origin. It was demonstrated that prolonged application of serotonin and noradrenalin evokes a change in structure of cortical neuron impulse activity more complex than the simple inhibition and excitation characteristic of acetylcholine or GABA. Different types were found of the reaction of neurons to the same monoaminergic stimulus, types whose characteristic feature is the dependence of the end result of the influence on the initial level of excitation in the neuron examined. The fundamental difference between the effects of preparations studied in the visual and sensorimotor regions of the cortex was not discovered. The data obtained are considered from the point of view of the modulating role of the biogenic amines in the regulation of the level of excitation of cerebral cortical neurons.