A biphasic change of afterdischarge threshold during the kindling process.

Cats were stimulated in the ventral hippocampus with low-frequency (about 3 Hz) square wave pulses. All subjects were kindled until generalized convulsion occurred. During the kindling process, the number of stimulating pulses required for the provocation of afterdischarge (AD), which was used as an indicator of AD threshold, decreased suddenly in the initial stage and increased gradually in the late stage. We consider this phenomenon to be important in deepening the understanding of seizure generation.