The research described here investigates the role played by inhibitory processes in the discriminations made by the nervous system of humans and animals between familiar and unfamiliar and significant and no significant events.The experiments in conscious non-immobilized rabbits showed that cessation of the reactions without reinforcement (elaboration of the internal inhibition) is accompanied by an enhanced phasic state, by alternation of activation and inhibition of neuron firing, and by the corresponding slow potential oscillation (SPO). These changes can be either localized, predominantly in the structures of conditioned stimulus, or under enhancement of the inhibitory state, generalized in the brain structures. On the basis of our experience and published data, it is concluded that the above event results from relative enhancement of the inhibitory hyperpolarizing processes due to increase in reactivity of the inhibitory systems to stimulus, which acquires inhibitory properties during learning. Changes in the excitability and reactivity of neuron populations appearing during enhancement of the hyperpolarizing inhibition, and differing in the various brain structures, play an active role in the execution of the main function of the internal inhibition: limitation of excitation transmission to the effectors. An inhibitory mediator gamma-aminobutyric acid (GABA) is of great importance in inhibiting the excitation in response to the stimulus which lost its biological significance. These experimental data and their interpretation in the light of published data give the basis for the development of the hyperpolarization theory of internal inhibition.
Сomparing of the effects of two inhibitory mediators of gamma-aminobutyric acid (GABA): 1) Phenibut, a nonselective agonist of ionotropic GABAA and metabotropic GABAB receptors and 2) Gaboxadol, a selective agonist of ionotropic GABAA receptors on the process of developing active defensive and inhibitory conditioned reflexes in alert non-immobilized rabbits. It was found that Phenibut, but not Gaboxadol, accelerates the development of defensive reflexes at an early stage of conditioning. Both Phenibut and Gaboxadol facilitate the development of conditioned inhibition, but the effect of Gaboxadol occurs at later stages of conditioning and is less stable than that of Phenibut. The earlier and more stable effects of Phenibut, as compared to Gaboxadol, on storage in memory of the inhibitory significance of a stimulus may occur because GABAB receptors play the dominant role in the development of internal inhibition during an early stage of conditioning. On the other hand this may occur because the participation of both GABAA and GABAB receptors are essential to the process. We discuss the polyfunctionality of GABA receptors as a function of their structure and the positions of the relevant neurons in the brain as this factor can affect regulation of various types of psychological processes
Results of own experiences at the accounting of data of literature allow to assume that both factors, and elaboration of internal inhibition, and Phenibut weaken freezing – the phenomenon used in experiments as biological analog fear, owing to increase of level of activity of GABA neurotransmitter system of a brain.
CHAPTER IV.
NEYROFIZIOLOGIC AND NEUROTRANSMITTER’S PROVIDING GENETICALLY CAUSED TYPES OF INHIBITION
In the work the analysis of data concerning neurophysiologic and neurotransmitter’s maintenance of inborn, genetically inherent inhibition of behavior is carried out. Inhibition of behavior without preliminary training arises or at action super strong stimuli, (exceeding the maximum value inhibition), or at interaction of two and more active systems from which more intensive system suppresses another (external inhibition, dominant inhibition, «freezing», «prepulse inhibition», etc.). These kinds of inhibitions arise against activation ЭЭГ that assumes participation in their realization of structures of the formation reticularis and corresponding neurotransmitters (acetylcholine, noradrenalin, dopamine, serotonin). At various forms of a pathology of behavior conditions of interaction of processes of excitation and inhibition in CNS become incorrect at realization as well as in the case of genetically inherent forms of inhibition of behavior and in the case of the internal inhibition.
CHAPTER V
EXPERIMENTS ON NEURONET MODEL FOR IMITATION OF PROCESSES OF INTERACTION OF EXCITING AND INHIBITORY NEYRONLIKE ELEMENTS WHEN TRAINING