Morphological plasticity in an infant monkey model of temporal lobe epilepsy

Abstract

Purpose/Methods: Seizures in early life are thought to contribute to the development of human temporal lobe epilepsy. To examine the consequences of early seizures, we elicited status epilepticus in immature, 5.5- to 7.0-month-old pigtailed macaques by unilateral microinfusion of bicuculline methiodide into the entorhinal cortex. Results: This report focuses on neuropathological changes in the hippocampus. Bicuculline infusion consistently elicited limbic-like seizures with prolonged, relatively localized electrographic activity. Magnetic resonance imaging revealed enhanced signal intensity in the ipsilateral hippocampus after seizures; in some cases, there was also progressive hippocampal atrophy. Histological changes were variable; in two of five monkeys, there was significant hippocampal neuron loss, gliosis, granule cell dispersion, and mossy fiber reorganization. Conclusions: The histopathological findings and associated magnetic resonance imaging abnormalities after bicuculline-induced status epilepticus in infant monkeys mimic common aspects of human temporal lobe epilepsy.