[Compensatory capabilities of the symmetrical regions of the dominant and subdominant hemispheres of the human brain]. / O kompensatornykh vozmozhnostiakh simmetrichnykh oblastei dominantnogo i subdominantnogo polusharii golovnogo mozga cheloveka

A comparison was made between the EEG characteristics and spectral power of EEG frequencies in symmetrical parts of both cerebral hemispheres in order to elucidate the involvement of these areas in compensatory processes in patients with tumours localized in one of the cerebral hemispheres, before and after the removal of the tumour. Before the operation, the presence of a focus of pathological activity causing inactivation of adjacent cortical cells, is attended with activation of cells in the symmetrical areas of the intact hemisphere. Elimination of the pathological focus results in the fluctuation of interhemispheric asymmetry; for certain time periods inactivation in the sick hemisphere is replaced by activation, while in the intact hemisphere activation changes over to inactivation. The revealed properties are termed by the authors as interhemispheric compensatory conjugation of reactions. They probably reflect the potential possibilities of different areas in the process of compensation.

[Correlation between electrical activity in symmetrical regions of the cerebral cortex and unilateral lesions]. / O sootnoshenii elektricheskoi aktivnosti v simmetrichnykh oblastiakh kory mozga pri ego odnostoronnikh proazheniiakh

Functional interrelations between cerebral hemispheres, and particularly, between their symmetrical areas, were studied during compensatory processes in patients with tumours localized in one of the hemispheres. Analysis of spontaneous electrical activity before the operation on the tumour revealed several types of interhemispheric relations. The existence of a sharply pronounced pathological activity in one hemisphere, testifying to inactivation of cortical cells, is, as a rule, accompanied by activation in the intact hemisphere, especially in the areas symmetrical with those injured. In cases of less pronounced pathology, with partial retention of activity of the cortical cells in the injured areas of the affected hemisphere, a lesser degree of activation is observed in the intact hemisphere. The data point to a development of substituting-compensatory processes in the areas of the intact hemisphere symmetrical with the injured ones and to the possibility of testing the processes electrophysiologically.