Meeting Abstract

P2.197  Saturday, Jan. 5  Variation in Hippocampal-Dependent Behaviors and Neurogenesis during a Range Expansion LIEBL, AL*; TROTTER, JH; KELLOGG, SL; FIORELLI, T; MARTIN, LB; Univ S. Florida; Univ S. Florida; Univ S. Florida; Univ S. Florida; Univ S. Florida aliebl@mail.usf.edu

Individuals in novel habitats are typically more innovative, more exploratory, and less fearful of novelty than individuals in familiar habitats; however, the mechanisms underlying these patterns have not been revealed, particularly in a species undergoing range expansion. The ability to form memories often influences behavior and in unfamiliar habitats, where the necessity to form memories of novel surroundings and resources is vital to survival, it may be a particularly strong predictor of observed behavioral differences among populations undergoing range expansion. Vertebrates typically form new memories through two mechanisms: morphological plasticity of existing neurons and the generation of new ones. Here, we compared house sparrows (Passer domesticus), differing in time of colonization (birds from areas that were colonized 60, 30, <10 years ago). Using behavioral tests as well as Golgi staining (to determine dendrite density and shape) and immune-histo-chemistry (to identify newly formed cells), we compared the relationship among range expansion, neurogenesis, and behavior (innovation and learning). We hypothesized that individuals at the edge of a range expansion (<10 years old) would be better innovators and have a greater capacity to form memories; we further predicted these differences were due to greater synaptic density and hippocampal neurogenesis. Sample analysis is ongoing, however this study is one of the first to evaluate the effects of a changing environment on neurogenesis and its associated behaviors.