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I N Knipst

Publications and source records attributed to I N Knipst.

10 recordsLinked to original sources
PubMedDate not supplied

[The functional testing of the interhemispheric asymmetry in the spatial organization of rabbit cortical potentials].

Interhemispheric asymmetry was studied of spatial-temporal potentials organization (STPO) of the cortex in non-fixated animals in the states of deep rest, behavioural activity and in the transition period between them. Despite the intrahemispheric differences of the STPO in each of these states, interhemispheric divergences in the character of reconstructions of momentary topograms of the cortical potentials, recorded at 24-channels leading, are limited by 35% of the epoch analysis time. Comparison of the dynamics of intrahemispheric changes of topograms of cortical potentials in the left and right hemispheres in the states of rest and activity revealed a narrowing of temporal period of the absence of resemblance in reconstructions of successive topograms of the left and right hemispheres in comparison with transition processes. In the phase of rest the interhemispheric conjugation of spatial reconstructions in topograms became lowered mainly because of the disturbances of monotony of changes of their reliefs in one of the hemispheres in turn. In the active phase, deviations from STPO of the cortex, characteristic of the state of rest, were met more frequently in the right hemisphere; in that case oscillations of the topograms general mean level connected with the activity of non-specific activating subcortical brain system acquired a significant role in regulation of interhemispheric relations. Presence of interhemispheric resemblance of reconstructions of topograms reliefs in the active phase, despite the tendency to its lowering in comparison with the rest, testifies to the contribution also of the intracortical processes to the interhemispheric spatial synchronization of the cortical potentials in this state.

Animals↗
PubMedDate not supplied

[The interhemispheric asymmetry of the spatial-temporal organization of cortical potentials in the rabbit].

In experiments on freely moving rabbits the existence of interhemispheric asymmetry of spatial-temporal organization of the cortical potentials in the state of calm alertness was shown. Episodes were revealed of interhemispheric discordance of spatial reconstructions of momentary reliefs of the cortical potentials topograms 1/64-1/3-1/5 s in duration, i.e. periods of the theta- or delta-rhythms. Total duration of time of interhemispheric asymmetry (according to significant divergences in dynamics of resemblance coefficients of consequent reliefs of the cortical potentials topograms) in most cases was not less than 10% and not more than 30% of time of analysis epoch and consisted of discordance episodes both of different global reconstructions of spatial correlations of the left and right hemisphere potentials and of interhemispheric local shifts in spatial organization of the cortex potentials.

Animals↗
PubMedDate not supplied

[The spatial organization of the cortical potentials in exposure to different forms of photic stimuli].

Reactive changes of spatial-temporal organization of cerebral cortex potentials of rabbits under the action of light stimuli of various shapes (circle, square, triangle, cross and weaker diffusive light presented prior to and after the application of structural stimuli) were studied on the basis of multi-channel EEG recording data (24 leads). The data were evaluated of spectral-correlative analysis of the electrical activity and the results of comparison of successive momentary topograms of cortical potentials (EEG) on two-second segments prior to and during the action of the applied light stimulus. The obtained results showed that localization of interconnected changes of the cortical potentials were more sensitive to the perception of the form of light stimuli than the change of frequency characteristics of the EEG rhythms.

Animals↗
PubMedDate not supplied

[Quantitative assessment of maps of the cortical background potentials during the adaptation of freely moving animals to environmental situations].

Utilization of spectral-correlation methods of EEG analysis, due to necessary averaging in time, does not make it possible to detect dynamic phenomena in spatial-temporal organization of brain potentials. Non-traditional method is presented of quantitative evaluation of the changes of spatial-temporal correlation of cortical potentials--comparison of successive momentary potentials relief (electroencephalotopograms--EETG). Joint utilization of dynamics of similarity coefficients of successive EETG (Ket), mean values of EETG (Yet) and some other parameters allows to judge about dynamic properties of spatial correlations of potentials of freely moving animals in adaptation process to the environment during which alternation is established of the active and passive phases in decaminute intervals. Quantitative evaluation of spatial-temporal organization of the parameters of rabbits cortical potentials in these phases and in transition periods has revealed their informative possibilities.

Adaptation, Physiological↗