Zhurnal Vysshei Nervnoi Deyatelnosti Imeni I P Pavlova最新文献

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.

The role of backward connections (from higher to lower hierarchical layers) in the generation of evoked brain esponses. to simple visual stimuli was explored using Dynamic Causal Modelling approach (DCM), and the contribution of backward connections to evoked responses was quantified as a function of post-stimulus time. The early components of visual evoked related potential (ERP) reflect exogenous (sensory) inputs and can be explained by connections from the lower to higher layers'(forward connections). The ERP components after 200 ms reflect endogenous activity and require the inclusion of both forward and backward connections in the model. Our results complement the work of other authors who showed earlier using DCM that the backward connections occur at the late latencies in auditory oddball experiment.

To develop the presynaptic mechanism of the short-term plasticity of synaptic transmission the influence of the rhythmical orthodromic stimulation of intestinal nerve on the spontaneous excitatory postsynaptic potentials (EPSPs) have been analyzed in the command neurons of the defensive behavior of land snail Helix lucorum. It was shown early that the tetanic stimulation induced the short-term potentiation of evoked EPSPs. The rhythmical stimulation did not influence the amplitude of spontaneous EPSPs, but considerably increased their number. Discovered augmentation of the frequency of spontaneous EPSPs makes it possible to assume the participation of presynaptic mechanism in the short-term potentiation of synaptic transmission. The presynaptic mechanism can include reduction in the thresh- old of action potentials (APs) generation in the presynaptic neurons, which will lead to an increase in the fraction of spontaneous active neurons and, correspondingly, it will increase the number of spontaneous presynaptic APs.

Elaboration of conditioned place preference (CPP) associated with own and foster pups, and maternal behavior were compared in females of WAG/Rij and Wistar rats. In addition, behavior of females in the open field, elevated plus-maze and forced swimming tests were investigated before pregnancy and after pup delivery. In has been found that females of WAG/Rij rats elaborate worse CPP task associated with both their own (WAG/Rij) and foster (Wistar) pups. Thus, the number of females that increase time spent in initially non-preferred compartment after its association with pups and the number of females that reach criterion of CPP elaboration in WAG/Rij rats were less than in Wistar controls. WAG/Rij females exhibited less maternal care in the place preference test both to their own and foster pups: less number of approaches to pups, pups carrying and the time spent in contact with pups non-associated with feeding. In WAG/Rij females compared with Wistar controls immobility time in the forced swimming test was higher both before pregnancy and after pup delivery indicating a stable depression-like state. Before pregnancy, statistically significant inter-strain differences in the anxiety level have not been revealed. After pup delivery, in WAG/Rij females anxiety level decreased but in Wistar females didn't substantially change. Results suggest that worse elaboration of CPP task and reduced maternal care in depressive WAG/Rij females are not associated with specific features of their own pups but are due to their depression-like state. Put into other words, pups for depressive mothers are less potent reinforcer than for "normal" (non-depressive) mothers.

The work is aimed to an assessment of the correlation between of autonomic nervous system tone and the level of reactivity of the students' cardiovascular system and hemostasis system under examination stress. It was found that the students under exam stress are characterized with high values of respiration rate and with lower ones of tidal volume. The value of respiratory minute volume decreases in male students due to the bronchoconstrictor effects of stress at the tracheobronchial tree. This finding confirms a statistically significant reduction in the flow of small, medium and large bronchi, indicating an increased parasympathetic nervous system tone. A statistically significant increase in the power of fast waves as a result of determining heart rate variability in students of both hender during the exam also testifies the activation of the vagus nerve and can be used as a marker of exam stress. While exam stress, trombocrite value decreases and only femail students show a statistically significant reduction in the platelet number and increase of their volume. The tendency to increased thrombotic events under exam stress is demonstarated, being reached statistically significant differences in the case of female students--an increase in the initial thrombosis rate. In the case of mail students, an increase of prothrombin time value is testified under exam stress.

GABA is the major inhibitory neurotransmitter in the central nervous system determining the efficacy of neuronal interaction. GABA-receptors play a key role in different aspects of fear memory--acquisition and consolidation, retention, reconsolidation and extinction. Extinction is an important behavioural phenomenon which allows organism to adapt its behavior to a changing environment. Extinction of fear memory is a form of new inhibitory learning which interferes with expression of the initial acquired fear conditioning. Resistance to extinction is symptom of depression and posttraumatic stress disorder. The aim of the present review was to summarize own and literary data about GABAergic modulation of fear extinction and pharmacological correction of extinction impairment at influences on GABA(A)- and GABA(B)- receptors.

As clinical practice and experimental studies show, symptoms of depression and anxiety often accompany each other. It is well known that combination of anxiety and depression in patients is treated more slowly, requires large doses of drugs, increases the likelihood of suicide and often leads to relapse. Furthermore, antidepressants and anxiolytics exert its therapeutic effect in limited cases even in monopolar anxiety or depression state. In this review of literature and our own data the relationship of anxiety and depression is analyzed. It has been shown with using the model of mixed anxiety/depression disorder caused by chronic social defeat stress, that the anxiety and depression are changed under the influence of psychotropic drugs independently.

Specifics and key regulation mechanisms of compartmentalised protein synthesis in dendrites are reviewed. The up-to-date literature data of the subject are analysed. The results of many molecular, cytological and physiological experiments are presented. Also there is some information about a number of neurological diseases connected with dendritic translation regulation malfunction.

In the current paper there were used two methods for assessment of the propranolol effect on reactivated memory at reconsolidation phase--a classical pavlovian conditioning and the two-ways escape reflex. The difference between these two models was that in the first case a tone was paired with electrocutaneous painful stimulation only once, while in the second case it was applied multiply. Reminding was produced in the first case by placing the animals into the same context, whereas in the second case by application of the same amount of pairings of conditional and unconditional stimuli as it was used at the first day of learning. Propranolol reduced intensity of freezing reaction on 25% from the baseline at the classical conditioning approach and practically led to disappearance of memory and complete regress of the two-ways escape reflex. There was suggested on existence of the possible different mechanisms of noradrenergic blockade on memory loss at the stage of its reconsolidation in the used models of learning.

EEG power changes in anaesthetized and conscious rats were studied (under repeated experiments) in wide frequency band (0.1-200 Hz) during cortical spreading depression wave (SD). In anaesthetized rats the decrease of EEG spectral power was shown through all diapasons under consideration. The most pronounced decay of the EEG power was marked in the 30-40 Hz band (27.3 ± 18.5, p = 2.46 x 10-(11)). In other frequency ranges the power decrease was less but its significance remained high. In conscious rats the simultaneous decay of the EEG power from 20 to 100 Hz range was also the most informative index of SD wave. The maximum power loss was found for band 30-40 Hz (11.2 ± 7.8, p = 2.55 x 10(-7)). It was shown that besides of EEG power decay the development of SD wave was characterized by the appearance of high frequency activity in front of SD and at the end of it. The increase of high-frequency activity in front of SD wave appeared in the ipsilateral hemisphere and moved along the cortex with the velocity of the SD wave itself. However the bursts of high frequency activity at the end of unilateral SD occurred simultaneously in both hemispheres and lasted 1.5-2.5 min. Findings contribute to detection of SD wave on basis of EEG spectral analysis.