Date of Award

Summer 2022

Document Type

Thesis

Degree Name

Master of Science in Research Psychology (MS)

Department

Psychology

Supervisor

Dr. Phillip M. Baker

Second Reader

Dr. Bethany Hoff

Keywords

Fear Behavior, Predation Cues, Effort-Based Decision Making, Rodents

Abstract

Existing research on the predator cue circuit has indicated there are observed differences between sexes of animals either directly or indirectly exposed to a predator stimulus. Exposure increases predator directed attention, and overrides other motivational systems (hunger, pain, reproductive behavior). Little research has explored whether exposure to predation is associated with differential responses to non-predator related decision-making across a variety of tasks. Therefore, understanding the prioritization of motivational states when a predator stressor is present can aid in understanding sex differences in these processes in both adaptative and maladaptive conditions. To determine how repeated exposure to a predator stressor differentially affects effort-based decision-making and fear-based behavior, a visual predator stressor in the form of a 3D realistic owl was utilized. Predation exposure was accomplished by plunging a decoy owl into an open foraging area until a total of nine exposures had been achieved. Following the final exposure to the owl stimulus, subsequent changes in effort-based decision making, and anxiety-like behavior were tracked across two days utilizing the Effort-Based Choice T-maze, Elevated Plus Maze (EPM), Marble Buying, and Defensive Withdrawal Tests. Results indicated that when not accounting for sex, predator exposed rats displayed significant reductions in effort-related choice behavior. Accounting for sex differences, female owl exposed rats, displayed significant reductions in effort-related choice behavior, but this difference was not observed in males. In stress related measures, male owl exposed rats displayed significant increases in fear-related behavior. These findings suggest that rodents exposed to a predator stimulus are differentially affected compared to controls following simulated predator exposure. Implying that male and female rodents may utilize different behavioral strategies when threatened by a repeated predator stimulus.

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