[Experimental bilateral focus model of complex partial seizure: clinical, electrophysiological and pathological...

Stereotactic surgery was performed in Wistar rats and stainless steel injection chemitrode were inserted in bilateral amygdala (AM). Stainless steel screws were placed on the dura over bilateral motor cortex (Cx). One week after the surgery, rats were placed in the recording chamber. Kainic acid (KA) injection was performed into the left AM and focal AM seizure status was induced. Seizures evolved into limbic seizure status during 3 days. Seven days after the first KA injection, KA was injected into the right AM. The limbic seizure status was elicited again, however, these seizures subsided within 3 days. About 3 week after the first KA injection, spontaneous limbic seizures developed. Three ictal EEG patterns were seen (1) Bilateral independent seizures, (2) Synchronous ictal discharge over the bilateral AM, and (3) Switch of lateralized ictal activity from one to the other AM. The histological study demonstrated bilateral hippocampal cell loss and hippocampal atrophy. These changes are very similar to those observed in human intractable complex partial seizures with bilateral mesial temporal focus. The result suggests that this model will be a good tool in order to resolve intractability of complex partial seizure in patients with bilateral temporal focus.