Meeting Abstract

P1.174  Wednesday, Jan. 4  Seasonal variation in neurogenesis in red-sided garter snakes (Thamnophis sirtalis) POWERS, S.D.*; MAINE, A.R.; LUTTERSCHMIDT, D.I.; Portland State University, Oregon; Portland State University, Oregon; Portland State University, Oregon sepowers@pdx.edu

Seasonal variation in neurogenesis (i.e., cell proliferation, migration, differentiation) is widespread across diverse taxonomic groups. However, the functional significance of such changes in the adult brain is often unknown. We examined if seasonal differences in neurogenesis occur in a population of red-sided garter snakes (Thamnophis sirtalis) in Manitoba, Canada. We also addressed whether seasonal neurogenesis is correlated with changes in courtship behavior. We collected male snakes from the den site during the spring mating season or fall pre-hibernation period. Snakes were treated with bromodeoxyuridine (BrdU; a thymidine analog that is incorporated into the DNA of newly proliferating cells) and housed in outdoor arenas. In the spring, courtship behavior was measured before males were euthanized at 1, 5, 10, 15, 20, or 28 days post-BrdU treatment. During the fall, neurogenesis was assessed at days 1, 5, and 10 post-treatment. Brains were processed for BrdU immunohistochemistry to visualize newly proliferated cells and data were analyzed by two-way ANOVA. We found that fall snakes had significantly more proliferating cells (F = 20.279; P < 0.001) and migrating cells (H = 15.604; P = 0.001) in the nucleus sphericus than spring males. In addition, the number of proliferating cells increased over time (F = 3.712; P = 0.047), while male courtship behavior decreased significantly during spring (H = 15.962; P = 0.007). Further research is necessary to determine if increased cell proliferation regulates seasonal transitions in behavior (e.g., the transition from courtship behavior to migration and summer foraging). Our results also suggest that increased neurogenesis during the fall may play a role in preparing for winter dormancy (e.g., neuroprotection).