[Interhemispheric correlations of electric activity of the brain in late depression]

A chronometric EEG analysis was made in 60 patients aged 50 to 86 years with affective psychosis in different stages of the depressive phase. It has been demonstrated that the development of depressive conditions gives rise not only to changes in the frequency and amplitude characteristics of the EEG but also in the ratios of interhemispheric asymmetry of the parameters of brain electric activity, attesting to a higher tone of the right hemisphere. This interhemispheric asymmetry was determined to a considerable measure by the presence in the reference EEG of generalized discharges of slow-wave activity. The use of the dipolar analysis of the EEG permitted detecting foci of maximum generation of discharges in the left temporal area and brain stem structures. These areas of generation were preserved after removing the depressive symptomatology with antidepressants. It is suggested that the superstem generators of discharges exert a more appreciable effect on right hemisphere function, which is specified by cortico-diencephalic relations.