Phasic paradoxical sleep precipitates focal motor and limbic seizures.

The facilitatory or inhibitory effect of paradoxical sleep (PxS) was investigated in two models of focal epilepsy: focal motor seizures induced by alumina cream in the frontal cortex and limbic seizures produced by intra-amygdaloid kainic acid microinjections in cats. We found that phasic episodes of PxS could trigger both types of seizures. Interictal spikes were generally blocked during PxS. We conclude that PxS exerts facilitatory or inhibitory effects depending on the particular event under analysis and the degree of epileptogenicity. The capacity of phasic PxS to precipitate focal ictal discharges may depend on ponto-limbic excitatory influences.