A Role of Hippocampal Pathway in Epileptic Transfer to the Contralateral Amygdala Following Amygdaloid Kindling in Cats

Abstract

The effect of surgical intervention of hippocampal pathway on the epileptic transfer to the contralateral amygdala was examined in amygdaloid kindling model of epilepsy. Sixteen adult cats were used. The animals were received electrolytic lesioning of the ipsilateral ventral hippocampus (5 cats) or fornix (5 cats), or commissural bisection (6 cats) prior to primary site amygdaloid kindling. 1) Epileptic transfer was inhibited by complete electrolytic destruction of mossy fibers (4 cats), but not by partial destruction (1 cats). 2) Commissural bisection inhibited epileptic transfer in 3 of 6 cats, but there was no correlation with the extent of bisection of the corpus callosum or hippocampal commissure. Rather, it was correlated with the destruction of ipsilateral fornix. 3) Epileptic transfer was inhibited by complete destruction of the ipsilateral fornix (4 cats), but not by partial destruction of the fornix or corpus callosum (1 cat). These findings indicate that the hippocampal pathway including mossy fibers and fornix plays a critical role for epileptic transfer to the contralateral amygdala induced by amygdaloid kindling, and that transsynaptic changes through hippocampal pathway may play a role for the development of intractable epilepsy. © 1988, JAPAN EPILEPSY SOCIETY. All rights reserved.