[Electrophysiological aspects of the indicators of hemispheric asymmetry during reparative processes in the brain after unilateral lesions]. / Elektrofiziologicheskaia kharakteristika pokazatelei mezhpolucharnoi asimmetrii pri vosstanovitel'nykh protsessakh v mozge posle ego odnostoronnego povrezhdeniia.

The gears of the conjugate activity of hemispheres in the presence of damage in one were studied before and after removal of a tumor by using an interhemispheric asymmetry index. On left hemispheric exposure, the index decreased in the anterior brain regions having mainly morphofunctional connections with the activating structures of the stem. The posterior cortical regions changed the index on exposures of the right hemisphere or synchronizing stem structures. In an operated-on patients, the damaging action at any site reduced the index in the anterior cortical regions. Interhemispheric asymmetry of the posterior regions increased or unchanged with left hemispheric damage and decreased with right hemispheric one. These changes are interpreted as a reflection of compensatory rearrangements of interhemispheric interactions which are accomplished under the influence of the activating and synchronizing systems of the brain stem.

[Interhemispheric asymmetry in the anterior and posterior sections of in the normal human brain and in unilateral cortical damage]. / Sostoianie mezhpolusharnoi asimmetrii v perednikh i zadnikh otdelakh mozga cheloveka v norme i pri odnostoronnem povrezhdenii kory.

The study of interhemispheric bioelectrical asymmetry (IBA) of the brain as a result of pair activity of the hemispheres has shown that in normal subjects IBA was greater in the frontal lobes than in the occipital ones. In patients with injured right hemisphere the asymmetry increased in the occipital lobes. In patients with injured left hemisphere the asymmetry diminished in the frontal lobes.

[Interhemispheric asymmetry in unilateral brain damage]. / Mezhpolusharnaia asimmetriia pri odnostoronnem povrezhdenii mozga.

Hemispheric functional changes and interhemispheric interactions were studied by the bioelectrical parameters of asymmetry in the unilateral brain damage. The magnitude of interhemispheric asymmetry was found to depend upon the site of injury, achieving its maximum at the right-sided localization of a pathological process and slightly changing at the left hemispheric tumor site. The application of functional tests was accompanied by profound increases in asymmetry as compared with the baseline. The findings may be an informative predictive tests for the course of an inflammatory process.

[Interhemispheric asymmetry in patients in the rehabilitation period after unilateral damage to the cerebral cortex]. / Sostoianie mezhpolusharnoi asimmetrii u bol'nykh v vosstanovitel'nom periode posle odnostoronnego povrezhdeniia kory golovnogo mozga.

The studies revealed that the level of interhemispheric bioelectric asymmetry, which reflects the functional relations between the hemispheres, is one of the major indices of the functional interaction of the two hemispheres. There were changes in interhemispheric asymmetry in relation to the tumor damage to the right or left hemisphere. The structural lesion of the left hemisphere did not appear to affect interhemispheric asymmetry, whereas right hemispheric dysfunction led to its significantly marked asymmetry, i. e. the mechanisms ensuring the stability and symmetry of electric activity of the two hemispheres are mainly associated with the structures of the right hemisphere.

[The electrophysiological characteristics of the compensatory and restorative processes in the central nervous system of neurosurgical patients in relation to the lateralization of the injury]. / Elektrofiziologicheskie kharakteristiki kompensatornykh i vosstanovitel'nykh protsessov v tsentral'noi nervnoi sisteme u neirokhirurgicheskikh bol'nykh s uchetom lateralizatsii porazheniia.

The authors studied the functional condition of the brain during the restorative period after operative damage to one of the hemispheres. In the early stages of the restorative period in neurosurgical patients with a slow rhythm afferent stimuli (rhythmic light stimulation) induced the appearance of a marked alpha-rhythm, which is evidence of restoration of the functional condition of the cortical and subcortical structures taking part in the generation of this rhythm. Such dynamic changes in the condition of the structures may be considered as a manifestation of their activation and evaluated as a favourable prognostic sign. Data were obtained which characterized the features of the restorative-compensatory process depending on which hemisphere, right or left, the damage was inflicted. According to the indices of the various rates of EEG, high-frequency waves of beta-range prevailed in the intact left hemisphere on the 12th-25th day; this phenomenon was not recorded in an intact right hemisphere in damage to the left hemisphere.

[The effect of a peptide-containing extract of the right hemispheric cortex on the recovery of conditioned reflex activity and on the level of neuromediators in the brain structures of rats after a unilateral frontal lobectomy]. / Vliianie peptidsoderzhashchego ékstrakta kory pravogo polushariia na vosstanovlenie uslovnoreflektornoi deiatel'nosti i uroven' neiromediatorov v strukturakh mozga krys posle odnostoronnei frontal'noi lobéktomii.

Experiments were conducted on 97 non-inbred [correction of unbred] male rats to study the effect of a peptide-containing extract of the cortex of the right hemisphere of donor rats, who underwent left lobectomy 9 days before the experiment, on restoration of conditioned reflexes of bilateral avoidance and level of neuromediators in the brain structures of recipient rats with a similar damage to the cerebral cortex. It is shown that the brain extract from the right hemisphere of operated on donors has a much higher effect on the restoration of reflexes. At the same time it was found that in left frontal lobectomy this extract produces a most manifest effect on monoamine metabolism in the structures of the right intact hemisphere. It is suggested that a directed effect may possibly be produced on the development of compensatory-restorative process in the central nervous system by endogenous substances of peptide origin which are isolated from brain structures actively contributing to the restoration of disturbed functions.

[Effects of peptide factors from right and left brain hemispheres of rats on amplitude-time characteristics of projective and interhemispheric evoked responses]. / Vliianie peptidnykh faktorov pravogo i levogo polusharii krys na amplitudno-vremennye kharakteristiki proektsionnykh i mezhpolusharnykh vyzvannykh otvetov.

Peptide extracts of the right and left hemispheres were applied to the projective (somatosensory and visual) and temporal associative regions of the left brain hemisphere in cats. In the zones of peptide application, evoked potentials (EP) in response to singular and coupled somatic, visual and transcallosal stimuli were registered. The data obtained showed that right and left peptide extracts had different effects on evoked potentials of the left hemisphere. Thus ipsilateral extract increased the amplitude of projective EP, decreased duration of their cycles and amplitude of transcallosal responses. Contralateral extract, on the contrary, activated interhemispheric inputs to brain cortex, suppressed thalamic inputs and increased multimodal properties of neurons. A differential approach to the problem of specific correction of pathological states of the right and left brain hemispheres is required. Right and left peptide extracts may be used in normalization of interhemispheric activity balance in compensatory-recovering processes.

[Experimental validation of the use of an ultrasonic surgical instrument in neurophysiology]. / Eksperimental'noe obosnovanie primeneniia ul'trazvukovogo khirurgicheskogo instrumenta v neirofiziologii.

The effect of ultrasonic and surgical instruments on nervous tissue in chronic experiments on the cats were investigated with electrophysiological and morphological methods. The authors compared the results of removal of the neocortex zones using ultrasonic and surgical instruments or routine methods. Electrophysiological and morphological studies have shown small injury effects made by ultrasonic and surgical instruments on the surrounding brain tissue.

[Action of cortical extracts of the left and right hemispheres on the recovery of conditioned reflex activity in rats after unilateral removal of the frontal cortex]. / Deistvie ékstraktov kory levogo i pravogo poluosharii na vosstanovlenie uslovno-reflektornoi deiatel'nosti krys posle odnostoronnego udaleniia lobnoi kory.

The recovery of active avoidance conditioned reflex (AACR) was investigated after unilateral frontal cortex extirpation. Intraperitoneal injection of extracts from left or right brain cortex (1 mg/kg) of healthy rats (LE or RE) stimulated AACR recovery in animals with lobectomy on the same side. If RE was extracted 9 days after left side brain extirpation, i.e. during the period of the development of compensatory processes, its effect on AACR recovery was stronger in left-operated animals, while in right-operated animals it remained unchanged.

[Advantages of ultrasonic surgical instruments in experimental neurophysiology]. / Preimushchestva ul'trazvukovogo khirurgicheskogo instrumenta v éksperimental'noi neirofiziologii.

The effect of ultrasonic neurosurgical instruments on the functional state of the brain and its individual structures was studied to establish the most adequate and the least traumatic method of brain structures extirpation. Cortical zones were destroyed by ultrasound, thermocoagulated or extirpated. Parallel recordings of evoked potentials to single and paired stimuli were performed in adjacent neocortical areas. It was established that ultrasonic instruments permit the least traumatic extirpation of brain cortical zones.

[Intravital morphometric characteristics of the pial network of associative and projection regions during contralateral cooling of the cat cortex]. / Prizhiznennaia morfometricheskaia kharakteristika pial'noio sosudistoi setki assotsiativnoi i proektsionnoi zon pri kontralateral'nom okhlazhdenii kory golovnogo mozga koshki.

Morphometric parameters of pial vessel bed in somatosensory (region 1) and parietal (middle third of f. supra-sylvii) zones of the right brain hemisphere were determined using automatic image analysis in acute experiments on normal cats and during 1-hour cooling blockade of the same regions in the left hemisphere. In normal conditions values of pial vessel bed area were higher in the somatosensory zone, with the vessels 16-50 micron in diameter prevailing. In the parietal zone vessels with a diameter of 5-15 micron prevailed. Primary vessel constriction was observed during cooling. Later the tendency to prolonged increase of specific bed length in the parietal zone, particularly during cooling of the symmetrical region, was noted. The data obtained reveal structural and functional peculiarities of pial system in associative and projection cortical zones and their significance in compensatory-restoration process after injury.

[Participation of monoamines in the recuperative responses of the central nervous system following experimental injury to the anterior portions of the cerebral cortex]. / Uchastie monoaminov v vosstanovitel'nykh reaktsiiakh tsentral'noi nervnoi sistemy pri éksperimental'nom povrezhdenii perednikh otdelov kory golovnogo mozga.

The role of biogenic amines (serotonine and noradrenalin) in the compensatory recovery processes was studied by means of conditioned reflexes in chronic experiments on rats after extirpation of the forebrain cortex. The recovery reactions are shown to proceed in the presence of significant shifts in the level of biogenic amines. Injection of 5-hydroxytryptophan to the operated on animals promotes rapid recovery of disturbed conditioned reflexes. It is suggested tht the increased serotonin brain level raises its compensatory potencies.

[Interhemispheric interactions following unilateral injury to the cerebral cortex]. / Mezhpolusharnye vzaimodeistviia v usloviiakh odnostoronnego povrezhdeniia kory golovnogo mozga.

The object of the study was to examine the time-course of interhemispheral relations under unilateral injury to the somatic or optical cortical pathways. Special attention was paid to the characteristics of the function of the associative parietal cortex and areas that are symmetrical to the location of injury. Transcallosal stimulation allows changing the functional condition of the studied zones. This can be considered as a possible factor inducing development of compensatory-rehabilitative processes in the central nervous system.