The overall goal of the following experiment is to study social interaction and memory in mice. This method is unique in that it places the control mouse under a wire cup, allowing the experimental animal to freely initiate or terminate interactions while preventing direct contact after habituating to a central chamber. The experimental mouse is allowed to freely explore two other chambers, one with an empty cup and another containing an unfamiliar mouse.
The next step allows the mouse a free choice between an already familiar animal and a newly introduced second mouse. Ultimately, results can be obtained that demonstrate differences in natural sociability and preference for social novelty in experimental versus control mice. The main advantage of this technique over existing methods such as one chamber social interaction test or resident intruder test, is that any direct physical contact between mice during this procedure is prohibited, allowing the experimental animal the freedom to terminate or initiate social interactions.
Crawley's sociability and preference for social novelty test is conducted in a rectangular three chamber box. Each chamber measures 19 by 45 centimeters and the dividing walls are made from clear plexiglass. The middle section opens to allow free access to each chamber.
The wire cups needed for this procedure should be large enough to hold a single mouse and have openings that allow ample air exchange, but prevent direct physical interaction. Place one cup into each side of the chamber behavior during the test is recorded. Using the Observer 6.0 program, all chambers are cleaned with 70%ethanol between mice and then with kaly, one to five to one between the cages to prevent olfactory Q bias and to ensure proper disinfection respectively begin by habituating the experimental animals to the test environment for 30 minutes.
With both cups in place and the dividing walls closed, introduce a naive mouse to the central chamber and allow five minutes for acclimation. Place a control mouse stranger one inside a wire containment cup, alternate the placement of the control from the left to the right side of the chamber between trials. After the habituation period, remove the walls between the compartments to allow the subject to freely explore all three chambers immediately begin to monitor and record behavior for 10 minutes.
In this example, the Observer program is used to monitor behaviors in real time using codes for the parameters of interest, record the duration and number of direct or active contacts between the subject mouse and either the empty cup or the cup housing, the stranger one mouse. An active contact is either a direct contact or a stretching of the subject's body in an area three to five centimeters around the cup. Also record the duration and number of other behaviors.
These include walking, self, grooming, lack of any body movements for more than five seconds or freezing, as well as any unusual behavior such as jumping, repetitive behavior, et cetera. The duration and number of entries into each compartment is also recorded. The mouse is considered to be in the chamber when its head and four pores have entered.
To test for social novelty or preference, place a second control mouse stranger two inside the cup in the opposite side of the chamber. Monitor the same parameters as described above for an additional 10 minutes. Clean all chambers with 70%ethanol, and then with kaleido one to five to one and demonstrated previously in addition to manual scoring of the experiments.
The use of a video recording system is strongly advised as this allows offline review of the experimental data in the future by an independent observer or the same person, as well as allowing the inclusion of additional secondary parameters if needed. Typically, a wild type animal will spend significantly more time in the compartment with stranger one compared to the compartment with the empty cup indicating normal sociability social motivation and affiliation in GSK three alpha knockout mice. However, there are no significant differences between the time spent with the empty cup compared to the cup containing stranger one indicating impaired sociability in this animal model.
The second session of the test is designed to estimate social novelty and social memory. Usually a wild type animal recalls its previous contact with stranger one and tends to spend more time with the newly encountered mouse indicating intact social memory and a predilection for novel experiences. Unlike wild type mice, GSK three alpha mutant animals do not show a preference for the chamber containing a newly introduced mouse over a chamber containing a.
Now familiar mouse indifferent behavior of knockout mice in this test is indicative of decreased social motivation and novelty Following this procedure. Other methods like elevated plus Mac light duck box, open field, FST TS T can be performed in order to answer additional questions about like emotion and anxiety and depression, which may affect the results of this test or their overall interpretation.
