PubMed Health⌕ Search

Biomedical subjects

I N Knipst

Publications and source records attributed to I N Knipst.

27 records · Page 2Linked to original sources
PubMedDate not supplied

[Relation between "rest-activity" behavioral phases and features of the spatial organization of cortical potentials in experimental neuroses].

The development of experimental neurosis in rabbits led to stable changes in the correlation between behavioural phases in "rest-activity", i.e. some prolongation of active phases and a considerable shortening of rest phases. The analysis of spatio-temporal organization of cortical potentials by comparing successive topograms showed that changes occurred not only in quantitative parameters of rest-activity phases but also in their qualitative characteristics. Thus the depth of the resting states in neurosis lessened and the spatio-temporal cortical potentials' characteristics during the active phases were disorganized. The described shifts in the cortex state probably hindered normal alternation of activity-rest behavioural phases providing for optimal conditions of animals' activity.

Animals↗
PubMedDate not supplied

[The characteristics of the spatial-temporal organization of the cortical potentials in the free-moving rabbit during training (a comparison of the stages in the generalization and specialization of the conditioned-reflex response)].

Analysis of successive topograms was applied to investigation of peculiarities of the spatio-temporal organization of cortical potentials of a rabbit at different stages of conditioning. Qualitative distinctions were shown between the stages in the character of regulation of the spatial synchronization (SS) related to variations in cortico-subcortical relations. Higher SS level at the stage of generalization changed for more complicated pattern of the spatio-temporal organization of cortical potentials. These complex spatio-temporal characteristics favoured facilitation of excitation spreading along the paths which provide specialization of the conditioned response under the action of the conditioned stimulus. Obtained results were correlated to specific membrane and synaptic modifications in the course of conditioning. The findings extend the notions of the cellular mechanisms which determine the features of the cortical SS at the stages of generalization and specialization of the conditioned reflex.

Animals↗
PubMedDate not supplied

[The spatial-temporal organization of the membrane-synaptic modifications and of the topograms of the slow fluctuations in the cortical potentials during learning].

This paper deals with an actual problem of specificity of organization of different stages of a conditioned reflex (CR). We suggest to consider this problem at the level of membrane-synaptic modifications comparing them with the indices of changes in the spatial organization of slow potentials in the cortex. The definite sequence of involvement of cellular mechanisms has been shown which can determine different features of the spatial organization of cortical slow potentials. Changes in cellular excitability of cortical neurons are probably connected with the variations of the general level of momentary electroencephalotopograms and, correspondingly, with the level of general spatial synchronization. Involvement of excitatory and inhibitory synaptic connections (with the efficiency corresponding to CR stages) determines the formation of electroencephalotopogram relief. Indices of both levels depend of hypothalamic effects on the cortex.

Animals↗
PubMedDate not supplied

[The spatial-temporal organization of the cortical potentials in freely moving rabbits during active behavior arising under the influence of intrinsic needs].

The studies of successive momentary topograms of cortical potentials in freely moving rabbits revealed peculiarities of the regulation of the EEG spatial synchronization (SS) during rest and active phases of the basic behavioural cycle. The animal's movements of the active phase caused by intrinsic need were related to an increase in the influence of the global level fluctuations of the momentary topograms. During conditioned motor activity the topogram relief reorganization played a prominent part in the process of the SS formation. Comparison of these data allowed a conclusion that the peculiarities of the SS structure of the cortical potentials were determined by the ratio between the two processes which make up the EEG spatio-temporal organization rather than the degree of their expression. In case of the dominance of the topogram relief reorganization the state of the animal was related with the most frequently occurring topogram forms.

Animals↗
PubMedDate not supplied

[The subsystems of the spatial-temporal organization of cortical potentials and their role in EEG spatial synchronization].

Studying successive topograms of potentials made it possible to reveal different types (subsystems) of the spatio-temporal organization of human and animal cortical electrical activity, which covered significant cortical surface. The dominance of the inversion of the sagittal potential gradient in the topograms of the resting state or complicated relief forms in the active states co-existed with oscillations of the mean level of topogram potentials, the contribution of which to the spatial EEG synchronization changed depending on the functional state of the brain. The role of the ratio between these subsystems was shown and the influence of this ratio was demonstrated on the spatial synchronization of cortical potentials in experiments with 11 rabbits (in the course of their adaptation to the environment and learning) and examination of 50 healthy adult subjects (during motor task performance and elaboration of verbal set). The spatial synchronization of cortical potentials was found to have a complex structure, which was determined by the ratio between the effects of subsystems of the spatio-temporal organization of cortical potentials.

Adolescent↗