Date of Award

2024

Document Type

Thesis

Degree Name

Bachelor of Science

Department

Psychology

First Advisor

Dr. Kelly Lambert

Abstract

This study investigated the effects of positive anticipation on depression-like symptoms in Long Evans male and female rats, using Unpredictable Positive Experience Response (UPER) training. Rats that received UPER training (UPER group) were exposed to cues followed by a positive reward at random times, fostering anticipation of three different positive experiences. Along with the UPER rats, there was a group of rats that received positive rewards without anticipation (ENR group) and a group that received no positive reward or anticipation (CTRL group). After 7 weeks of behavioral… training, we examined how training impacted the animal’s cognition, emotional resilience, and neurobiological markers of neuroplasticity. Following training, the rats were evaluated in three behavioral assessments: cognitive assessment (Dry Land Maze), emotional reward assessment (Sucrose Preference Test), and Problem-Solving and Persistence Assessment (Cat Ball Test). After completion of the behavioral tasks, animals were euthanized, and their brains were extracted and prepared for histological assessments of Brain-Derived Neurotrophic Factor (BDNF)- and Doublecortin (DCX)-immunoreactive tissue in the hippocampus to assess neuroplasticity. Results indicated that UPER-trained animals performed better on the cognitive tasks in the Dry Land Maze; specifically, they exhibited increased exploration and, and increased cognitive flexibility. Interestingly, the highest BDNF levels were found in the CTRL animals. Preliminary evidence, however, suggests that the UPERs have the highest DCX immunoreactive tissue. Together, these data suggest that UPER training enhances exploration and cognitive performance in rats, as well as sex-specific increases in persistence in the Cat Ball task. Further, the UPER training modifies aspects of neuroplasticity in varied ways. Additional research with UPER training will provide evidence related to the effectiveness of cognitive-behavioral therapeutic approaches for mental illnesses such as depression.

Available for download on Wednesday, May 07, 2025

Included in

Psychology Commons

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