Abstract
<jats:p>Foraging for resources, including food, water, and shelter is essential for animal’s survival. However, foraging would also increase the likelihood of encountering danger, e.g., predators. This approach-avoidance conflict is a complex psychological experience, and the responses to this conflict are crucial for animals' survival. Over many years, animals have evolved a neural circuitry that allows them to use a set of defensive behaviors to cope with the risk of predation, and its dysregulation is believed to play a significant role in the pathophysiology of human psychiatric disorders. Serotonin plays a significant role in regulating the responses. However, the functional effect of serotonin on rats’ foraging behavior under the fear of predation remains unclear. This thesis aims to explore how serotonin in the brain influences rats' perception of fear during foraging and how serotonin affects their foraging behavior. To this end, we established a semi-naturalistic behavioral paradigm to assess the rats' foraging behavior and assessed the role of the serotonin system by manipulating the system through pharmacological and gene knockout approaches.</jats:p>