Stereoelectrosubcorticography in epilepsy, the focus and epileptogenic system.

According to the conceptual electrophysiological model for epilepsy worked out by the authors earlier (1968-1971) the development of the disease has the following stages: "epileptic" neurone epileptogenic focus epileptogenic system epileptic brain. The mechanisms of the II and III stages are analysed in the given paper. The critical volume of the neuronal population capable of functioning as a triggering focus is shown to be 10(3)-10(5) cells (Microsystem). On the II stage the control is achieved by the lateral inhibition. Further on epileptogenic macrosystems and subsystems of discharge reverberation (vertical and horizontal) are formed with complex hierarchy on a reciprocal principle. A morpho-functional organization of pathological systems in petit mal, grand mal, uni- and bitemporal epilepsy was found during ictal and interictal periods. Inhibitory systems (low pontine and caudate) and reciprocal inhibition during the III stage were found to act as controls.