A Complex Diving-For-Food Task to Investigate Social Organization and Interactions in Rats

Summary

This protocol describes a method of examining social hierarchy in a rat model. Rats perform a complex diving-for-food task in which they form a distinct hierarchy according to their willingness to dive underwater and swim to obtain a food pellet. This method is used to understand decision making and social relationships among highly social animals in small groups.

Abstract

For many species, where status is a vital motivator that can affect health, social hierarchies influence behavior. Social hierarchies that include dominant-submissive relationships are common in both animal and human societies. These relationships can be affected by interactions with others and with their environment, making them difficult to analyze in a controlled study. Rather than a simple dominance hierarchy, this formation has a complicated presentation that allows rats to avoid aggression. Status can be stagnant or mutable, and results in complex societal stratifications. Here we describe a complex diving-for-food task to investigate rodent social hierarchy and behavioral interactions. This animal model may allow us to assess the relationship between a wide range of mental illnesses and social organization, as well as to study the effectiveness of therapy on social dysfunction.

Introduction

Rats are highly social animals, making them an ideal model for understanding social behavior and how it relates to decision making. Rats divide themselves into hierarchical groups based on dominant and submissive relationships. Rats can be trained for tasks that express cooperation, risk management, deceptive behavior, and behaviors that change depending on the decisions of other rats^1,2. Studies with rat models expressing these behaviors prove helpful in understanding social structure and its relationship to decision making with relevance for human psychology.

As a necessary resour....

Protocol

The experiments were conducted in accordance with recommendations of the Declarations of Helsinki and Tokyo and the Guidelines for the Use of Experimental Animals of the European Community. The experiments were approved by the Animal Care Committee of Ben-Gurion University of the Negev. The authorization code for this experiment was IL-55-8-12.

1. Rat preparation

1. Obtain approval for experiments from Institutional Animal Care and Use Committee (IACUC).
2. Select adult Sprague.......

Discussion

Social hierarchies determine the behavior of many species, including humans, and are often defined by relationships based on aggression and submission. These relationships often depend on environmental factors in additional to social structures³⁵. Social formations based on dominance and submission are multifaceted^36,37. Among humans, aggression is described as consisting of behaviors ranging from non-physical bullying to war and violence<.......

Materials

Name	Company	Catalog Number	Comments
Alcohol	Pharmacy		99% pharmaceutical alcohol diluted to 5% and used for cleaning the open field test box before the introduction of each rat
Bottles	Techniplast	ACBT0262SU	150 mL bottles filled with 100 mL of water and 100 mL of 1% (w/v) sucrose solution
Equipment for Diving for Food Task (Plexiglas)	self made in Ben Gurion University of Negev		Two cages (50 x 50 x 50 cm) to an aquarium (130 x 35 x 50 cm) via tunnels
Imipramine hydrochloride	SIGMA	Lot# SLBB9914V	(Tricyclic antidepressant) 20 mg/kg intraperitoneally once per day for 3 weeks
Purina Chow	Purina	5001	Rodent laboratory chow given to rats, mice and hamster is a life-cycle nutrition that has been used in biomedical researc for over 5
Rat Cages	Techniplast	2000P	Conventional housing for rodents. Was used for housing rats throughout the experiment
Video Camera	Canon		Digital video camera for high definition recording of rat behavior under plus maze test