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Biomedical subjects

V D Trush

Publications and source records attributed to V D Trush.

At least 19 recordsLinked to original sources
PubMed1977

[Excitability of the senso-motor cortex and red nucleus of rabbits with different levels of cortical potential spatial synchronization].

The motor reaction of the rabbit to the threshold electrical stimulation of the sensomotor cortex and red nucleus was studied to determine excitability of these structures. Under conditions of the computer-controlled experiment the excitability of the two structures was compardd for situations characterized by different levels of cortical potential correlation. An increase in the spatial synchronization of the cortical potentials is shown to be accompanied by intensification in excitability of the sensomotor cortex and red nucleus. This intensification seems to be one of possible neurophysiological mechanisms of the probability increase for the effector reaction to sensory stimuli when the cortical spatial synchronization rises.

Animals↗
PubMed1976

[Spectral-correlation analysis of the bioelectrical activity of rabbit brain structures during electrosleep].

Changes of electric activity of the rabbit cortical and subcortical structures were studied by means of spectrum-correlation analysis during sleep caused by low-frequency stimulation of the supraoptic hypothalamic nucleus. The electrosleep affected the similarity of the electric events in neocortex and subcortical structures. The disturbance of the spatial synchronization is supposed to be due to the activity of nonsynchronized autonomous bioelectric pace-makers in different brain structures.

Animals↗
PubMed1975

[Space-time parameters of the biopotentials in rabbit brain structures during natural sleep].

Different stages of natural slow-wave sleep were studied in rabbits with the aid of spectro-correlation analysis using the direct input of data to the computer. The main findings regularly observed after sleep were as follows: the decrease of synchronization between biopotentials led from different brain structures, the absence of uniform Q-band rhythms and the reduced coherence of this band, phase discrepancy between low-frequency components. Thereupon the state of inhibition is concluded to be characterized by the spatio-temporal discrepancy in the brain electric activity.

Animals↗
PubMedDate not supplied

[Electrophysiologic analysis of the process of recognizing target and non-target stimuli in healthy and oligophrenic children].

In an automatized experiment, with a computer on line, amplitude-temporal parameters of evoked potentials (EPs) to purposive and non-purposive stimuli (digits), were analyzed in normal and mental retarded children. At unilateral stimuli presentation to the left or right visual half-fields EPs were recorded simultaneously in projection, TPO, parietal and central areas of the left and right hemispheres. It has been shown that in normal children, differential involvement of projection and associative structures in the analysis of sensory information takes place in both hemispheres. The amplitudes of most EP components in the range of 100-400 ms to the purposive stimuli are higher than to the non-purposive ones. Considerable similarity of EPs developing in response to ipsi- and contralateral stimulations of visual fields ("direct" and "transmitted" EP) is observed. In mental retarded children significant changes are revealed in intra- and interhemisphere organization of the process of perception of purposive and non-purposive stimuli. In the right hemisphere structures there are no differential EP reactions to the two types of stimuli. Significant, in comparison with the norm, prolongation of the latencies of most EP components is noted, especially in the structures of the left hemisphere, to the purposive stimuli. In the process of perception, changes are seen of the integration of functions of both hemispheres. The totality of disturbances of systemic brain organization at perceptive activity in mental retarded children may reflect neurophysiological mechanisms of mental deficiency.

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PubMedDate not supplied

[Alpha-rhythm of the EEG in directed attention].

Degree of manifestation and synchronization of rhythmic alpha-range components in various cortical areas was studied in healthy adult subjects in conditions of controlled computer experiment by spectral-correlation method of EEG analysis during directed attention previous to discrimination of tactile, auditory and visual stimuli. The obtained results show that in preparation for discrimination of heteromodal stimuli, specific reconstructions take place of alpha-range electrical activity determined by signal modality. These changes are expressed in a local increase of the degree of synchronization of alpha oscillations in those projection and associative brain areas which are connected with the analysis of the given stimuli. Functional significance of these reconstructions is seen in the fact that they are significantly more expressed at correct recognition. A hypothesis is suggested about participation of the alpha-range in neurophysiological mechanisms of directed attention.

Adult↗
PubMedDate not supplied

[Electrophysiological analysis of the perceptive activities of children with normal and retarded mental development].

Visual EPs of the occipital, parieto-temporal-occipital, parietal and central areas of the left and right hemispheres in response to unilaterally presented stimuli (figures) were analyzed in normal and developmentally backward children. In tasks of detection and recognition of the signal, developmentally backward children manifested a lowered reactivity of associative cerebral structures, especially of the left hemisphere, during perceptive activity, and a changed, in comparison with normal, interhemispheric interaction in processing of sensory information. It is suggested that properties of brain system organization during perceptive activity reflect to a certain extent neurophysiological mechanisms of disturbance of cognitive processes in developmentally backward children.

Child↗
PubMedDate not supplied

[Rhythmic activity in a neuronally isolated strip of rabbit cortex].

To test the ability of the neocortex to generate rhythmic potential oscillations, the composition of summary electrical activity of neuronally isolated necortex strip in the background and following rhythmic electrical stimulation of the strip was studied by means of computer in chronic experiments on rabbits. In the strip background activity oscillations appear in delta-, theta- and alpha-ranges which in some cases represent regular-rhythmic processes. Along with endogene activity rythmic theta-activity may be recorded which penetrates passively from the hippocampus (when it generates a regular high-amplitude theta-rhythm). It was found that the strip activity followed the stimulation rhythm and reproduced it during several seconds after the end of the stimulation. Driving was easier when the stimulation frequency was of 5 -- 7 c/s. Besides driving response, rhythm rearrangement often occured following stimulation manifested in appearance of rhythmic oscillations within theta-range independently on the frequency of the preceding stimulation.

Animals↗