TubeScan is our latest addition to our product lines for social dominance hierarchy. The behavioral apparatus consists of a ventilated transparent 50cm long fiberglass tube with an opaque center door, which is connected at both ends to identical fiberglass boxes (12 x 8 cm) through automated opaque entrance doors. The box in which a mouse is initially placed is called the “starting box”, while the box at the opposite end would be the “goal box”. The inner diameter of the tube (2.5cm) is sufficiently wide to allow a single mouse to comfortably walk through, but not for two mice to pass each other.

Using a camera, the associated TopScan software records and analyzes the video to track each animal, identify their important body parts like nose, tail, and body center to determine its movement directions, such as forward motion and backtracking. A control unit is integrated with the TopScan software that controls the opening and closing of the 3 automatic doors based on the two animals’ positions and behaviors. All these operations and behavior detections are performed in real-time. The top of the tube has a slit of 1 cm wide that allows cables for optogenetics or mini-scope camera or EEG to go through while the animal moves freely, but does not the mice to escape.

Once the two mice are in their start boxes and they enter the tube from their respective ends, we need to make sure that they do not go back to the start box so the side door needs to close once the mouse leaves their respective start boxes. The mice should not start interacting before they are both at the middle of the tube in order to standardize the test, which is why the middle door needs to automatically open when both mice are at the midpoint. At that instant, the middle door as well as the two side doors open and the mice start interacting and the main portion of the match begins. The winning mouse will push the losing mouse into its start box and once the loser mouse has all four legs in its start box, that corresponding side door should close to stop any further interaction of the mice.