[Correlation between electrical activity in symmetrical regions of the cerebral cortex and unilateral lesions].

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.