Poster Presentation The International Congress of Neuroendocrinology 2014

Assessment of rapid estradiol effects in the hippocampus on social learning in female ovariectomized mice (#271)

Kelsy Ervin 1 , Kathryn Sinclair 1 , Amy Moore 1 , Elena Choleris 1
  1. University of Guelph, Guelph, ONT, Canada

Social learning is an adaptive form of learning involving an animal acquiring information from another, rather than by trial-and-error. The social transmission of food preferences (STFP) task assesses social learning in rodents. An observer interacts with a demonstrator who has eaten a novel-flavoured food. Given a choice of two novel foods, the observer preferentially eats the food smelled on the demonstrator’s breath. Estrogens modulate performance on this task through both genomic and rapid mechanisms. However, the brain regions involved in the rapid effects on social learning are currently unknown. We focused on the hippocampus, as systemic E2 increases dendritic spine density in the CA1 subregion (Phan et al 2012, Neuropsychopharm:2299), intrahippocampal E2 rapidly facilitates performance on nonsocial learning tasks, and hippocampal lesions may impair social learning. To examine its potential role in E2 effects on social learning, ovariectomized female observer mice were implanted with bilateral guide cannulae in the CA1 hippocampus. The observers received infusions of vehicle or E2 (25, 50, 100nM, 0.5μL per side) 15min prior to a brief social interaction with the demonstrator. Food preference was measured at 30min and 2, 4, 6 and 8h intervals during the choice test. The first measurement was therefore 45min after E2 infusion, when behavioural effects are likely due to rapid estrogen actions. We used a modified, “difficult” STFP paradigm, in which vehicle-treated observers typically show no social learning, enabling us to assess any enhancing effect of E2 treatment. Preliminary results suggest the hippocampus may not be the site of rapid estrogen facilitation of social learning. Hence, we are now assessing rapid E2 effects in the amygdala, which has also been implicated in the STFP and other social behaviours. We hope to further clarify how estrogens act in the brain to modify behaviour, specifically in a social learning context. NSERC Funded