Meeting Abstract

P1.172  Wednesday, Jan. 4  Fall migration is associated with changes in neurogenesis in red-sided garter snakes (Thamnophis sirtalis) MAINE, A.R.*; POWERS, S.D.; LUTTERSCHMIDT, D.I.; Portland State University, Oregon; Portland State University, Oregon; Portland State University, Oregon d.lutterschmidt@pdx.edu

Seasonal rhythms in physiology and behavior are often associated with changes in brain markers, including the generation of new cells (i.e., neurogenesis). In the present study, we asked whether neurogenesis is associated with seasonal migration in a population of red-sided garter snakes (Thamnophis sirtalis) in Manitoba, Canada. Following an attenuated mating season, snakes migrate up to 17 km to feeding grounds where they spend the summer activity period. Fall migration back to the hibernacula is associated with an inactivation of feeding behavior as well as other physiological changes that are necessary for winter dormancy. We collected fall premigratory and postmigratory male snakes from feeding grounds or the den site, respectively and treated them with bromodeoxyuridine (BrdU), a synthetic analog of thymidine that is incorporated into the DNA of proliferating cells. Snakes were housed in outdoor arenas and euthanized at 1, 4, 7, or 10 days post-BrdU treatment. Brains were processed for BrdU immunohistochemistry to visualize newly proliferated cells. Postmigratory snakes collected from the den site during the fall had significantly higher numbers of proliferating cells in the nucleus sphericus than premigratory snakes collected from feeding grounds (F = 12.01; P = 0.003). In contrast, premigratory snakes exhibited greater cell migration than postmigratory snakes (F = 8.35; P = 0.011). These results indicate that fall migration to winter hibernacula is concurrent with changes in both cell proliferation and cell migration in the brain of adult snakes. Further studies are needed to determine if these differences are related to changes in spatial memory necessary to relocate overwintering den sites or physiological changes associated with preparation for winter dormancy.