There are known disparities in susceptibility to psychiatric and stress-related disorders between sexes. Post-traumatic stress disorder (PTSD) is one such case. We used stress-enhanced fear learning (SEFL), a validated animal model for PTSD. However, it is unknown if sex differences stem from gonadal (Sry + vs. Sry -) or chromosomal (XX vs. XY) differences. The investigation of contributions the sex chromosomes and gonadal hormones have on the development of a sex difference in the brain is crucial for understanding sex biases observed in a variety of psychiatric disorders. Research was conducted using Four-Core Genotype (FCG) mice, a strain capable of producing four genotypes: XX SRY-, XY SRY+, XX SRY+, and XY SRY-. XX SRY- and XY SRY+ are wild types (females with ovaries and males with testies) and XX SRY+ and XX SRY- are mutants (females with testes and males with ovaries). The paradigm consisted of four consecutive behavioral testing days with 20 mice of each genotype. The mice were stressed via footshock in the first context and their fear memory of the context was tested the following day. Fear conditioning and a subsequent fear memory test occurred in a novel context. Freezing percentages were collected for data analysis. Data showed no difference in freezing across gonadal and chromosomal conditions indicating no clear influence of either on SEFL. A main effect of stress was observed, meaning the mice who underwent four footshocks showed higher freezing percentages than the no footshock mice. To look further into this possibility, the experiment will be rerun with the first context stress occurring in infancy instead of adulthood. We are interested in behavioral neuroscience with an emphasis on sex differentiated vulnerability and found this experience extremely informing as they both intend to pursue research-based careers in neuroscience.
Authors: Kiara D. Ream, Serina A. Gogusoglu, Amanda N. Reichert, Elizabeth A. Sneddon-Yepez, Anna K. Radke, Jennifer J. Quinn
Advisor: Jennifer Quinn, Psychology
Graduate Advisor: Amanda Reichert, Psychology
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