Introduction

T Choice Tube is a behavioral apparatus used to understand social behavior in rodents. Kinship is an old and complex social behavior in animals (Clemens, Wang & Brecht, 2020). Besides animals, kinship behavior has also been observed in plants and single cellular organisms (Holton, 1977; Dudley & File, 2007; Grosberg & Quinn, 1986). The kinship behavior has also been reported in rodents (Todrank et al., 2005; Clemens, Wang & Brecht, 2020). Rodents utilize multiple cues such as olfactory and auditory cues for kin recognition (Todrank et al., 2005; Clemens, Wang & Brecht, 2020). 

The T Choice Tube is a modification of the conventional T Maze designed to assess kin preferences in rodents. The apparatus consists of a T shaped tube which is connected with two-goal compartments. The subject located at the inlet of the T-tube utilizes olfactory cues from the kin and non-kin placed in the goal compartments and then choose to enter either side of the T-tube (Clemens, Wang & Brecht, 2020). The T Choice Tube task is easy to perform and doesn’t require pretraining of the subject. The T Choice Tube is highly efficient for the determination of sibling preferences in rodents. It can also be used to understand the neural mechanism behind kinship behavior in rodents. 

Other modifications of T Maze to understand learning and behaviors in rodents include the Continuous Angled T Maze, the Two Problem T Maze, the Light Dark T Maze, and the Elevated T Maze.

Apparatus and Equipment

The T Choice Tube is composed of a central T-tube (7.5 cm diameter) made up of transparent acrylic. The T-tube stem acts as the start area (7.5 cm length), while the two arms (12.7 cm length) of the T-tube acts as choice arms. Each arm is connected with a rectangular goal compartment (10.2 cm length x 10.2 cm width). There is a hole (7.5 cm diameter) between each arm and its respective goal compartment. Each hole is covered with a wire mesh to prevent the subject from entering the goal compartment. A fan is installed in each goal compartment, which blows air to the center of the T- tube. A third fan is installed in the center of the T-tube, which removes the odor.

Task Performance

Thoroughly clean the apparatus before each trial. Properly lit the apparatus. The tracking and recording software Nodulus Ethovision XT can be utilized to assist in observations and recordings. 

T Choice Tube Sibling Preference Task

Place the subject in the stem of the T-tube in the T Choice Tube. In one goal compartment, place the subject’s sibling, whereas place the non-sibling in the other goal compartment. Turn on the compartments’ fans to blow air toward the center of the T Choice Tube. Allow the subject to crawl towards the choice arms and make a choice by utilizing the odor stimuli. Once the subject makes a choice, place it back in its home cage. Conduct two trials daily with an intertrial interval of almost 4 hrs for eight consecutive days. Alternate the location of the goal compartments and rotate the compartment after each trail.

Literature Review

The investigation of the effects of lateral septum lesions on kinship preferences in the Long-Evans rats

 Clemens, Wang & Brecht, 2020 investigated the effects of lateral septum lesions on kinship preferences in the Long-Evans rats (n=77). The study involved two groups; a group without lesions in the lateral septum and a group with lateral septum lesions. The behavior preferences of the subjects based on odor sampling were tested. The T Choice Tube was utilized to understand kinship behavior. The results of the study found that the control group without lesions had a higher proportion of subjects that chose the sibling side as compared to the non-sibling side until 13–15 days of age. From 16 days and onwards, the subjects showed a preference for the non-sibling side. The results of the study revealed that the sibling preference behavior lowered in the group with lesions (40%) in lateral septum compared to controls (65%).  The results of the study revealed that the lesions eliminated the sibling preferences, and the neurons of the lateral septum were responsive to multisensory kinship stimuli.

Data Analysis

• The time required to complete the task (secs)
• Latency to make a choice (secs)
• Number of times a subject chooses the compartment with a sibling
• Number of times a subject chooses the compartment with a non-sibling
• Choice index

Strengths and Limitations

Strengths

The T Choice Tube task performance doesn’t require pretraining of the subject, thereby imposing limited stress on the subjects. It is an easy method to evaluate sibling preference or avoidance approach as it provides instant results. The task can be performed multiple times as required without much extensive labor. The stimuli of sibling odor can be coupled with other stimuli such as auditory stimuli that can motivate the subject to make an effective choice. The T Choice Tube can be utilized to understand the neuronal mechanisms involved in kinship behavior in rodents. 

Limitations

The presence of surrounding stimuli such as visual, auditory, and olfactory stimuli may alter observations. Factors such as age, gender, and strain of the subject may affect task performances.

Summary

• The T Choice Tube is a modified T Maze that is designed to understand kinship behavior in rodents.
• It consists of a T shaped Tube, with two-goal compartments attached to each arm of the tube. 
• The fan attached in each goal compartment blows the odor stimuli towards the center of the T tube towards the subject. 
• The subject utilizes the odor stimuli and then chooses to crawl into either side of the T-tube.
• The T Choice Tube doesn’t require pretraining of the subjects, thereby imposing limited stress on the subjects. 
• The T Choice Tube is useful for understanding sibling preference or avoidance approach and studying the underlying neuronal mechanisms in rodents.

References

Clemens, A. M., Wang, H., & Brecht, M. (2020). The lateral septum mediates kinship behavior in the rat. Nature communications, 11(1), 3161. https://doi.org/10.1038/s41467-020-16489-x

Dudley, S. A., & File, A. L. (2007). Kin recognition in an annual plant. Biology letters, 3(4), 435–438. https://doi.org/10.1098/rsbl.2007.0232

Grosberg, R., Quinn, J. (1986). The genetic control and consequences of kin recognition by the larvae of a colonial marine invertebrate. Nature, 322, 456–459. https://doi.org/10.1038/322456a0

Holton G. (1977). Sociobiology: the new synthesis?. Newsletter on science, technology & human values, (21), https://doi.org/10.1177/016224397700200432

Todrank, J., Busquet, N., Baudoin, C., & Heth, G. (2005). Preferences of newborn mice for odours indicating closer genetic relatedness: is experience necessary?. Proceedings. Biological Sciences, 272(1576), 2083–2088. https://doi.org/10.1098/rspb.2005.3187