Abstracts Psychology

Behavioral charqacterization of apolipoprotein e-knockout mice

by Jean-Bernard. Dupuy

Apolipoprotein E-knockout (apoEKO) mice were characterized behaviorally to evaluate the impact of apolipoprotein E deficiency on spatial learning and memory function at different ages. Wild type and knockout mice were tested in two tasks assessing spatial memory function, Morris water maze (MWM) and Radial arm maze (RAM). Both young and aged apoEKO mice backcrossed six generations displayed deficits in the MWM. However, young and aged 10th generation apoEKO mice did not display any deficits in the MWM or the RAM when spatial cues that could be used to solve these tasks were provided. Removal of spatial cues after training had occurred also did not result in an impairment. In contrast, apoEKO mice were impaired when spatial cues were removed from the beginning of training. This result suggests that these mice are less able to utilize non-spatial cues to solve these tasks. The impairments observed in the MWM and RAM were not the result of impaired reference memory function, but rather appeared to arise from a dysfunction in working memory. Additional tests assessing sensorimotor gating function (Prepulse inhibition), and emotionality (the Open field, the Elevated plus maze) suggested that these cognitive deficits did not arise from alterations in sensorimotor gating function or emotionality, as both young and aged apoEKO mice performed at levels similar to those observed in their aged C57BL/6J control groups.