An increase in synchronization of the activational type (coincidence of the presence of impulse activity), and a decrease of the inhibitory type (coincidence of both the presence and absence of impulse activity), in the operation of close-lying neurons were observed in the visual and sensorimotor areas of the new cortex and in the hippocampus of wakeful non-immobilized rabbits in response to the combination of flashes of light with electrodermal stimulation (EDS) of the extremity. An increase in the synchronization of the neurons of the inhibitory type took place in the visual cortex in response to flashes against the background of the conditional inhibitor, i.e., continuous light, and changes in synchronization, similar to the effect of pain reinforcement but significantly weaker, appeared in the sensorimotor cortex and in the hippocampus. An increase in synchronicity of the activational type took place primarily in pairs of neurons with increase in the same direction in the frequency of impulse activity in response to a stimulus, and of the inhibitory type, took place with its decrease. In addition, both kinds of changes in synchronization appeared in a significant portion of the pairs of neurons with changes in the frequency of impulse activity of different directions.

After the administration of a morphine-like opiate, DAGO (D), in a dose of 250 micrograms/kg, a decrease was observed in the probability of movements of a rabbit in response to light flashes, the signal for a defensive reflex. The level of the background impulse activity of the neurons gradually decreased in the sensorimotor cortex and in the hippocampus, and did not change in the visual cortex. The decrease and the recovery of the responses of the neurons to the reinforcing stimulus (electrodermal stimulation of the limb) proceeded unidirectionally in all of the areas of the cortex studied, while there were substantial differences in the relationship to the cortical area studied and to the biological significance of the stimulus in the dynamics of the responses to the inhibitory and reinforced light flashes. The identification of the features of the systemic organization of the neurons during training with change in the properties of the reinforcement under the influence of the preparation under study is discussed, as well as the similarity of some features in the mechanisms of the development of internal inhibition in the defensive situation and of the properties of positive reinforcement.

The principal difference in the effect of the preparations investigated resided in the fact that the nootropic agents did not change the effect of painful reinforcement on the synchronicity of neurons of the cerebral cortex of rabbits of the inhibitory type (coincidence of both the presence and absence of impulse activity), and of the activational type (the time of coincidence of only the presence of impulse activity). Both preparations mainly attenuated the initial influences of both the inhibitory and reinforced conditional stimuli on the synchronicity in the activity of the cortical neurons of both the activational and the inhibitory types.

No abstract