The effect of a high-intensity radiation exposure on the brain function of monkeys. The postradiation changes in the EEG response to rhythmic photostimulation]

In experiments with monkeys (Macaca fascicularis) it has been shown that whole-body irradiation with a dose of 45 Gy (6.5 Gy/s) causes considerable changes in the EEG response to rhythmic photostimulation (PS). These changes are: reduction of the desynchronizing effect of PS with regard to a background rhythmicity; decrease in the reception rate of the rhythms of light flashes (RLF); narrowing of the RLF frequency range; and increase in the reaction momentum. The postirradiation changes in the EEG response to PS are considered as a manifestation of inhibition of the cortex functional activity and impairment of sensory information processing in the brain.     

Effect of a high-intensity radiation exposure on brain function in monkeys. Postradiation changes in central coordination of brain bioelectrical processes

In experiments with Macaca fascicularis exposed to high-energy electrons (45 Gy, 6.5 Gy/s) revealed were early changes in the coherent spectrum of EEG semihemispheric leads. These changes were displayed by the increased interrelation between slow-wave fluctuations and decreased coherence within the mid- and high-frequency EEG-rhythms band. The relationship was noted between the changes observed and the clinical symptoms features of early radiation response as well as the dynamics of the CNS functions of exposed animals. Postirradiation changes in the intracellular bioelectric interaction are considered as one of the manifestations of the systemic response of the brain to the harmful effect of radiation.     

Some changes in bioelectrical activity of the brain during short regulated exposure to pulsed electrical fields

It was shown that short (10 s) exposures of white rats being at rest to impulse (1 ms) electromagnetic fields (170 A/m) at a fixed frequency of pulse sequence in the range of the theta-rhythm do not change the contribution to the electrocorticogram (ECoG) of the harmonic whose frequency corresponds to the frequency of pulse sequence. By contrast, treatments with a frequency-pulse modulation at which the interpulse intervals corresponding to the frequency of the harmonic being studied were not observed throughout the range of exposure but at which their high correlation was provided, assisted in decreasing the contribution of the harmonic to the ECoG spectrum. If the functional state of the central nervous system was changed by drugs leading to the predominance of the short-wavelength activity in the ECoG, both regimes of exposure significantly affected the contribution of the harmonic in the ECoG, whose direction and dynamics depended on the excitability of neurons.     

Phenomenology and genesis of changes in the total bioelectrical activity of the brain in response to electromagnetic radiation

A review of the date on phenomenology and genesis of changes in overall activity of brain in response to electromagnetic radiation is presented. It is validated the nonspecific synchronizing influence of the considered factor. This influence can be a reason of epileptoid class convulsions under growth of its biological significance as an irritant of central nervous system.     

The effect of chronic alcoholic intoxication on the bioelectrical activity of the human brain

Results from examinations of 110 spirit-abused men are presented. Changes in the EEG are found indicating the formation of an excitation focus that affect the reticular formation and induces an increase of the ascending activating effects on the cortex. Degree of these changes correlates with heaviness of the alcoholic disease. Results from the research permit a conclusion on diagnostic valuableness of the EEG examination with an aminazine test in case of alcoholism.     

The effect of anoxia on changes in the phosphoinositide content and bioelectrical activity in the cat cerebral cortex]

The dynamic of the phosphatidylinositol (PI), the phosphatidylinositol 4-phosphate (PIP) and the phosphatidylinositol-4,5-diphosphate (PIP2) contents were studied in the correlation with the neuronal spike activity in cat brain cortex under acute oxygen deficiency caused by cessation of artificial ventilation for 1, 2.5 and 5 min. It was shown that the 1-min anoxia produced the depression of both PIP and PIP2 contents. The depression was followed by the development of the 'asphyxia neuronal activation'. During 2.5 and 5 min of anoxia the decrease of PIP2 content and increase of PIP one were detected against a background of neuronal bioelectrical activity depression. The PI content was constant during all the anoxic period.     

Analysis of the modifying effect of testosterone on postradiation changes in spermatogenesis

Cytological analysis showed that disturbances referable to division and development of spermatogonia (intermediate and B types) and primary spermatocytes in irradiated animals are modified by injection of exogenous testosterone. It was established that the hormone exerts its modifying effect after radiation doses affecting mechanisms of spermatogenesis regulation. Testosterone bound to target cells initiates their division and decreases duration of spermatogonium mitosis block and delay in primary spermatocyte development increasing the number of germ cells.     

The dynamics of the evoked bioelectrical activity of the brain in unconscious states

In 93 patients with mental disorders evoked bioelectrical activity of brain was studied in states of changed consciousness. Methods of evoked potentials and conditioned negative wave were applied. The obtained data allow to consider that in parameters and dynamics of bioelectrical activity changes of consciousness sphere are reflected.     

The effect of electromagnetic radiation on the monoamine oxidase A activity in the rat brain

The effect of the ultralow power pulse-modulated electromagnetic radiation (EMR, power density 10 microW/cm2; carrying frequency 915 MHz; modulating pulses with frequency 2, 4, 6, 8, 12, 16 and 20 Hz) on activity of monoamine oxidase (MAO-A), enzyme involved in the oxidative deamination of monoamines, was investigated. It was established that the increase of activity MAO in hypothalamus reached the maximal meaning at modulation frequency of 6 Hz that corresponded 160% (p < 0.01) of the control level; and at modulation frequency of 20 Hz the decrease of enzyme activity up to 74% (p < 0.01) was found. Mainly the action of ultralow power pulse-modulated EMR on activity of MAO in hippocamp was activating; and the maximal increase of enzyme activity up to 174% (p < 0.01) was registered at modulation frequency of 4 Hz.     

A spectral analysis of the effect of sidnocarb on the bioelectrical activity of the rat brain]

A quantitative pharmaco-EEG analysis of the action of psychostimulant drug sydnocarb and its solvent polyethylenglycol-400 on bioelectrical activity of sensomotor cortex, dorsal hippocamp and lateral hypothalamus of wakeful rats in free behavior was carried out. Polyethylenglycol-400 proved to affect CNS, as it decreases slow-wave activity and causes displacement of the dominant peak to the region of more slow-wave frequencies, shows anticonvulsant action. Sydnocarb reduces absolute power of all frequency ranges and increases relative power of fast activity. It is concluded that sydnocarb increases in optimal limits the level of CNS vigilance which may underlie a psychostimulant action of the drug eventuating into optimization of behavioral functions, increasing physical and mental capacity for work.     

Dynamics of changes in the heparin-binding activity of rat brain proteins after fractionated exposure to ionizing radiation of low intensity

In experiment on white rats it was shown that fractionated exposure to 1 sGy/day during 25 days is followed by the directed change in the total heparin-binding activity of proteins in the rat brain (both in males and in females) with maximum deviation from control by the 7th day after accumulation of a total dose of 25 sGy. The diverse in hemisphere cortex and hippocampus were different from those in brain trunk regions and cerebellum. It is supposed that a thin overturning of the intercellular and "cell-matrix" interactions in CNS modulates compensation and adaptation processes under chronic X-ray irradiation with a small dose of low intensity due to regulation of the free/bound heparansulphate correlation.     

The intercentral relations of cortical bioelectrical activity in the human brain after surgical interventions on brain stem formations]

In the process of dynamic study of cortical bioelectrical activity and indices of its intercentral interaction in 52 neurosurgical patients with focal lesion on the brainstem level, the dependence was shown of the CNS reactions to the operative intervention on the character and degree of damage. Variants were described of compensatory neurodynamic reconstructions of electrical processes in observations with transient, stable and irreversible pathological foci of brainstem localization.     

Effects of tranquilizing agents on bioelectrical activity of the rat brain]

The action of diazepam, meprobamate, trioxazine and mexidol on bioelectrical activity of sensorimotor cortex and dorsal hippocamp of the left and right hemisphere of the brain in conscious rat in free behavior has been studied. All the drugs produced a decline in the frequency of the dominant peak of EEG power spectra. Diazepam and meprobamate increased beta-activity. It is concluded that the decreased frequency may be due to an anxiolytic effect of the tranquilizers, whereas high beta-activity is related to muscle relaxant effect of some drugs.