Effect of experimentally induced generalized seizures on the wakefulness--sleep cycle.

The effect of experimentally induced generalized seizures on the relations between the various phases of sleep in the wakefulness--sleep cycle was studied in cats with chronically implanted electrodes. After generalized convulsions induced by electrical stimulation of the dorsal hippocampus, unlike those of amygdalar origin, clearly defined changes were observed in the structure of the wakefulness--sleep cycle. In the postseizure period, with increasing wakefulness sharp depression of paradoxical sleep takes place. However, in slow wave sleep only slight changes were observed. Instead of a rebound phenomenon, paradoxical sleep was sharply induced in cats after preliminary deprivation of paradoxical sleep as a result of generalized seizures induced by electrical stimulation of the neocortex. Nonspecific hyperactivation of the brain, in the form of epileptiform discharges, thus has a particularly marked effect on the structure of paradoxical sleep.