PubMed Health⌕ Search

Biomedical subjects

A G Sukhov

Publications and source records attributed to A G Sukhov.

13 recordsLinked to original sources
PubMed2004

Characteristics of the post-tetanic modification of synaptic transmission in the thalamocortical input of the somatosensory cortex in rats.

The development of both long-term post-tetanic potentiation and depression of focal evoked potentials by identified columns in the somatosensory cortex of unanesthetized rats was shown to occur in conditions of stimulation of their thalamocortical afferents. Trains of theta stimulation induced the phase-dependent development of post-tetanic potentiation after tetanization on the negative phase of the theta wave, while depression occurred after stimulation on the positive phase. Continuous tetanization produced potentiation only with stimulation at optimum amplitude and duration; extremely strong tetanization generally induced depression of responses to test stimuli, evidently because of activation of recurrent inhibition.

Animals↗
PubMed1995

[Biotropic effects of electromagnetic fields: benefit or harm?].

An overview contains the analysis of controversial literary data on possible therapeutic and pathogenic effects of electromagnetic fields on humans. The non-specific character of body shifts induced by electromagnetic fields with a prevalence of adaptive reactions at the onset and an emergence of dysadaptive processes during extremely long exposure was displayed. The leading role in the development of a therapeutic or pathogenic effect is played by the functional characteristics of an individual postulating the interaction of cumulative and adaptive processes in the body during long-term exposure in an electromagnetic field.

Adaptation, Physiological↗
PubMed1990

[The comparative characteristics of the neuronal responses of the rat somatic cortex during active and passive movements of the vibrissae].

Responses of rat barrel-field cortex neurons were recorded during vibrissae deflection, voluntary movements of whiskers and vibrissae movements produced by stimulation of the motor cortex and facial muscles. Changes in the patterns of responses of the three groups of neurons were revealed during the performance of active vibrissae movements: neurons with short-latency responses, neurons with long-latency responses and neurons with changes in the activity occurred early before the movements onset. It is suggested that somatosensory cortical neurons receive peripheral (from the whiskers' follicles and facial muscles) as well as central (from the motor cortex) inputs that modulate their activity.

Animals↗
PubMed1989

[Convergence of projections from various thalamic nuclei on the rat somatosensory cortex columns].

The method of primuline fluorochrome retrograde transport was used to study sources of thalamo-cortical projections on a separate somatic cortical neuronal column connected with C3 vibrissae of albino rat. Labeled cells were found in 8 thalamic nuclei: tv, tvd, tpo, pf, rh, tvm, tvl, tr. The intensity of neuron staining and cell quantity and density varied in different nuclei. Hence their axon branching in the rat cortex was also different. The majority of intensively stained and densely packed cells have been observed in tv nucleus. The observed convergence of different thalamo-cortical inputs on single somatic cortex column explains heterogeneity in functional properties of the same column neurons and makes it possible for the column to form several neuronal assemblies with different functions.

Animals↗
PubMed1984

[Electrophysiological and catecholamine mechanisms of negative feedback in regulation of the hypothalamus by male sex glands].

The immediate response on the part of the sympathoadrenal system (SAS) in mature male rats to testosterone propionate involves an increase in the content of dopamine and lowering of adrenaline and noradrenaline content in the hypothalamus, brain cortex, adrenals and peripheral organs, paralleled by an increase in the amplitude of evoked potentials and reduction in the frequency of induced impulse activity of arcuate neurons of the hypothalamus. This attests to the specificity of the associated response of the SAS and the hypothalamus-pituitary-gonadal system (HPGS) to hyperandrogenization and to the dopaminergic nature of the negative feed-back mechanism in the HPGS.

Adrenal Glands↗
PubMed1977

[Neuronal organization of the central mechanisms of reflexes from vibrissae].

Functional characteristics (size of receptive fields, directional sensitivity, threshold sensitivity to amplitude, and speed of vibrissae deflection) of neurons in the rat cortical zone of vibrissae representation, were studied. Histological control showed that in the IV cortical layer these neurons form somatotopically structured barrel-shaped cytoarchitectonic clusters. It was found that each "barrel" consisted of several neuronal groups--elementary neuronal ensembles--which selectively detected different stimulus parameters: direction, speed, and amplitude of deflection of the corresponding vibrissa. The data obtained show that temporal and power competition of adjacent ensembles, on the basis of lateral inhibition, is an important mechanism for signal processing and selection of dominant afferent inputs.

Animals↗
PubMedDate not supplied

[Specifics of post-theta modification of synaptic transmission in thalamo-cortical input of the rat's barrel cortex].

The possibility of the development of either the long-term posttetanic potentiation or the depression of focal evoked potentials in identified columns of the barrel somatic cortex of unanaesthetized rats during stimulation of their specific thalamocortical afferent fibers was shown. Phase-dependent potentiation developed after burst tetanization with the frequency of theta rhythm at the negative phase of a theta wave, whereas the stimulation at the positive phase produced the depression. Potentiation after continuous tetanization was observed only at the optimal selection of stimuli amplitude and duration. Excessively intense tetanization more frequently caused the depression of tested responses probably due to the involvement of recurrent inhibition.

Animals↗