[Electrical activity of the neurons in an epileptic focus created in an isolated strip of cerebral cortex by electrical stimulation].

The peculiarities of the activity of cortical isolated slab neurons were investigated in experiments on unanaesthetized and immobilized cats during the development of seizure spikes evoked by repetitive powerful stimulation. It was shown that in the investigated focus of epileptiform discharges the neurons were not differentiated by the degree of pathological alterations, since paroxysmal membrane potential shifts of all neurons were recorded intracellularly. All these neurons were characterized by a lack of the spike activity. At the same time bursting spike discharges of isolated slab neurons were recorded extracellularly and they did not propagate to the soma. Simultaneous extra- and intracellular recordings of the activity from the same neurons have shown that during the epileptiform activity action potentials were generated in some trigger zones without propagating to the cell bodies. Possible mechanisms of the origin of the spike activity in isolated slab neurons during the development of generalized epileptiform state are discussed.