Abstracts

Rationale: We hypothesize that spatial cognitive deficits can be detected in a subset of rats who have experienced prolonged Experimental Febrile Status Epilepticus (EFSE). Furthermore, we hypothesize that these deficits in performance in a spatial task can be predicted by MRI taken shortly after the prolonged febrile seizure. The performance deficits of this subset of rats were also examined in relation to cellular function as well EEG in the hippocampus. The results of this study may provide biomarkers that may serve to predict those at risk for cognitive deficits following febrile seizures and set the stage for intervention.Methods: EFSE is induced in rat pups at P10 through prolonged hyperthermia while controls are kept at room temperature. MRI was carried out approximately 1 hour after the prolonged seizure for hyperthermic rats. Normothermic rats were also imaged. At 8-10 weeks old the rats are trained to perform a spatial task involving avoidance of a shock zone on a rotating arena. After 12 weeks the rats undergo chronic implantation of 4 separately drivable tetrodes in the left and right hippocampus. Cellular activity as well as local field potentials are recorded simultaneously from each hippocampus while the rat forages for food pellets on a stable arena or avoids a shock zone on a rotating arena.Results: Preliminary data suggest that MRI T2 levels may predict cognitive performance in a spatial task in adult EFSE animals. We also examine the stability of hippocampal firing fields for both EFSE and control rats on the stable arena as well as potential differences in firing activity in the transition between the stable and rotating arena conditions. Conclusions: Further study may provide insights into both the predicitive power of MRI with regard to cognitive deficits after EFSE as well as the underlying mechanisms of these deficits in the performance of a complex spatial task.