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.     

Altered excitability of rat cutaneous mechanoreceptors during transcranial electrical stimulation

Functional aspects of high, medium, and low threshold mechanoreceptor units were investigated in acute experiments under hexanol-induced anesthesia during transcranial electrical stimulation (TES). It was found that low and medium threshold receptor units ceased responding to mechanical stimulation 1 and 5 min respectively after the start of TES. Firing ended by 18–20 min of TES in high threshold units responding to mechanical stimuli produced by a needle. No significant alteration in parameters of response were produced by TES after prior i.p. or intracutaneous injection of naloxone. Potential mechanisms of TES action are discussed. It is suggested that changes produced in the function of cutaneous mechanoreceptors by TES may be put down to endogenous opioids acting on the receptors.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 22, No. 4, pp. 495–500, July–August, 1990.     

Spatiotemporal organization of bioelectrical brain activity during gestational dominanta

Spectral and coherent analysis of biolectrical brain activity was performed in 560 pregnant women in gestational dynamics and in the early post-natal period. According to the theory and the experiments, it can be concluded that the occurrence of one-fetus pregnancy is accompanied by formation of gestational dominanta (constellation of nervous centers) with its central units in the limbicodiencephalic and neocortical structures. Neocortical representation is formed within the frontal and central areas of the hemisphere contralateral to location of the placenta. Electrographic evidence in support of these ideas was found.     

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.     

Effect of the transcranial electrical stimulation of the endorphinergic brain structures on the functional activity of hepatocytes after toxic exposure

Biochemical events of the rat hepatocytes cytolysis and deterioration of their synthetic activity and detoxification ability, as well as morphological events of lipid degeneration after acute poisoning with dichloretane and CCl4, were significantly reduced by effects of transcranial stimulation (TES). Blockade of the TES effects with naloxone revealed its endorphinergic nature. Combined effects of the TES and Essenciale preparation were lower than separate those of these agents. The TES effects were clinically corroborated in treatment of toxic hepatitis.     

Changes in the brain bioelectrical activity and in the ACTH content of the blood plasma during voluntary hyperventilation in malignant neoplasm patients

A 3-5-min spontaneous hyperventilation caused normalization of initially altered electroencephalogram and inactivation of hypothalamic structures in 14 patients with malignant tumors, as well as negative dynamics of bioelectrical brain activity and activation of diencephalic area in 6 healthy subjects. In hyperventilation ACTH plasma concentration increased 13-fold on average (from 14.2 +/- 12.1, to 185 +/- 82 pg/ml) in normal subjects and 2.4-fold (from 45.5 +/- 19.8 to 110 +/- 17 pg/ml) in oncological patients. It is assumed that changes in hypothalamo-hypophyseal reactivity in patients with malignant neoplasias can be associated with generalized intracellular metabolic acidosis, partially, compensated by gas alkalosis in the plasma due to hyperventilation.     

Changes in the bioelectrical activity of the brain cortex in rats with infraorbital nerve compression]

Bioelectrical activity of the somatosensory cortex was studied in the Wistar rats with chronic (1.5-2 months) compression of the infraorbital nerve produced by two partial ligations. In 20% of rats spike-slow wave complex and slow waves were observed. Electrostimulation of the skin on the injured nerve side resulted in a considerable increase in the amplitude of early components of the contralaterally evoked potentials in comparison with the non-injured side stimulation in 75% of rats. A decrease in the evoked potential thresholds on the injured nerve stimulation was shown in both hemispheres. In most of the animals a hypersynchronous late component of the evoked potential was observed.     

Analysis of the brain bioelectrical activity of the suslik Citellus parryi during hibernation

Computer analysis has been made of the diurnal rhythm of the brain activity in the ground squirrel Citellus parryi during hibernation (body temperature 7-8 degrees C). The data obtained are presented in the form of graphical plots with two-dimensional density of probability of distribution of intermittent bursts of spindles and isoelectric EEG.     

Changes in electrical brain activity in patients with panic disorders

Brain electrical activity was recorded in 38 patients with typical and in 42 patients with atypical panic disorders, also in 30 normal controls. Compared to controls, patients both with typical and with atypical panic disorders differed significantly in reduced spectral power of the EEG alpha band in the right hemisphere. Moreover, in patients with typical panic disorders, the spectral power of the EEG beta1 band was increased in the frontal, temporal, central, and parietal areas of the right hemisphere. In patients with atypical panic disorders, the spectral power of the theta band was increased in the temporal areas of the right hemisphere. The changes in the EEG activity in patients with typical panic disorders are supposed to reflect an increase in activity of non-specific systems of the mesencephalic reticular formation, and the EEG changes in patients with atypical panic attacks may be associated with increased activity of the temporolimbic brain structures.