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Biomedical subjects

V F Fokin

Publications and source records attributed to V F Fokin.

At least 19 recordsLinked to original sources
PubMed2001

[The rate of cerebral energy metabolism: possibilities of its assessment by the electrophysiologic method].

The application of DC-potential method for estimation of the rate of human brain energy metabolism opens new vistas for the development of theoretical and applied aspects of neurophysiology. Theoretically, the close connection of information and energy processes of the brain is essential for gaining an insight into the brain energy-formation unit. In applied physiology, estimation of brain energy metabolism by the DC potential method is useful for studying the relationship of brain energy and memory processes during learning, for estimating the training in sportsmen, for predicting longevity in the elderly. The method reveals stress-induced changes in interhemispheric relationships. In medicine the method may be used to study the pathogenesis of primarily the diseases associated with impaired cerebral circulation and cerebral atrophic processes. Moreover, of particular diagnostic and prognostic value are these methods for drug addicts, as well as for monitoring suggestive therapeutical effects in the treatment of neuroses.

Adaptation, Physiological↗
PubMed1999

[Brain dysfunction in subjects at risk of Alzheimer's disease].

Visual evoked potentials versus flash (VEP) and brain DC-potentials were studied in the first-order relatives of patients (mean age 42.6 +/- 1.6 years) with Alzheimer's disease (AD) and probands (mean age 60.9 +/- 0.9 years) and age-matched healthy controls for the relatives and probands. In the relatives of AD patients, the latencies of N2, P3, N3 components were found to be delayed as compared with the controls. There was a delay in the latencies of the same components in the patients and their relatives, but it was smaller in the relatives of AD patients. The brain DC-potentials were higher in the relatives of AD patients than in the controls. Neurophysiological changes in the relatives of AD patients may be considered to be signs of latent neurodegeneration in the limbicoreticulocortical pathways, which may be associated with the excitotoxic processes and abnormal hyperactivity in the limbicoreticulocortical structures.

Adult↗
PubMed1999

[Analyzing correlation between neurophysiological parameters and level of stress hormone cortisol in aging].

A correlation between the serum levels of the stress hormone cortisole, neurophysiological parameters, and age was examined in 23 elderly healthy examinees (whose mean age was 65.7 +/- 2.1 years). The latency of the components of visual evoked potentials (VEP) was found to progressively increase with age. The individuals having high cortisole levels showed an increase in the latency of late VEP components associated with accelerated ageing and/or with the degenerative changes in the brain limbicoreticulocortical pathways. The DC potential level (DCPL) reflecting the intensity of brain energy expenditures correlated with the content of cortisole. Increased DCPL and longer latency of late VEP components were interrelated. It is suggested that high cortisole level produces a neurotoxic action and promotes accelerated ageing of brain regions having glucocorticoid receptors. Imbalance between the significant intensification of catabolic processes, the rise of energy expenditures and the limited increase in anabolism in elderly age is a course of this process.

Aged↗
PubMed1996

[The neuroimmune relationships during normal aging and in Alzheimer-type dementias].

Relationships between neurophysiological and immune parameters were studied in normal middle-aged and elderly subjects and in patients with dementia of Alzheimer's type (DAT). The rate of such interaction was minimal in normal aging, in DAT neuroimmune relations increased. The correlation between the immune parameters and the characteristics of components of visual evoked potentials and auditory brain-stem responses suggests that in the middle-aged healthy subjects, a primary role in neuroimmune relations belongs to limbicoreticular structures and to the mesencephalon. In normal aging, the influence of limbicoreticular structures on immune structures decreases. In DAT, the modulation of immune processes by limbicoreticular and thalamocortical structures, as well as the pontobulbar part of the brain stem increases. In middle age and in DAT, persons with different functional brain asymmetry (as estimated from electrophysiological criteria) have different lymphocytic functional activities and rates of neuroimmune interactions.

Adult↗
PubMed1995

[Neuroimmune interactions in normal aging and in Alzheimer disease].

The study was undertaken to examine nerve-immune processes and the specific visual and limbic-reticular-cortical systems by analysing visual evoked potentials (VEP), as well as nerve-immune relationships in 21 patients aged 62.2ë1.3 years who had Alzheimer's disease and in 15 healthy individuals of the same age. AD patients were found to have lower lymphocyte count, enhanced proliferative activity of T lymphocytes and to tend to have increased production of interleukin (IL-1) as compared to that in healthy individuals. In AD, latent periods of late EVP components are higher than normal age-specific ones. The relationship between VEP and immunity parameters differ in normal ageing and AD. In health, there is a negative correlation between the latencies of N1, P2, N2 VEP components and the lymphocyte count and between the amplitude of a N1 VEP component and the production of IL-1. There is a prevalent correlation of immune parameters with VEP parameters in the right hemisphere. In AD, the higher proliferative activity of T lymphocytes is associated with more prolonged latent periods of N3 VEP components, suggesting that there are abnormal changes in the limbic-reticular-cortical systems of the brain.

Aging↗
PubMed1994

[The energy aspect of the brain activity in normal aging and in Alzheimer's disease].

In normal aging and Alzheimer's disease, there are regular changes in brain energy homeostasis, which are associated both with the time course of the average level of catabolism and with the intensity rate of catabolic processes by hemispheres. In normal aging, there is generally decrease in the catabolic level estimated by the level of the DC potential. In Alzheimer's disease, the level of catabolism secondarily increases. The findings suggest that there is a causal relationship between the brain energetic homeostasis and the visual information processes. The correlation of energetic and information processes increases with normal and especially pathological aging. The authors' methods enabled them to observe the time course of energy metabolism and to reveal their critical levels. The correction of energetic processes in due time should be useful in preventing atrophic changes in the brain with aging.

Aging↗
PubMed1992

[Longitudinal approaches to the problem of clinical heterogeneity of Alzheimer-type dementia].

A total of 160 patients with Alzheimer-type dementias (ATD), including 84 with Alzheimer's diseases (AD) and 76 with senile dementia (SD), were examined. The initial signs of the disease were analyzed by making a retrospective assessment of informative history data. The prospective follow-up involved clinical, neuropsychological and electrophysiological (EEC mapping, evoked potentials) studies by applying the standardized assessment of results. There was shown to be a set of clinical and paraclinical parameters for the status of ATD patients, indicating a distinct-quantitative and qualitative difference between patients with AD and those with SD and supporting the heterogeneity of ATD.

Aged↗
PubMed1989

[The relationship of the electrical reactions of the brain to lipid peroxidation processes in pathological aging].

The content of breathing air pentane as in vivo index of lipid peroxidation and electrophysiological parameters (visual evoked potentials and direct current (DC) potential level) of healthy volunteers and patients with senile dementia and Alzheimer's disease following weak stress sound influence were investigated. Unlike healthy subjects correlation between stress-induced changes of pentane level and electrophysiological parameters for patients with psychopathology was shown.

Acoustic Stimulation↗
PubMed1984

[Reversible functional shutdown of the optic tract on exposure to focused ultrasound].

The possibility of reversible functional blockade of the optical tract and blockade of optical information conduction has been shown by means of undestructive doses of focused ultrasound. Electron microscopy of optic terminals in the superior colliculus in the period of restitution of the bioelectric activity of the optical tract has demonstrated that alterations in the ultrastructure of optic terminals were insignificant and reversible.

Animals↗
PubMed1979

[Organization of the connections of the putamen with the cerebral cortex and hypothalamus].

Connection between the putamen, the brain cortex and the hypothalamus, as well as the role of the former in different aspects of purposive behaviour have been studied in a complex morpho-physiological investigation. In 12 cats, after developing a symmetrical active-defensive conditioned reflex, unilateral electrolysis of the putamen has been performed and the number of conditioned-reflexive reactions have been counted before and after coagulation. The brains have been treated after Nauta--Gygax, Fink--Heimer with additional staining after Kawamura--Niimi. Monosynaptic connections of the putamen with frontal, precentral, postcentral, orbital, parietal cortical areas have been revealed; direct pathways from the putamen to the infundibulum of the grey tuber, to the posterior and lateral hypothalamic nucleus have been demonstrated; participation of the putamen in the formation of active-defensive conditioned reflexes has been stated, as well as in emotional behaviour with a preferable use either the right or the left foreleg.

Animals↗
PubMedDate not supplied

Interdependance of the level of the steady potential of the brain and visual evoked potentials in human aging: the norm and Alzheimer's disease.

The interrelationships between the amplitude-temporal parameters of the visual evoked potential (VEP) and of the level of the steady potential (LSP) of the brain in healthy middle-aged and elderly people and in Alzheimer's disease patients. The existence of a statistically significant correlation between the LSP and the amplitude-temporal characteristics of the VEP. The interrelationship is intensified both during aging in the norm and especially in Alzheimer's disease patients. The most stable positive correlation exists between the local LSP and in the occipital region and the amplitudes of the N1 and P2 components of the VEP.

Adult↗
PubMedDate not supplied

Possible neurophysiological markers of genetic predisposition to Alzheimer's disease.

Visual-evoked potentials (VEP) to a flash were studied in the first-order relatives of patients with Alzheimer's disease (AD) (mean age 38.2 +/- 2.6 years) in comparison with the patients (mean age 61.9 +/- 1.4 years) and age-matched normal controls. It was found that in the relatives of AD patients the latencies of N2, P3, N3 components were delayed compared with the age-matched normal controls. The delay in the latencies of the patients and their relatives concerned the same components but was smaller in the relatives of AD patients. The amplitude of the P2, N2 components was increased in the latter. The neurophysiological alteration in AD patients' relatives may be considered as signs of a latent neurodegeneration in limbico-reticulo-cortical pathways, which may be connected to the pathological hyperactivity of limbico-reticulo-cortical structures.

Adult↗
PubMedDate not supplied

[Asymmetry of aging of the large hemispheres of the rat brain].

The dynamics of the accumulation of free-radical oxidation products in the brain hemispheres of rats in rate ontogenesis was studied. Multiphase changes in the concentration of products in the right and left hemispheres in different age groups were registered. Significant differences in the contents of hydroperoxides, Schiff's bases of phospholipids and lipofuscin in brain hemispheres revealed, which correlates with different rate of ageing of hemispheres.

Aging↗
PubMedDate not supplied

[Physical criteria of pathological processes. II. Modulating role of functional interhemisphere asymmetry in forming and immune response in rheumatic diseases].

The level of the brain permanent potential as a physiological criterion of the functional interhemisphere asymmetry, as well as immunological and biochemical characteristics of peripheral blood in patients with systemic rheumatic diseases were studied. It was found that the distribution of the characteristics of immune response in patients with different types of interhemisphere asymmetry. Significant differences were observed for average values of biochemical and immunological characteristics, their dispersions, as well as for the structure of relationships between the type of the interhemisphere asymmetry and immunobiochemical characteristics.

Adolescent↗
PubMedDate not supplied

[Activity of the autoimmune process during systemic rheumatic diseases and distribution of constant brain potential].

The data obtained upon examination of patients with systemic rheumatic diseases were analyzed by the methods of multiple regression and step-by-step discriminant analysis. Is was shown that the activity of autoimmune process correlates with the parameters of distribution of constant potential level in the brain of each patient, irrespective of diagnosis. The scatter of potential values was the most important predictor of activity. An increase in the activity of the autoimmune process correlated with a decrease in the scatter of potential values at recording points; the cerebral cortex became equipotential.

Action Potentials↗
PubMedDate not supplied

[Constant brain potentials as neurophysiological markers of autoimmune process].

Neuroimmune interactions in systemic rheumatic diseases were studied. The state of the central nervous system was assessed from the parameters of constant brain potentials, and the state of the immune system, from a complex of immunobiochemical parameters. The highest multiple correlation coefficients were revealed between the immunobiochemical parameters and the parameters of the constant brain potential, which characterize linear and standard deviations of potentials in temporal zones from potentials at other points of recording. The results are discussed in terms of structural and functional integration of the immune and nervous systems.

Action Potentials↗