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Eighty patients with heroin addiction, aged from 15 to 20 years (most of them over the age of 16), were examined. The duration of illness was from 6 months to 3 years. The examination was conducted 2-3 weeks after arresting of withdrawal syndrome. In that period, patients had different mental disorders: depressive-dysphoric, neurosis-like, anxiety-hypochondriac, hysteriform and others. The aim of the examination was to find peculiarities of functioning of different cortical regions in the process of appraisal of conscious and unconscious stimuli using the method of visual evoked potentials with P300 recording. Stimuli were words highlighted on the screen--indifferent and potentially significant for a patient (e.g. heroin). The stimulus related to the dominating motivation caused in patients the higher diffuse cortical activation on the unconscious level compared to non-targeted stimuli.

Neural mechanisms are considered of such unconscious psychic phenomena as subliminal perception of semantic stimuli, psychological defence, unaccountable emotions. The results are given of many years studies conducted by means of conditioned, electrophysiological and psychophysiological methods. The possibility is proved of semantic analysis of perception on unconscious level and formation of association with the help of unrealized emotionally significant words. At present it is possible to describe only few neural mechanisms of consciousness and unconsciousness; however, the development of contemporary psychophysiology allows to state that the analysis of this problem from scientific positions is the most correct way to learn the nature of the brain processes which are the basis of these complicated psychic phenomena.

Evoked cortical potentials in response to conditioned visual stimuli were recorded in excitable psychopathic personalities in the course of formation and reproduction of temporary relations with a realized or non-realized emotional word. Diazepam (10 mg intramuscularly) suppresses cortical reaction worked out previously with the aid of a realized emotional word and fails to produce and action if that word was non-realized. The fact of the lack of the diazepam effect on conditioned emotional reactions formed at the non-realized level should be taken into consideration in the treatment of patients with disturbances in the emotional sphere.

In adult emotionally excitable persons the role was studied of unrecognized reinforcement forms in the function of differentiation of time microintervals. As feedback stimuli the word "good" (positive reinforcement) and a word connected with negative emotions of the subject (negative reinforcement) were applied. Experimental confirmation was obtained of the hypothesis that unrecognized phenomena of environment can influence conscious psychic activity, the process of man learning. Unrecognized semantic stimuli can function as a reinforcing factor and in this way participate in the process of learning of cognitive activity realized at conscious level.

The authors examined the functional interhemispheric relations in chronic alcoholics by registering evoked potentials. It was found that in those subjects the information processing was considerably delayed in both hemispheres, however, this delay was more marked in the right hemisphere. In this hemisphere also the magnitude of the evoked response was lowered, this lowering being statistically significant. On the basis of the prolongation of the latent period and the diminution of the amplitude of the P300 wave in the right hemisphere the authors conclude that in chronic alcoholics the interhemispheric relations are changed due to an impairment of the right hemisphere functioning.

By means of backward masking, the time of perception of letter stimuli presented to the left and right visual fields, was determined in practically healthy persons who were given different doses of alcohol, and in patients with chronic alcoholism. Evoked electrical activity to the same stimuli was recorded in identical conditions. A small dose of alcohol (0.41 g/kg) increases in healthy subjects the time of perception of visual signals only if they are presented in the left visual field: a medium dose (0.82 g/kg) increases the time of stimuli perception in both halves of the visual field, but obviously more so in the left one, in patients with chronic alcoholism the time of perception is substantially longer in the left visual field. A small dose of alcohol does not affect evoked electrical cortical activity in healthy persons. Distinct regional differences are exhibited in the action of the medium dose of alcohol on the cerebral cortex of healthy persons. Evoked potential in the central area is depressed to a greater extent than in the visual and associative (Brodman field 37) zones. With chronic alcohol intoxication, evoked activity in the right hemisphere is depressed considerably more than in the left one.

In emotionally labile persons the role of the limbic link in the structure of temporary connections formed by means of a realized emotionally significant word, was studied with the help of diazepam. The diazepam turned out to be an effective agent for studying the mechanisms underlying the formation and reproduction of temporary connections in man. Against the background of its action it is not possible to elaborate a conditioned cortical reaction on emotionally significant reinforcement. This is connected by the authors with predominant action of this tranquilizer on formations of the limbic system.

The influence of seduxen (diazepam) on cortical potentials P300 evoked by neutral and emotional words was studied in adult subjects having life conflicts. The therapeutic dose of seduxen (10 mg) had no significant effect on the amplitude of the late positive cortical response P300 to neutral words. Seduxen depresses the emotional activation of the cerebral cortex; that is manifested in selective elimination of those changes in latency and amplitude of P300 wave which are observed in response to emotionally significant words. Under the action of seduxen, the interhemispheric difference in the latency of cortical response disappears due to latency increase in the right hemisphere.

The study was made on adult humans in a conflict situation. A combination of a non-verbal visual stimulus with an unrecognized emotional word substantially changes interhemispheric functional relations. The latency of the P300 potential in response to the first stimulus becomes reduced in the left occipital area. The potential amplitude considerably diminishes in all the recorded cortical areas (occipital, associative and central), but the reductions more pronounced in the left hemisphere. The nature of the P300 wave changes in response to the conditional stimulus is determined by psychophysiological properties of the "reinforcing" stimulus, in particular by its being non-recognized. Conditioned changes of the P300 wave in tests, where the "reinforcing" stimulus is not recognized, are very stable, and are not extinguished, despite repetitive presentation of the signal without combining it with the emotional word.

11 right-handed subjects with normal vision were examined. The analysis of latencies and amplitudes of the late AEP components elicited by verbal stimuli, presented in different halves of the visual field, revealed that the late positive evoked potential P300 to a single word with neutral meaning develops in the right occipital area with a shorter latency and a greater amplitude, than in the left one. Interhemispheric differences are not observed in "the associative" zone (presumably at the junction of the temporal, parietal and occipital areas). In the process of perception of an emotional word interhemispheric relations are considerably changed: in the left occipital area the P300 wave latency is considerably shorter, than in the right one; no differences in the amplitude of P300 are visible. The changes in P300 wave latencies reflect a local nonspecific activation of the cortex, directly connected with the analysis of the emotional verbal signal. The obliteration of interhemispheric differences in P300 wave amplitude is largely due to background emotional excitation.

In the course of formation of temporary connection between a nonverbal visual stimulus and an emotional word, interhemispheric functional relations are significantly changed. The conditioned stimulus elicits local activation mainly in the visual cortex of the left hemisphere, which results in reversion of interhemispheric relations during latency of cortical evoked response. In the "associative" area, the elaboration of the temporary connection does not affect latency and amplitude of the evoked response to the conditioned stimulus. Extinction of the temporary connection and, hence, recovery of the interhemispheric functional relations observed before its elaboration, proceeds slowly, and sets in after 100-150 presentations of the signal without reinforcement.

Temporary connections are elaborated in adult subjects between subliminal visual stimuli and voluntary motor reaction. The observed gradual shortening of the reaction time is considered to be a result of learning by means of subliminal visual signals. This learning is unstable and is retained only in the short-term memory, unlike experiments in which the same visual stimuli are recognized. This fact explains discrepancies and uncertainty of the existing opinions on the role of subliminal visual signals in the voluntary behaviour of man.

Intramuscular injections of seduxen (10 mg), a benzodiasepin drug, with expressed tranquilizing and alarm suppressing effects, were used with the aim of experimental testing of a hypothesis on the neural mechanism of conditioned changes of the P300 wave. Under the action of seduxen no temporary connections could be formed between a perceived nonverbal visual stimulus and a unrecognized emotional word. The seduxen did not suppress the conditioned cortical reaction acquired due to combination of nonverbal stimulus with unrecognized emotional word. The suggestion is made that the necessary condition of temporary connection elaboration by means of a unrecognized verbal stimulus is the implication of the limbic structures where negative emotional reactions are integrated.

The wave P300 was recorded in both hemispheres in order to study interhemispheric differences in the process of perception of unrecognized verbal stimuli. The stimuli--unrecognized words, neutral and emotional--were alternately presented at random in the left and right visual fields. In response to an unrecognized emotional word, the amplitude of the P300 wave increases diffusely in both hemispheres, as compared to the response to a neutral word, with no changes in interhemispheric differences. They change considerably in the process of an "unaccountable" emotion, caused by an unrecognized word, due to unilateral activation of the right hemisphere. The conclusion is made on the predominant role of the right hemisphere in the cortical organization of such unconscious function as "unaccountable" emotion.