[GABAergic receptor system and its role in system activity of the brain].

In the review the analysis of structural and functional features of the main types of GABA-receptors and their distribution in various regions of a brain of vertebrata is carried out. Questions of an involvement of various types of GABA-receptors in various processes of brain activity are investigated. The data concerning tonic GABAergic inhibition in CNS, connected with extrasynaptic receptors, are shown. The physiological importance of mechanisms of tonic inhibition is discussed.

[EEG spectral characteristics in the dynamics of planned movements].

The spectral characteristics of the EEG in 11 healthy right-handed volunteers with no neurological disorders in dynamics of the unusual finger movements of both hands in random rhythm have been investigated. In particular, it is shown that the preparation and execution of voluntary finger movements compared to the rest were accompanied by a reduction level of activation within almost all the surface of cerebral cortex, except for right frontal lobe. It has been experimentally demonstrated that a significant increasing EEG activity of the right frontal area in high-frequency domain power spectrum was independent of the working limb. This might testify the direct participation of this cortical area in the processes of voluntary muscular activity planning, initiation and control.

[Electrographic correlates of real and imaginary movements: spectral analysis].

The research carried out with eight virtually healthy volunteers showed that movements were associated with the increased level of activation, primarily, in the central areas of the brain cortex, which was expressed in a reduction of the spectral power of alpha end beta frequencies and increase in the power of the gamma oscillations more expressed in the parietooccipital derivations of the left hemisphere. Mental reproduction of similar movements was accompanied by additional activation in the frontal, temporal, parietal, and occipitals regions and more pronounced increase in the power of the gamma oscillations. A number of electrographic phenomena associated with specific features of the movements were revealed.

General laws for the formation of the state of monotony.

Experimental studies have demonstrated that the formation of the state of optimum working ability in conditions of monotonous activity is associated with a decrease (compared to the rest state) in the level of "preventive" arousal of the CNS, manifest on the EEG as an increase in the power of slow rhythms on the background of a selective increase in the level of coherence at frequencies in the alpha rhythm in the caudal areas of the cortex. Prolonged exposure to monotonous conditions leads to increases in the power of slow (theta and alpha(1)) and beta frequencies in the EEG spectrum without marked changes in the level of coherence. Our results, along with published data, were used to propose the hypothesis that unlike the basic states of the sleep-waking cycle (sleep, rest, active waking, etc.), the state of monotony lacks intrinsic ("built-in") self-regulatory mechanisms; this results in instability in the operation of the regulatory systems of the brain. This leads to the appearance of marked periodicity in changes in both the functional state of the CNS and the quality of work performed by humans.

[Individual resistance to factors of monotony reflected in the EEG].

Three groups of operators substantially different in their performance quality were examined. Under conditions of monotonous activity, subjects with the highest initial level of activation, minimum EEG total spectral power, and minimum level of EEG coherence in the frontal cortical areas worked most steadily. Under the same conditions, subjects with a rather high spectral power of the theta and beta2 EEG frequency components, highest coherence in the frontal areas, and low coherence in the caudal areas of the cortex worked least steadily. EEG phenomena testify to a rather low level of activation of the frontal cortical areas associated with a facilitation of cortico-subcortical neuronal interactions and an attenuation of the operating neural streams. This results in a decrease in the level of any attention, its involuntary switching, and short-term loss of the control over the current performance.

[The general laws of formation of a condition monotony].

In article results of research of spectral characteristics and a level of coherence basic rhythms EEG being under inspection of 19 with use are of resulted multifactorial dispersive analyses surveyed. On the basis of the received material an assumption comes out, that realization of base conditions of wakefulness is provided by own "built-in" regulating with mechanisms. Absence of such "built-in" mechanisms for a condition of monotonous causes "search" character of activity of regulating systems which results in the expressed periodicity in changes both a functional condition of a brain, and quality of activity carried out by the person.

[The neuronal ensembles of the brain]. / Neironnye ansambli mozga.

The conclusion about availability of two types of neuron ensembles in the central nervous structures was made on the basis of proper experimental studies and appropriate literature data analysis. The first is presented by neurons functional cooperation (Hebbian ensembles) formed during learning process on the basis of synchronization by high-frequency oscillator activity. The second is presented by morphological-and-functional structures (Kogan's neuron ensembles) formed during neurogenesis process and genetically destined for biologically valuable patterns recognition. The control of functional state of the brain neuron networks and occurred information processes is realized by non-specific systems either restrict the neurons capability of joining in the rate of global synchronization by synchronization and desynchronization actions or form and maintain the common rhythm of activity in considerable neuron populations. The latter block single elements ability to enter into specific interactions.

[Space-time organization of the electrical activity of the human brain in a state of calm wakefulness and during the solution of intellectual tasks]. / Prostranstvenno-vremennáia organizatsiia élektricheskoi aktivnosti mozga cheloveka v sostoianii spokoinogo bodrstvovaniia i pri reshenii myslitel'nykh zadach.

In a series of experiments it has been shown that during solution of mental tasks of various complexity, a marked desynchronization is observed of the cortical rhythmic activity characteristic of the state of calm wakefulness. In the range of main wakefulness frequencies (alpha and beta), a significant lowering is observed of the level of spatial biopotential synchronizations. Its increase in these conditions is connected with the range of slow EEG rhythms; there exist different opinions about their functional significance in wakefulness.

[Reflection in the electrical activity of the brain of the activities of the mechanisms regulating the functional state]. / Otrazhenie v élektricheskoi aktivnosti mozga deiatel'nosti mekhanizmov reguliatsii funktsional'nogo sostoianiia.

On the basis of analysis of the results of author's studies and literature data, theoretical notions are developed, according to which spatial-temporal organization of cortical biopotentials is a result of activity of nonspecific different level systems subtly regulating current alertness in conformity with needs of the actual and forthcoming activities. In the hierarchy of regulating systems, in conditions of alertness, nonspecific thalamic and midbrain system is leading. Activity of these regulation levels provides in alertness for formation and destruction of functional neuronal ensembles which realize elementary informational transformations. The role is emphasized of asynchronous processes in the central nervous system activity.

[The mechanisms of the formation and the role of the oscillatory activity of the neuronal populations in brain systemic activities]. / Mekhanizmy formirovaniia i rol' ostsilliatornoi aktivnosti neironnykh populiatsi v sistemnoi deiatel'nosti mozga.

Experimental findings and theoretical concepts that have led to a new insight into the neurophysiological mechanisms underlying information processing and brain state are presented in this review. It is assumed that the brain information processing associated with elementary neuronal assembles is reflected by oscillations in the range of 30-70 Hz and their spatio-temporal organization in millisecond intervals. He functional brain state associated with the non-specific systems is reflected in synchronization or desynchronization of activity of large neuronal populations in the frequency range of 20 Hz.

[Changes in characteristics of sensory evoked potentials in dynamics of monotonous activity]. / Izmenenie kharakteristik sensornykh vyzvannykh potentsialov v dinamike monotonnoi deiatel'nosti.

Visual and auditory evoked potentials were recorded in 19 volunteers during their monotonous activity. Three groups of subjects different in performance quality were set aside. Characteristics of evoked potential components were subjected to analysis of variance. The latency of P1 component of visual and auditory evoked potentials recorded in respective projection cortical areas significantly increased over the course of the long-term monotonous activity. These changes were associated with performance deterioration. The observed changes in performance quality and brain functional state were determined by individual features of subjects.

[Changes in the space-time organization of the bioelectrical activity of the human brain on completing the solution of a mental task]. / Izmenenie prostranstvenno-vremennoi organizatsii bioélektricheskoi aktivnosti mozga cheloveka po okonchanii resheniia myslitel'noi zadachi.

Changes in spatial-temporal organization of human bioelectrical brain activity were studied following formal completion of the process of solution of mental tasks of various complexity. It was shown that in the first seconds after the response, desynchronization took place of cortical potentials, identical to the one observed in the process of solution; at frequencies of alpha- and beta-2-rhythms, predominant decrease took place of parameters of spatial-temporal biopotentials conjunction as compared to the level of calm alertness. Dynamics of recovery of calm alertness EEG characteristics is determined by subjective complexity for the subject of previous activity and by the degree of his confidence in the correctness of the obtained result. The latter is determined by individual-typological properties of the subject.

[The electroencephalographic correlates of the intellectual abilities of adolescents]. / Elektroéntsefalograficheskie korreliaty intellektual'nykh sposobnostei podrostkov.

Analysis of correlation between intellectual faculties of schoolchildren and spatiotemporal organization of their brain electrical activity was carried out. The less intelligent teen-agers showed more expressed alpha-activity in the EEG of rest, higher level of EEG coherence, and insignificant restructuring of the rhythmical activity under conditions of "open eyes" as compared with the "closed eyes". In the resting EEG of highly intelligent teen-agers beta-frequencies were more expressed and desynchronization after opening the eyes was clearly detectable.