The Barnes Maze Task Reveals Specific Impairment of Spatial Learning Strategy in the Intrahippocampal Kainic Acid Model for Temporal Lobe Epilepsy

Temporal lobe epilepsy (TLE) is an acquired form of focal epilepsy, in which patients not only suffer from unprovoked, devastating seizures, but also from severe comorbidities, such as cognitive dysfunction. Correspondingly, several animal models of TLE exhibit memory dysfunction, especially spatial memory. The Morris water maze test is the most commonly used test for assessing spatial learning and memory in rodents. However, high stress and poor swimming abilities are common confounders and may contribute to misinterpretation. Particularly epileptic mice show altered behaviour during the test as they fail to understand the paradigm context. In the Barnes maze test, a dry-land maze test for spatial learning and memory that uses milder aversive stimuli, these drawbacks have not yet been reported. In the present study, we use this task to evaluate spatial learning and memory in the intrahippocampal kainic acid mouse model of TLE. We demonstrate that the epileptic mice understand the Barnes maze paradigm context, as they learn the location of the escape-chamber by using a serial search strategy but fail to develop the more efficient spatial search strategy. Our data indicate that the Barnes maze may be a better alternative to the Morris water maze for assessing search strategies and impairment of learning and memory in epileptic mice.