Morgan Throckmorton

Honors in Psychology

Major: Psychology

Supervisor: Ruth Hurst, Psychology

Peak Interval Performance of Heterozygous Reeler Mice

Valid animal models are important to the development of our understanding and treatment of potentially problematic gene-behavior relations currently implicated in human neurodevelopmental disorders. Decisions about the validity of a model must be based on animal performance on behavioral tasks, and these tasks require validation in their own right. If tasks/tests used to assess behavior are irrelevant or insensitive to disorder, then there is an inability to detect potentially important and subtle differences between neurotypical and atypical animals. One mouse model that has not been proven as a behavioral model for neurodevelopmental disorder is the heterozygote reeler mouse (+/rl), although there is reason to believe it should behavior abnormally compared to wild type control mice (+/+). The peak interval procedure is an operant test that assesses the capacity to perceive, remember, and act upon temporal information. This study sought to determine whether middle aged +/rl and +/+ mice would also evidence differences in their performances on this task. Implications of these findings are discussed with special attention validation of this model for neurodevelopmental disorders and to the relationship between these findings and earlier findings with older mice. Our hypothesis is that the heterozygous reeler mice will have less temporal control than the wild type mice as a result of their deficiency in reelin. The results of this study suggests that +/rl mice respond in a way that suggests they are not as accurate as the +/+ mice in relation to receiving the reinforcer, which in this case was a food pellet. Further, the accuracy error is in the direction that would indicate overestimation of the passage of time.