Kindling of limbic structures induces synaptic reorganization of the mossy fiber pathway
in the dentate gyrus. To evaluate the hypothesis that kindling stimulation may also
cause neuronal loss in the hilus of the dentate gyrus that could play a role in this
synaptic reorganization, neuron counts were obtained using quantitative stereological
methods in the hilar polymorphic region of rats kindled by perforant path stimulation.
After 3 kindled generalized tonic clonic seizures, there was 12.7% neuronal loss in
the hilar polymorphic region compared to controls, but there was no visually apparent
lesion. After 30 generalized kindled seizures, the neuronal loss was 40.1%, was visually
apparent, and resembled one aspect of the pattern of hilar neuronal loss observed
in human hippocampal sclerosis. The results demonstrate that brief sporadic seizures
can induce neuronal loss in the hippocampal formation, a brain region implicated in
epilepsy, memory, and cognition.