[Comparative analysis of spontaneous unit activity of the cerebellum fastigial nucleus' neurons in different periods of vibration influence].

In conditions of acute experiment on white rats anaesthetized with Nembutal (40 mg/kg, interperitonially) recording and analysis of spontaneous impulse activity of the fastigial nucleus' neurons in norm and after 5, 10 and 15 days of vibration influence on the organism were carried out. Distribution of the neurons was evaluated by the dynamics of neuronal current flow and the modality of the interspike interval hystograms, as well as the statistical parameters: the average discharge frequency and the coefficient of the interspike interval variation. It is shown that more significant changes in neuronal activity of fastigial nucleus cells are formed during the first 10 days of vibration influence. On the 15th day, there was a tendency towards return to control levels of the parameters under study.

[The effects of influence of electromagnetic irradiation of millimeter wavelength on background impulse activity of supraoptic nucleus' neurons of rats' hypothalamus].

In conditions of acute experiment on white rats anaesthetized by Nembutal (40 mg/kg, intraperitoneally), the registration and analysis of background impulse activity of the supraoptic nucleus neurons of rats' hypothalamus in norm and after electromagnetic irradiation of millimeter wavelength on organism, were carried out. Distributions of neurons by the degree of rhythm regularity, the character of types of dynamics of the following impulse flows, the modality of histograms of interspike intervals, the average discharge frequency, the coefficient of interspike intervals variation, were found out. Changes of the background impulse activity which were related mainly to the changes of the inner structure of registered impulse flows, were revealed. Significant shifts were generally observed in the character of dynamics of neuronal current flows and degree of regularity of the impulse activity. Statistically significant changes of the average frequency of discharges of different frequency range neurons' populations were revealed.

[The hypothalamic regulation of the activity of vestibular neurons during exposure to vibration]. / Gipotalamicheskaia reguliatsiia aktivnosti vestibuliarnykh neironov pri vozdeistvii vibratsii.

In acute experiments in rabbits the influence of stimulation of the ventromedial hypothalamic nucleus on the activity of neurons of vestibular Deiters' nucleus was studied under conditions of 15-day exposure to vibration (60 Hz, 0.8 mm, 3 h daily). The mechanisms are discussed which underlie the observed phenomena.

[The effect of stimulation of the amygdala basolateral nuclei on the neuron activity of Deiters vestibular nuclei in rabbits]. / Vliianie stimuliatsii bazolateral'nykh iader mindalevidnogo kompleksa na aktivnost' neironov vestibuliarnogo iadra Deitersa u krolikov.

A modulating character of the amygdala basolateral nuclei effect upon the vestibular sensory system was determined in rabbits [correction of rats]. A mechanism of the descending effect of the amygdaloid complex on the activity of the Deiters nucleus neurons, is discussed.

[Limbic mechanisms regulating vestibular neuron reactions in vibration]. / Limbicheskie mekhanizmy reguliatsii vestibuliarnykh neironnykh reaktsii pri vibratsii.

Acute experiment on rabbits (extracellular registration) studied influence of limbic cortex on neuron activity of Deuters nucleus before and after exposure to low-frequency vibration (5 Hz, 30 minutes). The authors discuss mechanisms underlying changes in activity and response of vestibular neutrons to electric simulation (5 and 60 Hz) of limbic cortex before and after vibration.

[Cortical mechanisms of regulation of neuron activity of Deiters vestibular nucleus during vibration]. / Korkovye mekhanizmy reguliatsii aktivnosti neironov vestibuliarnogo iadra Deitersa pri vibratsii.

The peculiarities of the effect of vestibular, somatosensory, motor and limbic areas of brain cortex on the activity of neurons of lateral vestibular nucleus (LVN) are studied in the nembutal and chloralose anesthetized rabbits by the extracellular lead method before and after vibration exposure. It is found that the responses of neurons of Deiters's nucleus at all frequency ranges to stimulation of different areas of the cortex were predominantly of inhibitory type, being more pronounced during stimulation of the vestibular and motor areas. The facilitating corticofugal effect was noted in 20-30 % of cells and more pronounced influence was during stimulation of somatosensory and limbic areas of the cortex. During vibration there was a multidirectional effect of cortical areas on the neuronal activity of LVN. The vibration stimulus decreases an inhibitory effect and increases stimulating influence of vestibular cortex on the activity of Deiters's nucleus. The noted effect was more pronounced in neurons with low frequency of initial activity. On stimulation of other areas of the cortex an increase of inhibitory and suppression of facilitating descending effects were noted. The greatest amount of inhibited neurons was recorded during stimulation of motor cortex. The peculiarities and functional significance of the observed effects are discussed.

[The role of specific and nonspecific afferent systems in the mechanism of the changes in cortical evoked responses during vibration]. / Rol' spetsificheskikh i nespetsificheskikh afferentnykh sistem v mekhanizme izmenenii vyzvannykh otvetov kory pri vibratsii.

The correlation in activity of specific and unspecific afferent systems was measured in mechanisms changing electrical activity of the cortex during vibration. The character of postvibration shifts of vestibulo-, reticulo-cortical EPs was studied by means of isolated and combined exclusion of specific (vestibular) and unspecific afferent systems of the brain. The vestibular afferents seem to play a significant role in the mechanisms of postvibration shifts of vestibulo-cortical EPs. Impulses originating from the unspecific afferent systems, as well as proprioceptive, somatic and visceral afferents play similar role for the reticulo-cortical system.

[The effect of vibration on the electrocorticographic shifts during the switching off of specific and nonspecific afferent systems of the brain]. / Vliianie vibratsii na élektrokortikograficheskie sdvigi pri vkliuchenii spetsificheskoi i nespetsificheskoi afferentnykh sistem mozga.

Electrocorticograms of vibration induced effects were studied in intact and labyrinthectomized rabbits under midbrain reticular formation and renoreactive structures blockade. There was involvement of the specific (vestibular) and non-specific brain structures in the mechanisms underlying the cortex' electric activity. The article contains a review of the vibration-related shifts in the cortex, both specific and nonspecific--and in other afferent modalities (proprioceptive, somatic, visceral).

[The effect of vibration on the impulse activity of cortical neurons and their reaction to stimulation of the posterior hypothalamus and Deiters' vestibular nucleus]. / Vliianie vibratsii na impul'snuiu aktivnost' korkovykh neironov i ikh reaktsii na razdrazhenie zadnego gipotalamusa i vestibuliarnogo iadra Deitersa.

The effect of vibration on spontaneous unit activity, oxygen consumption in cortical neurons and their responses to stimulation of posterior hypothalamus and vestibular Deiters' nucleus, were studied. Biphasic changes occurred in frequency of cortical unit activity and in the latter interrelationships with the level of oxygen consumption after 3-hour exposure to the vibration. The 15-day vibration enhanced the mean frequency of unit activity, facilitated the effect of subcortical neurons and eliminated bursts of discharges. The effect of long-term vibration upon cortical unit activity response to stimulation of subcortical structures was quite obvious.

[The effect of whole-body vibration on the electrical activity and oxidative metabolism in different brain structures]. / Vliianie obshchei vibratsii na élektricheskuiu aktivnost' i okislitel'nyi metabolizm razlichnykh struktur mozga.

Chronic experiments on rabbits were performed to study the bioelectric activity, oxygen consumption and succinate dehydrogenase (DG) activity in different parts of the cortex and subcortex (mesencephalic reticular formation, lateral vestibular nucleus, thalamus posteroventrolateral nucleus), as well as the compound electric activity of the neck muscles, and rythm adoption. The phase character and different vibration sensitivity of the brain structures depending on the duration of vibration were revealed. At the initial phase, the following vibration effects were examined: reaction of activation on encephalogram, growing EMG and DG activity, increased oxygen consumption, and rythm adoption high frequency shifting. Prolonged vibration caused a vivid violation of the intracentral correlation between the cortex and subcortex. Correlation was also identified between electric activity and the brain structures' oxidation metabolism against the vibration dynamics levels.