Date of Award
Spring 5-16-2025
Document Type
Honors Thesis
Department/Major
Basic Biomedical Science
First Advisor
Dr. Cliff H. Summers
Second Advisor
Dr. Yohaan M. Fernandes
Third Advisor
Dr. Lisa M. McFadden
Keywords
Stress Alternatives Model (SAM), Inescapable Stress Alternatives Model (iSAM), Social Stress, Stress-Resilient, Stress-Vulnerable, social-spatial learning
Subject Categories
Animal Sciences | Social and Behavioral Sciences
Abstract
Social stress substantially contributes to psychological disorders, including anxiety, depression, and post-traumatic stress disorder. Recognizing these disorders affect millions, it is essential to understand social stress’s impacts on behavior and how these behaviors vary among affected populations. We address these questions through a social defeat/avoidance paradigm, the Stress-Alternatives Model (SAM), which demonstrates defeat (Stay) and avoidance (Escape) responses across species, including fish, rats, hamsters, and mice. Avoidance of social conflict in the SAM is possible by utilizing escape routes for smaller test mice during aggressive interactions. Additionally, measurements of SAM motivational behaviors, like time near and nose pokes into escape routes, indicate Escape mice display more motivation-related behaviors than Stay counterparts. SAM behavioral results identify stress-resilient and stress-vulnerable populations by Day 1. This study investigates biological underpinnings of stress responsiveness and motivational behaviors by comparing the SAM, from which escape is possible, with a modified version, the Inescapable Stress Alternatives Model (iSAM), from which escape is not. Male mice exposed to aggression display less motivational behavior than counterparts not exposed to social stress. These findings identify motivation during social stress as a factor in phenotypic resilience or vulnerability and mirror characteristics of human psychological disorders.
Recommended Citation
Brummels, Renee A., "Stress-Related Phenotypic Differentiation Identified by Motivational Behaviors in Male Mice" (2025). Honors Thesis. 388.
https://red.library.usd.edu/honors-thesis/388