[Neurophysiological and neurotransmitter mechanisms of behavior inhibition in normal and pathological conditions]

The data concerning neurophysiological and neurotransmitter mechanisms of two principal kinds of inhibition of behavior is carried out: the inborn genetically determined inhibition and that developed in the course of training. On the basis of the experiments performed by the author and the literature on general neurophysiology the conclusion is made that development of inhibition of behavior during training (i.e. internal inhibition, including "latent inhibition") is determined by the relative strengthening of inhibitory hyperpolarization processes either locally (in a conditioned stimulus analyzer) or globally in the brain cortex and other brain structures during intensification of the inhibitory state (profound inhibition of a reflex and sleep). The main neurotransmitter in development of internal inhibition is gamma-aminobutyric acid. Inhibition of behavior without preliminary training arises either during the action of superstrong stimuli, (exceeding the maximum value inhibition) or during interaction of two and more active systems. A stronger one of these two systems suppresses another one (external inhibition, dominant inhibition, "freezing", "prepulse inhibition", etc.). These kinds of inhibition develop on the background of EEG activation, which suggests participation in their realization of reticular structures and corresponding neurotransmitters (acetylcholine, noradrenalin, dopamine and serotonin). Behavior pathology causes a break of the balanced interaction between the excitation and inhibition in the central nervous system. This affects both genetically determined forms of behavior inhibition and the learned internal inhibition.