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Based on the process needs, motivations and emotions, are describing molecular, cellular and systemic mechanisms of goal-direction motivated behavior. Goal-direction behavior is impossible without the orientation in space and forming a cognitive map. This process implements the hippocampus, via the neocortical connections. The hippocampus is linked to the amygdala, which is involved in the implementation of emotional behavior and organizing emotionally intense cognitive map or context of the environment.

How do humans become aware of anything, be it a flash of light, a scent or a sensation of pain? There is no conclusive answer to this question yet, though it is a key to understanding any form of consciousness. This paper postulates a mechanism of auto-identification, which consists in the following: a pattern of input excitation, generated'by a stimulus in one or several cortical. areas, generates.a pattern of output excitation identical (i.e. broadly coincident) with the input excitationpattern. The output pattern of excitation is relayed by way of massively parallel feedback to the input of the same cortical areas. The identical patterns of excitation produced by the stimulus and relayed through back projections, add together in the same neuronal structures resulting in their intensive firing. This cyclic process accentuates the characteristics and intensifies the stimulus mapping thus-providing the best conditions for distributed longterm memory categorizing the stimulus. The sensory category is the cortical response to the input excitation and is mapped by a specific pattern of neuronal activity. The pattern of categorization is relayed to the input and is included in the cycle of auto-identification, thus providing for intensive mapping of the subjective meaning of the stimulus. The mapping of sensory categories (i.e. internal data) by input neuronal activity patterns is therefore representation of these categories to the subject as elements of the mapping of the world outside. As a result, the outside world is represented to.the subject not by the objective characteristics of the physical world, but by sensory categories: color, taste, odor, tactile sensa- tion, etc., which constitutes the phenomenon of sensory awareness.

Generalized spike and wave discharges (SWDs) are generated within the cortico-thalamo-cortical system, being an electroencephalographic sign of absence epilepsy. The current work aims to identify mechanisms of SWD initiation, maintenance and termination. Dynamics and directionality of mutual interactions between neocortex (occipital (OC) and frontal (FC) cortex) and thalamus (reticular (RTN) and ventral postero medial (VPM) thalamic nuclei) were investigated. SWD initiation process is revealed several seconds before seizure onset in interaction between all brain areas, except intrathalamic pair (RTN-VPM). This process begins at different moments relatively to SWD onset. The interaction increase is observed earlier and most obviously when thalamus and OC drive FC. The maintenance process (the first few seconds of SWD) is accompanied with high level interaction inside thalamus and increase of driving from thalamus to occipital cortex. Thus interaction from thalamus and occipital cortex to frontal cortex and influence to VPM occur to be below baseline level. At the SWD offset thalamo-cortical interactions were found to return to baseline level quickly.

Executive functions are an important ability of human brain to program, regulate and control various cognitive processes; one of these processes is the voluntary task switching. However, the sex differences in this process are poorly studied. In our study, these differences were investigated in 70 healthy subjects (36 men and 34 women) aged 21-48 years by means of functional magnetic resonance imaging (fMRI) and neuropsychological examination. During the fM RI study, the subjects had to shift their attention between two tasks (classifying figures according to their form or number). During neuropsychological examination, the subjects completed a series of visual attention, task switching and memory tests. The results of fMRI study showed that visual task switching in women is carried out by a neuronal network, consisting of dorsolateral prefrontal cortex, inferior parietal areas, secondary visual areas of both hemispheres and cerebellum cortex. Task switching in men involved the same areas and, in addition, right supplementary motor area, right insula and left thalamus. As compared with women, the rate of activation of prefrontal cortex, left parietal lobe and right insula in men was significantly higher. The results of neuropsychological tests showed that men completed the tasks with attention switching, searching and arranging of stimuli significantly slower than women. The data demonstrate the differences in the organization of task switching processes in men and women.

The present review is devoted to modern knowledge about a structure and function of the cat's lateral posterior-pulvinar complex of the thalamus (LP-P). The LP-P is a subcortical structure belonging to visual system. This complex appears in phylogenesis simultaneously with lateral geniculate body and visual cortex, develops structurally and in human, occupies about 1/3 of the thalamus. The LP-P is a so-called associative nucleus of the thalamus and it is anatomically and functionally complex structure. The complex has reciprocal connections with many cortical areas and may participate in the regulation of a flow of visual information to the cortex modulating cortical processes. The function of the LP-P is still not fully understood. Experimental data allows to believe that this complex participate in such cognitive processes as attention and orienting to visual stimuli, in visually-guided behavior and spatial coding of visual stimuli as well as in binding of particular features of visual objects in the whole percept and maybe in the processes of short-term memory during analysis of visual stimuli.

A hypothetical mechanism is suggested for processing of complex sounds and auditory attention in parallel neuronal loops including various auditory cortical areas connected with parts of the medial geniculate body, inferior colliculus and basal ganglia. Release of dopamine in the striatum promotes bidirectional modulation of strong and weak inputs from the neocortex to striatal neurons giving rise to direct and indirect pathways through the basal ganglia. Subsequent synergistic disinhibition of one and inhibition of other groups of thalamic neurons by the basal ganglia result in the creation of contrasted neuronal representations of properties of auditory stimuli in related cortical areas. Contrasting is strengthened due to a simultaneous disinhibition of pedunculopontine nucleus and action at muscarine receptors on neurons in the medial geniculate body. It follows from this mechanism that involuntary attention to sound tone can enhance an early component of the responses of neurons in the primary auditory cortical area (50 msec) in the absence of dopamine due to a disinhibition of thalamic neurons via the direct pathway through the basal ganglia, whereas voluntary attention to complex sounds can enhance only those components of responses of neurones in secondary auditory cortical areas which latencies exceeds latencies of dopaminergic cells (i.e. after 100 msec). Various consequences of proposed mechanism are in agreement with known experimental data.

A single session of heart rate variability (HRV) biofeedback in apparently healthy young people and adolescents aged 14-17 years in order to increase vagal effects on heart rhythm and also electroencephalograms were carried out. Different variants of EEG spectral power during the successful HRV biofeedback session were identified. In the case of I variant of EEG activity the increase of power spectrum of alpha-, betal-, theta-components takes place in all parts of the brain. In the case of II variant of EEG activity the reduction of power spectrum of alpha-, betal-, theta-activity in all parts of the brain was observed. I and II variants of EEG activity cause more intensive regime of cortical-subcortical interactions. During the III variant of EEG activity the successful biofeedback is accompanied by increase of alpha activity in the central, front and anteriofrontal brain parts and so indicates the formation of thalamocortical relations of neural network in order to optimize the vegetal regulation of heart function. There was an increase in alpha- and beta1-activity in the parietal, central, frontal and temporal brain parts during the IV variant of EEG activity and so that it provides the relief of neural networks communication for information processing. As a result of V variance of EEG activity there was the increase of power spectrum of theta activity in the central and frontal parts of both cerebral hemispheres, so it was associated with the cortical-hippocampal interactions to achieve a successful biofeedback.

The hypothetical mechanism of functioning of neural networks that include limbic structures, neocortex and basal ganglia is proposed. A hypothesis is based on known data that the hippocampus, amygdala and prefrontal cortex interreact with each other, that their efferents converge on spiny cells of nucleus accumbens, that these inputs are topically organised and could be modified. Since GABAergic spiny cells of nucleus accumbens innervate neurons in the output basal ganglia nuclei which inhibit excitatory transmission through the thalamic nuclei into limbic structures and neocortex, the degree of activation of neurones in mentioned structures and, hence, a behaviour selection essentially depends on the character of responses of spiny cells. A summation of excitation of spiny cells and amplification of their responses during simultaneous firing of neurons of a limbic structure and neocortex, ultimately will lead to rising in neocortical activity and increase of its influence on a behaviour selection. If two structures are excited with temporary shift, activation of neurons of that structure which has firstly been strongly excited can be additionally increased due to a disinhibition of thalamic nuclei through the basal ganglia, whereas activity of neurons in other structure can be depressed if responses of spiny cells evoked by excitation arriving from this structure are decreased. Such suppression can be a consequence of heterosynaptic depression which is based on potentiation of efficacy of excitatory inputs from the different structures converging on inhibitory interneurons in the nucleus accumbens and basolateral amygdala. As a result, the behaviour choice will be determined by that structure which has been involved in activity firstly. A damage of different inputs into the nucleus accumbens from limbic structures must result in various behaviour disorders owing to the topical organisation of these inputs.

The time-frequency characteristics and interneuron interaction in the cell ensembles of non-specific (CM-Pf) and motor (Voi) thalamus were analyzed. Neuronal activity was registered by microelectrode technique during 18 stereotactic neurosurgery operations in spasmodic torticollis patients. The presentation of functionally significant verbal stimuli was accompanied by the emergence of short-term (0.5-1.5 s) local synchronization and stabilization of the oscillatory (3-6 Hz) activity in nearby neurons of nonspecific (CM-Pf) thalamus. These focuses of synchronized oscillatory neuronal activity were correlated with the moment of the greatest concentration of selective attention. Similar phenomenon of short-term synchronization was observed in the motor (Voi) and nonspecific (CM-Pf) thalamus of the human brain during the voluntary movements. Synchronization of neuronal activity occurred at the height of the motor act implementation, correlating with the maximum muscle tension, as well as in aftereffect of the voluntary movement. Overall, the findings suggest an important role of the local oscillations (3-6 Hz) and synchronization ofthalamic neurons in the mechanisms of relevant information transmission during goal-directed human behavior.

We proposed that impairment of learning, memory, and attention evoked by sleep deprivation could be a consequence of following changes in neuromodulator concentrations and intracellular processes that influence synaptic plasticity and functioning of the hippocampal formation and cortico--basal ganglia--thalamocortical loops. Firstly, a decrease in Ca2+ concentration and NMDA-receptor expression prevents induction of LTP of efficacy of synaptic transmissions in the neocortex and hippocampus. Secondly, a decrease in orexin concentration also worsens conditions for LTP induction and suppresses transmission of excitation in trisynaptic pathway through the hippocampus, thus worsening a creation of neural representations of "object-place" associations. Thirdly, a decrease in concentration of dopamine, and increase in level of adenosine and number of A1 receptors in the striatum worsen the functioning ofcortico-basal ganglia-thalamocortical loops. These lead to decrease in voluntary and involuntary attention, worsens processing of sensory information, and motor reactions. Excitation of neurons in reinforcement loops is also decreased thus suppressing the motivational significance of stimuli.

A mechanism of time perception is suggested. It is based on a postulate that time when stimulus arrives (parameter "when") is such property of stimulus as its physical properties (parameters "what"), and association "what - when" is perceived in those area of neocortex in which property "what" is processed after its repeated excitation. The time of repeated excitation which determines clock rate of "intrinsic clock", depends on dopamine influence at functioning of the cortico - basal ganglia - thalamocortical loop that promotes contrasted amplification of activity of cortical neurones, firstly activated by stimulus. Accumulation of time counts is performed in the neocortex and coded by the number of neuronal discharges. Duration of current interval is proportional to the number and duration of cycles of repeated neocortical excitation. Time counting can be started involuntary by stimulus, or voluntary due to activation of prefrontal cortex. The mechanism of time perception is similar for stimuli of different modalities owing to resemblance of functioning of topically organised cortico - basal ganglia - thalamocortical loops, it follows from our model that the more (less) concentration of dopamine in the striatumm the higher (low) clock rate, so the real interval will be estimated more (less) precisely and perceived as longer (short). These consequences of the model are in accordance with known experimental data.

Relative quantitative distribution of all the associative and descending efferent fibers and the ultrastructural organization of the terminals of the parietal cortex areas 5 and 7 in the caudate (NC) and red nucleus (NR) in the cat were analyzed after a local, pointed destruction of the cortex of these areas. The maximal numbers of the associative fibers were found to project to the fundus areas of the motor cortex and to the area of Clare-Bishop; moderate projections were detected to the areas 31, 19 and single degenerating fibers were registered in the areas 1,2, 3a, 3b, 30, and 23. The descending efferents were maximally projecting to NC, NR, reticular nuclei of the thalamus, midbrain, and pons, in all of which, according to the immunocytochemical studies, GABA-ergic terminals are prevalent. On the basis on the electron microscopical studies, it was suggested that the influence of the parietal cortex is mediated by the axo-spinal synapses of the medium shortaxonal spiny cells of the dorsolateral part of NC caput and by the axo-dendritic synapses of Golgi II cells of the parvocellular part of NR. On the basis of the maximal involvement of the fundus areas of the motor cortex, as well as of the inhibitory subcortical (NC) and stem nuclei (NR, reticular nuclei of the thalamus, midbrain, and nuclei pontis), it is suggested that these structures serve as the morphological substrates for the realization of the inhibitory, integrative function of the parietal cortex.

The main purpose of this survey is to explain the importance of set-shifting for a flexible cognitive activity. Working memory overload may result in set-shifting slowdown, i.e., in a more rigid set and in a less flexible cognitive activity. This effect displays itself in an increase of erroneous perceptions of external stimuli. Set rigidity level also depends on the cognitive activity context (i.e., on the type of external stimuli the person has to deal with). We analyzed EEG-coherence function and induced synchronization/desynchronization responses in theta (4-7 Hz) and low alpha (8-10 Hz) bands. Basing on these data, we discuss the role of tonic and phasic forms of cortico-hippocampal and fronto-thalamic systems' activation in cognitive activity flexibility.

Visual cognitive set was studied in two groups of 8-year-old children: with normal development of fronto-thalamic system (FTS) (n = 21) and with functional immaturity of this system (n = 29). In most of the children with the FTS-immaturity a formed visual set was rigid. EEG was recorded from the frontal, central, temporal, parietal and occipital regions, and coherence function in theta-, alpha- and beta-bands was analyzed. The most vivid differences between two groups of children were revealed at the set actualization stage. If the set was a plastic one, the value of coherence function between frontal and dorsal areas was higher in children with FTS-immaturity, than in "normal" ones. In the group with FTS-immaturity the dependence of coherence function on the set's plasticity was more vivid, than in children without FTS-immaturity. In all children with a rigid set value of coherence function was higher during set formation, actualization and extinction, than at resting condition with eyes opened. In the group with FTS-immaturity the coherence of theta-band considerably increased at the set actualization stage, mainly in the right hemisphere. We consider this to be the evidence of a comparatively bigger role of cortico-hippocampal system and implicit episodic memory the set shifting. Probably these processes compensate the FTS-dysfunction and make a set more plastic.

Visual set (by D.N.Uznadze) was studied in three groups of 8-year-old children: children with EEG-signs of immaturity of fronto-thalamic activation system; children with a deficit of non-specific activation from mesencephalic reticular formation; children with normal development of these systems (control group). Children with a deficit of non-specific activation split in two groups: one group was similar to the control group in set-forming, set-shifting and response time dynamics; another group haven't displayed a set actualization stage and had a considerably bigger response time during attention shifting. Children with immaturity of fronto-thalamic system, when compared to the control group, had considerably more contrast illusions at set-testing stage and considerably bigger response time during attention shifting at set actualization stage. These data suggest a participation of fronto-thalamic system in set-forming and set-shifting.

The work deals with study of role of inhibitory interneurons in the process of regulation of sensory currents converging on soma of pyramidal cells of the dorsolateral amygdala nucleus as well as of role of these interneurons in mechanism of regulation of plasticity of amygdalar synapses. It has been shown that the part of the spontaneous inhibitory postsynaptic currents recorded on the dorsolateral amygdale pyramidal cells is relatively high and amounts to about a half of the total amount of the recorded events. Analysis of the evoked postsynaptic responses has shown the interneurons to regulate activity and duration of these responses due to the postsynaptic membrane hyperpolarization as a result of activation of GABA(A)-receptors. Also studied was role of interneurons in providing mechanisms of the long-term potentiation of the synaptic responses evoked by stimulation of cortical and thalamic inputs. Block of effect of interneurons with help of picrotoxin has been shown to lead to an increase of evoked potentiation of synaptic responses.

The mechanism of response decrement in hippocampal and dopaminergic neurons on repeating stimuli based on the dopamine-dependent negative feedback in the hippocampal--basal ganglia--thalamo--hippocampal loop is suggested. Activation of hippocampal neurons caused by new stimulus facilitates occurrence of reaction of dopaminergic cells due to their disinhibition through striatopallidal cells of nucleus accumbens and ventral pallidum. However, increase in dopamine level and activation accumbens and ventral pallidum. However, increase in dopamine level and activation of D2 receptors on the striatopallidal cell, while promoting depression of hippocampal inputs, prevents disinhibition of dopaminergic cells, and their reactions start their decrement. The subsequent decrease in D1 receptor activation leads to reduction of efficiency of neuron excitation in the hippocampal CA1 fields, as well as in striatonigral cells of nucleus accumbens. This leads to a decrease of disinhibition through a direct pathway via the basal ganglia of thalamic nucleus reunions which activates neurons of the CA1 field. This effect causes decrement of reactions of the hippocampal neurons, a subsequent reduction of dopaminergic cell disinhibition, and further decrement of their responses.

Investigation was fulfilled on healthy subjects (22) and on outpatients (62). The EEG by the standard scheme as recorded at resting with open and closed eyes and under different functional loads. These records were processed in accordance with the EEC phase structure with the aid of computer animation technology. The main idea of the phase structure technology consists in rejection of one supporting lead. Time shifts were measured only between two neighbouring electrodes, so that the oscillations under comparison were always highly coherent. Time errors were evaluated according to crosscorrelation function maximum shift. The differences between high- and low-frequency EEG rhythms were shown to be only quantitative from the phase structure viewpoint. Qualitatively, the rhythm properties were equal and came to slow (second) phase structure oscillations. Low frequency activity compared to high frequency one was characterized by greater phase shifts from electrode to electrode. Phase shifts of potentials are forming the structure which, as a whole, is very similar in different people and is reproduced in different states. Initial EEG waves appearance is statistical linked with main sensory projections: visual (occiput), auditory (temples) and somatic (parietal region) with addition of frontal region. Redistribution of phase leadership in favor of occipital pole and to both temporal regions when eyes are open is described. It is apparently dependent on the sensory surge level from thalamus to a given cortex region. Phase gradient direction seems to reflect the cortex current density gradient which is parallel to surface. It can be used for localization of compact sources lying near to cortex.

A hypothetical mechanism of the basal ganglia involvement in the occurrence of paradoxical sleep dreams and rapid eye movements is proposed. According to this mechanism, paradoxical sleep is provided by facilitation of activation of cholinergic neurons in the pedunculopontine nucleus as a result of suppression of their inhibition from the output basal ganglia nuclei. This disinhibition is promoted by activation of dopaminergic cells by pedunculopontine neurons, subsequent rise in dopamine concentration in the input basal ganglia structure. striatum, and modulation of the efficacy of cortico-striatal inputs. In the absence of signals from retina, a disinhibition of neurons in the pedunculopontine nucleus and superior colliculus allows them to excite neurons in the lateral geniculate body and other thalamic nuclei projecting to the primary and higher visual cortical areas, prefrontal cortex and back into the striatum. Dreams as visual images and "motor hallucinations" are the result of an increase in activity of definitely selected groups of thalamic and neocortical neurons. This selection is caused by modifiable action of dopamine on long-term changes in the efficacy of synaptic transmission during circulation of signals in closed interconnected loops, each of which includes one of the visual cortical areas (motor cortex), one of the thalamic nuclei, limbic and one of the visual areas (motor area) of the basal ganglia. pedunculopontine nucleus, and superior colliculus. Simultaneous modification and modulation of synapses in diverse units of neuronal loops is provided by PGO waves. Disinhibition of superioir colliculus neurons and their excitation by pedunculopontine nucleus lead to an appearance of rapid eye movements during paradoxical sleep.

An approach to modeling "sleeping" spindles (waxing and waning of characters patterns cycles 12-18 H) of electrical activity of mammalian brain was proposed, which is based on the idea of the pacemaker nature of the sigma rhythm. The spindles are assumed to result from the rhythmic interaction of cortical neurons and medial thalamus cells. A system of oscillatory links operating in the mode of small vacillations is taken as an analog of this interaction. A deepening of slow-wave sleep is considered to result from an increase in the density of interactions and the number of oscillatory links, which is associated with differences in the adaptation of organisms of high and low anxiety to environmental changes.

The method of statistical evaluation of probable interaction between the main constituents of bioelectrical activity of the brain (BEA) enables to reveal the character of intercentral relations both under normal conditions and at adaptation disorders of different severance. Several types of statistic interactions have been revealed between EEG components (SSIC) correlating with normal interrelations between cortex and subcortex, level of preferential involvement of non-specific brain formations (cortex, thalamic, hypothalamic and brain-stem) into the process, and the degree of instability of neuro-dynamic processes. The findings obtained have shown the degree of expression of adaptation disorders to be connected with gradual destruction of "functional nuclear" within alpha-range, amplification of statistical interrelations with beta-EEG and teta-EEG components and formation of pathological nuclear structures within the ranges aforesaid.

A possible mechanism of participation of cholinergic striatal interneurons and dopaminergic cells in conditioned selection of a certain types of motor activity is proposed. This selection is triggered by simultaneous increase in the activity of dopaminergic cells and a pause in the activity of cholinergic interneurons in response to a conditioned stimulus. This pause is promoted by activation of striatal inhibitory interneurons and action of dopamine at D2 receptors on cholinergic cells. Opposite changes in dopamine and acetylcholine concentration synergistically modulate the efficacy of corticostriatal inputs, modulation rules for the "strong" and "weak" corticostriatal inputs are opposite. Subsequent reorganization of neuronal firing in the loop cortex--basal ganglia--thalamus--cortex results in amplification of activity of the group of cortical neurons that strongly activate striatal cells, and simultaneous suppression of activity of another group of cortical neurons that weakly activate striatal cells. These changes can underlie a conditioned selection of motor activity performed with involvement of the motor cortex. As follows from the proposed model, if the time delay between conditioned and unconditioned stimuli does not exceed the latency of responses of dopaminergic and cholinergic cells (about 100 ms), conditioned selection of motor activity and learning is problematic.

The possibility of the development of either the long-term posttetanic potentiation or the depression of focal evoked potentials in identified columns of the barrel somatic cortex of unanaesthetized rats during stimulation of their specific thalamocortical afferent fibers was shown. Phase-dependent potentiation developed after burst tetanization with the frequency of theta rhythm at the negative phase of a theta wave, whereas the stimulation at the positive phase produced the depression. Potentiation after continuous tetanization was observed only at the optimal selection of stimuli amplitude and duration. Excessively intense tetanization more frequently caused the depression of tested responses probably due to the involvement of recurrent inhibition.

The article reviews published and own data on special features of organization of afferent cortical and infracortical correctional systems of the total striopallidaric nuclear complex in various species of mammals. The article focuses on analysis of organization of these flows in a dog being a classical object of behavioural experiments and a rare object of neuromorphological studies. It was discovered that the general trend towards segregated and converged flows of functionally different information at the level of striopallidum is retained in all tested mammals, being an evidence of the fundamental nature of the discussed principles of organization of the projection systems of basal ganglia. The reviewed morphological data confirm reliability of the presented concept of basal ganglia functioning.

The review is focused on attention as behavior-controlling process. Neurophysiological, electrophysiological and neuropsychological studies of different brain structures during voluntary attention are analyzed. These data show that selective voluntary attention modulates activity of sensory specific cortical zones involved in relevant signal processing. Fronto-thalamic system consisting of prefrontal cortex and thalamic mediodorsal nuclei is shown to be main source of top-down selective modulation of voluntary attention. The review proposed the hypothetical model of selective cortical activity modulation during voluntary attention based upon the available data and evidence of own electroencephalographic studies.

Possible mechanisms of amplification/attenuation of cortical signals opening or not opening NMDA-channels in striatal spine cells while passing through basal ganglio-thalamocortical network and relegated to either "strong" or "weak" signals, are considered. In absence of dopamine, a relative increase in intensity of the "strong" or "weak" cortical signals should result in the LTP/LTD on both striatonigral and striatopallidal cells, the thalamic cells being affected in the opposite way. Activation of the dopamine receptors on the striatonigral (striatopallidal) cells prompts the LTP/LTD expression. Thereof, the "strong" cortical signals are synergistically amplified whereas the "weak" signals are synergistically attenuated at the thalamic output.

On the basis of the mechanism of synaptic plasticity that we have earlier suggested for striatal spiny neurons and with regard to the known data about the predominance of dopamine-sensitive D1/D2 receptors on the striatonigral/striatopallidal cells it is hypothesized that the induction of the long-term potentiation/depression of the efficacy of excitatory cortical inputs to these cells can underlie the excitatory/inhibitory effect of dopamine on the activity of neurons that originate the "direct"/"indirect" pathways through the basal ganglia. Both these effects will lead to an enhancement of the activity of thalamic cells and activity of the efferent neocortical neurons excited by thalamic cells. The long-term potentiation of corticostriatal inputs to striosomal neurons, where, predominantly, D1 receptors are located, can also be induced by dopamine. This effect can be responsible of a rise of inhibition of dopaminergic cells and decrease in dopamine release by these cells. Such an event sequence can provide a stable dopamine concentration in the loop neocortex-basal ganglia-thalamus-neocortex.

Using the method based on retrograde transport of markers injected into different segments of caudate and accumbent nuclei and putamen peculiarities of labelled neurons distribution in thalamic nuclei of the dog brain were studied. Zones of projection of motor and limbic thalamic nuclei and overlapping of terminal fields of fibres projection neurons of thalamic nuclei that function in different systems were demonstrated in the striatum. Comparative analysis of thalamostriatal projections organization in dogs, cats and monkeys allowed to reveal certain diversities in their construction as well as similarities.

Distribution of labelled neurons in thalamic nuclei after the marker injection into the dog brain pallidal structures (globus pallidum, entopeduncular nucleus and ventral pallidum) was studied by retrograde axonic HRP and fluorochrome transport. Analysis of the material obtained allowed to conclude that in globus pallidum projections from motor thalamic nuclei (ventral anterior, ventral lateral, ventral medial and median centre) are dominating, although in ventral pallidum projections from limbic nuclei (parafascicular and median) are predominant. Entopeduncular nucleus receives projections from functionally different thalamic nuclei (intralaminar and nuclei of ventral and posterior groups). It is obvious that both segregated transmission of functionally specific information and possibility of its convergence at the level of pallidum might occur in organization of thalamo-palidal projections.

The pronounced benzodiazepine (antiphobic) modulation of the amplitude-temporal parameters of different components of the thalamocortical responses (TCR) of the sensorimotor cortex is observed in rabbits in their early postnatal ontogeny. This modulation is of a dose-dependent character and is registered not after the injection of tazepam in a concentration of the "therapeutic tranquilizing window" but also in the psychotoxic plasma range. A gradual increase in blood tazepam concentration in a young rabbit pup is accompanied by the wave-like and differential decrease in the amplitude of the second and third positive (P2 and P3) and third negative (N3) TCR components, while the second negative (N2) and fourth positive (P4) components tend to a wave-like increase. The dose-dependent dynamics of tazepam modulation of the P2, P3, and N3 latencies is characterized by a wave-like and differential increase. The latency of P4 decreases slightly and that of the N2 increases with a low degree of significance. The selective dynamics of benzodiazepine modulation appears to be related with peculiarities of the electrogenesis of each of the components. The dose-dependent modulation of the level of cortical DC potential is of the same character as the respective amplitude changes in P2, P3, and N3, but its fluctiatuons are more pronounced.

The authors review data on recently discovered temperature response of deep skin layers to the meal. The reaction is of a reflex nature and is one of the mechanisms regulating heat exchange in the body. In healthy people this reaction is weak. In alimentary obesity, it becomes much stronger, probably due to impaired heat exchange because of accumulated fat. In obesity related to diencephalic syndrome skin reaction is similar to control. In this obesity, pituitory seems to lose ability to regulate circulation in the blood. The above reaction can be used as a test differentiating the two forms of obesity.

Unlike physiologic pain which has a signal, adaptive role, pathologic pain is a pathogenic factor causing disturbances in activity of organism systems. Current views on the nature of pathologic pain are mainly concerned with neurochemical and plastic processes occurring in nociceptive neurons but not with systemic mechanisms of pathological pain. This limitation has been overcome with elaboration of the pathophysiologic theory of generatory and systemic mechanisms of algesic syndromes. According to this theory, a pathogenetic basis for a pathologic pain are formation and functioning of new pathologic integrations within algesthesia system--an aggregate of changed nociceptive neurons acting as a generator of pathologically enhanced excitation and a new pathodynamic organization from changed parts of algesthesia system which represents a pathological algic system. This theory is competent to explain many peculiarities of pain syndromes without denying cell-mediated and neurochemical mechanisms of pathological pain.

Long-lasting potentiation of the cat motor cortex units induced by tetanic stimulation of the VL + SCx led to an increase of the motor cortex unit discharge rate. The findings suggest that co-activation of cortico-cortical and thalamo-cortical afferents modifies neuronal activity of the motor cortex at the specific site which receives convergent sensory input from the thalamus and the somatosensory cortex.

Neurons of the medial thalamus and some cortical neurons revealed the same activity upon the spindle wave as upon the slow wave. The membrane potential was changing in a similar way. The data obtained suggests that the slow wave mechanism is analogous to the mechanism of the spindle waves, whereas the rhythm of complexes occurrence or their common with the "spontaneous" sleep spindles rhythm, are determined by a different mechanism.

A review of neurophysiological studies of human goal-directed behaviour performed with the aid of indwelled electrodes in Parkinsonian and epileptic patients. Functional role of the thalamo-cortical circuits is discussed.

In order to reveal the mechanisms of participation of the preoptic hypothalamic area in sleep-wake cycle regulation the effects of its electrical stimulation on activity of the thalamic median center were studied in chronic experiments in cats. Ipsi- and contralateral projections from the lateral preoptic area to the thalamic median center were electrophysiologically demonstrated. Activatory influence of the preoptic area was shown on the thalamic mechanisms of spindle activity generation. The obtained data suggest the interaction of the preoptic area with the structures of non-specific thalamus via the direct pathways to be one of the mechanisms of the preoptic area participation in sleep initiation and formation of the slow-wave sleep.

Long-term posttetanic modifications of the efficacy of inhibitory synaptic connections were studied in auditory thalamo-cortical assemblies. We demonstrated that intracortical microstimulation (ICMS, high-frequency pulse of 5 mcA) which activated a small group of cortical neurons produced long-term (at least 30 min) modifications (potentiation--LTPi and depression--LTDi of the efficacy of inhibitory monosynaptic transmission between numerous elements of thalamo-cortical network. LTPi was accompanied by an increase in the firing rate of inhibitory neuron. LTPi was input-specific and did not lead to decrease in the firing rate of the postsynaptic cell. LTP of the efficacy of excitatory and inhibitory inputs of the same target cell could be induced simultaneously. The efficacy of inhibitory synapses formed by the terminals of one axon on different cells could be modified variously. These results allowed us to suggest that we dealt with inhibitory synapses located on dendritic spines and that both pre- and postsynaptic mechanisms could underly long-term modifications of inhibitory transmission.

The long-term posttetanic modifications of the efficacy of excitatory synaptic connections were studied in auditory thalamo-cortical assemblies. We demonstrate that intracortical microstimulation--ICMS (high frequency pulses of 5 uA), which activated a small group of cortical neurons, produced long-term (at least 30 min) modifications (potentiation-LTP and depression-LTD) of the efficacy of excitatory monosynaptic transmission between numerous elements of thalamo-cortical network. Effectivity of "common input" also was potentiated or depressed. The amount of effective connections between neurons located in stimulated and nonstimulated loci of the cortex increased after ICMS. Some neurons in the network were favourable for inducing LTP. The efficacy of the synapses formed by terminals of one axon on different cells can be modified variously. The efficacy of the synapses formed by neurons from different loci of auditory cortex and MGB on the same target cell also can be modified variously.

The fact of marked neuroleptic modulation of the amplitude-temporal parameters of thalamo-cortical responses (TCR) of the sensorimotor cortex (SMC) in the range of "the therapeutic haloperidol window" and the psychotoxical phase was established in early postnatal ontogeny of rabbits. The gradual increase of blood haloperidol concentration was accompanied by non-harmonic increasing variations of the level of neuroleptic modulation of the amplitudes of separate TCR components. These dose-dependent variations with alternation of depression and potentiation of TCR components were observed not only in psychotoxical phase, but also inside "the therapeutic haloperidol window". In retarded, infantile individuals the lower threshold of haloperidol modulation of amplitude parameters of TCR SMC was observed in comparison with normally developing animals. In contrast to the amplitude parameters, dose-dependent modulation of latent periods of different components of TCR SMC was not of oscillatory but exponential character. This can testify to participation of different (by electrogenesis, biochemistry, and structure) neuronal pools in the processes of neuroleptically induced reorganization of amplitude and time markers of TCR SMC.

Auditory evoked potentials (AEPs) were recorded in 10 adult healthy subjects under conditions of simple rhythmical stimulation and during solving selective attention task. Middle- (10-60 ms) and long-latency (up to 400 ms) AEPs were analysed by AEP mapping and by evaluation of their spatio-temporal characteristics. it is suggested that interaction between the parietal, left temporal and left frontal cortical areas exerts efferent influence to brainstem structures over a period of 15-35 ms. Amplitudes of P90 and P250 components were reduced during selective attention task. The late P350 component increases, mainly, in the central and frontal cortical areas.

The work has been carried out in two steps. At the first one, in behavioural experiment, "punishment zones" were identified in animals, at the second step, in acute experiment, studies were made of the effect of stimulation of these zones on EP registered in CM-Pf in response to peripheral nociceptive stimulation. It was shown that stimulation of "punishment zones" inhibits the EP at currents lower critical level at which no avoidance reaction could be observed in behavioural experiment. Changes in the amplitude and duration of the EP depend on the aversive reaction to stimulation of these zones in the behavioural experiment. The sensitivity of CM-Pf to electrical stimulation of "punishment zones" remains constant with age.

Acute tests in mature cats, demonstrated, evoked potentials in the cortex and medial center of the thalamus resulting from test irritation of sciatic nerves and conditioning irritations of intra-osseous receptors. The test proved that electro-irritation of intra-osseous receptors as well as higher intra-osseous pressure caused by the impregnation of physiological solution into the bone facilitated afferent reactions during threshold electrostimulation of sciatic nerves. The results of these experiments were compared to those of clinical monitoring of patients with radicular syndromes of osteochondrosis after intra-osseous blockades which led the authors to suggest a hypothesis about trigger mechanisms of neuralgias, based on segmental alleviation of nociceptive afferentation resulting from overstimulation of intra-osseous receptors.

Effects of stimulation of areas of the negative reinforcement in hypothalamus and adjacent sites on the nociceptive evoked potentials (EP), recorded in the thalamic parafascicular complex to electrical skin stimulation of the hind paw in 30-40 days old rabbits were investigated. The stimulation of areas of the negative reinforcement in the anaesthetized animals resulted in the inhibition of the EP. Points, yielding the active-defense behaviour in the behavioural experiments, inhibited the EPs in the electrophysiological tests at the smaller current level (50-80%), than points, yielding the passive-defense behaviour (80-110%). On the contrary, the recovery period of the EP's parameters after the ceasing of the stimulation was shorter, if points were connected with the active-defense but not the passive-defense behaviour. The data obtained are considered in comparison with previous findings obtained in the investigation on the rabbits of the same age under the stimulation of areas of the positive reinforcement.

Acute cat experiments were conducted to study the effect of naloxone, moradol and dalargin on the formation of afferent reactions of gastroduodenal complex components by registration of cortical and subcortical evoked potentials during electrostimulation of the stomach and duodenum at an early stage of their acute lesion. It is found that agonists and antagonists of opiate receptors prevent the depression of afferentation of gastroduodenal complex components early after acute lesion. It is suggested that the main mechanism underlying the depression of gastric and duodenal afferent reactions at early post-alteration period may be related to activation of intraorganic opioid systems.