Investigation of perforant pathway stimulation effect on object recognition in rats

Abstract

Mesial Temporal Lobe Epilesy (MTLE) is the most frequent form of epilepsy found in adults, and pyramidal neuronal death is the most frequent neuropathological marker found in this condition. A MTLE model in rats consists in the electrical stimulation of the performant pathway of awake rats for 8 hours. This animal model induced lesions with morphological aspects similar to those found in human MTLE, with neuronal degeneration mostly restricted to the hippocampus. However, a pre-conditioning using electrical stimulation of the performant pathway for two days is required in order for rats to survive the long stimulation period used in this model. The exact mechanisms induced in the hippocampus after this pre-conditioning are not known, but probably involve an inhibitory neuronal response that counterbalance excitatory activity. The hippocampus is associated with many cognitive functions, especially those related to explicit memory. Therefore, pre-conditioning possibly affects hippocampal cognitive functions. The objective of the present study is to evaluate if pre-conditioning in the performant pathway electrical stimulation model affects the hippocampal function. In order to achieve such objective, Wistar rats will have its performance measured in the object recognition test following pre-conditioning, and will be compared to control animals that were not stimulated. These data may provide insights into the mechanisms that could potentially explain why pre-conditioning is required for the induction of hippocampal atrophy in the performant pathway electrical stimulation model. (AU)