According to a study from the United States, "Mesial temporal lobe epilepsy (MTLE) is a common form of epilepsy that affects the limbic system and is associated with decreases in memory and cognitive performance. The medial prefrontal cortex (PC) in rats, which has a role in memory, is associated with and linked anatomically to the limbic system, but it is unknown if and how MTLE affects the PC."

"We evoked responses in vivo in the PC by electrical stimulation of the mediodorsal (MD) and reuniens (RE) nuclei of the thalamus at several time points following status epilepticus, before and after onset of spontaneous seizures. Kindled animals were used as additional controls for the effect of seizures that were independent of epilepsy. Epileptic animals had decreased response amplitudes and significantly reduced recruiting compared to controls, whereas kindled animals showed an increase in both measures. These changes were not associated with neuronal loss in the PC, although there was significant loss in both the MD and RE in the epileptic animals. There is a significant reduction in the thalamically induced evoked responses in the PCs of epileptic animals," wrote D.M. Sloan and colleagues, University of Virginia, Medical Department (see also Epilepsy).

The researchers concluded: "This finding suggests that physiologic dysfunction in MTLE extends beyond primary limbic circuits into areas without overt neuronal injury."

Sloan and colleagues published the results of their research in Epilepsia (Changes in midline thalamic recruiting responses in the prefrontal cortex of the rat during the development of chronic limbic seizures. Epilepsia, 2009;50(3):556-565).

For additional information, contact E.H. Bertram, University of Virginia, School Medical, Dept. of Neurology, POB 800394, Charlottesville, VA 22908, USA.

The publisher of the journal Epilepsia can be contacted at: Wiley-Blackwell Publishing, Inc., Commerce Place, 350 Main St., Malden 02148, MA, USA.

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