[The characteristics of the synaptic reorganization in the sensorimotor cortex of cats after the destruction of the symmetrical portion of the cortex in the opposite hemisphere]. / Osobennosti sinapticheskoi reorganizatsii v sensomotornoi kore mozga u koshek posle razrusheniia simmetrichnogo otdela kory protivopolozhnogo polushariia.

Intracellular recording technique has been used to study reactions of corticospinal neurons (CSN) to stimulation of the ipsilateral ventrolateral nucleus (VLN) of the thalamus in acute experiments on adult intact cats and on cats after lesion on the contralateral sensorimotor cortex (exposition from 6 months to 1.5 years). Acceleration of the monosynaptic EPSPs rise phase in slow CSN was revealed in operated animals, which presumed the reorganization of the synaptic contacts in the SD membrane of flow CSN. Detailed analysis of features and branching of CSN axon, collaterals passing to VLN of the thalamus and participating in formation of the ipsilateral pyramidal tract was made by the method of collision test. The significance of the plastic synaptic reconstruction in the ipsilateral thalamo-cortex reverberating system during the outflow formation under conditions of the partial cortex interhemisphere deafferentation is discussed.

[Plastic synaptic reorganization in the sensorimotor cortex of adult cats after destruction of the contralateral nucleus intermedius of the cerebellum]. / Plasticheskaia sinapticheskaia reorganizatsiia v sensomotornoi kore mozga u vzroslykh koshek posle razrusheniia kontralateral'nogo promezhutochnogo iadra mozzhechka.

Using the intracellular microelectrode technique the reactions were investigated in corticospinal neurons (CSN) after stimulation of contralateral (cIP) and ipsilateral interpositus nucleus of cerebellum as well as ventrolateral nucleus of thalamus. Experiments were made on adult intact cats and the same preliminary lesion of cIP nucleus (exposition from 1 to 6 months). Acceleration of the monosynaptic thalamo-cortical EPSPs time to peak in slow CSN was revealed in operated animals. It indicated that there was remote terminal dendrosomatic sprouting and formation of new synapses on proximal segments of SD-membrane of CSN. This made it possible to suppose that there was formed ipsilateral interposito-thalamocortical way which duplicated the same contralateral in intact animals. The contralateral cortico-interposital collaterals in intact and the analogic ipsilateral sprouting in operated animals have been shown.

[Sources of thalamocortical afferentation of the area of forelimb representation in the first somatosensory zone of the cerebral cortex in the cat]. / Istochniki talamo-korkovoi afferentatsii oblasti predstavitel'stva perednei lapy v pervoi somatosensornoi zone kory mozga koshki.

Retrogradely labelled thalamic neurons--the sources of afferentation in the focus of maximal activity evoked by stimulation of n. radialis--were studied in adult cats by means of microiontophoretic injections of horseradish peroxidase into the first somatosensory zone of the cerebral cortex. The labelled cells were predominantly found in the thalamic nucleus ventralis posterolateralis; some cells (a minor part) were also found in the nucleus ventralis posteromedialis. The labelled neurons in these nuclei were distributed in groups whose composition according to many morphological characteristics was heterogeneous.

[Electrophysiological study of the role of the cerebral cortex in the compensatory recovery of functions]. / Elektrofiziologicheskoe issledovanie roli kory bol'shikh polusharii v kompenstornom vosstanovlenii funktsii.

Intracortical rearrangement of functions in the process of the compensatory rehabilitation of functions was studied in semichronical experiments using the technique of recording focal potentials in the parietal associative and somatosensory cortex after unilateral extirpation of their symmetrical regions. The recording zones for the focal associative and somatosensory (projecting) potentials were found to extend following the complete intracortical rearrangement (8-10 months after the unilateral extirpation). An assumption based on changes in the time-amplitude characteristics of the parameters of focal potentials recorded on the surface and at various levels of the somatosensory cortex of the intact hemisphere, was made that the positive wave of the focal surface response is not the result of deep (inner) negative potentials. As to the associative focal responses--no reversion of them could be observed across the whole depth of the cortex.