Schematic of the social interaction arena and representative front and side pictures of a wire-mesh enclosure. (a) Top-down view of the social interaction arena, delineated with zones and dimensions. (b) Picture of wire-mesh enclosure used to secure the target CD-1 during the `target present' portion of the social interaction test. Note that this is custom designed, and, assuming that dimensions are held constant, it can be fabricated with some flexibility in construction materials. Of importance is the ability for visual and olfactory cue transmission, with physical separation of the target aggressor and defeated mouse. On the left is a front view, and on the right a side view, of the same wire-mesh enclosure.