Hippocampal-dependent spatial memory in the water maze is preserved in an experimental model of temporal lobe epilepsy in rats

PLoS One. 2011;6(7):e22372. doi: 10.1371/journal.pone.0022372. Epub 2011 Jul 26.


Cognitive impairment is a major concern in temporal lobe epilepsy (TLE). While different experimental models have been used to characterize TLE-related cognitive deficits, little is known on whether a particular deficit is more associated with the underlying brain injuries than with the epileptic condition per se. Here, we look at the relationship between the pattern of brain damage and spatial memory deficits in two chronic models of TLE (lithium-pilocarpine, LIP and kainic acid, KA) from two different rat strains (Wistar and Sprague-Dawley) using the Morris water maze and the elevated plus maze in combination with MRI imaging and post-morten neuronal immunostaining. We found fundamental differences between LIP- and KA-treated epileptic rats regarding spatial memory deficits and anxiety. LIP-treated animals from both strains showed significant impairment in the acquisition and retention of spatial memory, and were unable to learn a cued version of the task. In contrast, KA-treated rats were differently affected. Sprague-Dawley KA-treated rats learned less efficiently than Wistar KA-treated animals, which performed similar to control rats in the acquisition and in a probe trial testing for spatial memory. Different anxiety levels and the extension of brain lesions affecting the hippocampus and the amydgala concur with spatial memory deficits observed in epileptic rats. Hence, our results suggest that hippocampal-dependent spatial memory is not necessarily affected in TLE and that comorbidity between spatial deficits and anxiety is more related with the underlying brain lesions than with the epileptic condition per se.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anxiety
  • Behavior, Animal
  • Disease Models, Animal*
  • Electrophysiology
  • Epilepsy, Temporal Lobe / drug therapy
  • Epilepsy, Temporal Lobe / pathology*
  • Epilepsy, Temporal Lobe / psychology
  • Excitatory Amino Acid Agonists / pharmacology
  • Hippocampus / drug effects
  • Hippocampus / pathology*
  • Kainic Acid / pharmacology
  • Learning / drug effects
  • Magnetic Resonance Imaging
  • Male
  • Maze Learning / drug effects*
  • Memory Disorders / pathology*
  • Muscarinic Agonists / pharmacology
  • Neurons / pathology
  • Pilocarpine / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Rats, Wistar
  • Spatial Behavior / drug effects*


  • Excitatory Amino Acid Agonists
  • Muscarinic Agonists
  • Pilocarpine
  • Kainic Acid