Graduation Year

2024

Date of Submission

12-2023

Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts

Department

Neuroscience

Reader 1

Tessa Solomon-lane

Reader 2

Brian Duistermars

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

2023 Kiren Kanazawa

Abstract

Animals interact in intricate social networks. Social behavior is imperative in shaping relationships, in communication, and adapting to changing environments. Despite its profound effects on individual fitness and health, neural-molecular mechanisms behind social behavior and social decision-making continue to be identified. In the present study, we focused on the regulation of social behavior by the Dopamine-2-Receptor (D2R), based on its role in context-dependent social behavior. We used juvenile African cichlid fish, Astatotilapia burtoni, to investigate the effect of dopamine signaling manipulation on their aggressive, territorial, and affiliative behaviors. We hypothesize that D2R manipulation affects social decision-making in juvenile A. burtoni. Specifically, we predict the D2R agonist will increase aggression and the antagonist will reduce aggression. The juveniles were grouped into a triad of 1 bigger fish and 2 smaller fish, then a triad was placed on both sides of a tank divided by an acrylic barrier. Following a 4-day habituation period where the triads could see each other across the barrier for 1 hr/day, the focal fish (larger fish on one side) was injected (intracerebroventricular) with a D2R agonist, antagonist, or control in addition to altering their social context by adding a larger intruder fish to the tank. The aggressive and territorial behaviors of focal, neighbor, and small fish were then scored. Our preliminary results suggest that the D2R manipulation in juvenile A. burtoni induced behavioral changes as the pattern of social interaction varied depending on the treatment group. For instance, the D2R agonist-injected focal had the highest average rate of total interaction while the antagonist group had the lowest average rate of total interaction. Furthermore, our research also showed that the D2R manipulation affect the behavior of unmanipulated fish, as the neighbor’s approach toward the focal substantially increased in the antagonist group. This research demonstrates a critical role for D2R signaling in the neuromolecular mechanisms behind social decision-making.

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