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Biomedical subjects

N E Sviderskaia

Publications and source records attributed to N E Sviderskaia.

At least 19 recordsLinked to original sources
PubMed2000

[EEG study of the anxiolytic effect of scopolamine].

Effect of the central M-cholinolytic scopolamine on spatial organization of the rat brain electrical activity was studied under conditions of high and low emotional-stress responses. The EEG changes were estimated by 840 parameters. A possibility of the EEG discrimination by means of interstrain differences in responses to scopolamine, was shown. A more obvious decrease in spectral power and potentials coherence was revealed in Maudsley Reactive rats (MR) as compared with the Maudsley Nonreactive rats (MNRA), in parieto-temporal and occipital areas of the right hemisphere, and the reverse interrelationship occurred in the anterior parts of the right and posterior parts of the left hemisphere. These findings suggest some specifics in the spatial distribution of the maximum scopolamine action foci depending on the initial emotional level. Changes occurring under the scopolamine effect in different EEG frequency bands are different in the MR and the MNRA rats. The findings are discussed in respect to the EEG indices of anxiolytic component of cholinergic regulation of the brain activity.

Animals↗
PubMed1992

[The trigger role of the left cerebral hemisphere in generalizing epileptic activity].

Overall 593 epileptic patients with left hemispheral lateralization of the focus and 46 patients with primary generalized epilepsy were examined. EEG and computerized mapping of cortical biopotentials were used. It has been shown that in right-handed patients, the left hemisphere triggers epileptogenesis whatever the site of the source of epileptic activity. The mechanism by which epileptogenesis is triggered includes the posterotemporal and central cortical areas of the left hemisphere.

Adolescent↗
PubMed1991

[Bioelectric activity of the cerebral cortex in patients with secondary generalized form of epilepsy under hypnosis].

A study was made of brain bioelectric activity in patients with secondarily generalized epilepsy under hypnosis. The disease manifestations were dependent on whether the site of the focus was in the right or in the left hemisphere. Hypnotic trance changes the neurodynamics of the focus and the level of interhemispheric relations, which depends on the focus lateralization. The authors demonstrate possibilities of that state, both positive connected with the diagnosis and treatment and negative ones restricting the use of hypnotherapy in the presence on the EEG of frequent epileptic phenomena or their slight provocation by hyperventilation.

Action Potentials↗
PubMed1991

[Various bioelectric correlations in primary and secondary epileptic foci].

Analysis was made of the EEG material of 122 patients, compiled on the basis of indispensable presence of bioelectric phenomena of both primary and secondary epileptic foci. Use was made of computerized mapping of spatial synchronism of cortical biopotentials. The authors show the differences between the secondary focal activity and the primary one, describe interrelations between the primary and secondary foci as the secondary focus is being formed.

Action Potentials↗
PubMed1991

[Study of the topographic organization of cortical electric activity during hypnotic analgesia].

Experiments on 10 right-handed subjects were carried out to study the topographic organization of cortical activation processes by means of toposcopy of synchronous electric activity in hypnotic analgesia. The authors demonstrate the priority role of the anterior cortical areas of the left hemisphere in analgesia effects, which is connected with their importance in data realization and formation of the motivation affective component of painful sensation. Experiments have shown different manifestations of the functioning of diffuse nonspecific and local specific activation processes maintaining sensory analysis of painful stimuli and their affective cognitive estimation in the systems responsible for individual tolerance to painful sensations and analgesia effects and demonstrated a possibility of observing at the level of objective electrophysiological parameters of the phenomenon of pain components dissociation as one of the mechanisms of hypnotic analgesia.

Action Potentials↗
PubMed1990

[Use of the indicators of spectral power of cortical biopotentials for evaluation of the processes of generalization of epileptic activity].

Spatial density of spectral power of bioelectric cortical activity was analyzed in patients with primary-generalized (PG) and secondary-generalized (SG) epilepsy within a range of 0.5-30 Hz divided by 22 narrow bands. The range 0.5-7.0 Hz was shown to play a special role in epileptic activity generalization. The PG forms and SG epilepsy with a focus in the left hemisphere are characterized by the predominance of spatial density of spectral power in some bands of the low-frequency range in the cortical structures of the left hemisphere. On the contrary, SG epilepsy with a focus in the right hemisphere is marked by the same features in the cortical structures of the right hemisphere.

Action Potentials↗
PubMed1990

[The differential-diagnostic role of low-frequency spectral characteristics of the bioelectric activity of the brain in epilepsy].

As many as 110 patients with primary-generalized (PG) and secondary-generalized (SG) attacks were examined by means of computer mapping of spectral power of cortical biopotentials within a range of 0.5-30 Hz divided by 22 frequency bands. As shown by differential diagnosis, the PG forms of epilepsy and SG epilepsy with focus localization in different hemispheres turned out dissimilar. The difference lay in cortical topography of an increase of spectral power in certain bands of the low-frequency range 0.5-7.25 Hz. The left hemisphere was noted to play the key role (in the right-handed) in the "trigger" of the processes of epileptic activity generalization.

Action Potentials↗
PubMed1990

[Relation between the functional state of cerebral hemispheres and the location and dynamics of the epileptic process].

Computer mapping of spatial synchronism of cortical potentials led away from 48 points was performed in 110 right-handed patients with primary- and secondary-generalized fits. The clinico-electrophysiological analysis was employed to demonstrate a special role played by the left hemisphere in the processes of epileptic activity generalization in different disease patterns and characteristic features of diagnosing the generalized patterns of epilepsy and determination of the focus of localization. The data obtained can be used for disease prediction and estimation of the treatment efficacy.

Action Potentials↗
PubMed1986

[Effect of haloperidol and clozapine on the bioelectric activity of the human cerebral cortex].

A study of spatial synchronization of the cortical biopotentials of man by multi-channel registration (leads from 48 points) made it possible to elucidate the common and specific characteristics of the action of typical (haloperidol) and atypical (clozapine) neuroleptics. The study was conducted on 10 subjects with the normal bioelectrical activity of the brain. Common for both drugs is their capacity to decrease the activity of the anterior cortical portions. They are different in that haloperidol, reducing the activity of the left hemisphere, perverts the inter-hemispherical relationships existing before its intake whereas clozapine does not change the nature of the inter-hemispherical relationships. These data may serve as the neurophysiological basis of the sedative and antipsychotic effects of typical and atypical neuroleptics.

Cerebral Cortex↗
PubMed1986

[Effect of neuroleptics on the epileptic process].

Using the parameters of the special synchronization of cortical biopotentials, the authors studied changes in the function of the cerebral cortex in patients with the generalized form of epilepsy with a further progression of the disease and under the effect of the typical neuroleptic haloperidol and atypical neuroleptic clozapine. These drugs have been found to act differently on the epileptic process and on the effects of the hyperventilation test, which appears to be due to their differing ability to block receptors of the nigrostriatal and mesolimbic dopaminergic systems. The data have shown that haloperidol increases the risk of the development of epileptic attacks while clozapine reduces epileptic manifestations.

Anticonvulsants↗
PubMed1982

[Study of the associative activity of schizophrenic patients by the technic of remote synchronization of cortical biopotentials].

To reveal physiological correlates of the schizophrenic thinking peculiarities associated with impaired mechanisms of information selection, spatial synchronization of the cortical biopotentials was studied in 10 healthy probands and 9 patients with continuously progressing schizophrenia. Both the healthy probands and the patients were asked to solve problems of comparing notions in situations where standard or non-standard criteria for the solution could be chosen. The bioelectrical activity was recorded at 48 cortical sites with subsequent estimation of the cross-correlation interconnections between the EEGs. It was found that in the solution of problems with the use of standard criteria the spatial-temporary organization of the biopotentials differed but little in the healthy probands and the patients, whereas in the solution of problems for which secondary, latent features of the subjects were required, these differences were rather marked in a number of characteristics, such as the general level of the synchronism, the character of interhemispheral asymmetries, the topographic distribution of the biopotential synchronization. The data obtained are discussed in the light of the present-day concepts on the functional specialization of the hemispheres.

Adolescent↗
PubMed1980

[Clinico-electrophysiologic characteristics of non-process personality changes and schizophrenia in adolescence].

The paper deals with a study of spatial organization in the biological processes during their toposcopical registration. These studies were necessary to determine the clinical and electrophysiological criteria for the differential diagnosis of schizophrenic patients and nonprocess personality deviations in adolescency. The data obtained demonstrated several differences, as shown by bioelectrical indices, in the intrahemispheric, interhemispheric, intracortical and cortical-subcortical interrelationships in the general system of functional contacts. On the basis of literary and personal experience certain assumptions are made, related to the differentiated influence of each of the links in the dynamic organization of brain activity on the character of psychopathological signs.

Adolescent↗
PubMedDate not supplied

[The effect of scopolamine on the spatial organization of rat cortical potentials].

The influence of scopolamine (1 mg/kg, i.p.) on the spatial organization of the neocortical electrical activity was studied in rats. A decrease in the spectral power and coherence of brain potentials in the range of the dominant theta-rhythm peak (6.00-7.25 Hz) and their increase in the adjacent low-frequency band were observed. Both indices were decreased in the wide beta band (19.00-30.00 Hz). The described changes took place over the whole areas of the right hemisphere and parieto-temporal region of the left hemisphere. The obtained results are discussed with respect to the role of the cholinergic brain system in the higher nervous activity.

Animals↗
PubMedDate not supplied

[Spatial organization of EEG in rats with genetically determined emotionality].

In order to study the possibility of EEG discrimination of genetically determined emotionality (increased propensity to emotional and stress reactions and anxiety) brain electrical activity was recorded in rats of two strains: Maudsley Reactive and Maudsley Nonreactive (24 derivations from the convexital skull surface were used). The program package "Synchro-EEG" was used for EEG processing. It was demonstrated that the two rat strains were significantly different in 120 EEG parameters of 840 ones analyzed. On the basis of 37 parameters, each rat was correctly recognized as belonging to the respective group with the error of 4.89%. The analysis of the detected signs allowed their classification to be performed in accordance with the peculiarities of the emotional and cognitive processes and the level of nonspecific activation. Specific forms of interaction between these components in the system of emotional reactions were revealed.

Animals↗
PubMedDate not supplied

[Characteristics of EEG signs of anxiety in human].

Influence of anxiety (tested by Luscher) on the spatial organization of brain electrical activity was studied using multichannel EEG recording. In subjects with a high-level of anxiety, the level of coherence and spectral power of some high-frequency EEG components was higher in the parieto-temporal regions of both hemispheres than that in the opposite group. Solving the inverse problem (classification of individuals with one of the groups) made it possible to work out the criteria of automated evaluation of the anxiety level at the preclinic state of neuropsychic disorders. The EEG signs of the influence of increased anxiety on psychophysiological and cognitive processes and autonomic functions were analyzed. The EEG signs of increased anxiety in animals (rats) and humans were compared and some similarity of the spatial-frequency organization was revealed. The main difference consists in a greater activation of the left parieto-temporal area in humans, which is interpreted as a morphofunctional basis of verbalization of anxiogenic stimuli.

Adolescent↗
PubMedDate not supplied

[EEG spatial organization and activation of creative processes].

Characteristic features of the spatino-temporal EEG organization of 24 right-handed children (aged from 8 to 13 years) were studied after stimulation of creative activity by the method of self-regulation of the brain functional state (Russian Inventor's Certificate no. 2157707, 01.06.1999). The multiparametric analysis of baseline recordings derived from 24 cortical points made it possible to find the most probable pattern of changes in the spatial synchronization of biopotentials, including increase in activity in the right anterior and left posterior cortical regions. These changes were accompanied by a rise in the information-energy parameter (the ratio between coherence and spectral power of potentials). This phenomenon may testify to a transition to the "economic" condition of information processing. Differences in EEG frequency characteristics corresponding to different levels of imagination and creative intuition were revealed.

Adolescent↗
PubMedDate not supplied

[Effect of novel anxiolytic agent aphobazole on coherence of the brain biopotentials in MR and MNRA rats].

Effect of the anxiolytic drugs afobazole, diazepam, and chlordiazepoxide on the cortical biopotential coherency was studied in MR and MNRA rats with increased and decreased level of emotionality, respectively. Afobazole increased a difference in the biopotential coherency between rats of the two lines in the range of EEG theta, alpha, and beta rhythms. In the subrange of dominating theta activity (6.00-7.25 Hz), this effect took place at the expense of reduced coherency in MNRA rats in the absence of changes in the MR line. Afobazole decreased the biopotential coherency in the alpha activity band (7.5-8.25 Hz) in the rats of both lines. This is indicative of the presence of a CNS-stimulating component in the pharmacological activity spectrum of afobazole. The expediency of using afobazole in patients with different levels of anxiety is discussed.

Animals↗